diff --git a/Documentation/virt/coco/sev-guest.rst b/Documentation/virt/coco/sev-guest.rst index aa3e4c6a1f90..68b0d2363af8 100644 --- a/Documentation/virt/coco/sev-guest.rst +++ b/Documentation/virt/coco/sev-guest.rst @@ -37,11 +37,11 @@ along with a description: the return value. General error numbers (-ENOMEM, -EINVAL) are not detailed, but errors with specific meanings are. -The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device. -The ioctl accepts struct snp_user_guest_request. The input and output structure is -specified through the req_data and resp_data field respectively. If the ioctl fails -to execute due to a firmware error, then fw_err code will be set. Otherwise, fw_err -will be set to 0x00000000ffffffff, i.e., the lower 32-bits are -1. +The guest ioctl should be issued on a file descriptor of the /dev/sev-guest +device. The ioctl accepts struct snp_user_guest_request. The input and +output structure is specified through the req_data and resp_data field +respectively. If the ioctl fails to execute due to a firmware error, then +the fw_error code will be set, otherwise fw_error will be set to -1. The firmware checks that the message sequence counter is one greater than the guests message sequence counter. If guest driver fails to increment message @@ -57,8 +57,14 @@ counter (e.g. counter overflow), then -EIO will be returned. __u64 req_data; __u64 resp_data; - /* firmware error code on failure (see psp-sev.h) */ - __u64 fw_err; + /* bits[63:32]: VMM error code, bits[31:0] firmware error code (see psp-sev.h) */ + union { + __u64 exitinfo2; + struct { + __u32 fw_error; + __u32 vmm_error; + }; + }; }; 2.1 SNP_GET_REPORT diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index b63be696b776..0759af9b1acf 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -128,10 +128,6 @@ struct snp_psc_desc { struct psc_entry entries[VMGEXIT_PSC_MAX_ENTRY]; } __packed; -/* 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 #define GHCB_MSR_TERM_REASON_SET_MASK 0xf diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index a0a58c4122ec..7ca5c9ec8b52 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -9,6 +9,8 @@ #define __ASM_ENCRYPTED_STATE_H #include +#include + #include #include #include @@ -185,6 +187,9 @@ static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) return rc; } + +struct snp_guest_request_ioctl; + void setup_ghcb(void); void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned long npages); @@ -196,7 +201,7 @@ void snp_set_memory_private(unsigned long vaddr, unsigned long npages); void snp_set_wakeup_secondary_cpu(void); bool snp_init(struct boot_params *bp); void __init __noreturn snp_abort(void); -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err); +int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -216,8 +221,7 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned long npa static inline void snp_set_wakeup_secondary_cpu(void) { } static inline bool snp_init(struct boot_params *bp) { return false; } static inline void snp_abort(void) { } -static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, - unsigned long *fw_err) +static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio) { return -ENOTTY; } diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index e7968c41ecf5..68b2a9d3dbc6 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -22,6 +22,8 @@ #include #include #include +#include +#include #include #include @@ -2205,7 +2207,7 @@ static int __init init_sev_config(char *str) } __setup("sev=", init_sev_config); -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err) +int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio) { struct ghcb_state state; struct es_em_ctxt ctxt; @@ -2213,8 +2215,7 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned struct ghcb *ghcb; int ret; - if (!fw_err) - return -EINVAL; + rio->exitinfo2 = SEV_RET_NO_FW_CALL; /* * __sev_get_ghcb() needs to run with IRQs disabled because it is using @@ -2239,16 +2240,16 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned if (ret) goto e_put; - *fw_err = ghcb->save.sw_exit_info_2; - switch (*fw_err) { + rio->exitinfo2 = ghcb->save.sw_exit_info_2; + switch (rio->exitinfo2) { case 0: break; - case SNP_GUEST_REQ_ERR_BUSY: + case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_BUSY): ret = -EAGAIN; break; - case SNP_GUEST_REQ_INVALID_LEN: + case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN): /* Number of expected pages are returned in RBX */ if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { input->data_npages = ghcb_get_rbx(ghcb); diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index 9e172f66a8ed..5cdc972e5ef4 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -334,11 +334,12 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 return __enc_payload(snp_dev, req, payload, sz); } -static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err) +static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, + struct snp_guest_request_ioctl *rio) { - unsigned long err = 0xff, override_err = 0; unsigned long req_start = jiffies; unsigned int override_npages = 0; + u64 override_err = 0; int rc; retry_request: @@ -348,7 +349,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, * sequence number must be incremented or the VMPCK must be deleted to * prevent reuse of the IV. */ - rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err); + rc = snp_issue_guest_request(exit_code, &snp_dev->input, rio); switch (rc) { case -ENOSPC: /* @@ -366,7 +367,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, * request buffer size was too small and give the caller the * required buffer size. */ - override_err = SNP_GUEST_REQ_INVALID_LEN; + override_err = SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN); /* * If this call to the firmware