diff options
| -rw-r--r-- | arch/x86/include/asm/sev-common.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/sev.c | 4 | ||||
| -rw-r--r-- | drivers/virt/coco/sev-guest/sev-guest.c | 19 |
3 files changed, 24 insertions, 2 deletions
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index b8357d6ecd47..b63be696b776 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -128,8 +128,9 @@ struct snp_psc_desc { struct psc_entry entries[VMGEXIT_PSC_MAX_ENTRY]; } __packed; -/* Guest message request error code */ +/* Guest message request error codes */ #define SNP_GUEST_REQ_INVALID_LEN BIT_ULL(32) +#define SNP_GUEST_REQ_ERR_BUSY BIT_ULL(33) #define GHCB_MSR_TERM_REQ 0x100 #define GHCB_MSR_TERM_REASON_SET_POS 12 diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 55df10e97456..c680ac6342bb 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2214,6 +2214,10 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned case 0: break; + case SNP_GUEST_REQ_ERR_BUSY: + ret = -EAGAIN; + break; + case SNP_GUEST_REQ_INVALID_LEN: /* Number of expected pages are returned in RBX */ if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index 4b738f2284b5..741d12f75726 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; @@ -322,7 +325,8 @@ 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; @@ -362,6 +366,19 @@ 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; } /* |