Secure TSC allows guests to securely use RDTSC/RDTSCP instructions as the
parameters being used cannot be changed by hypervisor once the guest is
launched. More details in the AMD64 APM Vol 2, Section "Secure TSC".
During the boot-up of the secondary cpus, SecureTSC enabled guests need to
query TSC info from AMD Security Processor. This communication channel is
encrypted between the AMD Security Processor and the guest, the hypervisor
is just the conduit to deliver the guest messages to the AMD Security
Processor. Each message is protected with an AEAD (AES-256 GCM). See "SEV
Secure Nested Paging Firmware ABI Specification" document (currently at
https://www.amd.com/system/files/TechDocs/56860.pdf) section "TSC Info"
Use a minimal GCM library to encrypt/decrypt SNP Guest messages to
communicate with the AMD Security Processor which is available at early
boot.
SEV-guest driver has the implementation for guest and AMD Security
Processor communication. As the TSC_INFO needs to be initialized during
early boot before smp cpus are started, move most of the sev-guest driver
code to kernel/sev.c and provide well defined APIs to the sev-guest driver
to use the interface to avoid code-duplication.
Patches:
01-08: Preparation and movement of sev-guest driver code
09-16: SecureTSC enablement patches.
Testing SecureTSC
-----------------
SecureTSC hypervisor patches based on top of SEV-SNP Guest MEMFD series:
https://github.com/nikunjad/linux/tree/snp-host-latest-securetsc_v5
QEMU changes:
https://github.com/nikunjad/qemu/tree/snp_securetsc_v5
QEMU commandline SEV-SNP-UPM with SecureTSC:
qemu-system-x86_64 -cpu EPYC-Milan-v2,+secure-tsc,+invtsc -smp 4 \
-object memory-backend-memfd-private,id=ram1,size=1G,share=true \
-object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-tsc=on \
-machine q35,confidential-guest-support=sev0,memory-backend=ram1,kvm-type=snp \
...
Changelog:
----------
v7:
* Drop mutex from the snp_dev and add snp_guest_cmd_{lock,unlock} API
* Added comments for secrets page failure
* Added define for maximum supported VMPCK
* Updated comments why sev_status is used directly instead of
cpu_feature_enabled()
v6:
* Add synthetic SecureTSC x86 feature bit
* Drop {__enc,dec}_payload() as they are pretty small and has one caller.
* Instead of a pointer use data_npages as variable
* Beautify struct snp_guest_req
* Make vmpck_id as unsigned int in snp_assign_vmpck()
* Move most of the functions to end of sev.c file
* Update commit/comments/error messages
* Mark free_shared_pages and alloc_shared_pages as inline
* Free snp_dev->certs_data when guest driver is removed
* Add lockdep assert in snp_inc_msg_seqno()
* Drop redundant enc_init NULL check
* Move SNP_TSC_INFO_REQ_SZ define out of structure
* Rename guest_tsc_{scale,offset} to snp_tsc_{scale,offset}
* Add new linux termination error code GHCB_TERM_SECURE_TSC
* Initialize and use cmd_mutex in snp_get_tsc_info()
* Set TSC as reliable in sme_early_init()
* Do not print firmware bug for Secure TSC enabled guests
https://lore.kernel.org/lkml/[email protected]/
v5:
* Rebased on v6.6 kernel
* Dropped link tag in first patch
* Dropped get_ctx_authsize() as it was redundant
https://lore.kernel.org/lkml/[email protected]/
v4:
* Drop handle_guest_request() and handle_guest_request_ext()
* Drop NULL check for key
* Corrected commit subject
* Added Reviewed-by from Tom
https://lore.kernel.org/lkml/[email protected]/
v3:
* Updated commit messages
* Made snp_setup_psp_messaging() generic that is accessed by both the
kernel and the driver
* Moved most of the context information to sev.c, sev-guest driver
does not need to know the secrets page layout anymore
* Add CC_ATTR_GUEST_SECURE_TSC early in the series therefore it can be
used in later patches.
* Removed data_gpa and data_npages from struct snp_req_data, as certs_data
and its size is passed to handle_guest_request_ext()
* Make vmpck_id as unsigned int
* Dropped unnecessary usage of memzero_explicit()
* Cache secrets_pa instead of remapping the cc_blob always
* Rebase on top of v6.4 kernel
https://lore.kernel.org/lkml/[email protected]/
v2:
* Rebased on top of v6.3-rc3 that has Boris's sev-guest cleanup series
https://lore.kernel.org/r/[email protected]/
v1: https://lore.kernel.org/r/[email protected]/
Nikunj A Dadhania (16):
virt: sev-guest: Use AES GCM crypto library
virt: sev-guest: Replace dev_dbg with pr_debug
virt: sev-guest: Add SNP guest request structure
virt: sev-guest: Add vmpck_id to snp_guest_dev struct
x86/sev: Cache the secrets page address
virt: sev-guest: Move SNP Guest command mutex
x86/sev: Move and reorganize sev guest request api
x86/mm: Add generic guest initialization hook
x86/cpufeatures: Add synthetic Secure TSC bit
x86/sev: Add Secure TSC support for SNP guests
x86/sev: Change TSC MSR behavior for Secure TSC enabled guests
x86/sev: Prevent RDTSC/RDTSCP interception for Secure TSC enabled
guests
x86/kvmclock: Skip kvmclock when Secure TSC is available
x86/sev: Mark Secure TSC as reliable
x86/cpu/amd: Do not print FW_BUG for Secure TSC
x86/sev: Enable Secure TSC for SNP guests
arch/x86/Kconfig | 1 +
arch/x86/boot/compressed/sev.c | 3 +-
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/asm/sev-common.h | 1 +
arch/x86/include/asm/sev-guest.h | 190 +++++++
arch/x86/include/asm/sev.h | 21 +-
arch/x86/include/asm/svm.h | 6 +-
arch/x86/include/asm/x86_init.h | 2 +
arch/x86/kernel/cpu/amd.c | 3 +-
arch/x86/kernel/kvmclock.c | 2 +-
arch/x86/kernel/sev-shared.c | 10 +
arch/x86/kernel/sev.c | 649 +++++++++++++++++++++--
arch/x86/kernel/x86_init.c | 2 +
arch/x86/mm/mem_encrypt.c | 12 +-
arch/x86/mm/mem_encrypt_amd.c | 12 +
drivers/virt/coco/sev-guest/Kconfig | 3 -
drivers/virt/coco/sev-guest/sev-guest.c | 668 +++---------------------
drivers/virt/coco/sev-guest/sev-guest.h | 63 ---
18 files changed, 917 insertions(+), 732 deletions(-)
create mode 100644 arch/x86/include/asm/sev-guest.h
delete mode 100644 drivers/virt/coco/sev-guest/sev-guest.h
base-commit: ceb6a6f023fd3e8b07761ed900352ef574010bcb
--
2.34.1
Add a snp_guest_req structure to simplify the function arguments. The
structure will be used to call the SNP Guest message request API
instead of passing a long list of parameters.
Update snp_issue_guest_request() prototype to include the new guest request
structure and move the prototype to sev_guest.h.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
.../x86/include/asm}/sev-guest.h | 18 +++
arch/x86/include/asm/sev.h | 8 --
arch/x86/kernel/sev.c | 15 ++-
drivers/virt/coco/sev-guest/sev-guest.c | 108 +++++++++++-------
4 files changed, 93 insertions(+), 56 deletions(-)
rename {drivers/virt/coco/sev-guest => arch/x86/include/asm}/sev-guest.h (78%)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/arch/x86/include/asm/sev-guest.h
similarity index 78%
rename from drivers/virt/coco/sev-guest/sev-guest.h
rename to arch/x86/include/asm/sev-guest.h
index ceb798a404d6..27cc15ad6131 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.h
+++ b/arch/x86/include/asm/sev-guest.h
@@ -63,4 +63,22 @@ struct snp_guest_msg {
u8 payload[4000];
} __packed;
+struct snp_guest_req {
+ void *req_buf;
+ size_t req_sz;
+
+ void *resp_buf;
+ size_t resp_sz;
+
+ void *data;
+ size_t data_npages;
+
+ u64 exit_code;
+ unsigned int vmpck_id;
+ u8 msg_version;
+ u8 msg_type;
+};
+
+int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
+ struct snp_guest_request_ioctl *rio);
#endif /* __VIRT_SEVGUEST_H__ */
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 5b4a1ce3d368..78465a8c7dc6 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -97,8 +97,6 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
struct snp_req_data {
unsigned long req_gpa;
unsigned long resp_gpa;
- unsigned long data_gpa;
- unsigned int data_npages;
};
struct sev_guest_platform_data {
@@ -209,7 +207,6 @@ void snp_set_memory_private(unsigned long vaddr, unsigned long npages);
void snp_set_wakeup_secondary_cpu(void);
bool snp_init(struct boot_params *bp);
void __init __noreturn snp_abort(void);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio);
void snp_accept_memory(phys_addr_t start, phys_addr_t end);
u64 snp_get_unsupported_features(u64 status);
u64 sev_get_status(void);
@@ -233,11 +230,6 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned long npa
static inline void snp_set_wakeup_secondary_cpu(void) { }
static inline bool snp_init(struct boot_params *bp) { return false; }
static inline void snp_abort(void) { }
-static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
-{
- return -ENOTTY;
-}
-
static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
static inline u64 sev_get_status(void) { return 0; }
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index c67285824e82..fd89aca22f6a 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -28,6 +28,7 @@
#include <asm/cpu_entry_area.h>
#include <asm/stacktrace.h>
#include <asm/sev.h>
+#include <asm/sev-guest.h>
#include <asm/insn-eval.h>
#include <asm/fpu/xcr.h>
#include <asm/processor.h>
@@ -2170,15 +2171,21 @@ static int __init init_sev_config(char *str)
}
__setup("sev=", init_sev_config);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
+int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
+ struct snp_guest_request_ioctl *rio)
{
struct ghcb_state state;
struct es_em_ctxt ctxt;
unsigned long flags;
struct ghcb *ghcb;
+ u64 exit_code;
int ret;
rio->exitinfo2 = SEV_RET_NO_FW_CALL;
+ if (!req)
+ return -EINVAL;
+
+ exit_code = req->exit_code;
/*
* __sev_get_ghcb() needs to run with IRQs disabled because it is using
@@ -2195,8 +2202,8 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct sn
vc_ghcb_invalidate(ghcb);
if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
- ghcb_set_rax(ghcb, input->data_gpa);
- ghcb_set_rbx(ghcb, input->data_npages);
+ ghcb_set_rax(ghcb, __pa(req->data));
+ ghcb_set_rbx(ghcb, req->data_npages);
}
ret = sev_es_ghcb_hv_call(ghcb, &ctxt, exit_code, input->req_gpa, input->resp_gpa);
@@ -2215,7 +2222,7 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct sn
case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN):
/* Number of expected pages are returned in RBX */
if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
- input->data_npages = ghcb_get_rbx(ghcb);
+ req->data_npages = ghcb_get_rbx(ghcb);
ret = -ENOSPC;
break;
}
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 469e10d9bf35..5cafbd1c42cb 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -27,8 +27,7 @@
#include <asm/svm.h>
#include <asm/sev.h>
-
-#include "sev-guest.h"
+#include <asm/sev-guest.h>
#define DEVICE_NAME "sev-guest"
@@ -169,7 +168,7 @@ static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
return ctx;
}
-static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
+static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *guest_req)
{
struct snp_guest_msg *resp = &snp_dev->secret_response;
struct snp_guest_msg *req = &snp_dev->secret_request;
@@ -198,36 +197,35 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
* If the message size is greater than our buffer length then return
* an error.
*/
- if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
+ if (unlikely((resp_hdr->msg_sz + ctx->authsize) > guest_req->resp_sz))
return -EBADMSG;
/* Decrypt the payload */
memcpy(iv, &resp_hdr->msg_seqno, sizeof(resp_hdr->msg_seqno));
- if (!aesgcm_decrypt(ctx, payload, resp->payload, resp_hdr->msg_sz,
+ if (!aesgcm_decrypt(ctx, guest_req->resp_buf, resp->payload, resp_hdr->msg_sz,
&resp_hdr->algo, AAD_LEN, iv, resp_hdr->authtag))
return -EBADMSG;
return 0;
}
-static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
- void *payload, size_t sz)
+static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, struct snp_guest_req *req)
{
- struct snp_guest_msg *req = &snp_dev->secret_request;
- struct snp_guest_msg_hdr *hdr = &req->hdr;
+ struct snp_guest_msg *msg = &snp_dev->secret_request;
+ struct snp_guest_msg_hdr *hdr = &msg->hdr;
struct aesgcm_ctx *ctx = snp_dev->ctx;
u8 iv[GCM_AES_IV_SIZE] = {};
- memset(req, 0, sizeof(*req));
+ memset(msg, 0, sizeof(*msg));
hdr->algo = SNP_AEAD_AES_256_GCM;
hdr->hdr_version = MSG_HDR_VER;
hdr->hdr_sz = sizeof(*hdr);
- hdr->msg_type = type;
- hdr->msg_version = version;
+ hdr->msg_type = req->msg_type;
+ hdr->msg_version = req->msg_version;
hdr->msg_seqno = seqno;
- hdr->msg_vmpck = vmpck_id;
- hdr->msg_sz = sz;
+ hdr->msg_vmpck = req->vmpck_id;
+ hdr->msg_sz = req->req_sz;
/* Verify the sequence number is non-zero */
if (!hdr->msg_seqno)
@@ -236,17 +234,17 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
pr_debug("request [seqno %lld type %d version %d sz %d]\n",
hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
- if (WARN_ON((sz + ctx->authsize) > sizeof(req->payload)))
+ if (WARN_ON((req->req_sz + ctx->authsize) > sizeof(msg->payload)))
return -EBADMSG;
memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
- aesgcm_encrypt(ctx, req->payload, payload, sz, &hdr->algo, AAD_LEN,
- iv, hdr->authtag);
+ aesgcm_encrypt(ctx, msg->payload, req->req_buf, req->req_sz, &hdr->algo,
+ AAD_LEN, iv, hdr->authtag);
return 0;
}
-static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
+static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
struct snp_guest_request_ioctl *rio)
{
unsigned long req_start = jiffies;
@@ -261,7 +259,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
* sequence number must be incremented or the VMPCK must be deleted to
* prevent reuse of the IV.
*/
- rc = snp_issue_guest_request(exit_code, &snp_dev->input, rio);
+ rc = snp_issue_guest_request(req, &snp_dev->input, rio);
switch (rc) {
case -ENOSPC:
/*
@@ -271,8 +269,8 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
* order to increment the sequence number and thus avoid
* IV reuse.
*/
- override_npages = snp_dev->input.data_npages;
- exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+ override_npages = req->data_npages;
+ req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
/*
* Override the error to inform callers the given extended
@@ -327,15 +325,13 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
}
if (override_npages)
- snp_dev->input.data_npages = override_npages;
+ req->data_npages = override_npages;
return rc;
}
-static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
- struct snp_guest_request_ioctl *rio, u8 type,
- void *req_buf, size_t req_sz, void *resp_buf,
- u32 resp_sz)
+static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio)
{
u64 seqno;
int rc;
@@ -349,7 +345,7 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
/* Encrypt the userspace provided payload in snp_dev->secret_request. */
- rc = enc_payload(snp_dev, seqno, rio->msg_version, type, req_buf, req_sz);
+ rc = enc_payload(snp_dev, seqno, req);
if (rc)
return rc;
@@ -360,7 +356,7 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
memcpy(snp_dev->request, &snp_dev->secret_request,
sizeof(snp_dev->secret_request));
- rc = __handle_guest_request(snp_dev, exit_code, rio);
+ rc = __handle_guest_request(snp_dev, req, rio);
if (rc) {
if (rc == -EIO &&
rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
@@ -369,12 +365,11 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
dev_alert(snp_dev->dev,
"Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n",
rc, rio->exitinfo2);
-
snp_disable_vmpck(snp_dev);
return rc;
}
- rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
+ rc = verify_and_dec_payload(snp_dev, req);
if (rc) {
dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
snp_disable_vmpck(snp_dev);
@@ -392,6 +387,7 @@ struct snp_req_resp {
static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
struct snp_report_req *req = &snp_dev->req.report;
+ struct snp_guest_req guest_req = {0};
struct snp_report_resp *resp;
int rc, resp_len;
@@ -413,9 +409,16 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
if (!resp)
return -ENOMEM;
- rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
- SNP_MSG_REPORT_REQ, req, sizeof(*req), resp->data,
- resp_len);
+ guest_req.msg_version = arg->msg_version;
+ guest_req.msg_type = SNP_MSG_REPORT_REQ;
+ guest_req.vmpck_id = vmpck_id;
+ guest_req.req_buf = req;
+ guest_req.req_sz = sizeof(*req);
+ guest_req.resp_buf = resp->data;
+ guest_req.resp_sz = resp_len;
+ guest_req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ rc = snp_send_guest_request(snp_dev, &guest_req, arg);
if (rc)
goto e_free;
@@ -431,6 +434,7 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
{
struct snp_derived_key_req *req = &snp_dev->req.derived_key;
struct snp_derived_key_resp resp = {0};
+ struct snp_guest_req guest_req = {0};
int rc, resp_len;
/* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
u8 buf[64 + 16];
@@ -452,8 +456,16 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req)))
return -EFAULT;
- rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
- SNP_MSG_KEY_REQ, req, sizeof(*req), buf, resp_len);
+ guest_req.msg_version = arg->msg_version;
+ guest_req.msg_type = SNP_MSG_KEY_REQ;
+ guest_req.vmpck_id = vmpck_id;
+ guest_req.req_buf = req;
+ guest_req.req_sz = sizeof(*req);
+ guest_req.resp_buf = buf;
+ guest_req.resp_sz = resp_len;
+ guest_req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ rc = snp_send_guest_request(snp_dev, &guest_req, arg);
if (rc)
return rc;
@@ -472,9 +484,10 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
{
struct snp_ext_report_req *req = &snp_dev->req.ext_report;
+ struct snp_guest_req guest_req = {0};
struct snp_report_resp *resp;
- int ret, npages = 0, resp_len;
sockptr_t certs_address;
+ int ret, resp_len;
lockdep_assert_held(&snp_cmd_mutex);
@@ -507,7 +520,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
* zeros to indicate that certificate data was not provided.
*/
memset(snp_dev->certs_data, 0, req->certs_len);
- npages = req->certs_len >> PAGE_SHIFT;
+ guest_req.data_npages = req->certs_len >> PAGE_SHIFT;
cmd:
/*
* The intermediate response buffer is used while decrypting the
@@ -519,14 +532,21 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
if (!resp)
return -ENOMEM;
- snp_dev->input.data_npages = npages;
- ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg,
- SNP_MSG_REPORT_REQ, &req->data,
- sizeof(req->data), resp->data, resp_len);
+ guest_req.msg_version = arg->msg_version;
+ guest_req.msg_type = SNP_MSG_REPORT_REQ;
+ guest_req.vmpck_id = vmpck_id;
+ guest_req.req_buf = &req->data;
+ guest_req.req_sz = sizeof(req->data);
+ guest_req.resp_buf = resp->data;
+ guest_req.resp_sz = resp_len;
+ guest_req.exit_code = SVM_VMGEXIT_EXT_GUEST_REQUEST;
+ guest_req.data = snp_dev->certs_data;
+
+ ret = snp_send_guest_request(snp_dev, &guest_req, arg);
/* If certs length is invalid then copy the returned length */
if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) {
- req->certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
+ req->certs_len = guest_req.data_npages << PAGE_SHIFT;
if (copy_to_sockptr(io->req_data, req, sizeof(*req)))
ret = -EFAULT;
@@ -535,7 +555,8 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
if (ret)
goto e_free;
- if (npages && copy_to_sockptr(certs_address, snp_dev->certs_data, req->certs_len)) {
+ if (guest_req.data_npages && req->certs_len &&
+ copy_to_sockptr(certs_address, snp_dev->certs_data, req->certs_len)) {
ret = -EFAULT;
goto e_free;
}
@@ -868,7 +889,6 @@ static int __init sev_guest_probe(struct platform_device *pdev)
/* initial the input address for guest request */
snp_dev->input.req_gpa = __pa(snp_dev->request);
snp_dev->input.resp_gpa = __pa(snp_dev->response);
- snp_dev->input.data_gpa = __pa(snp_dev->certs_data);
ret = tsm_register(&sev_tsm_ops, snp_dev, &tsm_report_extra_type);
if (ret)
--
2.34.1
Drop vmpck and os_area_msg_seqno pointers so that secret page layout
does not need to be exposed to the sev-guest driver after the rework.
Instead, add helper APIs to access vmpck and os_area_msg_seqno when
needed. Added define for maximum supported VMPCK.
Also, change function is_vmpck_empty() to snp_is_vmpck_empty() in
preparation for moving to sev.c.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Reviewed-by: Tom Lendacky <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/include/asm/sev.h | 1 +
drivers/virt/coco/sev-guest/sev-guest.c | 95 ++++++++++++-------------
2 files changed, 48 insertions(+), 48 deletions(-)
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 78465a8c7dc6..97ff8c28d3b8 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -121,6 +121,7 @@ struct secrets_os_area {
} __packed;
#define VMPCK_KEY_LEN 32
+#define VMPCK_MAX_NUM 4
/* See the SNP spec version 0.9 for secrets page format */
struct snp_secrets_page_layout {
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 5cafbd1c42cb..9c0ff69a16da 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -56,8 +56,7 @@ struct snp_guest_dev {
struct snp_derived_key_req derived_key;
struct snp_ext_report_req ext_report;
} req;
- u32 *os_area_msg_seqno;
- u8 *vmpck;
+ unsigned int vmpck_id;
};
static u32 vmpck_id;
@@ -67,14 +66,22 @@ MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.
/* Mutex to serialize the shared buffer access and command handling. */
static DEFINE_MUTEX(snp_cmd_mutex);
-static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
+static inline u8 *snp_get_vmpck(struct snp_guest_dev *snp_dev)
{
- char zero_key[VMPCK_KEY_LEN] = {0};
+ return snp_dev->layout->vmpck0 + snp_dev->vmpck_id * VMPCK_KEY_LEN;
+}
- if (snp_dev->vmpck)
- return !memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN);
+static inline u32 *snp_get_os_area_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+ return &snp_dev->layout->os_area.msg_seqno_0 + snp_dev->vmpck_id;
+}
- return true;
+static bool snp_is_vmpck_empty(struct snp_guest_dev *snp_dev)
+{
+ char zero_key[VMPCK_KEY_LEN] = {0};
+ u8 *key = snp_get_vmpck(snp_dev);
+
+ return !memcmp(key, zero_key, VMPCK_KEY_LEN);
}
/*
@@ -96,20 +103,22 @@ static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
*/
static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
{
- dev_alert(snp_dev->dev, "Disabling vmpck_id %d to prevent IV reuse.\n",
- vmpck_id);
- memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
- snp_dev->vmpck = NULL;
+ u8 *key = snp_get_vmpck(snp_dev);
+
+ dev_alert(snp_dev->dev, "Disabling vmpck_id %u to prevent IV reuse.\n",
+ snp_dev->vmpck_id);
+ memzero_explicit(key, VMPCK_KEY_LEN);
}
static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
{
+ u32 *os_area_msg_seqno = snp_get_os_area_msg_seqno(snp_dev);
u64 count;
lockdep_assert_held(&snp_cmd_mutex);
/* Read the current message sequence counter from secrets pages */
- count = *snp_dev->os_area_msg_seqno;
+ count = *os_area_msg_seqno;
return count + 1;
}
@@ -137,11 +146,13 @@ static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
{
+ u32 *os_area_msg_seqno = snp_get_os_area_msg_seqno(snp_dev);
+
/*
* The counter is also incremented by the PSP, so increment it by 2
* and save in secrets page.