succeeds, the sequence number can @@ -379,7 +380,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, goto retry_request; /* - * The host may return SNP_GUEST_REQ_ERR_EBUSY if the request has been + * The host may return SNP_GUEST_VMM_ERR_BUSY if the request has been * throttled. Retry in the driver to avoid returning and reusing the * message sequence number on a different message. */ @@ -400,27 +401,29 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, */ snp_inc_msg_seqno(snp_dev); - if (fw_err) - *fw_err = override_err ?: err; + if (override_err) { + rio->exitinfo2 = override_err; + + /* + * If an extended guest request was issued and the supplied certificate + * buffer was not large enough, a standard guest request was issued to + * prevent IV reuse. If the standard request was successful, return -EIO + * back to the caller as would have originally been returned. + */ + if (!rc && override_err == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN)) + rc = -EIO; + } if (override_npages) snp_dev->input.data_npages = override_npages; - /* - * If an extended guest request was issued and the supplied certificate - * buffer was not large enough, a standard guest request was issued to - * prevent IV reuse. If the standard request was successful, return -EIO - * back to the caller as would have originally been returned. - */ - if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN) - return -EIO; - return rc; } -static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver, - u8 type, void *req_buf, size_t req_sz, void *resp_buf, - u32 resp_sz, __u64 *fw_err) +static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, + struct snp_guest_request_ioctl *rio, u8 type, + void *req_buf, size_t req_sz, void *resp_buf, + u32 resp_sz) { u64 seqno; int rc; @@ -434,7 +437,7 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in memset(snp_dev->response, 0, sizeof(struct snp_guest_msg)); /* Encrypt the userspace provided payload in snp_dev->secret_request. */ - rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz); + rc = enc_payload(snp_dev, seqno, rio->msg_version, type, req_buf, req_sz); if (rc) return rc; @@ -445,12 +448,16 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in memcpy(snp_dev->request, &snp_dev->secret_request, sizeof(snp_dev->secret_request)); - rc = __handle_guest_request(snp_dev, exit_code, fw_err); + rc = __handle_guest_request(snp_dev, exit_code, rio); if (rc) { - if (rc == -EIO && *fw_err == SNP_GUEST_REQ_INVALID_LEN) + if (rc == -EIO && + rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN)) return rc; - dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n", rc, *fw_err); + dev_alert(snp_dev->dev, + "Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n", + rc, rio->exitinfo2); + snp_disable_vmpck(snp_dev); return rc; } @@ -490,9 +497,9 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io if (!resp) return -ENOMEM; - rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version, + rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg, SNP_MSG_REPORT_REQ, &req, sizeof(req), resp->data, - resp_len, &arg->fw_err); + resp_len); if (rc) goto e_free; @@ -530,9 +537,8 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) return -EFAULT; - rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version, - SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len, - &arg->fw_err); + rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg, + SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len); if (rc) return rc; @@ -592,12 +598,12 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques return -ENOMEM; snp_dev->input.data_npages = npages; - ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version, + ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg, SNP_MSG_REPORT_REQ, &req.data, - sizeof(req.data), resp->data, resp_len, &arg->fw_err); + sizeof(req.data), resp->data, resp_len); /* If certs length is invalid then copy the returned length */ - if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) { + if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) { req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT; if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req))) @@ -632,7 +638,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long if (copy_from_user(&input, argp, sizeof(input))) return -EFAULT; - input.fw_err = 0xff; + input.exitinfo2 = 0xff; /* Message version must be non-zero */ if (!input.msg_version) @@ -663,7 +669,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long mutex_unlock(&snp_cmd_mutex); - if (input.fw_err && copy_to_user(argp, &input, sizeof(input))) + if (input.exitinfo2 && copy_to_user(argp, &input, sizeof(input))) return -EFAULT; return ret; diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h index 256aaeff7e65..2aa39112cf8d 100644 --- a/include/uapi/linux/sev-guest.h +++ b/include/uapi/linux/sev-guest.h @@ -52,8 +52,14 @@ struct snp_guest_request_ioctl { __u64 req_data; __u64 resp_data; - /* firmware error code on failure (see psp-sev.h) */ - __u64 fw_err; + /* bits[63:32]: VMM error code, bits[31:0] firmware error code (see psp-sev.h) */ + union { + __u64 exitinfo2; + struct { + __u32 fw_error; + __u32 vmm_error; + }; + }; }; struct snp_ext_report_req { @@ -77,4 +83,12 @@ struct snp_ext_report_req { /* Get SNP extended report as defined in the GHCB specification version 2. */ #define SNP_GET_EXT_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x2, struct snp_guest_request_ioctl) +/* Guest message request EXIT_INFO_2 constants */ +#define SNP_GUEST_FW_ERR_MASK GENMASK_ULL(31, 0) +#define SNP_GUEST_VMM_ERR_SHIFT 32 +#define SNP_GUEST_VMM_ERR(x) (((u64)x) << SNP_GUEST_VMM_ERR_SHIFT) + +#define SNP_GUEST_VMM_ERR_INVALID_LEN 1 +#define SNP_GUEST_VMM_ERR_BUSY 2 + #endif /* __UAPI_LINUX_SEV_GUEST_H_ */