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From: Nikunj A Dadhania <nikunj@amd.com>
To: <linux-kernel@vger.kernel.org>, <thomas.lendacky@amd.com>, <bp@alien8.de>,
	<x86@kernel.org>, <kvm@vger.kernel.org>
CC: <mingo@redhat.com>, <tglx@linutronix.de>, <dave.hansen@linux.intel.com>,
	<pgonda@google.com>, <seanjc@google.com>, <pbonzini@redhat.com>,
	<nikunj@amd.com>
Subject: [PATCH v9 13/24] x86/sev: Make sev-guest driver functional again
Date: Fri, 31 May 2024 10:00:27 +0530
Message-ID: <20240531043038.3370793-14-nikunj@amd.com>
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After the pure mechanical code movement of core SEV guest driver routines,
SEV guest driver is not yet functional. Export SNP guest messaging APIs for
the sev-guest driver. Drop the stubbed routines in sev-guest driver and use
the newly exported APIs

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
 arch/x86/include/asm/sev.h              | 14 ++++++++++
 arch/x86/kernel/sev.c                   | 23 +++++++++------
 drivers/virt/coco/sev-guest/sev-guest.c | 37 ++-----------------------
 3 files changed, 31 insertions(+), 43 deletions(-)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 109185daff2c..f58052fd6cb3 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -322,6 +322,12 @@ 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 sev_show_status(void);
+bool snp_assign_vmpck(struct snp_guest_dev *snp_dev, unsigned int vmpck_id);
+bool snp_is_vmpck_empty(struct snp_guest_dev *snp_dev);
+int snp_guest_messaging_init(struct snp_guest_dev *snp_dev, u64 secrets_gpa);
+void snp_guest_messaging_exit(struct snp_guest_dev *snp_dev);
+int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+			   struct snp_guest_request_ioctl *rio);
 
 static inline void free_shared_pages(void *buf, size_t sz)
 {
@@ -384,6 +390,14 @@ 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 sev_show_status(void) { }
+static inline bool snp_assign_vmpck(struct snp_guest_dev *snp_dev,
+				    unsigned int vmpck_id) { return false; }
+static inline bool snp_is_vmpck_empty(struct snp_guest_dev *snp_dev) { return true; }
+static inline int
+snp_guest_messaging_init(struct snp_guest_dev *snp_dev, u64 secrets_gpa) { return -EINVAL; }
+static inline void snp_guest_messaging_exit(struct snp_guest_dev *snp_dev) { }
+static inline int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
+					 struct snp_guest_request_ioctl *rio) { return -EINVAL; }
 static inline void free_shared_pages(void *buf, size_t sz) { }
 static inline void *alloc_shared_pages(size_t sz) { return NULL; }
 #endif
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index c2508809d4e2..878575b05b2d 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2309,7 +2309,7 @@ static inline u8 *get_vmpck(struct snp_guest_dev *snp_dev)
 	return snp_dev->secrets->vmpck[snp_dev->vmpck_id];
 }
 
-static bool __maybe_unused assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id)
+bool snp_assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id)
 {
 	if ((vmpck_id + 1) > VMPCK_MAX_NUM)
 		return false;
@@ -2318,14 +2318,16 @@ static bool __maybe_unused assign_vmpck(struct snp_guest_dev *dev, unsigned int
 
 	return true;
 }
+EXPORT_SYMBOL_GPL(snp_assign_vmpck);
 
-static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
+bool snp_is_vmpck_empty(struct snp_guest_dev *snp_dev)
 {
 	char zero_key[VMPCK_KEY_LEN] = {0};
 	u8 *key = get_vmpck(snp_dev);
 
 	return !memcmp(key, zero_key, VMPCK_KEY_LEN);
 }
+EXPORT_SYMBOL_GPL(snp_is_vmpck_empty);
 
 /*
  * If an error is received from the host or AMD Secure Processor (ASP) there
@@ -2348,7 +2350,7 @@ static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
 {
 	u8 *key = get_vmpck(snp_dev);
 
-	if (is_vmpck_empty(snp_dev))
+	if (snp_is_vmpck_empty(snp_dev))
 		return;
 
 	pr_alert("Disabling VMPCK%u to prevent IV reuse.\n", snp_dev->vmpck_id);
@@ -2392,7 +2394,7 @@ static struct aesgcm_ctx *snp_init_crypto(struct snp_guest_dev *snp_dev)
 	struct aesgcm_ctx *ctx;
 	u8 *key;
 