*/
- *snp_dev->os_area_msg_seqno += 2;
+ *os_area_msg_seqno += 2;
}
static inline struct snp_guest_dev *to_snp_dev(struct file *file)
@@ -151,15 +162,22 @@ static inline struct snp_guest_dev *to_snp_dev(struct file *file)
return container_of(dev, struct snp_guest_dev, misc);
}
-static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
+static struct aesgcm_ctx *snp_init_crypto(struct snp_guest_dev *snp_dev)
{
struct aesgcm_ctx *ctx;
+ u8 *key;
+
+ if (snp_is_vmpck_empty(snp_dev)) {
+ pr_err("VM communication key VMPCK%u is null\n", vmpck_id);
+ return NULL;
+ }
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
if (!ctx)
return NULL;
- if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) {
+ key = snp_get_vmpck(snp_dev);
+ if (aesgcm_expandkey(ctx, key, VMPCK_KEY_LEN, AUTHTAG_LEN)) {
pr_err("Crypto context initialization failed\n");
kfree(ctx);
return NULL;
@@ -589,7 +607,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
mutex_lock(&snp_cmd_mutex);
/* Check if the VMPCK is not empty */
- if (is_vmpck_empty(snp_dev)) {
+ if (snp_is_vmpck_empty(snp_dev)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
mutex_unlock(&snp_cmd_mutex);
return -ENOTTY;
@@ -666,32 +684,14 @@ static const struct file_operations snp_guest_fops = {
.unlocked_ioctl = snp_guest_ioctl,
};
-static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
+bool snp_assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id)
{
- u8 *key = NULL;
+ if (WARN_ON((vmpck_id + 1) > VMPCK_MAX_NUM))
+ return false;
- switch (id) {
- case 0:
- *seqno = &layout->os_area.msg_seqno_0;
- key = layout->vmpck0;
- break;
- case 1:
- *seqno = &layout->os_area.msg_seqno_1;
- key = layout->vmpck1;
- break;
- case 2:
- *seqno = &layout->os_area.msg_seqno_2;
- key = layout->vmpck2;
- break;
- case 3:
- *seqno = &layout->os_area.msg_seqno_3;
- key = layout->vmpck3;
- break;
- default:
- break;
- }
+ dev->vmpck_id = vmpck_id;
- return key;
+ return true;
}
struct snp_msg_report_resp_hdr {
@@ -727,7 +727,7 @@ static int sev_report_new(struct tsm_report *report, void *data)
guard(mutex)(&snp_cmd_mutex);
/* Check if the VMPCK is not empty */
- if (is_vmpck_empty(snp_dev)) {
+ if (snp_is_vmpck_empty(snp_dev)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
return -ENOTTY;
}
@@ -847,21 +847,20 @@ static int __init sev_guest_probe(struct platform_device *pdev)
goto e_unmap;
ret = -EINVAL;
- snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
- if (!snp_dev->vmpck) {
- dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
+ snp_dev->layout = layout;
+ if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
+ dev_err(dev, "invalid vmpck id %u\n", vmpck_id);
goto e_unmap;
}
/* Verify that VMPCK is not zero. */
- if (is_vmpck_empty(snp_dev)) {
- dev_err(dev, "vmpck id %d is null\n", vmpck_id);
+ if (snp_is_vmpck_empty(snp_dev)) {
+ dev_err(dev, "vmpck id %u is null\n", vmpck_id);
goto e_unmap;
}
platform_set_drvdata(pdev, snp_dev);
snp_dev->dev = dev;
- snp_dev->layout = layout;
/* Allocate the shared page used for the request and response message. */
snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
@@ -877,7 +876,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
goto e_free_response;
ret = -EIO;
- snp_dev->ctx = snp_init_crypto(snp_dev->vmpck, VMPCK_KEY_LEN);
+ snp_dev->ctx = snp_init_crypto(snp_dev);
if (!snp_dev->ctx)
goto e_free_cert_data;
@@ -902,7 +901,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
if (ret)
goto e_free_ctx;
- dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id);
+ dev_info(dev, "Initialized SEV guest driver (using vmpck_id %u)\n", vmpck_id);
return 0;
e_free_ctx:
--
2.34.1
The sev-guest driver encryption code uses Crypto API for SNP guest
messaging to interact with AMD Security processor. For enabling SecureTSC,
SEV-SNP guests need to send a TSC_INFO request guest message before the
smpboot phase starts. Details from the TSC_INFO response will be used to
program the VMSA before the secondary CPUs are brought up. The Crypto API
is not available this early in the boot phase.
In preparation of moving the encryption code out of sev-guest driver to
support SecureTSC and make reviewing the diff easier, start using AES GCM
library implementation instead of Crypto API.
Drop __enc_payload() and dec_payload() helpers as both are pretty small and
can be moved to the respective callers.
CC: Ard Biesheuvel <[email protected]>
Signed-off-by: Nikunj A Dadhania <[email protected]>
Reviewed-by: Tom Lendacky <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
drivers/virt/coco/sev-guest/Kconfig | 4 +-
drivers/virt/coco/sev-guest/sev-guest.c | 175 ++++++------------------
drivers/virt/coco/sev-guest/sev-guest.h | 3 +
3 files changed, 43 insertions(+), 139 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/Kconfig b/drivers/virt/coco/sev-guest/Kconfig
index 1cffc72c41cb..0b772bd921d8 100644
--- a/drivers/virt/coco/sev-guest/Kconfig
+++ b/drivers/virt/coco/sev-guest/Kconfig
@@ -2,9 +2,7 @@ config SEV_GUEST
tristate "AMD SEV Guest driver"
default m
depends on AMD_MEM_ENCRYPT
- select CRYPTO
- select CRYPTO_AEAD2
- select CRYPTO_GCM
+ select CRYPTO_LIB_AESGCM
select TSM_REPORTS
help
SEV-SNP firmware provides the guest a mechanism to communicate with
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index bc564adcf499..aedc842781b6 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -17,8 +17,7 @@
#include <linux/set_memory.h>
#include <linux/fs.h>
#include <linux/tsm.h>
-#include <crypto/aead.h>
-#include <linux/scatterlist.h>
+#include <crypto/gcm.h>
#include <linux/psp-sev.h>
#include <linux/sockptr.h>
#include <linux/cleanup.h>
@@ -32,24 +31,16 @@
#include "sev-guest.h"
#define DEVICE_NAME "sev-guest"
-#define AAD_LEN 48
-#define MSG_HDR_VER 1
#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
#define SNP_REQ_RETRY_DELAY (2*HZ)
-struct snp_guest_crypto {
- struct crypto_aead *tfm;
- u8 *iv, *authtag;
- int iv_len, a_len;
-};
-
struct snp_guest_dev {
struct device *dev;
struct miscdevice misc;
void *certs_data;
- struct snp_guest_crypto *crypto;
+ struct aesgcm_ctx *ctx;
/* request and response are in unencrypted memory */
struct snp_guest_msg *request, *response;
@@ -161,132 +152,31 @@ static inline struct snp_guest_dev *to_snp_dev(struct file *file)
return container_of(dev, struct snp_guest_dev, misc);
}
-static struct snp_guest_crypto *init_crypto(struct snp_guest_dev *snp_dev, u8 *key, size_t keylen)
+static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
{
- struct snp_guest_crypto *crypto;
+ struct aesgcm_ctx *ctx;
- crypto = kzalloc(sizeof(*crypto), GFP_KERNEL_ACCOUNT);
- if (!crypto)
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
+ if (!ctx)
return NULL;
- crypto->tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
- if (IS_ERR(crypto->tfm))
- goto e_free;
-
- if (crypto_aead_setkey(crypto->tfm, key, keylen))
- goto e_free_crypto;
-
- crypto->iv_len = crypto_aead_ivsize(crypto->tfm);
- crypto->iv = kmalloc(crypto->iv_len, GFP_KERNEL_ACCOUNT);
- if (!crypto->iv)
- goto e_free_crypto;
-
- if (crypto_aead_authsize(crypto->tfm) > MAX_AUTHTAG_LEN) {
- if (crypto_aead_setauthsize(crypto->tfm, MAX_AUTHTAG_LEN)) {
- dev_err(snp_dev->dev, "failed to set authsize to %d\n", MAX_AUTHTAG_LEN);
- goto e_free_iv;
- }
+ if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) {
+ pr_err("Crypto context initialization failed\n");
+ kfree(ctx);
+ return NULL;
}
- crypto->a_len = crypto_aead_authsize(crypto->tfm);
- crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT);
- if (!crypto->authtag)
- goto e_free_iv;
-
- return crypto;
-
-e_free_iv:
- kfree(crypto->iv);
-e_free_crypto:
- crypto_free_aead(crypto->tfm);
-e_free:
- kfree(crypto);
-
- return NULL;
-}
-
-static void deinit_crypto(struct snp_guest_crypto *crypto)
-{
- crypto_free_aead(crypto->tfm);
- kfree(crypto->iv);
- kfree(crypto->authtag);
- kfree(crypto);
-}
-
-static int enc_dec_message(struct snp_guest_crypto *crypto, struct snp_guest_msg *msg,
- u8 *src_buf, u8 *dst_buf, size_t len, bool enc)
-{
- struct snp_guest_msg_hdr *hdr = &msg->hdr;
- struct scatterlist src[3], dst[3];
- DECLARE_CRYPTO_WAIT(wait);
- struct aead_request *req;
- int ret;
-
- req = aead_request_alloc(crypto->tfm, GFP_KERNEL);
- if (!req)
- return -ENOMEM;
-
- /*
- * AEAD memory operations:
- * +------ AAD -------+------- DATA -----+---- AUTHTAG----+
- * | msg header | plaintext | hdr->authtag |
- * | bytes 30h - 5Fh | or | |
- * | | cipher | |
- * +------------------+------------------+----------------+
- */
- sg_init_table(src, 3);
- sg_set_buf(&src[0], &hdr->algo, AAD_LEN);
- sg_set_buf(&src[1], src_buf, hdr->msg_sz);
- sg_set_buf(&src[2], hdr->authtag, crypto->a_len);
-
- sg_init_table(dst, 3);
- sg_set_buf(&dst[0], &hdr->algo, AAD_LEN);
- sg_set_buf(&dst[1], dst_buf, hdr->msg_sz);
- sg_set_buf(&dst[2], hdr->authtag, crypto->a_len);
-
- aead_request_set_ad(req, AAD_LEN);
- aead_request_set_tfm(req, crypto->tfm);
- aead_request_set_callback(req, 0, crypto_req_done, &wait);
-
- aead_request_set_crypt(req, src, dst, len, crypto->iv);
- ret = crypto_wait_req(enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req), &wait);
-
- aead_request_free(req);
- return ret;
-}
-
-static int __enc_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
- void *plaintext, size_t len)
-{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
- struct snp_guest_msg_hdr *hdr = &msg->hdr;
-
- memset(crypto->iv, 0, crypto->iv_len);
- memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
-
- return enc_dec_message(crypto, msg, plaintext, msg->payload, len, true);
-}
-
-static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
- void *plaintext, size_t len)
-{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
- struct snp_guest_msg_hdr *hdr = &msg->hdr;
-
- /* Build IV with response buffer sequence number */
- memset(crypto->iv, 0, crypto->iv_len);
- memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
-
- return enc_dec_message(crypto, msg, msg->payload, plaintext, len, false);
+ return ctx;
}
static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_guest_msg *resp = &snp_dev->secret_response;
struct snp_guest_msg *req = &snp_dev->secret_request;
struct snp_guest_msg_hdr *req_hdr = &req->hdr;
struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
+ struct aesgcm_ctx *ctx = snp_dev->ctx;
+ u8 iv[GCM_AES_IV_SIZE] = {};
dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
@@ -307,11 +197,16 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
* If the message size is greater than our buffer length then return
* an error.
*/
- if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
+ if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
return -EBADMSG;
/* Decrypt the payload */
- return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
+ memcpy(iv, &resp_hdr->msg_seqno, sizeof(resp_hdr->msg_seqno));
+ if (!aesgcm_decrypt(ctx, payload, resp->payload, resp_hdr->msg_sz,
+ &resp_hdr->algo, AAD_LEN, iv, resp_hdr->authtag))
+ return -EBADMSG;
+
+ return 0;
}
static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
@@ -319,6 +214,8 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
{
struct snp_guest_msg *req = &snp_dev->secret_request;
struct snp_guest_msg_hdr *hdr = &req->hdr;
+ struct aesgcm_ctx *ctx = snp_dev->ctx;
+ u8 iv[GCM_AES_IV_SIZE] = {};
memset(req, 0, sizeof(*req));
@@ -338,7 +235,14 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
- return __enc_payload(snp_dev, req, payload, sz);
+ if (WARN_ON((sz + ctx->authsize) > sizeof(req->payload)))
+ return -EBADMSG;
+
+ memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+ aesgcm_encrypt(ctx, req->payload, payload, sz, &hdr->algo, AAD_LEN,
+ iv, hdr->authtag);
+
+ return 0;
}
static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
@@ -486,7 +390,6 @@ struct snp_req_resp {
static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_report_req *req = &snp_dev->req.report;
struct snp_report_resp *resp;
int rc, resp_len;
@@ -504,7 +407,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp->data) + crypto->a_len;
+ resp_len = sizeof(resp->data) + snp_dev->ctx->authsize;
resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
if (!resp)
return -ENOMEM;
@@ -526,7 +429,6 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
struct snp_derived_key_req *req = &snp_dev->req.derived_key;
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_derived_key_resp resp = {0};
int rc, resp_len;
/* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
@@ -542,7 +444,7 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp.data) + crypto->a_len;
+ resp_len = sizeof(resp.data) + snp_dev->ctx->authsize;
if (sizeof(buf) < resp_len)
return -ENOMEM;
@@ -569,7 +471,6 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
{
struct snp_ext_report_req *req = &snp_dev->req.ext_report;
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_report_resp *resp;
int ret, npages = 0, resp_len;
sockptr_t certs_address;
@@ -612,7 +513,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp->data) + crypto->a_len;
+ resp_len = sizeof(resp->data) + snp_dev->ctx->authsize;
resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
if (!resp)
return -ENOMEM;
@@ -954,8 +855,8 @@ static int __init sev_guest_probe(struct platform_device *pdev)
goto e_free_response;
ret = -EIO;
- snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN);
- if (!snp_dev->crypto)
+ snp_dev->ctx = snp_init_crypto(snp_dev->vmpck, VMPCK_KEY_LEN);
+ if (!snp_dev->ctx)
goto e_free_cert_data;
misc = &snp_dev->misc;
@@ -978,11 +879,13 @@ static int __init sev_guest_probe(struct platform_device *pdev)
ret = misc_register(misc);
if (ret)
- goto e_free_cert_data;
+ goto e_free_ctx;
dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id);
return 0;
+e_free_ctx:
+ kfree(snp_dev->ctx);
e_free_cert_data:
free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
e_free_response:
@@ -1001,7 +904,7 @@ static int __exit sev_guest_remove(struct platform_device *pdev)
free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
- deinit_crypto(snp_dev->crypto);
+ kfree(snp_dev->ctx);
misc_deregister(&snp_dev->misc);
return 0;
diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/drivers/virt/coco/sev-guest/sev-guest.h
index 21bda26fdb95..ceb798a404d6 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.h
+++ b/drivers/virt/coco/sev-guest/sev-guest.h
@@ -13,6 +13,9 @@
#include <linux/types.h>
#define MAX_AUTHTAG_LEN 32
+#define AUTHTAG_LEN 16
+#define AAD_LEN 48
+#define MSG_HDR_VER 1
/* See SNP spec SNP_GUEST_REQUEST section for the structure */
enum msg_type {
--
2.34.1
Save the secrets page address during snp_init() from the CC blob. Use
secrets_pa instead of calling get_secrets_page() that remaps the CC
blob for getting the secrets page every time.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Reviewed-by: Tom Lendacky <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/kernel/sev.c | 54 +++++++++++++++----------------------------
1 file changed, 18 insertions(+), 36 deletions(-)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index fd89aca22f6a..6aa0bdf8a7a0 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -72,6 +72,9 @@ static struct ghcb *boot_ghcb __section(".data");
/* Bitmap of SEV features supported by the hypervisor */
static u64 sev_hv_features __ro_after_init;
+/* Secrets page physical address from the CC blob */
+static u64 secrets_pa __ro_after_init;
+
/* #VC handler runtime per-CPU data */
struct sev_es_runtime_data {
struct ghcb ghcb_page;
@@ -598,45 +601,16 @@ void noinstr __sev_es_nmi_complete(void)
__sev_put_ghcb(&state);
}
-static u64 __init get_secrets_page(void)
-{
- u64 pa_data = boot_params.cc_blob_address;
- struct cc_blob_sev_info info;
- void *map;
-
- /*
- * The CC blob contains the address of the secrets page, check if the
- * blob is present.
- */
- if (!pa_data)
- return 0;
-
- map = early_memremap(pa_data, sizeof(info));
- if (!map) {
- pr_err("Unable to locate SNP secrets page: failed to map the Confidential Computing blob.\n");
- return 0;
- }
- memcpy(&info, map, sizeof(info));
- early_memunmap(map, sizeof(info));
-
- /* smoke-test the secrets page passed */
- if (!info.secrets_phys || info.secrets_len != PAGE_SIZE)
- return 0;
-
- return info.secrets_phys;
-}
-
static u64 __init get_snp_jump_table_addr(void)
{
struct snp_secrets_page_layout *layout;
void __iomem *mem;
- u64 pa, addr;
+ u64 addr;
- pa = get_secrets_page();
- if (!pa)
+ if (!secrets_pa)
return 0;
- mem = ioremap_encrypted(pa, PAGE_SIZE);
+ mem = ioremap_encrypted(secrets_pa, PAGE_SIZE);
if (!mem) {
pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n");
return 0;
@@ -2086,6 +2060,12 @@ static __init struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp)
return cc_info;
}
+static void __init set_secrets_pa(const struct cc_blob_sev_info *cc_info)
+{
+ if (cc_info && cc_info->secrets_phys && cc_info->secrets_len == PAGE_SIZE)
+ secrets_pa = cc_info->secrets_phys;
+}
+
bool __init snp_init(struct boot_params *bp)
{
struct cc_blob_sev_info *cc_info;
@@ -2097,6 +2077,8 @@ bool __init snp_init(struct boot_params *bp)
if (!cc_info)
return false;
+ set_secrets_pa(cc_info);
+
setup_cpuid_table(cc_info);
/*
@@ -2249,16 +2231,16 @@ static struct platform_device sev_guest_device = {
static int __init snp_init_platform_device(void)
{
struct sev_guest_platform_data data;
- u64 gpa;
if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
return -ENODEV;
- gpa = get_secrets_page();
- if (!gpa)
+ if (!secrets_pa) {
+ pr_err("SNP secrets page not found\n");
return -ENODEV;
+ }
- data.secrets_gpa = gpa;
+ data.secrets_gpa = secrets_pa;
if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
return -ENODEV;
--
2.34.1
SNP command mutex is used to serialize the shared buffer access, command
handling and message sequence number races. Move the SNP guest command
mutex out of the sev guest driver and provide accessors to sev-guest
driver. Remove multiple lockdep check in sev-guest driver, next patch adds
a single lockdep check in snp_send_guest_request().
Signed-off-by: Nikunj A Dadhania <[email protected]>
---
arch/x86/include/asm/sev-guest.h | 3 +++
arch/x86/kernel/sev.c | 21 +++++++++++++++++++++
drivers/virt/coco/sev-guest/sev-guest.c | 23 +++++++----------------
3 files changed, 31 insertions(+), 16 deletions(-)
diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
index 27cc15ad6131..2f3cceb88396 100644
--- a/arch/x86/include/asm/sev-guest.h
+++ b/arch/x86/include/asm/sev-guest.h
@@ -81,4 +81,7 @@ struct snp_guest_req {
int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
struct snp_guest_request_ioctl *rio);
+void snp_guest_cmd_lock(void);
+void snp_guest_cmd_unlock(void);
+
#endif /* __VIRT_SEVGUEST_H__ */
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 6aa0bdf8a7a0..191193924b22 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -941,6 +941,21 @@ static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
free_page((unsigned long)vmsa);
}
+/* SNP Guest command mutex to serialize the shared buffer access and command handling. */
+static struct mutex snp_guest_cmd_mutex;
+
+void snp_guest_cmd_lock(void)
+{
+ mutex_lock(&snp_guest_cmd_mutex);
+}
+EXPORT_SYMBOL_GPL(snp_guest_cmd_lock);
+
+void snp_guest_cmd_unlock(void)
+{
+ mutex_unlock(&snp_guest_cmd_mutex);
+}
+EXPORT_SYMBOL_GPL(snp_guest_cmd_unlock);
+
static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
{
struct sev_es_save_area *cur_vmsa, *vmsa;
@@ -2240,6 +2255,12 @@ static int __init snp_init_platform_device(void)
return -ENODEV;
}
+ /*
+ * Initialize snp command mutex that is used to serialize the shared
+ * buffer access and use of the vmpck and message sequence number
+ */
+ mutex_init(&snp_guest_cmd_mutex);
+
data.secrets_gpa = secrets_pa;
if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
return -ENODEV;
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 9c0ff69a16da..bd30a9ff82c1 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -63,9 +63,6 @@ static u32 vmpck_id;
module_param(vmpck_id, uint, 0444);
MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
-/* Mutex to serialize the shared buffer access and command handling. */
-static DEFINE_MUTEX(snp_cmd_mutex);
-
static inline u8 *snp_get_vmpck(struct snp_guest_dev *snp_dev)
{
return snp_dev->layout->vmpck0 + snp_dev->vmpck_id * VMPCK_KEY_LEN;
@@ -115,8 +112,6 @@ static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
u32 *os_area_msg_seqno = snp_get_os_area_msg_seqno(snp_dev);
u64 count;
- lockdep_assert_held(&snp_cmd_mutex);
-
/* Read the current message sequence counter from secrets pages */
count = *os_area_msg_seqno;
@@ -409,8 +404,6 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
struct snp_report_resp *resp;
int rc, resp_len;
- lockdep_assert_held(&snp_cmd_mutex);
-
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -457,8 +450,6 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
/* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
u8 buf[64 + 16];
- lockdep_assert_held(&snp_cmd_mutex);
-
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -507,8 +498,6 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
sockptr_t certs_address;
int ret, resp_len;
- lockdep_assert_held(&snp_cmd_mutex);
-
if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data))
return -EINVAL;
@@ -604,12 +593,12 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
if (!input.msg_version)
return -EINVAL;
- mutex_lock(&snp_cmd_mutex);
+ snp_guest_cmd_lock();
/* Check if the VMPCK is not empty */
if (snp_is_vmpck_empty(snp_dev)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
- mutex_unlock(&snp_cmd_mutex);
+ snp_guest_cmd_unlock();
return -ENOTTY;
}
@@ -634,7 +623,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
break;
}
- mutex_unlock(&snp_cmd_mutex);
+ snp_guest_cmd_unlock();
if (input.exitinfo2 && copy_to_user(argp, &input, sizeof(input)))
return -EFAULT;
@@ -724,14 +713,14 @@ static int sev_report_new(struct tsm_report *report, void *data)
if (!buf)
return -ENOMEM;
- guard(mutex)(&snp_cmd_mutex);
-
/* Check if the VMPCK is not empty */
if (snp_is_vmpck_empty(snp_dev)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
return -ENOTTY;
}
+ snp_guest_cmd_lock();
+
cert_table = buf + report_size;
struct snp_ext_report_req ext_req = {
.data = { .vmpl = desc->privlevel },
@@ -752,6 +741,8 @@ static int sev_report_new(struct tsm_report *report, void *data)
};
ret = get_ext_report(snp_dev, &input, &io);
+ snp_guest_cmd_unlock();
+
if (ret)
return ret;
--
2.34.1
For enabling Secure TSC, SEV-SNP guests need to communicate with the
AMD Security Processor early during boot. Many of the required
functions are implemented in the sev-guest driver and therefore not
available at early boot. Move the required functions and provide
API to the sev guest driver for sending guest message and vmpck
routines.
