2024-03-25 18:08:47

by Kirill A. Shutemov

[permalink] [raw]
Subject: [PATCHv9 06/17] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno

TDX is going to have more than one reason to fail
enc_status_change_prepare().

Change the callback to return errno instead of assuming -EIO;
enc_status_change_finish() changed too to keep the interface symmetric.

Signed-off-by: Kirill A. Shutemov <[email protected]>
Reviewed-by: Dave Hansen <[email protected]>
---
arch/x86/coco/tdx/tdx.c | 20 +++++++++++---------
arch/x86/hyperv/ivm.c | 9 +++------
arch/x86/include/asm/x86_init.h | 4 ++--
arch/x86/kernel/x86_init.c | 4 ++--
arch/x86/mm/mem_encrypt_amd.c | 8 ++++----
arch/x86/mm/pat/set_memory.c | 8 +++++---
6 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index c1cb90369915..26fa47db5782 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -798,28 +798,30 @@ static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc)
return true;
}

-static bool tdx_enc_status_change_prepare(unsigned long vaddr, int numpages,
- bool enc)
+static int tdx_enc_status_change_prepare(unsigned long vaddr, int numpages,
+ bool enc)
{
/*
* Only handle shared->private conversion here.
* See the comment in tdx_early_init().
*/
- if (enc)
- return tdx_enc_status_changed(vaddr, numpages, enc);
- return true;
+ if (enc && !tdx_enc_status_changed(vaddr, numpages, enc))
+ return -EIO;
+
+ return 0;
}

-static bool tdx_enc_status_change_finish(unsigned long vaddr, int numpages,
+static int tdx_enc_status_change_finish(unsigned long vaddr, int numpages,
bool enc)
{
/*
* Only handle private->shared conversion here.
* See the comment in tdx_early_init().
*/
- if (!enc)
- return tdx_enc_status_changed(vaddr, numpages, enc);
- return true;
+ if (!enc && !tdx_enc_status_changed(vaddr, numpages, enc))
+ return -EIO;
+
+ return 0;
}

void __init tdx_early_init(void)
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 768d73de0d09..870b82fce5ce 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -536,7 +536,7 @@ static bool hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc
* with host. This function works as wrap of hv_mark_gpa_visibility()
* with memory base and size.
*/
-static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
+static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
{
enum hv_mem_host_visibility visibility = enc ?
VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
@@ -544,7 +544,6 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
phys_addr_t paddr;
void *vaddr;
int ret = 0;
- bool result = true;
int i, pfn;

pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
@@ -568,10 +567,8 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
ret = hv_mark_gpa_visibility(pfn, pfn_array,
visibility);
- if (ret) {
- result = false;
+ if (ret)
goto err_free_pfn_array;
- }
pfn = 0;
}
}
@@ -589,7 +586,7 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
if (set_memory_p(kbuffer, pagecount))
result = false;

- return result;
+ return ret;
}

static bool hv_vtom_tlb_flush_required(bool private)
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index b89b40f250e6..4770af4d6015 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -150,8 +150,8 @@ struct x86_init_acpi {
* @enc_cache_flush_required Returns true if a cache flush is needed before changing page encryption status
*/
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);
+ int (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
+ int (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
bool (*enc_tlb_flush_required)(bool enc);
bool (*enc_cache_flush_required)(void);
};
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index a42830dc151b..69413ca37bfe 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -132,8 +132,8 @@ struct x86_cpuinit_ops x86_cpuinit = {

static void default_nmi_init(void) { };

-static bool enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { return true; }
-static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return true; }
+static int enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { return 0; }
+static int enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return 0; }
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; }
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 70b91de2e053..d314e577836d 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -283,7 +283,7 @@ static void enc_dec_hypercall(unsigned long vaddr, unsigned long size, bool enc)
#endif
}

-static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
+static int amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
{
/*
* To maintain the security guarantees of SEV-SNP guests, make sure
@@ -292,11 +292,11 @@ static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool
if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !enc)
snp_set_memory_shared(vaddr, npages);

- return true;
+ return 0;
}

/* Return true unconditionally: return value doesn't matter for the SEV side */
-static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
+static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
{
/*
* After memory is mapped encrypted in the page table, validate it
@@ -308,7 +308,7 @@ static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool e
if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
enc_dec_hypercall(vaddr, npages << PAGE_SHIFT, enc);