-	if (is_vmpck_empty(snp_dev)) {
+	if (snp_is_vmpck_empty(snp_dev)) {
 		pr_err("VM communication key VMPCK%u is invalid\n", snp_dev->vmpck_id);
 		return NULL;
 	}
@@ -2573,9 +2575,9 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues
 	return rc;
 }
 
-static int __maybe_unused snp_send_guest_request(struct snp_guest_dev *snp_dev,
-						 struct snp_guest_req *req,
-						 struct snp_guest_request_ioctl *rio)
+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;
@@ -2622,8 +2624,9 @@ static int __maybe_unused snp_send_guest_request(struct snp_guest_dev *snp_dev,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(snp_send_guest_request);
 
-static int __maybe_unused snp_guest_messaging_init(struct snp_guest_dev *snp_dev, u64 secrets_gpa)
+int snp_guest_messaging_init(struct snp_guest_dev *snp_dev, u64 secrets_gpa)
 {
 	int ret = -ENOMEM;
 
@@ -2677,8 +2680,9 @@ static int __maybe_unused snp_guest_messaging_init(struct snp_guest_dev *snp_dev
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(snp_guest_messaging_init);
 
-static void __maybe_unused snp_guest_messaging_exit(struct snp_guest_dev *snp_dev)
+void snp_guest_messaging_exit(struct snp_guest_dev *snp_dev)
 {
 	if (!snp_dev)
 		return;
@@ -2690,3 +2694,4 @@ static void __maybe_unused snp_guest_messaging_exit(struct snp_guest_dev *snp_de
 	kfree(snp_dev->secret_request);
 	iounmap(snp_dev->secrets);
 }
+EXPORT_SYMBOL_GPL(snp_guest_messaging_exit);
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 567b3684eae5..41878bd968d5 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -34,12 +34,6 @@ 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.");
 
-static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
-{
-	/* Place holder function to be removed after code movement */
-	return true;
-}
-
 static inline struct snp_guest_dev *to_snp_dev(struct file *file)
 {
 	struct miscdevice *dev = file->private_data;
@@ -47,13 +41,6 @@ static inline struct snp_guest_dev *to_snp_dev(struct file *file)
 	return container_of(dev, struct snp_guest_dev, misc);
 }
 
-static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req,
-				  struct snp_guest_request_ioctl *rio)
-{
-	/* Place holder function to be removed after code movement */
-	return -EIO;
-}
-
 struct snp_req_resp {
 	sockptr_t req_data;
 	sockptr_t resp_data;
@@ -258,7 +245,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
 		return -EINVAL;
 
 	/* 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;
 	}
@@ -295,12 +282,6 @@ static const struct file_operations snp_guest_fops = {
 	.unlocked_ioctl = snp_guest_ioctl,
 };
 
-static bool assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id)
-{
-	/* Place holder function to be removed after code movement */
-	return false;
-}
-
 struct snp_msg_report_resp_hdr {
 	u32 status;
 	u32 report_size;
@@ -332,7 +313,7 @@ static int sev_report_new(struct tsm_report *report, void *data)
 		return -ENOMEM;
 
 	/* 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;
 	}
@@ -423,18 +404,6 @@ static void unregister_sev_tsm(void *data)
 	tsm_unregister(&sev_tsm_ops);
 }
 
-static int snp_guest_messaging_init(struct snp_guest_dev *snp_dev, u64 secrets_gpa)
-{
-	/* Place holder function to be removed after code movement */
-	return 0;
-}
-
-static void snp_guest_messaging_exit(struct snp_guest_dev *snp_dev)
-{
-	/* Place holder function to be removed after code movement */
-	return;
-}
-
 static int __init sev_guest_probe(struct platform_device *pdev)
 {
 	struct sev_guest_platform_data *data;
@@ -456,7 +425,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	ret = -EINVAL;
-	if (!assign_vmpck(snp_dev, vmpck_id)) {
+	if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
 		dev_err(dev, "Invalid VMPCK%d communication key\n", vmpck_id);
 		return ret;
 	}
-- 
2.34.1