As there is no external caller for snp_issue_guest_request() anymore,
make it static and drop the prototype from sev-guest.h.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/sev-guest.h | 87 ++++-
arch/x86/include/asm/sev.h | 10 -
arch/x86/kernel/sev.c | 448 +++++++++++++++++++++-
drivers/virt/coco/sev-guest/Kconfig | 1 -
drivers/virt/coco/sev-guest/sev-guest.c | 478 ++----------------------
6 files changed, 546 insertions(+), 479 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 3762f41bb092..b8f374ec5651 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1534,6 +1534,7 @@ config AMD_MEM_ENCRYPT
select ARCH_HAS_CC_PLATFORM
select X86_MEM_ENCRYPT
select UNACCEPTED_MEMORY
+ select CRYPTO_LIB_AESGCM
help
Say yes to enable support for the encryption of system memory.
This requires an AMD processor that supports Secure Memory
diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
index 2f3cceb88396..ed5c158ec29b 100644
--- a/arch/x86/include/asm/sev-guest.h
+++ b/arch/x86/include/asm/sev-guest.h
@@ -11,6 +11,11 @@
#define __VIRT_SEVGUEST_H__
#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <asm/sev.h>
+
+#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
+#define SNP_REQ_RETRY_DELAY (2*HZ)
#define MAX_AUTHTAG_LEN 32
#define AUTHTAG_LEN 16
@@ -58,11 +63,49 @@ struct snp_guest_msg_hdr {
u8 rsvd3[35];
} __packed;
+/* SNP Guest message request */
+struct snp_req_data {
+ unsigned long req_gpa;
+ unsigned long resp_gpa;
+};
+
struct snp_guest_msg {
struct snp_guest_msg_hdr hdr;
u8 payload[4000];
} __packed;
+struct sev_guest_platform_data {
+ /* request and response are in unencrypted memory */
+ struct snp_guest_msg *request;
+ struct snp_guest_msg *response;
+
+ struct snp_secrets_page_layout *layout;
+ struct snp_req_data input;
+};
+
+struct snp_guest_dev {
+ struct device *dev;
+ struct miscdevice misc;
+
+ void *certs_data;
+ struct aesgcm_ctx *ctx;
+
+ /*
+ * Avoid information leakage by double-buffering shared messages
+ * in fields that are in regular encrypted memory
+ */
+ struct snp_guest_msg secret_request;
+ struct snp_guest_msg secret_response;
+
+ struct sev_guest_platform_data *pdata;
+ union {
+ struct snp_report_req report;
+ struct snp_derived_key_req derived_key;
+ struct snp_ext_report_req ext_report;
+ } req;
+ unsigned int vmpck_id;
+};
+
struct snp_guest_req {
void *req_buf;
size_t req_sz;
@@ -79,9 +122,49 @@ struct snp_guest_req {
u8 msg_type;
};
-int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
- struct snp_guest_request_ioctl *rio);
void snp_guest_cmd_lock(void);
void snp_guest_cmd_unlock(void);
+bool snp_assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id);
+bool snp_is_vmpck_empty(unsigned int vmpck_id);
+int snp_setup_psp_messaging(struct snp_guest_dev *snp_dev);
+int snp_send_guest_request(struct snp_guest_dev *dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio);
+
+static inline void free_shared_pages(void *buf, size_t sz)
+{
+ unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+ int ret;
+
+ if (!buf)
+ return;
+
+ ret = set_memory_encrypted((unsigned long)buf, npages);
+ if (ret) {
+ WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n");
+ return;
+ }
+
+ __free_pages(virt_to_page(buf), get_order(sz));
+}
+
+static inline void *alloc_shared_pages(size_t sz)
+{
+ unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+ struct page *page;
+ int ret;
+
+ page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
+ if (!page)
+ return NULL;
+
+ ret = set_memory_decrypted((unsigned long)page_address(page), npages);
+ if (ret) {
+ pr_err("%s: failed to mark page shared, ret=%d\n", __func__, ret);
+ __free_pages(page, get_order(sz));
+ return NULL;
+ }
+
+ return page_address(page);
+}
#endif /* __VIRT_SEVGUEST_H__ */
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 97ff8c28d3b8..f8377b49b88d 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -93,16 +93,6 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
#define RMPADJUST_VMSA_PAGE_BIT BIT(16)
-/* SNP Guest message request */
-struct snp_req_data {
- unsigned long req_gpa;
- unsigned long resp_gpa;
-};
-
-struct sev_guest_platform_data {
- u64 secrets_gpa;
-};
-
/*
* The secrets page contains 96-bytes of reserved field that can be used by
* the guest OS. The guest OS uses the area to save the message sequence
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 191193924b22..5e8afdc6af9e 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -24,6 +24,7 @@
#include <linux/io.h>
#include <linux/psp-sev.h>
#include <uapi/linux/sev-guest.h>
+#include <crypto/gcm.h>
#include <asm/cpu_entry_area.h>
#include <asm/stacktrace.h>
@@ -2168,8 +2169,8 @@ static int __init init_sev_config(char *str)
}
__setup("sev=", init_sev_config);
-int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
- struct snp_guest_request_ioctl *rio)
+static int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
+ struct snp_guest_request_ioctl *rio)
{
struct ghcb_state state;
struct es_em_ctxt ctxt;
@@ -2236,7 +2237,6 @@ int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *inpu
return ret;
}
-EXPORT_SYMBOL_GPL(snp_issue_guest_request);
static struct platform_device sev_guest_device = {
.name = "sev-guest",
@@ -2245,30 +2245,456 @@ static struct platform_device sev_guest_device = {
static int __init snp_init_platform_device(void)
{
- struct sev_guest_platform_data data;
-
if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
return -ENODEV;
+ if (platform_device_register(&sev_guest_device))
+ return -ENODEV;
+
+ pr_info("SNP guest platform device initialized.\n");
+ return 0;
+}
+device_initcall(snp_init_platform_device);
+
+static struct sev_guest_platform_data *platform_data;
+
+static inline u8 *snp_get_vmpck(unsigned int vmpck_id)
+{
+ if (!platform_data)
+ return NULL;
+
+ return platform_data->layout->vmpck0 + vmpck_id * VMPCK_KEY_LEN;
+}
+
+static inline u32 *snp_get_os_area_msg_seqno(unsigned int vmpck_id)
+{
+ if (!platform_data)
+ return NULL;
+
+ return &platform_data->layout->os_area.msg_seqno_0 + vmpck_id;
+}
+
+bool snp_is_vmpck_empty(unsigned int vmpck_id)
+{
+ char zero_key[VMPCK_KEY_LEN] = {0};
+ u8 *key = snp_get_vmpck(vmpck_id);
+
+ if (key)
+ return !memcmp(key, zero_key, VMPCK_KEY_LEN);
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(snp_is_vmpck_empty);
+
+/*
+ * If an error is received from the host or AMD Secure Processor (ASP) there
+ * are two options. Either retry the exact same encrypted request or discontinue
+ * using the VMPCK.
+ *
+ * This is because in the current encryption scheme GHCB v2 uses AES-GCM to
+ * encrypt the requests. The IV for this scheme is the sequence number. GCM
+ * cannot tolerate IV reuse.
+ *
+ * The ASP FW v1.51 only increments the sequence numbers on a successful
+ * guest<->ASP back and forth and only accepts messages at its exact sequence
+ * number.
+ *
+ * So if the sequence number were to be reused the encryption scheme is
+ * vulnerable. If the sequence number were incremented for a fresh IV the ASP
+ * will reject the request.
+ */
+static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
+{
+ u8 *key = snp_get_vmpck(snp_dev->vmpck_id);
+
+ pr_alert("Disabling vmpck_id %u to prevent IV reuse.\n", snp_dev->vmpck_id);
+ memzero_explicit(key, VMPCK_KEY_LEN);
+}
+
+static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+ u32 *os_area_msg_seqno = snp_get_os_area_msg_seqno(snp_dev->vmpck_id);
+ u64 count;
+
+ if (!os_area_msg_seqno) {
+ pr_err("SNP unable to get message sequence counter\n");
+ return 0;
+ }
+
+ /* Read the current message sequence counter from secrets pages */
+ count = *os_area_msg_seqno;
+
+ return count + 1;
+}
+
+/* Return a non-zero on success */
+static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+ u64 count = __snp_get_msg_seqno(snp_dev);
+
+ /*
+ * The message sequence counter for the SNP guest request is a 64-bit
+ * value but the version 2 of GHCB specification defines a 32-bit storage
+ * for it. If the counter exceeds the 32-bit value then return zero.
+ * The caller should check the return value, but if the caller happens to
+ * not check the value and use it, then the firmware treats zero as an
+ * invalid number and will fail the message request.
+ */
+ if (count >= UINT_MAX) {
+ pr_err("SNP request message sequence counter overflow\n");
+ return 0;
+ }
+
+ return count;
+}
+
+static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+ u32 *os_area_msg_seqno = snp_get_os_area_msg_seqno(snp_dev->vmpck_id);
+
+ if (!os_area_msg_seqno) {
+ pr_err("SNP unable to get message sequence counter\n");
+ return;
+ }
+
+ /*
+ * The counter is also incremented by the PSP, so increment it by 2
+ * and save in secrets page.
+ */
+ *os_area_msg_seqno += 2;
+}
+
+static struct aesgcm_ctx *snp_init_crypto(unsigned int vmpck_id)
+{
+ struct aesgcm_ctx *ctx;
+ u8 *key;
+
+ if (snp_is_vmpck_empty(vmpck_id)) {
+ pr_err("VM communication key VMPCK%u is null\n", vmpck_id);
+ return NULL;
+ }
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
+ if (!ctx)
+ return NULL;
+
+ key = snp_get_vmpck(vmpck_id);
+ if (aesgcm_expandkey(ctx, key, VMPCK_KEY_LEN, AUTHTAG_LEN)) {
+ pr_err("Crypto context initialization failed\n");
+ kfree(ctx);
+ return NULL;
+ }
+
+ return ctx;
+}
+
+int snp_setup_psp_messaging(struct snp_guest_dev *snp_dev)
+{
+ struct sev_guest_platform_data *pdata;
+ int ret;
+
+ if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
+ pr_err("SNP not supported\n");
+ return 0;
+ }
+
+ if (platform_data) {
+ pr_debug("SNP platform data already initialized.\n");
+ goto create_ctx;
+ }
+
if (!secrets_pa) {
pr_err("SNP secrets page not found\n");
return -ENODEV;
}
+ pdata = kzalloc(sizeof(struct sev_guest_platform_data), GFP_KERNEL);
+ if (!pdata) {
+ pr_err("Allocation of SNP guest platform data failed\n");
+ return -ENOMEM;
+ }
+
+ ret = -ENOMEM;
+ pdata->layout = (__force void *)ioremap_encrypted(secrets_pa, PAGE_SIZE);
+ if (!pdata->layout) {
+ pr_err("Failed to map SNP secrets page.\n");
+ goto e_free_pdata;
+ }
+
+ /* Allocate the shared page used for the request and response message. */
+ pdata->request = alloc_shared_pages(sizeof(struct snp_guest_msg));
+ if (!pdata->request)
+ goto e_unmap;
+
+ pdata->response = alloc_shared_pages(sizeof(struct snp_guest_msg));
+ if (!pdata->response)
+ goto e_free_request;
+
/*
* Initialize snp command mutex that is used to serialize the shared
* buffer access and use of the vmpck and message sequence number
*/
mutex_init(&snp_guest_cmd_mutex);
- data.secrets_gpa = secrets_pa;
- if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
- return -ENODEV;
+ /* initial the input address for guest request */
+ pdata->input.req_gpa = __pa(pdata->request);
+ pdata->input.resp_gpa = __pa(pdata->response);
+ platform_data = pdata;
- if (platform_device_register(&sev_guest_device))
+
+create_ctx:
+ ret = -EIO;
+ snp_dev->ctx = snp_init_crypto(snp_dev->vmpck_id);
+ if (!snp_dev->ctx) {
+ pr_err("SNP crypto context initialization failed\n");
+ platform_data = NULL;
+ goto e_free_response;
+ }
+
+ snp_dev->pdata = platform_data;
+
+ return 0;
+
+e_free_response:
+ free_shared_pages(pdata->response, sizeof(struct snp_guest_msg));
+e_free_request:
+ free_shared_pages(pdata->request, sizeof(struct snp_guest_msg));
+e_unmap:
+ iounmap(pdata->layout);
+e_free_pdata:
+ kfree(pdata);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(snp_setup_psp_messaging);
+
+static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *guest_req,
+ struct sev_guest_platform_data *pdata)
+{
+ struct snp_guest_msg *resp = &snp_dev->secret_response;
+ struct snp_guest_msg *req = &snp_dev->secret_request;
+ struct snp_guest_msg_hdr *req_hdr = &req->hdr;
+ struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
+ struct aesgcm_ctx *ctx = snp_dev->ctx;
+ u8 iv[GCM_AES_IV_SIZE] = {};
+
+ pr_debug("response [seqno %lld type %d version %d sz %d]\n",
+ resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
+ resp_hdr->msg_sz);
+
+ /* Copy response from shared memory to encrypted memory. */
+ memcpy(resp, pdata->response, sizeof(*resp));
+
+ /* Verify that the sequence counter is incremented by 1 */
+ if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
+ return -EBADMSG;
+
+ /* Verify response message type and version number. */
+ if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
+ resp_hdr->msg_version != req_hdr->msg_version)
+ return -EBADMSG;
+
+ /*
+ * If the message size is greater than our buffer length then return
+ * an error.
+ */
+ if (unlikely((resp_hdr->msg_sz + ctx->authsize) > guest_req->resp_sz))
+ return -EBADMSG;
+
+ /* Decrypt the payload */
+ memcpy(iv, &resp_hdr->msg_seqno, sizeof(resp_hdr->msg_seqno));
+ if (!aesgcm_decrypt(ctx, guest_req->resp_buf, resp->payload, resp_hdr->msg_sz,
+ &resp_hdr->algo, AAD_LEN, iv, resp_hdr->authtag))
+ return -EBADMSG;
+
+ return 0;
+}
+
+static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, struct snp_guest_req *req)
+{
+ struct snp_guest_msg *msg = &snp_dev->secret_request;
+ struct snp_guest_msg_hdr *hdr = &msg->hdr;
+ struct aesgcm_ctx *ctx = snp_dev->ctx;
+ u8 iv[GCM_AES_IV_SIZE] = {};
+
+ memset(msg, 0, sizeof(*msg));
+
+ hdr->algo = SNP_AEAD_AES_256_GCM;
+ hdr->hdr_version = MSG_HDR_VER;
+ hdr->hdr_sz = sizeof(*hdr);
+ hdr->msg_type = req->msg_type;
+ hdr->msg_version = req->msg_version;
+ hdr->msg_seqno = seqno;
+ hdr->msg_vmpck = req->vmpck_id;
+ hdr->msg_sz = req->req_sz;
+
+ /* Verify the sequence number is non-zero */
+ if (!hdr->msg_seqno)
+ return -ENOSR;
+
+ pr_debug("request [seqno %lld type %d version %d sz %d]\n",
+ hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
+
+ if (WARN_ON((req->req_sz + ctx->authsize) > sizeof(msg->payload)))
+ return -EBADMSG;
+
+ memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+ aesgcm_encrypt(ctx, msg->payload, req->req_buf, req->req_sz, &hdr->algo,
+ AAD_LEN, iv, hdr->authtag);
+
+ return 0;
+}
+
+static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio,
+ struct sev_guest_platform_data *pdata)
+{
+ unsigned long req_start = jiffies;
+ unsigned int override_npages = 0;
+ u64 override_err = 0;
+ int rc;
+
+retry_request:
+ /*
+ * Call firmware to process the request. In this function the encrypted
+ * message enters shared memory with the host. So after this call the
+ * sequence number must be incremented or the VMPCK must be deleted to
+ * prevent reuse of the IV.
+ */
+ rc = snp_issue_guest_request(req, &pdata->input, rio);
+ switch (rc) {
+ case -ENOSPC:
+ /*
+ * If the extended guest request fails due to having too
+ * small of a certificate data buffer, retry the same
+ * guest request without the extended data request in
+ * order to increment the sequence number and thus avoid
+ * IV reuse.
+ */
+ override_npages = req->data_npages;
+ req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ /*
+ * Override the error to inform callers the given extended
+ * request buffer size was too small and give the caller the
+ * required buffer size.
+ */
+ override_err = SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN);
+
+ /*
+ * If this call to the firmware succeeds, the sequence number can
+ * be incremented allowing for continued use of the VMPCK. If
+ * there is an error reflected in the return value, this value
+ * is checked further down and the result will be the deletion
+ * of the VMPCK and the error code being propagated back to the
+ * user as an ioctl() return code.
+ */
+ goto retry_request;
+
+ /*
+ * The host may return SNP_GUEST_REQ_ERR_BUSY if the request has been
+ * throttled. Retry in the driver to avoid returning and reusing the
+ * message sequence number on a different message.
+ */
+ case -EAGAIN:
+ if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) {
+ rc = -ETIMEDOUT;
+ break;
+ }
+ schedule_timeout_killable(SNP_REQ_RETRY_DELAY);
+ goto retry_request;
+ }
+
+ /*
+ * Increment the message sequence number. There is no harm in doing
+ * this now because decryption uses the value stored in the response
+ * structure and any failure will wipe the VMPCK, preventing further
+ * use anyway.
+ */
+ snp_inc_msg_seqno(snp_dev);
+
+ if (override_err) {
+ rio->exitinfo2 = override_err;
+
+ /*
+ * If an extended guest request was issued and the supplied certificate
+ * buffer was not large enough, a standard guest request was issued to
+ * prevent IV reuse. If the standard request was successful, return -EIO
+ * back to the caller as would have originally been returned.
+ */
+ if (!rc && override_err == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
+ rc = -EIO;
+ }
+
+ if (override_npages)
+ req->data_npages = override_npages;
+
+ return rc;
+}
+
+int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio)
+{
+ struct sev_guest_platform_data *pdata;
+ u64 seqno;
+ int rc;
+
+ if (!snp_dev || !snp_dev->pdata || !req || !rio)
return -ENODEV;
- pr_info("SNP guest platform device initialized.\n");
+ lockdep_assert_held(&snp_guest_cmd_mutex);
+
+ pdata = snp_dev->pdata;
+
+ /* Get message sequence and verify that its a non-zero */
+ seqno = snp_get_msg_seqno(snp_dev);
+ if (!seqno)
+ return -EIO;
+
+ /* Clear shared memory's response for the host to populate. */
+ memset(pdata->response, 0, sizeof(struct snp_guest_msg));
+
+ /* Encrypt the userspace provided payload in pdata->secret_request. */
+ rc = enc_payload(snp_dev, seqno, req);
+ if (rc)
+ return rc;
+
+ /*
+ * Write the fully encrypted request to the shared unencrypted
+ * request page.
+ */
+ memcpy(pdata->request, &snp_dev->secret_request, sizeof(snp_dev->secret_request));
+
+ rc = __handle_guest_request(snp_dev, req, rio, pdata);
+ if (rc) {
+ if (rc == -EIO &&
+ rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
+ return rc;
+
+ pr_alert("Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n",
+ rc, rio->exitinfo2);
+ snp_disable_vmpck(snp_dev);
+ return rc;
+ }
+
+ rc = verify_and_dec_payload(snp_dev, req, pdata);
+ if (rc) {
+ pr_alert("Detected unexpected decode failure from ASP. rc: %d\n", rc);
+ snp_disable_vmpck(snp_dev);
+ return rc;
+ }
+
return 0;
}
-device_initcall(snp_init_platform_device);
+EXPORT_SYMBOL_GPL(snp_send_guest_request);
+
+bool snp_assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id)
+{
+ if (WARN_ON((vmpck_id + 1) > VMPCK_MAX_NUM))
+ return false;
+
+ dev->vmpck_id = vmpck_id;
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(snp_assign_vmpck);
diff --git a/drivers/virt/coco/sev-guest/Kconfig b/drivers/virt/coco/sev-guest/Kconfig
index 0b772bd921d8..a6405ab6c2c3 100644
--- a/drivers/virt/coco/sev-guest/Kconfig
+++ b/drivers/virt/coco/sev-guest/Kconfig
@@ -2,7 +2,6 @@ config SEV_GUEST
tristate "AMD SEV Guest driver"
default m
depends on AMD_MEM_ENCRYPT
- select CRYPTO_LIB_AESGCM
select TSM_REPORTS
help
SEV-SNP firmware provides the guest a mechanism to communicate with
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index bd30a9ff82c1..709a0d031c99 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -31,125 +31,10 @@
#define DEVICE_NAME "sev-guest"
-#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
-#define SNP_REQ_RETRY_DELAY (2*HZ)
-
-struct snp_guest_dev {
- struct device *dev;
- struct miscdevice misc;
-
- void *certs_data;
- struct aesgcm_ctx *ctx;
- /* request and response are in unencrypted memory */
- struct snp_guest_msg *request, *response;
-
- /*
- * Avoid information leakage by double-buffering shared messages
- * in fields that are in regular encrypted memory.
- */
- struct snp_guest_msg secret_request, secret_response;
-
- struct snp_secrets_page_layout *layout;
- struct snp_req_data input;
- union {
- struct snp_report_req report;
- struct snp_derived_key_req derived_key;
- struct snp_ext_report_req ext_report;
- } req;
- unsigned int vmpck_id;
-};
-
static u32 vmpck_id;
module_param(vmpck_id, uint, 0444);
MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
-static inline u8 *snp_get_vmpck(struct snp_guest_dev *snp_dev)
-{
- return snp_dev->layout->vmpck0 + snp_dev->vmpck_id * VMPCK_KEY_LEN;
-}
-
-static inline u32 *snp_get_os_area_msg_seqno(struct snp_guest_dev *snp_dev)
-{
- return &snp_dev->layout->os_area.msg_seqno_0 + snp_dev->vmpck_id;
-}
-
-static bool snp_is_vmpck_empty(struct snp_guest_dev *snp_dev)
-{
- char zero_key[VMPCK_KEY_LEN] = {0};
- u8 *key = snp_get_vmpck(snp_dev);
-
- return !memcmp(key, zero_key, VMPCK_KEY_LEN);
-}
-
-/*
- * If an error is received from the host or AMD Secure Processor (ASP) there
- * are two options. Either retry the exact same encrypted request or discontinue
- * using the VMPCK.
- *
- * This is because in the current encryption scheme GHCB v2 uses AES-GCM to
- * encrypt the requests. The IV for this scheme is the sequence number. GCM
- * cannot tolerate IV reuse.
