Messages in this thread Patch in this message | | | From | Nikunj A Dadhania <> | Subject | [PATCH v3 05/14] virt: sev-guest: Add vmpck_id to snp_guest_dev struct | Date | Sat, 22 Jul 2023 16:49:00 +0530 |
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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.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> --- drivers/virt/coco/sev-guest/sev-guest.c | 84 +++++++++++++------------ 1 file changed, 43 insertions(+), 41 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index d4241048b397..8ad43e007d3b 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -50,8 +50,7 @@ struct snp_guest_dev { struct snp_secrets_page_layout *layout; struct snp_req_data input; - u32 *os_area_msg_seqno; - u8 *vmpck; + unsigned int vmpck_id; }; static u32 vmpck_id; @@ -67,12 +66,23 @@ static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev) return 0; } -static bool is_vmpck_empty(struct snp_guest_dev *snp_dev) +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); - if (snp_dev->vmpck) - return !memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN); + if (key) + return !memcmp(key, zero_key, VMPCK_KEY_LEN); return true; } @@ -96,20 +106,22 @@ static bool is_vmpck_empty(struct snp_guest_dev *snp_dev) */ 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 %d to prevent IV reuse.\n", - vmpck_id); - memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN); - snp_dev->vmpck = NULL; + 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_dev->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 +149,13 @@ 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 +165,22 @@ 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("SNP: vmpck id %d is null\n", snp_dev->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("SNP: crypto init failed\n"); kfree(ctx); return NULL; @@ -606,7 +627,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long mutex_lock(&snp_dev->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_dev->cmd_mutex); return -ENOTTY; @@ -676,32 +697,14 @@ 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, int vmpck_id) { - u8 *key = NULL; + if (WARN_ON(vmpck_id > 3)) + 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; } static int __init sev_guest_probe(struct platform_device *pdev) @@ -733,14 +736,14 @@ 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) { + snp_dev->layout = layout; + if (!snp_assign_vmpck(snp_dev, vmpck_id)) { dev_err(dev, "invalid vmpck id %d\n", vmpck_id); goto e_unmap; } /* Verify that VMPCK is not zero. */ - if (is_vmpck_empty(snp_dev)) { + if (snp_is_vmpck_empty(snp_dev)) { dev_err(dev, "vmpck id %d is null\n", vmpck_id); goto e_unmap; } @@ -748,7 +751,6 @@ static int __init sev_guest_probe(struct platform_device *pdev) mutex_init(&snp_dev->cmd_mutex); 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)); @@ -764,7 +766,7 @@ 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; -- 2.34.1
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