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-rw-r--r--drivers/virt/coco/sev-guest/sev-guest.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 81a53c31ff46..46f1a8d558b0 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -31,6 +31,9 @@
#define AAD_LEN 48
#define MSG_HDR_VER 1
+#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
+#define SNP_REQ_RETRY_DELAY (2*HZ)
+
struct snp_guest_crypto {
struct crypto_aead *tfm;
u8 *iv, *authtag;
@@ -320,7 +323,8 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
{
- unsigned long err, override_err = 0;
+ unsigned long err = 0xff, override_err = 0;
+ unsigned long req_start = jiffies;
unsigned int override_npages = 0;
int rc;
@@ -360,6 +364,19 @@ retry_request:
* user as an ioctl() return code.
*/
goto retry_request;
+
+ /*
+ * The host may return SNP_GUEST_REQ_ERR_EBUSY if the request has been
+ * throttled. Retry in the driver to avoid returning and reusing the
+ * message sequence number on a different message.
+ */
+ case -EAGAIN:
+ if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) {
+ rc = -ETIMEDOUT;
+ break;
+ }
+ schedule_timeout_killable(SNP_REQ_RETRY_DELAY);
+ goto retry_request;
}
/*