- *
- * The ASP FW v1.51 only increments the sequence numbers on a successful
- * guest<->ASP back and forth and only accepts messages at its exact sequence
- * number.
- *
- * So if the sequence number were to be reused the encryption scheme is
- * vulnerable. If the sequence number were incremented for a fresh IV the ASP
- * will reject the request.
- */
-static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
-{
- u8 *key = snp_get_vmpck(snp_dev);
-
- dev_alert(snp_dev->dev, "Disabling vmpck_id %u to prevent IV reuse.\n",
- snp_dev->vmpck_id);
- memzero_explicit(key, VMPCK_KEY_LEN);
-}
-
-static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
-{
- u32 *os_area_msg_seqno = snp_get_os_area_msg_seqno(snp_dev);
- u64 count;
-
- /* Read the current message sequence counter from secrets pages */
- count = *os_area_msg_seqno;
-
- return count + 1;
-}
-
-/* Return a non-zero on success */
-static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
-{
- u64 count = __snp_get_msg_seqno(snp_dev);
-
- /*
- * The message sequence counter for the SNP guest request is a 64-bit
- * value but the version 2 of GHCB specification defines a 32-bit storage
- * for it. If the counter exceeds the 32-bit value then return zero.
- * The caller should check the return value, but if the caller happens to
- * not check the value and use it, then the firmware treats zero as an
- * invalid number and will fail the message request.
- */
- if (count >= UINT_MAX) {
- dev_err(snp_dev->dev, "request message sequence counter overflow\n");
- return 0;
- }
-
- return count;
-}
-
-static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
-{
- u32 *os_area_msg_seqno = snp_get_os_area_msg_seqno(snp_dev);
-
- /*
- * The counter is also incremented by the PSP, so increment it by 2
- * and save in secrets page.
- */
- *os_area_msg_seqno += 2;
-}
-
static inline struct snp_guest_dev *to_snp_dev(struct file *file)
{
struct miscdevice *dev = file->private_data;
@@ -157,241 +42,6 @@ static inline struct snp_guest_dev *to_snp_dev(struct file *file)
return container_of(dev, struct snp_guest_dev, misc);
}
-static struct aesgcm_ctx *snp_init_crypto(struct snp_guest_dev *snp_dev)
-{
- struct aesgcm_ctx *ctx;
- u8 *key;
-
- if (snp_is_vmpck_empty(snp_dev)) {
- pr_err("VM communication key VMPCK%u is null\n", vmpck_id);
- return NULL;
- }
-
- ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
- if (!ctx)
- return NULL;
-
- key = snp_get_vmpck(snp_dev);
- if (aesgcm_expandkey(ctx, key, VMPCK_KEY_LEN, AUTHTAG_LEN)) {
- pr_err("Crypto context initialization failed\n");
- kfree(ctx);
- return NULL;
- }
-
- return ctx;
-}
-
-static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *guest_req)
-{
- struct snp_guest_msg *resp = &snp_dev->secret_response;
- struct snp_guest_msg *req = &snp_dev->secret_request;
- struct snp_guest_msg_hdr *req_hdr = &req->hdr;
- struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
- struct aesgcm_ctx *ctx = snp_dev->ctx;
- u8 iv[GCM_AES_IV_SIZE] = {};
-
- pr_debug("response [seqno %lld type %d version %d sz %d]\n",
- resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
- resp_hdr->msg_sz);
-
- /* Copy response from shared memory to encrypted memory. */
- memcpy(resp, snp_dev->response, sizeof(*resp));
-
- /* Verify that the sequence counter is incremented by 1 */
- if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
- return -EBADMSG;
-
- /* Verify response message type and version number. */
- if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
- resp_hdr->msg_version != req_hdr->msg_version)
- return -EBADMSG;
-
- /*
- * If the message size is greater than our buffer length then return
- * an error.
- */
- if (unlikely((resp_hdr->msg_sz + ctx->authsize) > guest_req->resp_sz))
- return -EBADMSG;
-
- /* Decrypt the payload */
- memcpy(iv, &resp_hdr->msg_seqno, sizeof(resp_hdr->msg_seqno));
- if (!aesgcm_decrypt(ctx, guest_req->resp_buf, resp->payload, resp_hdr->msg_sz,
- &resp_hdr->algo, AAD_LEN, iv, resp_hdr->authtag))
- return -EBADMSG;
-
- return 0;
-}
-
-static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, struct snp_guest_req *req)
-{
- struct snp_guest_msg *msg = &snp_dev->secret_request;
- struct snp_guest_msg_hdr *hdr = &msg->hdr;
- struct aesgcm_ctx *ctx = snp_dev->ctx;
- u8 iv[GCM_AES_IV_SIZE] = {};
-
- memset(msg, 0, sizeof(*msg));
-
- hdr->algo = SNP_AEAD_AES_256_GCM;
- hdr->hdr_version = MSG_HDR_VER;
- hdr->hdr_sz = sizeof(*hdr);
- hdr->msg_type = req->msg_type;
- hdr->msg_version = req->msg_version;
- hdr->msg_seqno = seqno;
- hdr->msg_vmpck = req->vmpck_id;
- hdr->msg_sz = req->req_sz;
-
- /* Verify the sequence number is non-zero */
- if (!hdr->msg_seqno)
- return -ENOSR;
-
- pr_debug("request [seqno %lld type %d version %d sz %d]\n",
- hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
-
- if (WARN_ON((req->req_sz + ctx->authsize) > sizeof(msg->payload)))
- return -EBADMSG;
-
- memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
- aesgcm_encrypt(ctx, msg->payload, req->req_buf, req->req_sz, &hdr->algo,
- AAD_LEN, iv, hdr->authtag);
-
- return 0;
-}
-
-static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
- struct snp_guest_request_ioctl *rio)
-{
- unsigned long req_start = jiffies;
- unsigned int override_npages = 0;
- u64 override_err = 0;
- int rc;
-
-retry_request:
- /*
- * Call firmware to process the request. In this function the encrypted
- * message enters shared memory with the host. So after this call the
- * sequence number must be incremented or the VMPCK must be deleted to
- * prevent reuse of the IV.
- */
- rc = snp_issue_guest_request(req, &snp_dev->input, rio);
- switch (rc) {
- case -ENOSPC:
- /*
- * If the extended guest request fails due to having too
- * small of a certificate data buffer, retry the same
- * guest request without the extended data request in
- * order to increment the sequence number and thus avoid
- * IV reuse.
- */
- override_npages = req->data_npages;
- req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
-
- /*
- * Override the error to inform callers the given extended
- * request buffer size was too small and give the caller the
- * required buffer size.
- */
- override_err = SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN);
-
- /*
- * If this call to the firmware succeeds, the sequence number can
- * be incremented allowing for continued use of the VMPCK. If
- * there is an error reflected in the return value, this value
- * is checked further down and the result will be the deletion
- * of the VMPCK and the error code being propagated back to the
- * user as an ioctl() return code.
- */
- goto retry_request;
-
- /*
- * The host may return SNP_GUEST_VMM_ERR_BUSY if the request has been
- * throttled. Retry in the driver to avoid returning and reusing the
- * message sequence number on a different message.
- */
- case -EAGAIN:
- if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) {
- rc = -ETIMEDOUT;
- break;
- }
- schedule_timeout_killable(SNP_REQ_RETRY_DELAY);
- goto retry_request;
- }
-
- /*
- * Increment the message sequence number. There is no harm in doing
- * this now because decryption uses the value stored in the response
- * structure and any failure will wipe the VMPCK, preventing further
- * use anyway.
- */
- snp_inc_msg_seqno(snp_dev);
-
- if (override_err) {
- rio->exitinfo2 = override_err;
-
- /*
- * If an extended guest request was issued and the supplied certificate
- * buffer was not large enough, a standard guest request was issued to
- * prevent IV reuse. If the standard request was successful, return -EIO
- * back to the caller as would have originally been returned.
- */
- if (!rc && override_err == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
- rc = -EIO;
- }
-
- if (override_npages)
- req->data_npages = override_npages;
-
- return rc;
-}
-
-static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
- struct snp_guest_request_ioctl *rio)
-{
- u64 seqno;
- int rc;
-
- /* Get message sequence and verify that its a non-zero */
- seqno = snp_get_msg_seqno(snp_dev);
- if (!seqno)
- return -EIO;
-
- /* Clear shared memory's response for the host to populate. */
- memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
-
- /* Encrypt the userspace provided payload in snp_dev->secret_request. */
- rc = enc_payload(snp_dev, seqno, req);
- if (rc)
- return rc;
-
- /*
- * Write the fully encrypted request to the shared unencrypted
- * request page.
- */
- memcpy(snp_dev->request, &snp_dev->secret_request,
- sizeof(snp_dev->secret_request));
-
- rc = __handle_guest_request(snp_dev, req, rio);
- if (rc) {
- if (rc == -EIO &&
- rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
- return rc;
-
- dev_alert(snp_dev->dev,
- "Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n",
- rc, rio->exitinfo2);
- snp_disable_vmpck(snp_dev);
- return rc;
- }
-
- rc = verify_and_dec_payload(snp_dev, req);
- if (rc) {
- dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
- snp_disable_vmpck(snp_dev);
- return rc;
- }
-
- return 0;
-}
-
struct snp_req_resp {
sockptr_t req_data;
sockptr_t resp_data;
@@ -596,7 +246,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
snp_guest_cmd_lock();
/* Check if the VMPCK is not empty */
- if (snp_is_vmpck_empty(snp_dev)) {
+ if (snp_is_vmpck_empty(snp_dev->vmpck_id)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
snp_guest_cmd_unlock();
return -ENOTTY;
@@ -631,58 +281,11 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
return ret;
}
-static void free_shared_pages(void *buf, size_t sz)
-{
- unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
- int ret;
-
- if (!buf)
- return;
-
- ret = set_memory_encrypted((unsigned long)buf, npages);
- if (ret) {
- WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n");
- return;
- }
-
- __free_pages(virt_to_page(buf), get_order(sz));
-}
-
-static void *alloc_shared_pages(struct device *dev, size_t sz)
-{
- unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
- struct page *page;
- int ret;
-
- page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
- if (!page)
- return NULL;
-
- ret = set_memory_decrypted((unsigned long)page_address(page), npages);
- if (ret) {
- dev_err(dev, "failed to mark page shared, ret=%d\n", ret);
- __free_pages(page, get_order(sz));
- return NULL;
- }
-
- return page_address(page);
-}
-
static const struct file_operations snp_guest_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = snp_guest_ioctl,
};
-bool snp_assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id)
-{
- if (WARN_ON((vmpck_id + 1) > VMPCK_MAX_NUM))
- return false;
-
- dev->vmpck_id = vmpck_id;
-
- return true;
-}
-
struct snp_msg_report_resp_hdr {
u32 status;
u32 report_size;
@@ -714,7 +317,7 @@ static int sev_report_new(struct tsm_report *report, void *data)
return -ENOMEM;
/* Check if the VMPCK is not empty */
- if (snp_is_vmpck_empty(snp_dev)) {
+ if (snp_is_vmpck_empty(snp_dev->vmpck_id)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
return -ENOTTY;
}
@@ -811,75 +414,44 @@ static void unregister_sev_tsm(void *data)
static int __init sev_guest_probe(struct platform_device *pdev)
{
- struct snp_secrets_page_layout *layout;
- struct sev_guest_platform_data *data;
struct device *dev = &pdev->dev;
struct snp_guest_dev *snp_dev;
struct miscdevice *misc;
- void __iomem *mapping;
int ret;
if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
return -ENODEV;
- if (!dev->platform_data)
- return -ENODEV;
-
- data = (struct sev_guest_platform_data *)dev->platform_data;
- mapping = ioremap_encrypted(data->secrets_gpa, PAGE_SIZE);
- if (!mapping)
- return -ENODEV;
-
- layout = (__force void *)mapping;
-
- ret = -ENOMEM;
snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL);
if (!snp_dev)
- goto e_unmap;
+ return -ENOMEM;
- ret = -EINVAL;
- snp_dev->layout = layout;
if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
dev_err(dev, "invalid vmpck id %u\n", vmpck_id);
- goto e_unmap;
+ ret = -EINVAL;
+ goto e_free_snpdev;
}
- /* Verify that VMPCK is not zero. */
- if (snp_is_vmpck_empty(snp_dev)) {
- dev_err(dev, "vmpck id %u is null\n", vmpck_id);
- goto e_unmap;
+ if (snp_setup_psp_messaging(snp_dev)) {
+ dev_err(dev, "Unable to setup PSP messaging vmpck id %u\n", snp_dev->vmpck_id);
+ ret = -ENODEV;
+ goto e_free_snpdev;
}
platform_set_drvdata(pdev, snp_dev);
snp_dev->dev = dev;
- /* Allocate the shared page used for the request and response message. */
- snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
- if (!snp_dev->request)
- goto e_unmap;
-
- snp_dev->response = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
- if (!snp_dev->response)
- goto e_free_request;
-
- snp_dev->certs_data = alloc_shared_pages(dev, SEV_FW_BLOB_MAX_SIZE);
- if (!snp_dev->certs_data)
- goto e_free_response;
-
- ret = -EIO;
- snp_dev->ctx = snp_init_crypto(snp_dev);
- if (!snp_dev->ctx)
- goto e_free_cert_data;
+ snp_dev->certs_data = alloc_shared_pages(SEV_FW_BLOB_MAX_SIZE);
+ if (!snp_dev->certs_data) {
+ ret = -ENOMEM;
+ goto e_free_ctx;
+ }
misc = &snp_dev->misc;
misc->minor = MISC_DYNAMIC_MINOR;
misc->name = DEVICE_NAME;
misc->fops = &snp_guest_fops;
- /* initial the input address for guest request */
- snp_dev->input.req_gpa = __pa(snp_dev->request);
- snp_dev->input.resp_gpa = __pa(snp_dev->response);
-
ret = tsm_register(&sev_tsm_ops, snp_dev, &tsm_report_extra_type);
if (ret)
goto e_free_cert_data;
@@ -890,21 +462,18 @@ static int __init sev_guest_probe(struct platform_device *pdev)
ret = misc_register(misc);
if (ret)
- goto e_free_ctx;
+ goto e_free_cert_data;
+
+ dev_info(dev, "Initialized SEV guest driver (using vmpck_id %u)\n", snp_dev->vmpck_id);
- dev_info(dev, "Initialized SEV guest driver (using vmpck_id %u)\n", vmpck_id);
return 0;
-e_free_ctx:
- kfree(snp_dev->ctx);
e_free_cert_data:
free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
-e_free_response:
- free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
-e_free_request:
- free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
-e_unmap:
- iounmap(mapping);
+e_free_ctx:
+ kfree(snp_dev->ctx);
+e_free_snpdev:
+ kfree(snp_dev);
return ret;
}
@@ -913,10 +482,9 @@ static int __exit sev_guest_remove(struct platform_device *pdev)
struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev);
free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
- free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
- free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
- kfree(snp_dev->ctx);
misc_deregister(&snp_dev->misc);
+ kfree(snp_dev->ctx);
+ kfree(snp_dev);
return 0;
}
--
2.34.1
Add generic enc_init guest hook for performing any type of initialization
that is vendor specific. Generic enc_init hook can be used for early guest
feature initialization before secondary processors are up.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/include/asm/x86_init.h | 2 ++
arch/x86/kernel/x86_init.c | 2 ++
arch/x86/mm/mem_encrypt.c | 2 ++
3 files changed, 6 insertions(+)
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index c878616a18b8..8095553e14a7 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -148,12 +148,14 @@ struct x86_init_acpi {
* @enc_status_change_finish Notify HV after the encryption status of a range is changed
* @enc_tlb_flush_required Returns true if a TLB flush is needed before changing page encryption status
* @enc_cache_flush_required Returns true if a cache flush is needed before changing page encryption status
+ * @enc_init Prepare and initialize encryption features
*/
struct x86_guest {
bool (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
bool (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
bool (*enc_tlb_flush_required)(bool enc);
bool (*enc_cache_flush_required)(void);
+ void (*enc_init)(void);
};
/**
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index a37ebd3b4773..a07985a96ca5 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -136,6 +136,7 @@ static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool
static bool enc_tlb_flush_required_noop(bool enc) { return false; }
static bool enc_cache_flush_required_noop(void) { return false; }
static bool is_private_mmio_noop(u64 addr) {return false; }
+static void enc_init_noop(void) { }
struct x86_platform_ops x86_platform __ro_after_init = {
.calibrate_cpu = native_calibrate_cpu_early,
@@ -158,6 +159,7 @@ struct x86_platform_ops x86_platform __ro_after_init = {
.enc_status_change_finish = enc_status_change_finish_noop,
.enc_tlb_flush_required = enc_tlb_flush_required_noop,
.enc_cache_flush_required = enc_cache_flush_required_noop,
+ .enc_init = enc_init_noop,
},
};
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index c290c55b632b..d5bcd63211de 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -85,6 +85,8 @@ void __init mem_encrypt_init(void)
/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
swiotlb_update_mem_attributes();
+ x86_platform.guest.enc_init();
+
print_mem_encrypt_feature_info();
}
--
2.34.1
Add support for Secure TSC in SNP enabled guests. Secure TSC allows
guest to securely use RDTSC/RDTSCP instructions as the parameters
being used cannot be changed by hypervisor once the guest is launched.
During the boot-up of the secondary cpus, SecureTSC enabled guests
need to query TSC info from AMD Security Processor. This communication
channel is encrypted between the AMD Security Processor and the guest,
the hypervisor is just the conduit to deliver the guest messages to
the AMD Security Processor. Each message is protected with an
AEAD (AES-256 GCM). Use minimal AES GCM library to encrypt/decrypt SNP
Guest messages to communicate with the PSP.
Use the guest enc_init hook to fetch SNP TSC info from the AMD Security
Processor and initialize the snp_tsc_scale and snp_tsc_offset. During
secondary CPU initialization set VMSA fields GUEST_TSC_SCALE (offset 2F0h)
and GUEST_TSC_OFFSET(offset 2F8h) with snp_tsc_scale and snp_tsc_offset
respectively.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/include/asm/sev-common.h | 1 +
arch/x86/include/asm/sev-guest.h | 20 ++++++
arch/x86/include/asm/sev.h | 2 +
arch/x86/include/asm/svm.h | 6 +-
arch/x86/kernel/sev.c | 107 ++++++++++++++++++++++++++++--
arch/x86/mm/mem_encrypt_amd.c | 6 ++
6 files changed, 133 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index b463fcbd4b90..6adc8e27feeb 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -159,6 +159,7 @@ struct snp_psc_desc {
#define GHCB_TERM_NOT_VMPL0 3 /* SNP guest is not running at VMPL-0 */
#define GHCB_TERM_CPUID 4 /* CPUID-validation failure */
#define GHCB_TERM_CPUID_HV 5 /* CPUID failure during hypervisor fallback */
+#define GHCB_TERM_SECURE_TSC 6 /* Secure TSC initialization failed */
#define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK)
diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
index ed5c158ec29b..c82c78571020 100644
--- a/arch/x86/include/asm/sev-guest.h
+++ b/arch/x86/include/asm/sev-guest.h
@@ -39,6 +39,8 @@ enum msg_type {
SNP_MSG_ABSORB_RSP,
SNP_MSG_VMRK_REQ,
SNP_MSG_VMRK_RSP,
+ SNP_MSG_TSC_INFO_REQ = 17,
+ SNP_MSG_TSC_INFO_RSP,
SNP_MSG_TYPE_MAX
};
@@ -83,6 +85,23 @@ struct sev_guest_platform_data {
struct snp_req_data input;
};
+#define SNP_TSC_INFO_REQ_SZ 128
+
+struct snp_tsc_info_req {
+ /* Must be zero filled */
+ u8 rsvd[SNP_TSC_INFO_REQ_SZ];
+} __packed;
+
+struct snp_tsc_info_resp {
+ /* Status of TSC_INFO message */
+ u32 status;
+ u32 rsvd1;
+ u64 tsc_scale;
+ u64 tsc_offset;
+ u32 tsc_factor;
+ u8 rsvd2[100];
+} __packed;
+
struct snp_guest_dev {
struct device *dev;
struct miscdevice misc;
@@ -102,6 +121,7 @@ struct snp_guest_dev {
struct snp_report_req report;
struct snp_derived_key_req derived_key;
struct snp_ext_report_req ext_report;
+ struct snp_tsc_info_req tsc_info;
} req;
unsigned int vmpck_id;
};
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index f8377b49b88d..880cfee3c3ad 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -201,6 +201,7 @@ void __init __noreturn snp_abort(void);
void snp_accept_memory(phys_addr_t start, phys_addr_t end);
u64 snp_get_unsupported_features(u64 status);
u64 sev_get_status(void);
+void __init snp_secure_tsc_prepare(void);
#else
static inline void sev_es_ist_enter(struct pt_regs *regs) { }
static inline void sev_es_ist_exit(void) { }
@@ -224,6 +225,7 @@ static inline void snp_abort(void) { }
static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
static inline u64 sev_get_status(void) { return 0; }
+static inline void __init snp_secure_tsc_prepare(void) { }
#endif
#endif
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 87a7b917d30e..3a8294bbd109 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -410,7 +410,9 @@ struct sev_es_save_area {
u8 reserved_0x298[80];
u32 pkru;
u32 tsc_aux;
- u8 reserved_0x2f0[24];
+ u64 tsc_scale;
+ u64 tsc_offset;
+ u8 reserved_0x300[8];
u64 rcx;
u64 rdx;
u64 rbx;
@@ -542,7 +544,7 @@ static inline void __unused_size_checks(void)
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298);
- BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2f0);
+ BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x300);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x3f0);
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 5e8afdc6af9e..1d6200b57643 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -76,6 +76,10 @@ static u64 sev_hv_features __ro_after_init;
/* Secrets page physical address from the CC blob */
static u64 secrets_pa __ro_after_init;
+/* Secure TSC values read using TSC_INFO SNP Guest request */
+static u64 snp_tsc_scale __ro_after_init;
+static u64 snp_tsc_offset __ro_after_init;
+
/* #VC handler runtime per-CPU data */
struct sev_es_runtime_data {
struct ghcb ghcb_page;
@@ -957,6 +961,83 @@ void snp_guest_cmd_unlock(void)
}
EXPORT_SYMBOL_GPL(snp_guest_cmd_unlock);
+static struct snp_guest_dev tsc_snp_dev __initdata;
+
+static int __snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio);
+
+static int __init snp_get_tsc_info(void)
+{
+ struct snp_tsc_info_req *tsc_req = &tsc_snp_dev.req.tsc_info;
+ static u8 buf[SNP_TSC_INFO_REQ_SZ + AUTHTAG_LEN];
+ struct snp_guest_request_ioctl rio;
+ struct snp_tsc_info_resp tsc_resp;
+ struct snp_guest_req req;
+ int rc, resp_len;
+
+ /*
+ * The intermediate response buffer is used while decrypting the
+ * response payload. Make sure that it has enough space to cover the
+ * authtag.
