[PATCH v4 02/14] virt: sev-guest: Move mutex to SNP guest device structure

From: Nikunj A Dadhania
Date: Mon Aug 14 2023 - 01:54:10 EST


In preparation for providing a new API to the sev-guest driver for sending
an SNP guest message, move the SNP command mutex to the snp_guest_dev
structure.

Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx>
Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
drivers/virt/coco/sev-guest/sev-guest.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 520e2b6613a7..8ba624088d73 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -35,6 +35,9 @@ struct snp_guest_dev {
struct device *dev;
struct miscdevice misc;

+ /* Mutex to serialize the shared buffer access and command handling. */
+ struct mutex cmd_mutex;
+
void *certs_data;
struct aesgcm_ctx *ctx;
/* request and response are in unencrypted memory */
@@ -56,9 +59,6 @@ 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 unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
{
if (snp_dev && snp_dev->ctx)
@@ -107,7 +107,7 @@ static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
{
u64 count;

- lockdep_assert_held(&snp_cmd_mutex);
+ lockdep_assert_held(&snp_dev->cmd_mutex);

/* Read the current message sequence counter from secrets pages */
count = *snp_dev->os_area_msg_seqno;
@@ -403,7 +403,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
struct snp_report_req req;
int rc, resp_len;

- lockdep_assert_held(&snp_cmd_mutex);
+ lockdep_assert_held(&snp_dev->cmd_mutex);

if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -443,7 +443,7 @@ 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);
+ lockdep_assert_held(&snp_dev->cmd_mutex);

if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -481,7 +481,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
struct snp_report_resp *resp;
int ret, npages = 0, resp_len;

- lockdep_assert_held(&snp_cmd_mutex);
+ lockdep_assert_held(&snp_dev->cmd_mutex);

if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -566,12 +566,12 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
if (!input.msg_version)
return -EINVAL;

- mutex_lock(&snp_cmd_mutex);
+ mutex_lock(&snp_dev->cmd_mutex);

/* Check if the VMPCK is not empty */
if (is_vmpck_empty(snp_dev)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
- mutex_unlock(&snp_cmd_mutex);
+ mutex_unlock(&snp_dev->cmd_mutex);
return -ENOTTY;
}

@@ -589,7 +589,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
break;
}

- mutex_unlock(&snp_cmd_mutex);
+ mutex_unlock(&snp_dev->cmd_mutex);

if (input.exitinfo2 && copy_to_user(argp, &input, sizeof(input)))
return -EFAULT;
@@ -708,6 +708,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
goto e_unmap;
}

+ mutex_init(&snp_dev->cmd_mutex);
platform_set_drvdata(pdev, snp_dev);
snp_dev->dev = dev;
snp_dev->layout = layout;
--
2.34.1