- return true;
+ return 0;
}

static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 80c9037ffadf..e5b454036bf3 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2156,7 +2156,8 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
cpa_flush(&cpa, x86_platform.guest.enc_cache_flush_required());

/* Notify hypervisor that we are about to set/clr encryption attribute. */
- if (!x86_platform.guest.enc_status_change_prepare(addr, numpages, enc))
+ ret = x86_platform.guest.enc_status_change_prepare(addr, numpages, enc);
+ if (ret)
goto vmm_fail;

ret = __change_page_attr_set_clr(&cpa, 1);
@@ -2174,7 +2175,8 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
return ret;

/* Notify hypervisor that we have successfully set/clr encryption attribute. */
- if (!x86_platform.guest.enc_status_change_finish(addr, numpages, enc))
+ ret = x86_platform.guest.enc_status_change_finish(addr, numpages, enc);
+ if (ret)
goto vmm_fail;

return 0;
@@ -2183,7 +2185,7 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
WARN_ONCE(1, "CPA VMM failure to convert memory (addr=%p, numpages=%d) to %s.\n",
(void *)addr, numpages, enc ? "private" : "shared");

- return -EIO;
+ return ret;
}

static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
--
2.43.0



2024-03-26 10:33:22

by Huang, Kai

[permalink] [raw]
Subject: Re: [PATCHv9 06/17] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno

On Mon, 2024-03-25 at 12:39 +0200, Kirill A. Shutemov wrote:
> TDX is going to have more than one reason to fail
> enc_status_change_prepare().
>
> Change the callback to return errno instead of assuming -EIO;
> enc_status_change_finish() changed too to keep the interface symmetric.
>
> Signed-off-by: Kirill A. Shutemov <[email protected]>
> Reviewed-by: Dave Hansen <[email protected]>
>

Reviewed-by: Kai Huang <[email protected]>

2024-03-27 14:10:17

by Kirill A. Shutemov

[permalink] [raw]
Subject: [PATCHv9.1 06/17] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno

TDX is going to have more than one reason to fail
enc_status_change_prepare().

Change the callback to return errno instead of assuming -EIO;
enc_status_change_finish() changed too to keep the interface symmetric.

Signed-off-by: Kirill A. Shutemov <[email protected]>
Reviewed-by: Dave Hansen <[email protected]>
Reviewed-by: Kai Huang <[email protected]>
Tested-by: Tao Liu <[email protected]>
---
v9.1:
- Fix build error in Hyper-V code after rebase;
---
arch/x86/coco/tdx/tdx.c | 20 +++++++++++---------
arch/x86/hyperv/ivm.c | 22 ++++++++++------------
arch/x86/include/asm/x86_init.h | 4 ++--
arch/x86/kernel/x86_init.c | 4 ++--
arch/x86/mm/mem_encrypt_amd.c | 8 ++++----
arch/x86/mm/pat/set_memory.c | 8 +++++---
6 files changed, 34 insertions(+), 32 deletions(-)

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index c1cb90369915..26fa47db5782 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -798,28 +798,30 @@ static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc)
return true;
}

-static bool tdx_enc_status_change_prepare(unsigned long vaddr, int numpages,
- bool enc)
+static int tdx_enc_status_change_prepare(unsigned long vaddr, int numpages,
+ bool enc)
{
/*
* Only handle shared->private conversion here.
* See the comment in tdx_early_init().
*/
- if (enc)
- return tdx_enc_status_changed(vaddr, numpages, enc);
- return true;
+ if (enc && !tdx_enc_status_changed(vaddr, numpages, enc))
+ return -EIO;
+
+ return 0;
}

-static bool tdx_enc_status_change_finish(unsigned long vaddr, int numpages,
+static int tdx_enc_status_change_finish(unsigned long vaddr, int numpages,
bool enc)
{
/*
* Only handle private->shared conversion here.
* See the comment in tdx_early_init().
*/
- if (!enc)
- return tdx_enc_status_changed(vaddr, numpages, enc);
- return true;
+ if (!enc && !tdx_enc_status_changed(vaddr, numpages, enc))
+ return -EIO;
+
+ return 0;
}

void __init tdx_early_init(void)
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 768d73de0d09..b4a851d27c7c 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -523,9 +523,9 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
* transition is complete, hv_vtom_set_host_visibility() marks the pages
* as "present" again.
*/
-static bool hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc)
+static int hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc)
{
- return !set_memory_np(kbuffer, pagecount);
+ return set_memory_np(kbuffer, pagecount);
}