+ */
+ resp_len = sizeof(tsc_resp) + AUTHTAG_LEN;
+ if (sizeof(buf) < resp_len)
+ return -EINVAL;
+
+ memset(tsc_req, 0, sizeof(*tsc_req));
+ memset(&req, 0, sizeof(req));
+ memset(&rio, 0, sizeof(rio));
+ memset(buf, 0, sizeof(buf));
+
+ if (!snp_assign_vmpck(&tsc_snp_dev, 0))
+ return -EINVAL;
+
+ /* Initialize the PSP channel to send snp messages */
+ rc = snp_setup_psp_messaging(&tsc_snp_dev);
+ if (rc)
+ return rc;
+
+ req.msg_version = MSG_HDR_VER;
+ req.msg_type = SNP_MSG_TSC_INFO_REQ;
+ req.vmpck_id = tsc_snp_dev.vmpck_id;
+ req.req_buf = tsc_req;
+ req.req_sz = sizeof(*tsc_req);
+ req.resp_buf = buf;
+ req.resp_sz = resp_len;
+ req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ rc = __snp_send_guest_request(&tsc_snp_dev, &req, &rio);
+ if (rc)
+ goto err_req;
+
+ memcpy(&tsc_resp, buf, sizeof(tsc_resp));
+ pr_debug("%s: Valid response status %x scale %llx offset %llx factor %x\n",
+ __func__, tsc_resp.status, tsc_resp.tsc_scale, tsc_resp.tsc_offset,
+ tsc_resp.tsc_factor);
+
+ snp_tsc_scale = tsc_resp.tsc_scale;
+ snp_tsc_offset = tsc_resp.tsc_offset;
+
+err_req:
+ /* The response buffer contains the sensitive data, explicitly clear it. */
+ memzero_explicit(buf, sizeof(buf));
+ memzero_explicit(&tsc_resp, sizeof(tsc_resp));
+ memzero_explicit(&req, sizeof(req));
+
+ return rc;
+}
+
+void __init snp_secure_tsc_prepare(void)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC))
+ return;
+
+ if (snp_get_tsc_info())
+ sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC);
+
+ pr_debug("SecureTSC enabled\n");
+}
+
static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
{
struct sev_es_save_area *cur_vmsa, *vmsa;
@@ -1057,6 +1138,12 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
vmsa->vmpl = 0;
vmsa->sev_features = sev_status >> 2;
+ /* Setting Secure TSC parameters */
+ if (cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) {
+ vmsa->tsc_scale = snp_tsc_scale;
+ vmsa->tsc_offset = snp_tsc_offset;
+ }
+
/* Switch the page over to a VMSA page now that it is initialized */
ret = snp_set_vmsa(vmsa, true);
if (ret) {
@@ -2632,18 +2719,13 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues
return rc;
}
-int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
- struct snp_guest_request_ioctl *rio)
+static int __snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio)
{
struct sev_guest_platform_data *pdata;
u64 seqno;
int rc;
- if (!snp_dev || !snp_dev->pdata || !req || !rio)
- return -ENODEV;
-
- lockdep_assert_held(&snp_guest_cmd_mutex);
-
pdata = snp_dev->pdata;
/* Get message sequence and verify that its a non-zero */
@@ -2686,6 +2768,17 @@ int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *
return 0;
}
+
+int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio)
+{
+ if (!snp_dev || !snp_dev->pdata || !req || !rio)
+ return -ENODEV;
+
+ lockdep_assert_held(&snp_guest_cmd_mutex);
+
+ return __snp_send_guest_request(snp_dev, req, rio);
+}
EXPORT_SYMBOL_GPL(snp_send_guest_request);
bool snp_assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id)
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 70b91de2e053..c81b57ca03b6 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -214,6 +214,11 @@ void __init sme_map_bootdata(char *real_mode_data)
__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);
}
+static void __init amd_enc_init(void)
+{
+ snp_secure_tsc_prepare();
+}
+
static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
{
unsigned long pfn = 0;
@@ -467,6 +472,7 @@ void __init sme_early_init(void)
x86_platform.guest.enc_status_change_finish = amd_enc_status_change_finish;
x86_platform.guest.enc_tlb_flush_required = amd_enc_tlb_flush_required;
x86_platform.guest.enc_cache_flush_required = amd_enc_cache_flush_required;
+ x86_platform.guest.enc_init = amd_enc_init;
/*
* AMD-SEV-ES intercepts the RDMSR to read the X2APIC ID in the
--
2.34.1
Secure TSC enabled guests should not write MSR_IA32_TSC(10H) register
as the subsequent TSC value reads are undefined. MSR_IA32_TSC related
accesses should not exit to the hypervisor for such guests.
Accesses to MSR_IA32_TSC needs special handling in the #VC handler for
the guests with Secure TSC enabled. Writes to MSR_IA32_TSC should be
ignored, and reads of MSR_IA32_TSC should return the result of the
RDTSC instruction.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Reviewed-by: Tom Lendacky <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/kernel/sev.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 1d6200b57643..393d3be13934 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1280,6 +1280,30 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
/* Is it a WRMSR? */
exit_info_1 = (ctxt->insn.opcode.bytes[1] == 0x30) ? 1 : 0;
+ /*
+ * TSC related accesses should not exit to the hypervisor when a
+ * guest is executing with SecureTSC enabled, so special handling
+ * is required for accesses of MSR_IA32_TSC:
+ *
+ * Writes: Writing to MSR_IA32_TSC can cause subsequent reads
+ * of the TSC to return undefined values, so ignore all
+ * writes.
+ * Reads: Reads of MSR_IA32_TSC should return the current TSC
+ * value, use the value returned by RDTSC.
+ */
+ if (regs->cx == MSR_IA32_TSC && cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) {
+ u64 tsc;
+
+ if (exit_info_1)
+ return ES_OK;
+
+ tsc = rdtsc();
+ regs->ax = UINT_MAX & tsc;
+ regs->dx = UINT_MAX & (tsc >> 32);
+
+ return ES_OK;
+ }
+
ghcb_set_rcx(ghcb, regs->cx);
if (exit_info_1) {
ghcb_set_rax(ghcb, regs->ax);
--
2.34.1
The hypervisor should not be intercepting RDTSC/RDTSCP when Secure TSC
is enabled. A #VC exception will be generated if the RDTSC/RDTSCP
instructions are being intercepted. If this should occur and Secure
TSC is enabled, terminate guest execution.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/kernel/sev-shared.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index ccb0915e84e1..716aea6fc90c 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -991,6 +991,16 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb,
bool rdtscp = (exit_code == SVM_EXIT_RDTSCP);
enum es_result ret;
+ /*
+ * RDTSC and RDTSCP should not be intercepted when Secure TSC is
+ * enabled. Terminate the SNP guest when the interception is enabled.
+ * This file is included from kernel/sev.c and boot/compressed/sev.c,
+ * use sev_status here as cpu_feature_enabled() is not available when
+ * compiling boot/compressed/sev.c.
+ */
+ if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
+ return ES_VMM_ERROR;
+
ret = sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, 0, 0);
if (ret != ES_OK)
return ret;
--
2.34.1
Add support for the synthetic CPUID flag which indicates that the SNP
guest is running with secure tsc enabled (MSR_AMD64_SEV Bit 11 -
SecureTsc_Enabled) . This flag is there so that this capability in the
guests can be detected easily without reading MSRs every time accessors.
Suggested-by: Kirill A. Shutemov <[email protected]>
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/include/asm/cpufeatures.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 4af140cf5719..e9dafc8cd9dc 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -237,6 +237,7 @@
#define X86_FEATURE_PVUNLOCK ( 8*32+20) /* "" PV unlock function */
#define X86_FEATURE_VCPUPREEMPT ( 8*32+21) /* "" PV vcpu_is_preempted function */
#define X86_FEATURE_TDX_GUEST ( 8*32+22) /* Intel Trust Domain Extensions Guest */
+#define X86_FEATURE_SNP_SECURE_TSC ( 8*32+23) /* "" AMD SNP Secure TSC */
/* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
#define X86_FEATURE_FSGSBASE ( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
--
2.34.1
For AMD SNP guests having Secure TSC enabled, skip using the kvmclock.
The guest kernel will fallback and use Secure TSC based clocksource.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/kernel/kvmclock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index fb8f52149be9..e3de354abf74 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -288,7 +288,7 @@ void __init kvmclock_init(void)
{
u8 flags;
- if (!kvm_para_available() || !kvmclock)
+ if (!kvm_para_available() || !kvmclock || cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC))
return;
if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) {
--
2.34.1
AMD SNP guests may have Secure TSC feature enabled. Use the Secure TSC
as the only reliable clock source in SEV-SNP guests when enabled,
bypassing unstable calibration.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/mm/mem_encrypt_amd.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index c81b57ca03b6..cc936999efc8 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -498,6 +498,10 @@ void __init sme_early_init(void)
*/
if (sev_status & MSR_AMD64_SEV_ENABLED)
ia32_disable();
+
+ /* Mark the TSC as reliable when Secure TSC is enabled */
+ if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
+ setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
}
void __init mem_encrypt_free_decrypted_mem(void)
--
2.34.1
When SecureTSC is enabled and TscInvariant (bit 8) in CPUID_8000_0007_edx
is set, kernel complains with the below firmware bug:
[Firmware Bug]: TSC doesn't count with P0 frequency!
Secure TSC need not run at P0 frequency, the TSC frequency is set by the
VMM as part of the SNP_LAUNCH_START command. Avoid the check when Secure
TSC is enabled
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/kernel/cpu/amd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index f322ebd053a9..b4a19e3fda8d 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -551,7 +551,8 @@ static void early_init_amd_mc(struct cpuinfo_x86 *c)
static void bsp_init_amd(struct cpuinfo_x86 *c)
{
- if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
+ if (cpu_has(c, X86_FEATURE_CONSTANT_TSC) &&
+ !cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) {
if (c->x86 > 0x10 ||
(c->x86 == 0x10 && c->x86_model >= 0x2)) {
--
2.34.1
Now that all the required plumbing is done for enabling SNP Secure TSC
feature, add Secure TSC to snp features present list.
Set the CPUID feature bit (X86_FEATURE_SNP_SECURE_TSC) when SNP guest is
started with Secure TSC.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
arch/x86/boot/compressed/sev.c | 3 ++-
arch/x86/mm/mem_encrypt.c | 10 ++++++++--
arch/x86/mm/mem_encrypt_amd.c | 4 +++-
3 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 454acd7a2daf..2829908602e5 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -375,7 +375,8 @@ static void enforce_vmpl0(void)
* by the guest kernel. As and when a new feature is implemented in the
* guest kernel, a corresponding bit should be added to the mask.
*/
-#define SNP_FEATURES_PRESENT MSR_AMD64_SNP_DEBUG_SWAP
+#define SNP_FEATURES_PRESENT (MSR_AMD64_SNP_DEBUG_SWAP | \
+ MSR_AMD64_SNP_SECURE_TSC)
u64 snp_get_unsupported_features(u64 status)
{
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index d5bcd63211de..b0db76dc4a9d 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -70,8 +70,14 @@ static void print_mem_encrypt_feature_info(void)
pr_cont(" SEV-ES");
/* Secure Nested Paging */
- if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
- pr_cont(" SEV-SNP");
+ if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
+ pr_cont(" SEV-SNP\n");
+ pr_cont("SNP Features active: ");
+
+ /* SNP Secure TSC */
+ if (cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC))
+ pr_cont(" SECURE-TSC");
+ }
pr_cont("\n");
}
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index cc936999efc8..7ee0a537a22e 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -500,8 +500,10 @@ void __init sme_early_init(void)
ia32_disable();
/* Mark the TSC as reliable when Secure TSC is enabled */
- if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
+ if (sev_status & MSR_AMD64_SNP_SECURE_TSC) {
+ setup_force_cpu_cap(X86_FEATURE_SNP_SECURE_TSC);
setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
+ }
}
void __init mem_encrypt_free_decrypted_mem(void)
--
2.34.1
On 12/20/2023 8:43 PM, Nikunj A Dadhania wrote:
> Secure TSC allows guests to securely use RDTSC/RDTSCP instructions as the
> parameters being used cannot be changed by hypervisor once the guest is
> launched. More details in the AMD64 APM Vol 2, Section "Secure TSC".
>
> During the boot-up of the secondary cpus, SecureTSC enabled guests need to
> query TSC info from AMD Security Processor. This communication channel is
> encrypted between the AMD Security Processor and the guest, the hypervisor
> is just the conduit to deliver the guest messages to the AMD Security
> Processor. Each message is protected with an AEAD (AES-256 GCM). See "SEV
> Secure Nested Paging Firmware ABI Specification" document (currently at
> https://www.amd.com/system/files/TechDocs/56860.pdf) section "TSC Info"
>
> Use a minimal GCM library to encrypt/decrypt SNP Guest messages to
> communicate with the AMD Security Processor which is available at early
> boot.
>
> SEV-guest driver has the implementation for guest and AMD Security
> Processor communication. As the TSC_INFO needs to be initialized during
> early boot before smp cpus are started, move most of the sev-guest driver
> code to kernel/sev.c and provide well defined APIs to the sev-guest driver
> to use the interface to avoid code-duplication.
>
> Patches:
> 01-08: Preparation and movement of sev-guest driver code
> 09-16: SecureTSC enablement patches.
>
> Testing SecureTSC
> -----------------
>
> SecureTSC hypervisor patches based on top of SEV-SNP Guest MEMFD series:
> https://github.com/nikunjad/linux/tree/snp-host-latest-securetsc_v5
>
> QEMU changes:
> https://github.com/nikunjad/qemu/tree/snp_securetsc_v5
>
> QEMU commandline SEV-SNP-UPM with SecureTSC:
>
> qemu-system-x86_64 -cpu EPYC-Milan-v2,+secure-tsc,+invtsc -smp 4 \
> -object memory-backend-memfd-private,id=ram1,size=1G,share=true \
> -object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-tsc=on \
> -machine q35,confidential-guest-support=sev0,memory-backend=ram1,kvm-type=snp \
> ...
>
> Changelog:
> ----------
> v7:
> * Drop mutex from the snp_dev and add snp_guest_cmd_{lock,unlock} API
> * Added comments for secrets page failure
> * Added define for maximum supported VMPCK
> * Updated comments why sev_status is used directly instead of
> cpu_feature_enabled()
A gentle reminder.
Regards
Nikunj
On Wed, Dec 20, 2023 at 08:43:43PM +0530, Nikunj A Dadhania wrote:
> @@ -307,11 +197,16 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
> * If the message size is greater than our buffer length then return
> * an error.
> */
> - if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
> + if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
> return -EBADMSG;
>
> /* Decrypt the payload */
> - return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
> + memcpy(iv, &resp_hdr->msg_seqno, sizeof(resp_hdr->msg_seqno));
sizeof(iv) != sizeof(resp_hdr->msg_seqno) and it fits now.
However, for protection against future bugs, this should be:
memcpy(iv, &resp_hdr->msg_seqno, min(sizeof(iv), sizeof(resp_hdr->msg_seqno)));
> + if (!aesgcm_decrypt(ctx, payload, resp->payload, resp_hdr->msg_sz,
> + &resp_hdr->algo, AAD_LEN, iv, resp_hdr->authtag))
> + return -EBADMSG;
> +
> + return 0;
> }
>
> static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
> @@ -319,6 +214,8 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
> {
> struct snp_guest_msg *req = &snp_dev->secret_request;
> struct snp_guest_msg_hdr *hdr = &req->hdr;
> + struct aesgcm_ctx *ctx = snp_dev->ctx;
> + u8 iv[GCM_AES_IV_SIZE] = {};
>
> memset(req, 0, sizeof(*req));
>
> @@ -338,7 +235,14 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
> dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
> hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
>
> - return __enc_payload(snp_dev, req, payload, sz);
> + if (WARN_ON((sz + ctx->authsize) > sizeof(req->payload)))
> + return -EBADMSG;
> +
> + memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
Ditto.
> + aesgcm_encrypt(ctx, req->payload, payload, sz, &hdr->algo, AAD_LEN,
> + iv, hdr->authtag);
> +
> + return 0;
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On Wed, Dec 20, 2023 at 08:43:45PM +0530, Nikunj A Dadhania wrote:
> -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
> +int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
> + struct snp_guest_request_ioctl *rio)
> {
> struct ghcb_state state;
> struct es_em_ctxt ctxt;
> unsigned long flags;
> struct ghcb *ghcb;
> + u64 exit_code;
Silly local vars. Just use req->exit_code everywhere instead.
> int ret;
>
> rio->exitinfo2 = SEV_RET_NO_FW_CALL;
> + if (!req)
> + return -EINVAL;
Such tests are done under the variable which is assigned, not randomly.
Also, what's the point in testing req? Will that ever be NULL? What are
you actually protecting against here?
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
> index 469e10d9bf35..5cafbd1c42cb 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.c
> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
> @@ -27,8 +27,7 @@
>
> #include <asm/svm.h>
> #include <asm/sev.h>
> -
> -#include "sev-guest.h"
> +#include <asm/sev-guest.h>
>
> #define DEVICE_NAME "sev-guest"
>
> @@ -169,7 +168,7 @@ static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
> return ctx;
> }
>
> -static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
> +static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *guest_req)
So we call the request everywhere "req". But you've called it
"guest_req" here because...
> {
> struct snp_guest_msg *resp = &snp_dev->secret_response;
> struct snp_guest_msg *req = &snp_dev->secret_request;
.. there already is a "req" variable which is not a guest request thing
but a guest message. So why don't you call it "req_msg" instead and the
"resp" "resp_msg" so that it is clear what is what?
And then you can call the actual request var "req" and then the code
becomes more readable...
..
> static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> {
> struct snp_report_req *req = &snp_dev->req.report;
> + struct snp_guest_req guest_req = {0};
You have the same issue here.
If we aim at calling the local vars in every function the same, the code
becomes automatically much more readable.
And so on...
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On Wed, Jan 24, 2024 at 10:08 PM Nikunj A. Dadhania <[email protected]> wrote:
>
> On 12/20/2023 8:43 PM, Nikunj A Dadhania wrote:
> > Secure TSC allows guests to securely use RDTSC/RDTSCP instructions as the
> > parameters being used cannot be changed by hypervisor once the guest is
> > launched. More details in the AMD64 APM Vol 2, Section "Secure TSC".
> >
> > During the boot-up of the secondary cpus, SecureTSC enabled guests need to
> > query TSC info from AMD Security Processor. This communication channel is
> > encrypted between the AMD Security Processor and the guest, the hypervisor
> > is just the conduit to deliver the guest messages to the AMD Security
> > Processor. Each message is protected with an AEAD (AES-256 GCM). See "SEV
> > Secure Nested Paging Firmware ABI Specification" document (currently at
> > https://www.amd.com/system/files/TechDocs/56860.pdf) section "TSC Info"
> >
> > Use a minimal GCM library to encrypt/decrypt SNP Guest messages to
> > communicate with the AMD Security Processor which is available at early
> > boot.
> >
> > SEV-guest driver has the implementation for guest and AMD Security
> > Processor communication. As the TSC_INFO needs to be initialized during
> > early boot before smp cpus are started, move most of the sev-guest driver
> > code to kernel/sev.c and provide well defined APIs to the sev-guest driver
> > to use the interface to avoid code-duplication.
> >
> > Patches:
> > 01-08: Preparation and movement of sev-guest driver code
> > 09-16: SecureTSC enablement patches.
> >
> > Testing SecureTSC
> > -----------------
> >
> > SecureTSC hypervisor patches based on top of SEV-SNP Guest MEMFD series:
> > https://github.com/nikunjad/linux/tree/snp-host-latest-securetsc_v5
> >
> > QEMU changes:
> > https://github.com/nikunjad/qemu/tree/snp_securetsc_v5
> >
> > QEMU commandline SEV-SNP-UPM with SecureTSC:
> >
> > qemu-system-x86_64 -cpu EPYC-Milan-v2,+secure-tsc,+invtsc -smp 4 \
> > -object memory-backend-memfd-private,id=ram1,size=1G,share=true \
> > -object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-tsc=on \
> > -machine q35,confidential-guest-support=sev0,memory-backend=ram1,kvm-type=snp \
> > ...
> >
> > Changelog:
> > ----------
> > v7:
> > * Drop mutex from the snp_dev and add snp_guest_cmd_{lock,unlock} API
> > * Added comments for secrets page failure
> > * Added define for maximum supported VMPCK
> > * Updated comments why sev_status is used directly instead of
> > cpu_feature_enabled()
>
> A gentle reminder.
>
From the Google testing side of things, we may not get to this for
another while.
> Regards
> Nikunj
>
--
-Dionna Glaze, PhD (she/her)
On 12/20/23 09:13, Nikunj A Dadhania wrote:
> Add a snp_guest_req structure to simplify the function arguments. The
> structure will be used to call the SNP Guest message request API
> instead of passing a long list of parameters.
>
> Update snp_issue_guest_request() prototype to include the new guest request
> structure and move the prototype to sev_guest.h.
>
> Signed-off-by: Nikunj A Dadhania <[email protected]>
> Tested-by: Peter Gonda <[email protected]>
> ---
> .../x86/include/asm}/sev-guest.h | 18 +++
> arch/x86/include/asm/sev.h | 8 --
> arch/x86/kernel/sev.c | 15 ++-
> drivers/virt/coco/sev-guest/sev-guest.c | 108 +++++++++++-------
> 4 files changed, 93 insertions(+), 56 deletions(-)
> rename {drivers/virt/coco/sev-guest => arch/x86/include/asm}/sev-guest.h (78%)
>
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/arch/x86/include/asm/sev-guest.h
> similarity index 78%
> rename from drivers/virt/coco/sev-guest/sev-guest.h
> rename to arch/x86/include/asm/sev-guest.h
> index ceb798a404d6..27cc15ad6131 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.h
> +++ b/arch/x86/include/asm/sev-guest.h
> @@ -63,4 +63,22 @@ struct snp_guest_msg {
> u8 payload[4000];
> } __packed;
>
> +struct snp_guest_req {
> + void *req_buf;
> + size_t req_sz;
> +
> + void *resp_buf;
> + size_t resp_sz;
> +
> + void *data;
> + size_t data_npages;
> +
> + u64 exit_code;
> + unsigned int vmpck_id;
> + u8 msg_version;
> + u8 msg_type;
> +};
> +
> +int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
> + struct snp_guest_request_ioctl *rio);
This seems odd to have in this file. It's arch/x86/kernel/sev.c that
exports the call and so this should probably stay in
arch/x86/include/asm/sev.h and put the struct there, too, no?
Thanks,
Tom
> #endif /* __VIRT_SEVGUEST_H__ */
> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
> index 5b4a1ce3d368..78465a8c7dc6 100644
> --- a/arch/x86/include/asm/sev.h
> +++ b/arch/x86/include/asm/sev.h
> @@ -97,8 +97,6 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
> struct snp_req_data {
> unsigned long req_gpa;
> unsigned long resp_gpa;
> - unsigned long data_gpa;
> - unsigned int data_npages;
> };
>
> struct sev_guest_platform_data {
> @@ -209,7 +207,6 @@ void snp_set_memory_private(unsigned long vaddr, unsigned long npages);
> void snp_set_wakeup_secondary_cpu(void);
> bool snp_init(struct boot_params *bp);
> void __init __noreturn snp_abort(void);
> -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio);
> void snp_accept_memory(phys_addr_t start, phys_addr_t end);
> u64 snp_get_unsupported_features(u64 status);
> u64 sev_get_status(void);
> @@ -233,11 +230,6 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned long npa
> static inline void snp_set_wakeup_secondary_cpu(void) { }
> static inline bool snp_init(struct boot_params *bp) { return false; }
> static inline void snp_abort(void) { }
> -static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
> -{
> - return -ENOTTY;
> -}
> -
> static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
> static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
> static inline u64 sev_get_status(void) { return 0; }
On 12/20/23 09:13, Nikunj A Dadhania wrote:
> SNP command mutex is used to serialize the shared buffer access, command
> handling and message sequence number races. Move the SNP guest command
> mutex out of the sev guest driver and provide accessors to sev-guest
> driver. Remove multiple lockdep check in sev-guest driver, next patch adds
> a single lockdep check in snp_send_guest_request().
