[PATCH v9 13/24] x86/sev: Make sev-guest driver functional again

Nikunj A Dadhania
2024-05-31T04:34:01Z

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