/*
@@ -536,20 +536,19 @@ static bool hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc
* with host. This function works as wrap of hv_mark_gpa_visibility()
* with memory base and size.
*/
-static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
+static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
{
enum hv_mem_host_visibility visibility = enc ?
VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
u64 *pfn_array;
phys_addr_t paddr;
+ int i, pfn, err;
void *vaddr;
int ret = 0;
- bool result = true;
- int i, pfn;

pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
if (!pfn_array) {
- result = false;
+ ret = -ENOMEM;
goto err_set_memory_p;
}

@@ -568,10 +567,8 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
ret = hv_mark_gpa_visibility(pfn, pfn_array,
visibility);
- if (ret) {
- result = false;
+ if (ret)
goto err_free_pfn_array;
- }
pfn = 0;
}
}
@@ -586,10 +583,11 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
* order to avoid leaving the memory range in a "broken" state. Setting
* the PRESENT bits shouldn't fail, but return an error if it does.
*/
- if (set_memory_p(kbuffer, pagecount))
- result = false;
+ err = set_memory_p(kbuffer, pagecount);
+ if (err && !ret)
+ ret = err;

- return result;
+ return ret;
}

static bool hv_vtom_tlb_flush_required(bool private)
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index b89b40f250e6..4770af4d6015 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -150,8 +150,8 @@ struct x86_init_acpi {
* @enc_cache_flush_required Returns true if a cache flush is needed before changing page encryption status
*/
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);
+ int (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
+ int (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
bool (*enc_tlb_flush_required)(bool enc);
bool (*enc_cache_flush_required)(void);
};
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index a42830dc151b..69413ca37bfe 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -132,8 +132,8 @@ struct x86_cpuinit_ops x86_cpuinit = {

static void default_nmi_init(void) { };

-static bool enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { return true; }
-static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return true; }
+static int enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { return 0; }
+static int enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return 0; }
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; }
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 70b91de2e053..d314e577836d 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -283,7 +283,7 @@ static void enc_dec_hypercall(unsigned long vaddr, unsigned long size, bool enc)
#endif
}

-static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
+static int amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
{
/*
* To maintain the security guarantees of SEV-SNP guests, make sure
@@ -292,11 +292,11 @@ static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool
if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !enc)
snp_set_memory_shared(vaddr, npages);

- return true;
+ return 0;
}

/* Return true unconditionally: return value doesn't matter for the SEV side */
-static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
+static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
{
/*
* After memory is mapped encrypted in the page table, validate it
@@ -308,7 +308,7 @@ static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool e
if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
enc_dec_hypercall(vaddr, npages << PAGE_SHIFT, enc);

- return true;
+ return 0;
}

static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 80c9037ffadf..e5b454036bf3 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2156,7 +2156,8 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
cpa_flush(&cpa, x86_platform.guest.enc_cache_flush_required());

/* Notify hypervisor that we are about to set/clr encryption attribute. */
- if (!x86_platform.guest.enc_status_change_prepare(addr, numpages, enc))
+ ret = x86_platform.guest.enc_status_change_prepare(addr, numpages, enc);
+ if (ret)
goto vmm_fail;

ret = __change_page_attr_set_clr(&cpa, 1);
@@ -2174,7 +2175,8 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
return ret;

/* Notify hypervisor that we have successfully set/clr encryption attribute. */
- if (!x86_platform.guest.enc_status_change_finish(addr, numpages, enc))
+ ret = x86_platform.guest.enc_status_change_finish(addr, numpages, enc);
+ if (ret)
goto vmm_fail;

return 0;
@@ -2183,7 +2185,7 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
WARN_ONCE(1, "CPA VMM failure to convert memory (addr=%p, numpages=%d) to %s.\n",
(void *)addr, numpages, enc ? "private" : "shared");

- return -EIO;
+ return ret;
}

static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
--
2.43.0