>
> Signed-off-by: Nikunj A Dadhania <[email protected]>
> ---
> arch/x86/include/asm/sev-guest.h | 3 +++
> arch/x86/kernel/sev.c | 21 +++++++++++++++++++++
> drivers/virt/coco/sev-guest/sev-guest.c | 23 +++++++----------------
> 3 files changed, 31 insertions(+), 16 deletions(-)
>
> diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
> index 27cc15ad6131..2f3cceb88396 100644
> --- a/arch/x86/include/asm/sev-guest.h
> +++ b/arch/x86/include/asm/sev-guest.h
> @@ -81,4 +81,7 @@ struct snp_guest_req {
>
> int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
> struct snp_guest_request_ioctl *rio);
> +void snp_guest_cmd_lock(void);
> +void snp_guest_cmd_unlock(void);
> +
> #endif /* __VIRT_SEVGUEST_H__ */
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index 6aa0bdf8a7a0..191193924b22 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -941,6 +941,21 @@ static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
> free_page((unsigned long)vmsa);
> }
>
> +/* SNP Guest command mutex to serialize the shared buffer access and command handling. */
> +static struct mutex snp_guest_cmd_mutex;
You should probably use:
static DEFINE_MUTEX(snp_guest_cmd_mutex);
That way you can avoid the initialization in snp_init_platform_device().
With that:
Reviewed-by: Tom Lendacky <[email protected]>
> +
> +void snp_guest_cmd_lock(void)
> +{
> + mutex_lock(&snp_guest_cmd_mutex);
> +}
> +EXPORT_SYMBOL_GPL(snp_guest_cmd_lock);
> +
> +void snp_guest_cmd_unlock(void)
> +{
> + mutex_unlock(&snp_guest_cmd_mutex);
> +}
> +EXPORT_SYMBOL_GPL(snp_guest_cmd_unlock);
> +
> static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
> {
> struct sev_es_save_area *cur_vmsa, *vmsa;
> @@ -2240,6 +2255,12 @@ static int __init snp_init_platform_device(void)
> return -ENODEV;
> }
>
> + /*
> + * Initialize snp command mutex that is used to serialize the shared
> + * buffer access and use of the vmpck and message sequence number
> + */
> + mutex_init(&snp_guest_cmd_mutex);
> +
> data.secrets_gpa = secrets_pa;
> if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
> return -ENODEV;
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
> index 9c0ff69a16da..bd30a9ff82c1 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.c
> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
> @@ -63,9 +63,6 @@ static u32 vmpck_id;
> module_param(vmpck_id, uint, 0444);
> MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
>
> -/* Mutex to serialize the shared buffer access and command handling. */
> -static DEFINE_MUTEX(snp_cmd_mutex);
> -
> static inline u8 *snp_get_vmpck(struct snp_guest_dev *snp_dev)
> {
> return snp_dev->layout->vmpck0 + snp_dev->vmpck_id * VMPCK_KEY_LEN;
> @@ -115,8 +112,6 @@ static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> u32 *os_area_msg_seqno = snp_get_os_area_msg_seqno(snp_dev);
> u64 count;
>
> - lockdep_assert_held(&snp_cmd_mutex);
> -
> /* Read the current message sequence counter from secrets pages */
> count = *os_area_msg_seqno;
>
> @@ -409,8 +404,6 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
> struct snp_report_resp *resp;
> int rc, resp_len;
>
> - lockdep_assert_held(&snp_cmd_mutex);
> -
> if (!arg->req_data || !arg->resp_data)
> return -EINVAL;
>
> @@ -457,8 +450,6 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
> /* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
> u8 buf[64 + 16];
>
> - lockdep_assert_held(&snp_cmd_mutex);
> -
> if (!arg->req_data || !arg->resp_data)
> return -EINVAL;
>
> @@ -507,8 +498,6 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
> sockptr_t certs_address;
> int ret, resp_len;
>
> - lockdep_assert_held(&snp_cmd_mutex);
> -
> if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data))
> return -EINVAL;
>
> @@ -604,12 +593,12 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
> if (!input.msg_version)
> return -EINVAL;
>
> - mutex_lock(&snp_cmd_mutex);
> + snp_guest_cmd_lock();
>
> /* Check if the VMPCK is not empty */
> if (snp_is_vmpck_empty(snp_dev)) {
> dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
> - mutex_unlock(&snp_cmd_mutex);
> + snp_guest_cmd_unlock();
> return -ENOTTY;
> }
>
> @@ -634,7 +623,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
> break;
> }
>
> - mutex_unlock(&snp_cmd_mutex);
> + snp_guest_cmd_unlock();
>
> if (input.exitinfo2 && copy_to_user(argp, &input, sizeof(input)))
> return -EFAULT;
> @@ -724,14 +713,14 @@ static int sev_report_new(struct tsm_report *report, void *data)
> if (!buf)
> return -ENOMEM;
>
> - guard(mutex)(&snp_cmd_mutex);
> -
> /* Check if the VMPCK is not empty */
> if (snp_is_vmpck_empty(snp_dev)) {
> dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
> return -ENOTTY;
> }
>
> + snp_guest_cmd_lock();
> +
> cert_table = buf + report_size;
> struct snp_ext_report_req ext_req = {
> .data = { .vmpl = desc->privlevel },
> @@ -752,6 +741,8 @@ static int sev_report_new(struct tsm_report *report, void *data)
> };
>
> ret = get_ext_report(snp_dev, &input, &io);
> + snp_guest_cmd_unlock();
> +
> if (ret)
> return ret;
>
On 1/25/2024 4:06 PM, Borislav Petkov wrote:
> On Wed, Dec 20, 2023 at 08:43:43PM +0530, Nikunj A Dadhania wrote:
>> @@ -307,11 +197,16 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
>> * If the message size is greater than our buffer length then return
>> * an error.
>> */
>> - if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
>> + if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
>> return -EBADMSG;
>>
>> /* Decrypt the payload */
>> - return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
>> + memcpy(iv, &resp_hdr->msg_seqno, sizeof(resp_hdr->msg_seqno));
>
> sizeof(iv) != sizeof(resp_hdr->msg_seqno) and it fits now.
>
> However, for protection against future bugs, this should be:
>
> memcpy(iv, &resp_hdr->msg_seqno, min(sizeof(iv), sizeof(resp_hdr->msg_seqno)));
Sure, will change.
>
>> + if (!aesgcm_decrypt(ctx, payload, resp->payload, resp_hdr->msg_sz,
>> + &resp_hdr->algo, AAD_LEN, iv, resp_hdr->authtag))
>> + return -EBADMSG;
>> +
>> + return 0;
>> }
>>
>> static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
>> @@ -319,6 +214,8 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
>> {
>> struct snp_guest_msg *req = &snp_dev->secret_request;
>> struct snp_guest_msg_hdr *hdr = &req->hdr;
>> + struct aesgcm_ctx *ctx = snp_dev->ctx;
>> + u8 iv[GCM_AES_IV_SIZE] = {};
>>
>> memset(req, 0, sizeof(*req));
>>
>> @@ -338,7 +235,14 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
>> dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
>> hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
>>
>> - return __enc_payload(snp_dev, req, payload, sz);
>> + if (WARN_ON((sz + ctx->authsize) > sizeof(req->payload)))
>> + return -EBADMSG;
>> +
>> + memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
>
> Ditto.
Sure.
>
>> + aesgcm_encrypt(ctx, req->payload, payload, sz, &hdr->algo, AAD_LEN,
>> + iv, hdr->authtag);
>> +
>> + return 0;
>
Thanks,
Nikunj
On 1/25/2024 5:29 PM, Borislav Petkov wrote:
> On Wed, Dec 20, 2023 at 08:43:45PM +0530, Nikunj A Dadhania wrote:
>> -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
>> +int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
>> + struct snp_guest_request_ioctl *rio)
>> {
>> struct ghcb_state state;
>> struct es_em_ctxt ctxt;
>> unsigned long flags;
>> struct ghcb *ghcb;
>> + u64 exit_code;
>
> Silly local vars. Just use req->exit_code everywhere instead.
Sure, will change.
>
>> int ret;
>>
>> rio->exitinfo2 = SEV_RET_NO_FW_CALL;
>> + if (!req)
>> + return -EINVAL;
>
> Such tests are done under the variable which is assigned, not randomly.
>
> Also, what's the point in testing req? Will that ever be NULL? What are
> you actually protecting against here?
Right, and in the later code, this is checked at snp_send_guest_request() API. So this is redundant.
>> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
>> index 469e10d9bf35..5cafbd1c42cb 100644
>> --- a/drivers/virt/coco/sev-guest/sev-guest.c
>> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
>> @@ -27,8 +27,7 @@
>>
>> #include <asm/svm.h>
>> #include <asm/sev.h>
>> -
>> -#include "sev-guest.h"
>> +#include <asm/sev-guest.h>
>>
>> #define DEVICE_NAME "sev-guest"
>>
>> @@ -169,7 +168,7 @@ static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
>> return ctx;
>> }
>>
>> -static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
>> +static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *guest_req)
>
> So we call the request everywhere "req". But you've called it
> "guest_req" here because...
Yes, I was thinking about it and came up with this.
>
>> {
>> struct snp_guest_msg *resp = &snp_dev->secret_response;
>> struct snp_guest_msg *req = &snp_dev->secret_request;
>
> ... there already is a "req" variable which is not a guest request thing
> but a guest message. So why don't you call it "req_msg" instead and the
> "resp" "resp_msg" so that it is clear what is what?
>
This naming is much better, thanks.
> And then you can call the actual request var "req" and then the code
> becomes more readable...
>
> ...
>
>> static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
>> {
>> struct snp_report_req *req = &snp_dev->req.report;
>> + struct snp_guest_req guest_req = {0};
>
> You have the same issue here.
>
> If we aim at calling the local vars in every function the same, the code
> becomes automatically much more readable.
>
> And so on...
Will change accordingly,
Regards
Nikunj
On 1/26/2024 6:30 AM, Dionna Amalie Glaze wrote:
> On Wed, Jan 24, 2024 at 10:08 PM Nikunj A. Dadhania <[email protected]> wrote:
>>
>> On 12/20/2023 8:43 PM, Nikunj A Dadhania wrote:
>>> Secure TSC allows guests to securely use RDTSC/RDTSCP instructions as the
>>> parameters being used cannot be changed by hypervisor once the guest is
>>> launched. More details in the AMD64 APM Vol 2, Section "Secure TSC".
>>>
>>> During the boot-up of the secondary cpus, SecureTSC enabled guests need to
>>> query TSC info from AMD Security Processor. This communication channel is
>>> encrypted between the AMD Security Processor and the guest, the hypervisor
>>> is just the conduit to deliver the guest messages to the AMD Security
>>> Processor. Each message is protected with an AEAD (AES-256 GCM). See "SEV
>>> Secure Nested Paging Firmware ABI Specification" document (currently at
>>> https://www.amd.com/system/files/TechDocs/56860.pdf) section "TSC Info"
>>>
>>> Use a minimal GCM library to encrypt/decrypt SNP Guest messages to
>>> communicate with the AMD Security Processor which is available at early
>>> boot.
>>>
>>> SEV-guest driver has the implementation for guest and AMD Security
>>> Processor communication. As the TSC_INFO needs to be initialized during
>>> early boot before smp cpus are started, move most of the sev-guest driver
>>> code to kernel/sev.c and provide well defined APIs to the sev-guest driver
>>> to use the interface to avoid code-duplication.
>>>
>>> Patches:
>>> 01-08: Preparation and movement of sev-guest driver code
>>> 09-16: SecureTSC enablement patches.
>>>
>>> Testing SecureTSC
>>> -----------------
>>>
>>> SecureTSC hypervisor patches based on top of SEV-SNP Guest MEMFD series:
>>> https://github.com/nikunjad/linux/tree/snp-host-latest-securetsc_v5
>>>
>>> QEMU changes:
>>> https://github.com/nikunjad/qemu/tree/snp_securetsc_v5
>>>
>>> QEMU commandline SEV-SNP-UPM with SecureTSC:
>>>
>>> qemu-system-x86_64 -cpu EPYC-Milan-v2,+secure-tsc,+invtsc -smp 4 \
>>> -object memory-backend-memfd-private,id=ram1,size=1G,share=true \
>>> -object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-tsc=on \
>>> -machine q35,confidential-guest-support=sev0,memory-backend=ram1,kvm-type=snp \
>>> ...
>>>
>>> Changelog:
>>> ----------
>>> v7:
>>> * Drop mutex from the snp_dev and add snp_guest_cmd_{lock,unlock} API
>>> * Added comments for secrets page failure
>>> * Added define for maximum supported VMPCK
>>> * Updated comments why sev_status is used directly instead of
>>> cpu_feature_enabled()
I missed this in the change log:
* Added Tested-by from Peter Gonda (https://lore.kernel.org/lkml/CAMkAt6pULjLVUO6Ys4Sq1a79d93_5w5URgLYNXY-aW2jSemruA@mail.gmail.com/)
>>
>> A gentle reminder.
>>
>
> From the Google testing side of things, we may not get to this for
> another while.
Thanks Dionna
Regards
Nikunj
On 1/27/2024 2:46 AM, Tom Lendacky wrote:
> On 12/20/23 09:13, Nikunj A Dadhania wrote:
>> Add a snp_guest_req structure to simplify the function arguments. The
>> structure will be used to call the SNP Guest message request API
>> instead of passing a long list of parameters.
>>
>> Update snp_issue_guest_request() prototype to include the new guest request
>> structure and move the prototype to sev_guest.h.
>>
>> Signed-off-by: Nikunj A Dadhania <[email protected]>
>> Tested-by: Peter Gonda <[email protected]>
>> ---
>> .../x86/include/asm}/sev-guest.h | 18 +++
>> arch/x86/include/asm/sev.h | 8 --
>> arch/x86/kernel/sev.c | 15 ++-
>> drivers/virt/coco/sev-guest/sev-guest.c | 108 +++++++++++-------
>> 4 files changed, 93 insertions(+), 56 deletions(-)
>> rename {drivers/virt/coco/sev-guest => arch/x86/include/asm}/sev-guest.h (78%)
>>
>> diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/arch/x86/include/asm/sev-guest.h
>> similarity index 78%
>> rename from drivers/virt/coco/sev-guest/sev-guest.h
>> rename to arch/x86/include/asm/sev-guest.h
>> index ceb798a404d6..27cc15ad6131 100644
>> --- a/drivers/virt/coco/sev-guest/sev-guest.h
>> +++ b/arch/x86/include/asm/sev-guest.h
>> @@ -63,4 +63,22 @@ struct snp_guest_msg {
>> u8 payload[4000];
>> } __packed;
>> +struct snp_guest_req {
>> + void *req_buf;
>> + size_t req_sz;
>> +
>> + void *resp_buf;
>> + size_t resp_sz;
>> +
>> + void *data;
>> + size_t data_npages;
>> +
>> + u64 exit_code;
>> + unsigned int vmpck_id;
>> + u8 msg_version;
>> + u8 msg_type;
>> +};
>> +
>> +int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
>> + struct snp_guest_request_ioctl *rio);
>
> This seems odd to have in this file. It's arch/x86/kernel/sev.c that exports the call and so this should probably stay in arch/x86/include/asm/sev.h and put the struct there, too, no?
The prototype is removed in 7/16, I have it here to make sure that compilation does not break with minimal churn.
Regards
Nikunj
On 1/27/2024 3:41 AM, Tom Lendacky wrote:
> On 12/20/23 09:13, Nikunj A Dadhania wrote:
>> SNP command mutex is used to serialize the shared buffer access, command
>> handling and message sequence number races. Move the SNP guest command
>> mutex out of the sev guest driver and provide accessors to sev-guest
>> driver. Remove multiple lockdep check in sev-guest driver, next patch adds
>> a single lockdep check in snp_send_guest_request().
>>
>> Signed-off-by: Nikunj A Dadhania <[email protected]>
>> ---
>> arch/x86/include/asm/sev-guest.h | 3 +++
>> arch/x86/kernel/sev.c | 21 +++++++++++++++++++++
>> drivers/virt/coco/sev-guest/sev-guest.c | 23 +++++++----------------
>> 3 files changed, 31 insertions(+), 16 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
>> index 27cc15ad6131..2f3cceb88396 100644
>> --- a/arch/x86/include/asm/sev-guest.h
>> +++ b/arch/x86/include/asm/sev-guest.h
>> @@ -81,4 +81,7 @@ struct snp_guest_req {
>> int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
>> struct snp_guest_request_ioctl *rio);
>> +void snp_guest_cmd_lock(void);
>> +void snp_guest_cmd_unlock(void);
>> +
>> #endif /* __VIRT_SEVGUEST_H__ */
>> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
>> index 6aa0bdf8a7a0..191193924b22 100644
>> --- a/arch/x86/kernel/sev.c
>> +++ b/arch/x86/kernel/sev.c
>> @@ -941,6 +941,21 @@ static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
>> free_page((unsigned long)vmsa);
>> }
>> +/* SNP Guest command mutex to serialize the shared buffer access and command handling. */
>> +static struct mutex snp_guest_cmd_mutex;
>
> You should probably use:
>
> static DEFINE_MUTEX(snp_guest_cmd_mutex);
>
> That way you can avoid the initialization in snp_init_platform_device().
>
> With that:
>
> Reviewed-by: Tom Lendacky <[email protected]>
Sure, will change.
Regards
Nikunj
On 1/25/2024 5:29 PM, Borislav Petkov wrote:
> On Wed, Dec 20, 2023 at 08:43:45PM +0530, Nikunj A Dadhania wrote:
>> -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
>> +int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
>> + struct snp_guest_request_ioctl *rio)
>> {
>> struct ghcb_state state;
>> struct es_em_ctxt ctxt;
>> unsigned long flags;
>> struct ghcb *ghcb;
>> + u64 exit_code;
>
> Silly local vars. Just use req->exit_code everywhere instead.
>
>> int ret;
>>
>> rio->exitinfo2 = SEV_RET_NO_FW_CALL;
>> + if (!req)
>> + return -EINVAL;
>
> Such tests are done under the variable which is assigned, not randomly.
>
> Also, what's the point in testing req? Will that ever be NULL? What are
> you actually protecting against here?
>
>> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
>> index 469e10d9bf35..5cafbd1c42cb 100644
>> --- a/drivers/virt/coco/sev-guest/sev-guest.c
>> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
>> @@ -27,8 +27,7 @@
>>
>> #include <asm/svm.h>
>> #include <asm/sev.h>
>> -
>> -#include "sev-guest.h"
>> +#include <asm/sev-guest.h>
>>
>> #define DEVICE_NAME "sev-guest"
>>
>> @@ -169,7 +168,7 @@ static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
>> return ctx;
>> }
>>
>> -static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
>> +static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *guest_req)
>
> So we call the request everywhere "req". But you've called it
> "guest_req" here because...
>
>> {
>> struct snp_guest_msg *resp = &snp_dev->secret_response;
>> struct snp_guest_msg *req = &snp_dev->secret_request;
>
> ... there already is a "req" variable which is not a guest request thing
> but a guest message. So why don't you call it "req_msg" instead and the
> "resp" "resp_msg" so that it is clear what is what?
>
> And then you can call the actual request var "req" and then the code
> becomes more readable...
>
> ...
>
>> static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
>> {
>> struct snp_report_req *req = &snp_dev->req.report;
>> + struct snp_guest_req guest_req = {0};
>
> You have the same issue here.
>
> If we aim at calling the local vars in every function the same, the code
> becomes automatically much more readable.
>
> And so on...
>
Changed to "req" for all the guest request throughout the file. Other "req"
usage are renamed appropriately.
Subject: [PATCH] virt: sev-guest: Add SNP guest request structure
Add a snp_guest_req structure to simplify the function arguments. The
structure will be used to call the SNP Guest message request API
instead of passing a long list of parameters. Use "req" as variable name
for guest req throughout the file and rename other variables appropriately.
Update snp_issue_guest_request() prototype to include the new guest request
structure and move the prototype to sev_guest.h.
Signed-off-by: Nikunj A Dadhania <[email protected]>
Tested-by: Peter Gonda <[email protected]>
---
.../x86/include/asm}/sev-guest.h | 18 ++
arch/x86/include/asm/sev.h | 8 -
arch/x86/kernel/sev.c | 16 +-
drivers/virt/coco/sev-guest/sev-guest.c | 195 ++++++++++--------
4 files changed, 135 insertions(+), 102 deletions(-)
rename {drivers/virt/coco/sev-guest => arch/x86/include/asm}/sev-guest.h (78%)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/arch/x86/include/asm/sev-guest.h
similarity index 78%
rename from drivers/virt/coco/sev-guest/sev-guest.h
rename to arch/x86/include/asm/sev-guest.h
index ceb798a404d6..27cc15ad6131 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.h
+++ b/arch/x86/include/asm/sev-guest.h
@@ -63,4 +63,22 @@ struct snp_guest_msg {
u8 payload[4000];
} __packed;
+struct snp_guest_req {
+ void *req_buf;
+ size_t req_sz;
+
+ void *resp_buf;
+ size_t resp_sz;
+
+ void *data;
+ size_t data_npages;
+
+ u64 exit_code;
+ unsigned int vmpck_id;
+ u8 msg_version;
+ u8 msg_type;
+};
+
+int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
+ struct snp_guest_request_ioctl *rio);
#endif /* __VIRT_SEVGUEST_H__ */
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 5b4a1ce3d368..78465a8c7dc6 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -97,8 +97,6 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
struct snp_req_data {
unsigned long req_gpa;
unsigned long resp_gpa;
- unsigned long data_gpa;
- unsigned int data_npages;
};
struct sev_guest_platform_data {
@@ -209,7 +207,6 @@ void snp_set_memory_private(unsigned long vaddr, unsigned long npages);
void snp_set_wakeup_secondary_cpu(void);
bool snp_init(struct boot_params *bp);
void __init __noreturn snp_abort(void);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio);
void snp_accept_memory(phys_addr_t start, phys_addr_t end);
u64 snp_get_unsupported_features(u64 status);
u64 sev_get_status(void);
@@ -233,11 +230,6 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned long npa
static inline void snp_set_wakeup_secondary_cpu(void) { }
static inline bool snp_init(struct boot_params *bp) { return false; }
static inline void snp_abort(void) { }
-static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
-{
- return -ENOTTY;
-}
-
static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
static inline u64 sev_get_status(void) { return 0; }
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index c67285824e82..43ffd307731f 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -28,6 +28,7 @@
#include <asm/cpu_entry_area.h>
#include <asm/stacktrace.h>
#include <asm/sev.h>
+#include <asm/sev-guest.h>
#include <asm/insn-eval.h>
#include <asm/fpu/xcr.h>
#include <asm/processor.h>
@@ -2170,7 +2171,8 @@ static int __init init_sev_config(char *str)
}
__setup("sev=", init_sev_config);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
+int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
+ struct snp_guest_request_ioctl *rio)
{
struct ghcb_state state;
struct es_em_ctxt ctxt;
@@ -2194,12 +2196,12 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct sn
vc_ghcb_invalidate(ghcb);
- if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
- ghcb_set_rax(ghcb, input->data_gpa);
- ghcb_set_rbx(ghcb, input->data_npages);
+ if (req->exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
+ ghcb_set_rax(ghcb, __pa(req->data));
+ ghcb_set_rbx(ghcb, req->data_npages);
}
- ret = sev_es_ghcb_hv_call(ghcb, &ctxt, exit_code, input->req_gpa, input->resp_gpa);
+ ret = sev_es_ghcb_hv_call(ghcb, &ctxt, req->exit_code, input->req_gpa, input->resp_gpa);
if (ret)
goto e_put;
@@ -2214,8 +2216,8 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct sn
case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN):
/* Number of expected pages are returned in RBX */
- if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
- input->data_npages = ghcb_get_rbx(ghcb);
+ if (req->exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
+ req->data_npages = ghcb_get_rbx(ghcb);
ret = -ENOSPC;
break;
}
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 0450c5383476..b6c8f70e936c 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -27,8 +27,7 @@
#include <asm/svm.h>
#include <asm/sev.h>
-
-#include "sev-guest.h"
+#include <asm/sev-guest.h>
#define DEVICE_NAME "sev-guest"
@@ -169,65 +168,64 @@ static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
return ctx;
}
-static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
+static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
{
- struct snp_guest_msg *resp = &snp_dev->secret_response;
- struct snp_guest_msg *req = &snp_dev->secret_request;
- struct snp_guest_msg_hdr *req_hdr = &req->hdr;
- struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
+ struct snp_guest_msg *resp_msg = &snp_dev->secret_response;
+ struct snp_guest_msg *req_msg = &snp_dev->secret_request;
+ struct snp_guest_msg_hdr *req_msg_hdr = &req_msg->hdr;
+ struct snp_guest_msg_hdr *resp_msg_hdr = &resp_msg->hdr;
struct aesgcm_ctx *ctx = snp_dev->ctx;
u8 iv[GCM_AES_IV_SIZE] = {};
pr_debug("response [seqno %lld type %d version %d sz %d]\n",
- resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
- resp_hdr->msg_sz);
+ resp_msg_hdr->msg_seqno, resp_msg_hdr->msg_type, resp_msg_hdr->msg_version,
+ resp_msg_hdr->msg_sz);
/* Copy response from shared memory to encrypted memory. */
- memcpy(resp, snp_dev->response, sizeof(*resp));
+ memcpy(resp_msg, snp_dev->response, sizeof(*resp_msg));
/* Verify that the sequence counter is incremented by 1 */
- if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
+ if (unlikely(resp_msg_hdr->msg_seqno != (req_msg_hdr->msg_seqno + 1)))
return -EBADMSG;
/* Verify response message type and version number. */
- if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
- resp_hdr->msg_version != req_hdr->msg_version)
+ if (resp_msg_hdr->msg_type != (req_msg_hdr->msg_type + 1) ||
+ resp_msg_hdr->msg_version != req_msg_hdr->msg_version)
return -EBADMSG;
/*
* If the message size is greater than our buffer length then return
* an error.
*/
- if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
+ if (unlikely((resp_msg_hdr->msg_sz + ctx->authsize) > req->resp_sz))
return -EBADMSG;
/* Decrypt the payload */
- memcpy(iv, &resp_hdr->msg_seqno, min(sizeof(iv), sizeof(resp_hdr->msg_seqno)));
- if (!aesgcm_decrypt(ctx, payload, resp->payload, resp_hdr->msg_sz,
- &resp_hdr->algo, AAD_LEN, iv, resp_hdr->authtag))
+ memcpy(iv, &resp_msg_hdr->msg_seqno, min(sizeof(iv), sizeof(resp_msg_hdr->msg_seqno)));
+ if (!aesgcm_decrypt(ctx, req->resp_buf, resp_msg->payload, resp_msg_hdr->msg_sz,
+ &resp_msg_hdr->algo, AAD_LEN, iv, resp_msg_hdr->authtag))
return -EBADMSG;
return 0;
}
-static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
- void *payload, size_t sz)
+static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, struct snp_guest_req *req)
{
- struct snp_guest_msg *req = &snp_dev->secret_request;
- struct snp_guest_msg_hdr *hdr = &req->hdr;
+ struct snp_guest_msg *msg = &snp_dev->secret_request;
+ struct snp_guest_msg_hdr *hdr = &msg->hdr;
struct aesgcm_ctx *ctx = snp_dev->ctx;
u8 iv[GCM_AES_IV_SIZE] = {};
- memset(req, 0, sizeof(*req));
+ memset(msg, 0, sizeof(*msg));
hdr->algo = SNP_AEAD_AES_256_GCM;
hdr->hdr_version = MSG_HDR_VER;
hdr->hdr_sz = sizeof(*hdr);
- hdr->msg_type = type;
- hdr->msg_version = version;
+ hdr->msg_type = req->msg_type;
+ hdr->msg_version = req->msg_version;
hdr->msg_seqno = seqno;
- hdr->msg_vmpck = vmpck_id;
- hdr->msg_sz = sz;
+ hdr->msg_vmpck = req->vmpck_id;
+ hdr->msg_sz = req->req_sz;
/* Verify the sequence number is non-zero */
if (!hdr->msg_seqno)
@@ -236,17 +234,17 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
pr_debug("request [seqno %lld type %d version %d sz %d]\n",
hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
- if (WARN_ON((sz + ctx->authsize) > sizeof(req->payload)))
+ if (WARN_ON((req->req_sz + ctx->authsize) > sizeof(msg->payload)))
return -EBADMSG;
memcpy(iv, &hdr->msg_seqno, min(sizeof(iv), sizeof(hdr->msg_seqno)));
- aesgcm_encrypt(ctx, req->payload, payload, sz, &hdr->algo, AAD_LEN,
- iv, hdr->authtag);
+ aesgcm_encrypt(ctx, msg->payload, req->req_buf, req->req_sz, &hdr->algo,
+ AAD_LEN, iv, hdr->authtag);
return 0;
}
-static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
+static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
struct snp_guest_request_ioctl *rio)
{
unsigned long req_start = jiffies;
@@ -261,7 +259,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
* sequence number must be incremented or the VMPCK must be deleted to
* prevent reuse of the IV.
*/
- rc = snp_issue_guest_request(exit_code, &snp_dev->input, rio);
+ rc = snp_issue_guest_request(req, &snp_dev->input, rio);
switch (rc) {
case -ENOSPC:
/*
@@ -271,8 +269,8 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
* order to increment the sequence number and thus avoid
* IV reuse.
*/
- override_npages = snp_dev->input.data_npages;
- exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+ override_npages = req->data_npages;
+ req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
/*
* Override the error to inform callers the given extended
@@ -327,15 +325,13 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
}
if (override_npages)
- snp_dev->input.data_npages = override_npages;
+ req->data_npages = override_npages;
return rc;
}
-static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
- struct snp_guest_request_ioctl *rio, u8 type,
- void *req_buf, size_t req_sz, void *resp_buf,
- u32 resp_sz)
+static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio)
{
u64 seqno;
int rc;
@@ -349,7 +345,7 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
/* Encrypt the userspace provided payload in snp_dev->secret_request. */
- rc = enc_payload(snp_dev, seqno, rio->msg_version, type, req_buf, req_sz);
+ rc = enc_payload(snp_dev, seqno, req);
if (rc)
return rc;
@@ -360,7 +356,7 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
memcpy(snp_dev->request, &snp_dev->secret_request,
sizeof(snp_dev->secret_request));
- rc = __handle_guest_request(snp_dev, exit_code, rio);
+ rc = __handle_guest_request(snp_dev, req, rio);
if (rc) {
if (rc == -EIO &&
rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
@@ -369,12 +365,11 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
dev_alert(snp_dev->dev,
"Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n",
rc, rio->exitinfo2);
-
snp_disable_vmpck(snp_dev);
return rc;
}
- rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
+ rc = verify_and_dec_payload(snp_dev, req);
if (rc) {
dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
snp_disable_vmpck(snp_dev);
@@ -391,8 +386,9 @@ struct snp_req_resp {
static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
- struct snp_report_req *req = &snp_dev->req.report;
- struct snp_report_resp *resp;
+ struct snp_report_req *report_req = &snp_dev->req.report;
+ struct snp_guest_req req = {0};
+ struct snp_report_resp *report_resp;
int rc, resp_len;
lockdep_assert_held(&snp_cmd_mutex);
@@ -400,7 +396,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
- if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req)))
+ if (copy_from_user(report_req, (void __user *)arg->req_data, sizeof(*report_req)))
return -EFAULT;
/*
@@ -408,29 +404,37 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp->data) + snp_dev->ctx->authsize;
- resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
- if (!resp)
+ resp_len = sizeof(report_resp->data) + snp_dev->ctx->authsize;
+ report_resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
+ if (!report_resp)
return -ENOMEM;
- rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
- SNP_MSG_REPORT_REQ, req, sizeof(*req), resp->data,
- resp_len);
+ req.msg_version = arg->msg_version;
+ req.msg_type = SNP_MSG_REPORT_REQ;
+ req.vmpck_id = vmpck_id;
+ req.req_buf = report_req;
+ req.req_sz = sizeof(*report_req);
+ req.resp_buf = report_resp->data;
+ req.resp_sz = resp_len;
+ req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ rc = snp_send_guest_request(snp_dev, &req, arg);
if (rc)
goto e_free;
- if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
+ if (copy_to_user((void __user *)arg->resp_data, report_resp, sizeof(*report_resp)))
rc = -EFAULT;
e_free:
- kfree(resp);
+ kfree(report_resp);
return rc;
}
static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
- struct snp_derived_key_req *req = &snp_dev->req.derived_key;
- struct snp_derived_key_resp resp = {0};
+ struct snp_derived_key_req *derived_key_req = &snp_dev->req.derived_key;
+ struct snp_derived_key_resp derived_key_resp = {0};
+ struct snp_guest_req req = {0};
int rc, resp_len;
/* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
u8 buf[64 + 16];
@@ -445,25 +449,34 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp.data) + snp_dev->ctx->authsize;
+ resp_len = sizeof(derived_key_resp.data) + snp_dev->ctx->authsize;
if (sizeof(buf) < resp_len)
return -ENOMEM;
- if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req)))
+ if (copy_from_user(derived_key_req, (void __user *)arg->req_data,
+ sizeof(*derived_key_req)))
return -EFAULT;
- rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
- SNP_MSG_KEY_REQ, req, sizeof(*req), buf, resp_len);
+ req.msg_version = arg->msg_version;
+ req.msg_type = SNP_MSG_KEY_REQ;
+ req.vmpck_id = vmpck_id;
+ req.req_buf = derived_key_req;
+ req.req_sz = sizeof(*derived_key_req);
+ req.resp_buf = buf;
+ req.resp_sz = resp_len;
+ req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ rc = snp_send_guest_request(snp_dev, &req, arg);
if (rc)
return rc;
- memcpy(resp.data, buf, sizeof(resp.data));
- if (copy_to_user((void __user *)arg->resp_data, &resp, sizeof(resp)))
+ memcpy(derived_key_resp.data, buf, sizeof(derived_key_resp.data));
+ if (copy_to_user((void __user *)arg->resp_data, &derived_key_resp, sizeof(derived_key_resp)))
rc = -EFAULT;
/* The response buffer contains the sensitive data, explicitly clear it. */
memzero_explicit(buf, sizeof(buf));
- memzero_explicit(&resp, sizeof(resp));
+ memzero_explicit(&derived_key_resp, sizeof(derived_key_resp));
return rc;
}
@@ -471,32 +484,33 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
struct snp_req_resp *io)
{
- struct snp_ext_report_req *req = &snp_dev->req.ext_report;
- struct snp_report_resp *resp;
- int ret, npages = 0, resp_len;
+ struct snp_ext_report_req *report_req = &snp_dev->req.ext_report;
+ struct snp_guest_req req = {0};
+ struct snp_report_resp *report_resp;
sockptr_t certs_address;
+ int ret, resp_len;
lockdep_assert_held(&snp_cmd_mutex);
if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data))
return -EINVAL;
- if (copy_from_sockptr(req, io->req_data, sizeof(*req)))
+ if (copy_from_sockptr(report_req, io->req_data, sizeof(*report_req)))
return -EFAULT;
/* caller does not want certificate data */
- if (!req->certs_len || !req->certs_address)
+ if (!report_req->certs_len || !report_req->certs_address)
goto cmd;
- if (req->certs_len > SEV_FW_BLOB_MAX_SIZE ||
- !IS_ALIGNED(req->certs_len, PAGE_SIZE))
+ if (report_req->certs_len > SEV_FW_BLOB_MAX_SIZE ||
+ !IS_ALIGNED(report_req->certs_len, PAGE_SIZE))
return -EINVAL;
if (sockptr_is_kernel(io->resp_data)) {
- certs_address = KERNEL_SOCKPTR((void *)req->certs_address);
+ certs_address = KERNEL_SOCKPTR((void *)report_req->certs_address);
} else {
- certs_address = USER_SOCKPTR((void __user *)req->certs_address);
- if (!access_ok(certs_address.user, req->certs_len))
+ certs_address = USER_SOCKPTR((void __user *)report_req->certs_address);
+ if (!access_ok(certs_address.user, report_req->certs_len))
return -EFAULT;
}
@@ -506,45 +520,53 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
* the host. If host does not supply any certs in it, then copy
* zeros to indicate that certificate data was not provided.
*/
- memset(snp_dev->certs_data, 0, req->certs_len);
- npages = req->certs_len >> PAGE_SHIFT;
+ memset(snp_dev->certs_data, 0, report_req->certs_len);
+ req.data_npages = report_req->certs_len >> PAGE_SHIFT;
cmd:
/*
* The intermediate response buffer is used while decrypting the
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp->data) + snp_dev->ctx->authsize;
- resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
- if (!resp)
+ resp_len = sizeof(report_resp->data) + snp_dev->ctx->authsize;
+ report_resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
+ if (!report_resp)
return -ENOMEM;
- snp_dev->input.data_npages = npages;
- ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg,
- SNP_MSG_REPORT_REQ, &req->data,
- sizeof(req->data), resp->data, resp_len);
+ req.msg_version = arg->msg_version;
+ req.msg_type = SNP_MSG_REPORT_REQ;
+ req.vmpck_id = vmpck_id;
+ req.req_buf = &report_req->data;
+ req.req_sz = sizeof(report_req->data);
+ req.resp_buf = report_resp->data;
+ req.resp_sz = resp_len;
+ req.exit_code = SVM_VMGEXIT_EXT_GUEST_REQUEST;
+ req.data = snp_dev->certs_data;
+
+ ret = snp_send_guest_request(snp_dev, &req, arg);
/* If certs length is invalid then copy the returned length */
if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) {
- req->certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
+ report_req->certs_len = req.data_npages << PAGE_SHIFT;
- if (copy_to_sockptr(io->req_data, req, sizeof(*req)))
+ if (copy_to_sockptr(io->req_data, report_req, sizeof(*report_req)))
ret = -EFAULT;
}
if (ret)
goto e_free;
- if (npages && copy_to_sockptr(certs_address, snp_dev->certs_data, req->certs_len)) {
+ if (req.data_npages && report_req->certs_len &&
+ copy_to_sockptr(certs_address, snp_dev->certs_data, report_req->certs_len)) {
ret = -EFAULT;
goto e_free;
}
- if (copy_to_sockptr(io->resp_data, resp, sizeof(*resp)))
+ if (copy_to_sockptr(io->resp_data, report_resp, sizeof(*report_resp)))
ret = -EFAULT;
e_free:
- kfree(resp);
+ kfree(report_resp);
return ret;
}
@@ -868,7 +890,6 @@ static int __init sev_guest_probe(struct platform_device *pdev)
/* initial the input address for guest request */
snp_dev->input.req_gpa = __pa(snp_dev->request);
snp_dev->input.resp_gpa = __pa(snp_dev->response);
- snp_dev->input.data_gpa = __pa(snp_dev->certs_data);
ret = tsm_register(&sev_tsm_ops, snp_dev, &tsm_report_extra_type);
if (ret)
--
2.34.1
On Wed, Jan 31, 2024 at 07:28:05PM +0530, Nikunj A. Dadhania wrote:
> Changed to "req" for all the guest request throughout the file. Other "req"
> usage are renamed appropriately.
Yes, better from what I can tell.
However, I can't apply this patch in order to have a better look, it is
mangled. Next time, before you send a patch this way, send it yourself
first and try applying it.
If it doesn't work, throw away your mailer and use a proper one:
Documentation/process/email-clients.rst
> Subject: [PATCH] virt: sev-guest: Add SNP guest request structure
>
> Add a snp_guest_req structure to simplify the function arguments. The
> structure will be used to call the SNP Guest message request API
> instead of passing a long list of parameters. Use "req" as variable name
> for guest req throughout the file and rename other variables appropriately.
>
> Update snp_issue_guest_request() prototype to include the new guest request
> structure and move the prototype to sev_guest.h.
>
> Signed-off-by: Nikunj A Dadhania <[email protected]>
> Tested-by: Peter Gonda <[email protected]>
Tested-by: tags must be dropped if you change a patch in a non-trivial
way. And this change is not that trivial I'd say.
> ---
> .../x86/include/asm}/sev-guest.h | 18 ++
> arch/x86/include/asm/sev.h | 8 -
> arch/x86/kernel/sev.c | 16 +-
> drivers/virt/coco/sev-guest/sev-guest.c | 195 ++++++++++--------
> 4 files changed, 135 insertions(+), 102 deletions(-)
> rename {drivers/virt/coco/sev-guest => arch/x86/include/asm}/sev-guest.h (78%)
I didn't notice this before: why am I getting a sev-guest.h header in
arch/x86/?
Lemme quote again the file paths we agreed upon:
https://lore.kernel.org/all/[email protected]/
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On 2/1/2024 3:59 PM, Borislav Petkov wrote:
> On Wed, Jan 31, 2024 at 07:28:05PM +0530, Nikunj A. Dadhania wrote:
>> Changed to "req" for all the guest request throughout the file. Other "req"
>> usage are renamed appropriately.
>
> Yes, better from what I can tell.
>
> However, I can't apply this patch in order to have a better look, it is
> mangled. Next time, before you send a patch this way, send it yourself
> first and try applying it.
>
> If it doesn't work, throw away your mailer and use a proper one:
>
> Documentation/process/email-clients.rst
Sorry for that, will fix it.
>
>> Subject: [PATCH] virt: sev-guest: Add SNP guest request structure
>>
>> Add a snp_guest_req structure to simplify the function arguments. The
>> structure will be used to call the SNP Guest message request API
>> instead of passing a long list of parameters. Use "req" as variable name
>> for guest req throughout the file and rename other variables appropriately.
>>
>> Update snp_issue_guest_request() prototype to include the new guest request
>> structure and move the prototype to sev_guest.h.
>>
>> Signed-off-by: Nikunj A Dadhania <[email protected]>
>> Tested-by: Peter Gonda <[email protected]>
>
> Tested-by: tags must be dropped if you change a patch in a non-trivial
> way. And this change is not that trivial I'd say.
>
>> ---
>> .../x86/include/asm}/sev-guest.h | 18 ++
>> arch/x86/include/asm/sev.h | 8 -
>> arch/x86/kernel/sev.c | 16 +-
>> drivers/virt/coco/sev-guest/sev-guest.c | 195 ++++++++++--------
>> 4 files changed, 135 insertions(+), 102 deletions(-)
>> rename {drivers/virt/coco/sev-guest => arch/x86/include/asm}/sev-guest.h (78%)
>
> I didn't notice this before: why am I getting a sev-guest.h header in
> arch/x86/?
>
> Lemme quote again the file paths we agreed upon:
>
> https://lore.kernel.org/all/[email protected]/
I will move it to arch/x86/coco/sev, do we need a separate "include" directory ?
As we are doing this movement, should we move guest messaging related code to arch/x86/coco/sev/guest-msg.c ?
Regards
Nikunj
On Thu, Feb 01, 2024 at 04:40:10PM +0530, Nikunj A. Dadhania wrote:
> I will move it to arch/x86/coco/sev, do we need a separate "include" directory ?
I still don't understand why you need to move it at all?
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On Wed, Dec 20, 2023 at 4:16 PM Nikunj A Dadhania <[email protected]> wrote:
> + /* Setting Secure TSC parameters */
> + if (cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) {
> + vmsa->tsc_scale = snp_tsc_scale;
> + vmsa->tsc_offset = snp_tsc_offset;
> + }
This needs to use guest_cpu_has, otherwise updating the hypervisor or
processor will change the initial VMSA and any measurement derived
from there.
In fact, the same issue exists for DEBUG_SWAP and I will shortly post
a series to allow enabling/disabling DEBUG_SWAP per-VM, so that
updating the kernel does not break existing measurements.
Paolo
On Thu, Feb 1, 2024 at 4:46 PM Paolo Bonzini <[email protected]> wrote:
>
> On Wed, Dec 20, 2023 at 4:16 PM Nikunj A Dadhania <[email protected]> wrote:
>
> > + /* Setting Secure TSC parameters */
> > + if (cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) {
> > + vmsa->tsc_scale = snp_tsc_scale;
> > + vmsa->tsc_offset = snp_tsc_offset;
> > + }
>
> This needs to use guest_cpu_has, otherwise updating the hypervisor or
> processor will change the initial VMSA and any measurement derived
> from there.
>
> In fact, the same issue exists for DEBUG_SWAP and I will shortly post
> a series to allow enabling/disabling DEBUG_SWAP per-VM, so that
> updating the kernel does not break existing measurements.
Nevermind, I keep confusing guest and host-side patches.
/me goes in the corner.
Paolo
On 2/1/2024 7:37 PM, Borislav Petkov wrote:
> On Thu, Feb 01, 2024 at 04:40:10PM +0530, Nikunj A. Dadhania wrote:
>> I will move it to arch/x86/coco/sev, do we need a separate "include" directory ?
>
> I still don't understand why you need to move it at all?
>
To support Secure TSC, SNP guest messages need to be used during the early boot.
Most of the guest messaging code is currently part of sev-guest driver
and header. I have opportunistically moved the header in this patch as I was adding
guest request structure. Movement of rest of the functions implementation
from sev-guest.c => kernel/sev.c is done in patch 7/16.
As per https://lore.kernel.org/all/[email protected]/, I can move the snp
guest messaging code implementation to arch/x86/coco/sev/guest-msg.[ch]
Regards
Nikunj
On Fri, Feb 02, 2024 at 09:20:22AM +0530, Nikunj A. Dadhania wrote:
> I have opportunistically moved the header in this patch as I was
> adding guest request structure. Movement of rest of the functions
> implementation from sev-guest.c => kernel/sev.c is done in patch 7/16.
And kernel/sev.c has a corresponding header arch/x86/include/asm/sev.h
which is kinda *begging* to collect all the stuff that sev.c is
using instead of introducing a sev-guest.h thing which doesn't make
a lot of sense, TU-wise.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On 2/2/2024 9:44 PM, Borislav Petkov wrote:
> On Fri, Feb 02, 2024 at 09:20:22AM +0530, Nikunj A. Dadhania wrote:
>> I have opportunistically moved the header in this patch as I was
>> adding guest request structure. Movement of rest of the functions
>> implementation from sev-guest.c => kernel/sev.c is done in patch 7/16.
>
> And kernel/sev.c has a corresponding header arch/x86/include/asm/sev.h
> which is kinda *begging* to collect all the stuff that sev.c is
> using instead of introducing a sev-guest.h thing which doesn't make
> a lot of sense, TU-wise.
>
Sure, below is the updated patch. Complete series is pushed here
https://github.com/AMDESE/linux-kvm/commits/sectsc-guest-latest/
Subject: virt: sev-guest: Add SNP guest request structure
Add a snp_guest_req structure to simplify the function arguments. The
structure will be used to call the SNP Guest message request API
instead of passing a long list of parameters.
Update snp_issue_guest_request() prototype to include the new guest request
structure and move the prototype to sev.h.
Signed-off-by: Nikunj A Dadhania <[email protected]>
---
arch/x86/include/asm/sev.h | 75 ++++++++-
arch/x86/kernel/sev.c | 15 +-
drivers/virt/coco/sev-guest/sev-guest.c | 194 +++++++++++++-----------
drivers/virt/coco/sev-guest/sev-guest.h | 66 --------
4 files changed, 186 insertions(+), 164 deletions(-)
delete mode 100644 drivers/virt/coco/sev-guest/sev-guest.h
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 5b4a1ce3d368..56b07c79945a 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -97,8 +97,6 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
struct snp_req_data {
unsigned long req_gpa;
unsigned long resp_gpa;
- unsigned long data_gpa;
- unsigned int data_npages;
};
struct sev_guest_platform_data {
@@ -140,6 +138,73 @@ struct snp_secrets_page_layout {
u8 rsvd3[3840];
} __packed;
+#define MAX_AUTHTAG_LEN 32
+#define AUTHTAG_LEN 16
+#define AAD_LEN 48
+#define MSG_HDR_VER 1
+
+/* See SNP spec SNP_GUEST_REQUEST section for the structure */
+enum msg_type {
+ SNP_MSG_TYPE_INVALID = 0,
+ SNP_MSG_CPUID_REQ,
+ SNP_MSG_CPUID_RSP,
+ SNP_MSG_KEY_REQ,
+ SNP_MSG_KEY_RSP,
+ SNP_MSG_REPORT_REQ,
+ SNP_MSG_REPORT_RSP,
+ SNP_MSG_EXPORT_REQ,
+ SNP_MSG_EXPORT_RSP,
+ SNP_MSG_IMPORT_REQ,
+ SNP_MSG_IMPORT_RSP,
+ SNP_MSG_ABSORB_REQ,
+ SNP_MSG_ABSORB_RSP,
+ SNP_MSG_VMRK_REQ,
+ SNP_MSG_VMRK_RSP,
+
+ SNP_MSG_TYPE_MAX
+};
+
+enum aead_algo {
+ SNP_AEAD_INVALID,
+ SNP_AEAD_AES_256_GCM,
+};
+
+struct snp_guest_msg_hdr {
+ u8 authtag[MAX_AUTHTAG_LEN];
+ u64 msg_seqno;
+ u8 rsvd1[8];
+ u8 algo;
+ u8 hdr_version;
+ u16 hdr_sz;
+ u8 msg_type;
+ u8 msg_version;
+ u16 msg_sz;
+ u32 rsvd2;
+ u8 msg_vmpck;
+ u8 rsvd3[35];
+} __packed;
+
+struct snp_guest_msg {
+ struct snp_guest_msg_hdr hdr;
+ u8 payload[4000];
+} __packed;
+
+struct snp_guest_req {
+ void *req_buf;
+ size_t req_sz;
+
+ void *resp_buf;
+ size_t resp_sz;
+
+ void *data;
+ size_t data_npages;
+
+ u64 exit_code;
+ unsigned int vmpck_id;
+ u8 msg_version;
+ u8 msg_type;
+};
+
#ifdef CONFIG_AMD_MEM_ENCRYPT
extern void __sev_es_ist_enter(struct pt_regs *regs);
extern void __sev_es_ist_exit(void);
@@ -209,7 +274,8 @@ void snp_set_memory_private(unsigned long vaddr, unsigned long npages);
void snp_set_wakeup_secondary_cpu(void);
bool snp_init(struct boot_params *bp);
void __init __noreturn snp_abort(void);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio);
+int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
+ struct snp_guest_request_ioctl *rio);
void snp_accept_memory(phys_addr_t start, phys_addr_t end);
u64 snp_get_unsupported_features(u64 status);
u64 sev_get_status(void);
@@ -233,7 +299,8 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned long npa
static inline void snp_set_wakeup_secondary_cpu(void) { }
static inline bool snp_init(struct boot_params *bp) { return false; }
static inline void snp_abort(void) { }
-static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
+static inline int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
+ struct snp_guest_request_ioctl *rio)
{
return -ENOTTY;
}
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index c67285824e82..3d6429321536 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2170,7 +2170,8 @@ static int __init init_sev_config(char *str)
}
__setup("sev=", init_sev_config);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
+int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
+ struct snp_guest_request_ioctl *rio)
{
struct ghcb_state state;
struct es_em_ctxt ctxt;
@@ -2194,12 +2195,12 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct sn
vc_ghcb_invalidate(ghcb);
- if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
- ghcb_set_rax(ghcb, input->data_gpa);
- ghcb_set_rbx(ghcb, input->data_npages);
+ if (req->exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
+ ghcb_set_rax(ghcb, __pa(req->data));
+ ghcb_set_rbx(ghcb, req->data_npages);
}
- ret = sev_es_ghcb_hv_call(ghcb, &ctxt, exit_code, input->req_gpa, input->resp_gpa);
+ ret = sev_es_ghcb_hv_call(ghcb, &ctxt, req->exit_code, input->req_gpa, input->resp_gpa);
if (ret)
goto e_put;
@@ -2214,8 +2215,8 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct sn
case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN):
/* Number of expected pages are returned in RBX */
- if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
- input->data_npages = ghcb_get_rbx(ghcb);
+ if (req->exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
+ req->data_npages = ghcb_get_rbx(ghcb);
ret = -ENOSPC;
break;
}
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 0450c5383476..894f6974e192 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -28,8 +28,6 @@
#include <asm/svm.h>
#include <asm/sev.h>
-#include "sev-guest.h"
-
#define DEVICE_NAME "sev-guest"
#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
@@ -169,65 +167,64 @@ static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
return ctx;
}
-static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
+static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
{
- struct snp_guest_msg *resp = &snp_dev->secret_response;
- struct snp_guest_msg *req = &snp_dev->secret_request;
- struct snp_guest_msg_hdr *req_hdr = &req->hdr;
- struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
+ struct snp_guest_msg *resp_msg = &snp_dev->secret_response;
+ struct snp_guest_msg *req_msg = &snp_dev->secret_request;
+ struct snp_guest_msg_hdr *req_msg_hdr = &req_msg->hdr;
+ struct snp_guest_msg_hdr *resp_msg_hdr = &resp_msg->hdr;
struct aesgcm_ctx *ctx = snp_dev->ctx;
u8 iv[GCM_AES_IV_SIZE] = {};
pr_debug("response [seqno %lld type %d version %d sz %d]\n",
- resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
- resp_hdr->msg_sz);
+ resp_msg_hdr->msg_seqno, resp_msg_hdr->msg_type, resp_msg_hdr->msg_version,
+ resp_msg_hdr->msg_sz);
/* Copy response from shared memory to encrypted memory. */
- memcpy(resp, snp_dev->response, sizeof(*resp));
+ memcpy(resp_msg, snp_dev->response, sizeof(*resp_msg));
/* Verify that the sequence counter is incremented by 1 */
- if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
+ if (unlikely(resp_msg_hdr->msg_seqno != (req_msg_hdr->msg_seqno + 1)))
return -EBADMSG;
/* Verify response message type and version number. */
- if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
- resp_hdr->msg_version != req_hdr->msg_version)
+ if (resp_msg_hdr->msg_type != (req_msg_hdr->msg_type + 1) ||
+ resp_msg_hdr->msg_version != req_msg_hdr->msg_version)
return -EBADMSG;
/*
* If the message size is greater than our buffer length then return
* an error.
*/
- if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
+ if (unlikely((resp_msg_hdr->msg_sz + ctx->authsize) > req->resp_sz))
return -EBADMSG;
/* Decrypt the payload */
- memcpy(iv, &resp_hdr->msg_seqno, min(sizeof(iv), sizeof(resp_hdr->msg_seqno)));
- if (!aesgcm_decrypt(ctx, payload, resp->payload, resp_hdr->msg_sz,
- &resp_hdr->algo, AAD_LEN, iv, resp_hdr->authtag))
+ memcpy(iv, &resp_msg_hdr->msg_seqno, min(sizeof(iv), sizeof(resp_msg_hdr->msg_seqno)));
+ if (!aesgcm_decrypt(ctx, req->resp_buf, resp_msg->payload, resp_msg_hdr->msg_sz,
+ &resp_msg_hdr->algo, AAD_LEN, iv, resp_msg_hdr->authtag))
return -EBADMSG;
return 0;
}
-static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
- void *payload, size_t sz)
+static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, struct snp_guest_req *req)
{
- struct snp_guest_msg *req = &snp_dev->secret_request;
- struct snp_guest_msg_hdr *hdr = &req->hdr;
+ struct snp_guest_msg *msg = &snp_dev->secret_request;
+ struct snp_guest_msg_hdr *hdr = &msg->hdr;
struct aesgcm_ctx *ctx = snp_dev->ctx;
u8 iv[GCM_AES_IV_SIZE] = {};
- memset(req, 0, sizeof(*req));
+ memset(msg, 0, sizeof(*msg));
hdr->algo = SNP_AEAD_AES_256_GCM;
hdr->hdr_version = MSG_HDR_VER;
hdr->hdr_sz = sizeof(*hdr);
- hdr->msg_type = type;
- hdr->msg_version = version;
+ hdr->msg_type = req->msg_type;
+ hdr->msg_version = req->msg_version;
hdr->msg_seqno = seqno;
- hdr->msg_vmpck = vmpck_id;
- hdr->msg_sz = sz;
+ hdr->msg_vmpck = req->vmpck_id;
+ hdr->msg_sz = req->req_sz;
/* Verify the sequence number is non-zero */
if (!hdr->msg_seqno)
@@ -236,17 +233,17 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
pr_debug("request [seqno %lld type %d version %d sz %d]\n",
hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
- if (WARN_ON((sz + ctx->authsize) > sizeof(req->payload)))
+ if (WARN_ON((req->req_sz + ctx->authsize) > sizeof(msg->payload)))
return -EBADMSG;
memcpy(iv, &hdr->msg_seqno, min(sizeof(iv), sizeof(hdr->msg_seqno)));
- aesgcm_encrypt(ctx, req->payload, payload, sz, &hdr->algo, AAD_LEN,
- iv, hdr->authtag);
+ aesgcm_encrypt(ctx, msg->payload, req->req_buf, req->req_sz, &hdr->algo,
+ AAD_LEN, iv, hdr->authtag);
return 0;
}
-static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
+static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
struct snp_guest_request_ioctl *rio)
{
unsigned long req_start = jiffies;
@@ -261,7 +258,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
* sequence number must be incremented or the VMPCK must be deleted to
* prevent reuse of the IV.
*/
- rc = snp_issue_guest_request(exit_code, &snp_dev->input, rio);
+ rc = snp_issue_guest_request(req, &snp_dev->input, rio);
switch (rc) {
case -ENOSPC:
/*
@@ -271,8 +268,8 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
* order to increment the sequence number and thus avoid
* IV reuse.
*/
- override_npages = snp_dev->input.data_npages;
- exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+ override_npages = req->data_npages;
+ req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
/*
* Override the error to inform callers the given extended
@@ -327,15 +324,13 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
}
if (override_npages)
- snp_dev->input.data_npages = override_npages;
+ req->data_npages = override_npages;
return rc;
}
-static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
- struct snp_guest_request_ioctl *rio, u8 type,
- void *req_buf, size_t req_sz, void *resp_buf,
- u32 resp_sz)
+static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+ struct snp_guest_request_ioctl *rio)
{
u64 seqno;
int rc;
@@ -349,7 +344,7 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
/* Encrypt the userspace provided payload in snp_dev->secret_request. */
- rc = enc_payload(snp_dev, seqno, rio->msg_version, type, req_buf, req_sz);
+ rc = enc_payload(snp_dev, seqno, req);
if (rc)
return rc;
@@ -360,7 +355,7 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
memcpy(snp_dev->request, &snp_dev->secret_request,
sizeof(snp_dev->secret_request));
- rc = __handle_guest_request(snp_dev, exit_code, rio);
+ rc = __handle_guest_request(snp_dev, req, rio);
if (rc) {
if (rc == -EIO &&
rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
@@ -369,12 +364,11 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
dev_alert(snp_dev->dev,
"Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n",
rc, rio->exitinfo2);
-
snp_disable_vmpck(snp_dev);
return rc;
}
- rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
+ rc = verify_and_dec_payload(snp_dev, req);
if (rc) {
dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
snp_disable_vmpck(snp_dev);
@@ -391,8 +385,9 @@ struct snp_req_resp {
static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
- struct snp_report_req *req = &snp_dev->req.report;
- struct snp_report_resp *resp;
+ struct snp_report_req *report_req = &snp_dev->req.report;
+ struct snp_guest_req req = {0};
+ struct snp_report_resp *report_resp;
int rc, resp_len;
lockdep_assert_held(&snp_cmd_mutex);
@@ -400,7 +395,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
- if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req)))
+ if (copy_from_user(report_req, (void __user *)arg->req_data, sizeof(*report_req)))
return -EFAULT;
/*
@@ -408,29 +403,37 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp->data) + snp_dev->ctx->authsize;
- resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
- if (!resp)
+ resp_len = sizeof(report_resp->data) + snp_dev->ctx->authsize;
+ report_resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
+ if (!report_resp)
return -ENOMEM;
- rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
- SNP_MSG_REPORT_REQ, req, sizeof(*req), resp->data,
- resp_len);
+ req.msg_version = arg->msg_version;
+ req.msg_type = SNP_MSG_REPORT_REQ;
+ req.vmpck_id = vmpck_id;
+ req.req_buf = report_req;
+ req.req_sz = sizeof(*report_req);
+ req.resp_buf = report_resp->data;
+ req.resp_sz = resp_len;
+ req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ rc = snp_send_guest_request(snp_dev, &req, arg);
if (rc)
goto e_free;
- if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
+ if (copy_to_user((void __user *)arg->resp_data, report_resp, sizeof(*report_resp)))
rc = -EFAULT;
e_free:
- kfree(resp);
+ kfree(report_resp);
return rc;
}
static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
- struct snp_derived_key_req *req = &snp_dev->req.derived_key;
- struct snp_derived_key_resp resp = {0};
+ struct snp_derived_key_req *derived_key_req = &snp_dev->req.derived_key;
+ struct snp_derived_key_resp derived_key_resp = {0};
+ struct snp_guest_req req = {0};
int rc, resp_len;
/* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
u8 buf[64 + 16];
@@ -445,25 +448,34 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp.data) + snp_dev->ctx->authsize;
+ resp_len = sizeof(derived_key_resp.data) + snp_dev->ctx->authsize;
if (sizeof(buf) < resp_len)
return -ENOMEM;
- if (copy_from_user(req, (void __user *)arg->req_data, sizeof(*req)))
+ if (copy_from_user(derived_key_req, (void __user *)arg->req_data,
+ sizeof(*derived_key_req)))
return -EFAULT;
- rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
- SNP_MSG_KEY_REQ, req, sizeof(*req), buf, resp_len);
+ req.msg_version = arg->msg_version;
+ req.msg_type = SNP_MSG_KEY_REQ;
+ req.vmpck_id = vmpck_id;
+ req.req_buf = derived_key_req;
+ req.req_sz = sizeof(*derived_key_req);
+ req.resp_buf = buf;
+ req.resp_sz = resp_len;
+ req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ rc = snp_send_guest_request(snp_dev, &req, arg);
if (rc)
return rc;
- memcpy(resp.data, buf, sizeof(resp.data));
- if (copy_to_user((void __user *)arg->resp_data, &resp, sizeof(resp)))
+ memcpy(derived_key_resp.data, buf, sizeof(derived_key_resp.data));
+ if (copy_to_user((void __user *)arg->resp_data, &derived_key_resp, sizeof(derived_key_resp)))
rc = -EFAULT;
/* The response buffer contains the sensitive data, explicitly clear it. */
memzero_explicit(buf, sizeof(buf));
- memzero_explicit(&resp, sizeof(resp));
+ memzero_explicit(&derived_key_resp, sizeof(derived_key_resp));
return rc;
}
@@ -471,32 +483,33 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
struct snp_req_resp *io)
{
- struct snp_ext_report_req *req = &snp_dev->req.ext_report;
- struct snp_report_resp *resp;
- int ret, npages = 0, resp_len;
+ struct snp_ext_report_req *report_req = &snp_dev->req.ext_report;
+ struct snp_guest_req req = {0};
+ struct snp_report_resp *report_resp;
sockptr_t certs_address;
+ int ret, resp_len;
lockdep_assert_held(&snp_cmd_mutex);
if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data))
return -EINVAL;
- if (copy_from_sockptr(req, io->req_data, sizeof(*req)))
+ if (copy_from_sockptr(report_req, io->req_data, sizeof(*report_req)))
return -EFAULT;
/* caller does not want certificate data */
- if (!req->certs_len || !req->certs_address)
+ if (!report_req->certs_len || !report_req->certs_address)
goto cmd;
- if (req->certs_len > SEV_FW_BLOB_MAX_SIZE ||
- !IS_ALIGNED(req->certs_len, PAGE_SIZE))
+ if (report_req->certs_len > SEV_FW_BLOB_MAX_SIZE ||
+ !IS_ALIGNED(report_req->certs_len, PAGE_SIZE))
return -EINVAL;
if (sockptr_is_kernel(io->resp_data)) {
- certs_address = KERNEL_SOCKPTR((void *)req->certs_address);
+ certs_address = KERNEL_SOCKPTR((void *)report_req->certs_address);
} else {
- certs_address = USER_SOCKPTR((void __user *)req->certs_address);
- if (!access_ok(certs_address.user, req->certs_len))
+ certs_address = USER_SOCKPTR((void __user *)report_req->certs_address);
+ if (!access_ok(certs_address.user, report_req->certs_len))
return -EFAULT;
}
@@ -506,45 +519,53 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
* the host. If host does not supply any certs in it, then copy
* zeros to indicate that certificate data was not provided.
*/
- memset(snp_dev->certs_data, 0, req->certs_len);
- npages = req->certs_len >> PAGE_SHIFT;
+ memset(snp_dev->certs_data, 0, report_req->certs_len);
+ req.data_npages = report_req->certs_len >> PAGE_SHIFT;
cmd:
/*
* The intermediate response buffer is used while decrypting the
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp->data) + snp_dev->ctx->authsize;
- resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
- if (!resp)
+ resp_len = sizeof(report_resp->data) + snp_dev->ctx->authsize;
+ report_resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
+ if (!report_resp)
return -ENOMEM;
- snp_dev->input.data_npages = npages;
- ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg,
- SNP_MSG_REPORT_REQ, &req->data,
- sizeof(req->data), resp->data, resp_len);
+ req.msg_version = arg->msg_version;
+ req.msg_type = SNP_MSG_REPORT_REQ;
+ req.vmpck_id = vmpck_id;
+ req.req_buf = &report_req->data;
+ req.req_sz = sizeof(report_req->data);
+ req.resp_buf = report_resp->data;
+ req.resp_sz = resp_len;
+ req.exit_code = SVM_VMGEXIT_EXT_GUEST_REQUEST;
+ req.data = snp_dev->certs_data;
+
+ ret = snp_send_guest_request(snp_dev, &req, arg);
/* If certs length is invalid then copy the returned length */
if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) {
- req->certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
+ report_req->certs_len = req.data_npages << PAGE_SHIFT;
- if (copy_to_sockptr(io->req_data, req, sizeof(*req)))
+ if (copy_to_sockptr(io->req_data, report_req, sizeof(*report_req)))
ret = -EFAULT;
}
if (ret)
goto e_free;
- if (npages && copy_to_sockptr(certs_address, snp_dev->certs_data, req->certs_len)) {
+ if (req.data_npages && report_req->certs_len &&
+ copy_to_sockptr(certs_address, snp_dev->certs_data, report_req->certs_len)) {
ret = -EFAULT;
goto e_free;
}
- if (copy_to_sockptr(io->resp_data, resp, sizeof(*resp)))
+ if (copy_to_sockptr(io->resp_data, report_resp, sizeof(*report_resp)))
ret = -EFAULT;
e_free:
- kfree(resp);
+ kfree(report_resp);
return ret;
}
@@ -868,7 +889,6 @@ static int __init sev_guest_probe(struct platform_device *pdev)
/* initial the input address for guest request */
snp_dev->input.req_gpa = __pa(snp_dev->request);
snp_dev->input.resp_gpa = __pa(snp_dev->response);
- snp_dev->input.data_gpa = __pa(snp_dev->certs_data);
ret = tsm_register(&sev_tsm_ops, snp_dev, &tsm_report_extra_type);
if (ret)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/drivers/virt/coco/sev-guest/sev-guest.h
deleted file mode 100644
index ceb798a404d6..000000000000
--- a/drivers/virt/coco/sev-guest/sev-guest.h
+++ /dev/null
@@ -1,66 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2021 Advanced Micro Devices, Inc.
- *
- * Author: Brijesh Singh <[email protected]>
- *
- * SEV-SNP API spec is available at https://developer.amd.com/sev
- */
-
-#ifndef __VIRT_SEVGUEST_H__
-#define __VIRT_SEVGUEST_H__
-
-#include <linux/types.h>
-
-#define MAX_AUTHTAG_LEN 32
-#define AUTHTAG_LEN 16
-#define AAD_LEN 48
-#define MSG_HDR_VER 1
-
-/* See SNP spec SNP_GUEST_REQUEST section for the structure */
-enum msg_type {
- SNP_MSG_TYPE_INVALID = 0,
- SNP_MSG_CPUID_REQ,
- SNP_MSG_CPUID_RSP,
- SNP_MSG_KEY_REQ,
- SNP_MSG_KEY_RSP,
- SNP_MSG_REPORT_REQ,
- SNP_MSG_REPORT_RSP,
- SNP_MSG_EXPORT_REQ,
- SNP_MSG_EXPORT_RSP,
- SNP_MSG_IMPORT_REQ,
- SNP_MSG_IMPORT_RSP,
- SNP_MSG_ABSORB_REQ,
- SNP_MSG_ABSORB_RSP,
- SNP_MSG_VMRK_REQ,
- SNP_MSG_VMRK_RSP,
-
- SNP_MSG_TYPE_MAX
-};
-
-enum aead_algo {
- SNP_AEAD_INVALID,
- SNP_AEAD_AES_256_GCM,
-};
-
-struct snp_guest_msg_hdr {
- u8 authtag[MAX_AUTHTAG_LEN];
- u64 msg_seqno;
- u8 rsvd1[8];
- u8 algo;
- u8 hdr_version;
- u16 hdr_sz;
- u8 msg_type;
- u8 msg_version;
- u16 msg_sz;
- u32 rsvd2;
- u8 msg_vmpck;
- u8 rsvd3[35];
-} __packed;
-
-struct snp_guest_msg {
- struct snp_guest_msg_hdr hdr;
- u8 payload[4000];
-} __packed;
-
-#endif /* __VIRT_SEVGUEST_H__ */
--
2.34.1
On Mon, Feb 05, 2024 at 02:53:30PM +0530, Nikunj A. Dadhania wrote:
> Sure, below is the updated patch. Complete series is pushed here
>
> https://github.com/AMDESE/linux-kvm/commits/sectsc-guest-latest/
Yap, that looks more like it.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette