@@ -206,6 +206,7 @@ struct snp_psc_desc {
#define GHCB_TERM_NO_SVSM 7 /* SVSM is not advertised in the secrets page */
#define GHCB_TERM_SVSM_VMPL0 8 /* SVSM is present but has set VMPL to 0 */
#define GHCB_TERM_SVSM_CAA 9 /* SVSM is present but CAA is not page aligned */
+#define GHCB_TERM_SECURE_TSC 10 /* Secure TSC initialization failed */
#define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK)
@@ -146,6 +146,9 @@ enum msg_type {
SNP_MSG_VMRK_REQ,
SNP_MSG_VMRK_RSP,
+ SNP_MSG_TSC_INFO_REQ = 17,
+ SNP_MSG_TSC_INFO_RSP,
+
SNP_MSG_TYPE_MAX
};
@@ -174,6 +177,22 @@ struct snp_guest_msg {
u8 payload[PAGE_SIZE - sizeof(struct snp_guest_msg_hdr)];
} __packed;
+#define SNP_TSC_INFO_REQ_SZ 128
+#define SNP_TSC_INFO_RESP_SZ 128
+
+struct snp_tsc_info_req {
+ u8 rsvd[SNP_TSC_INFO_REQ_SZ];
+} __packed;
+
+struct snp_tsc_info_resp {
+ u32 status;
+ u32 rsvd1;
+ u64 tsc_scale;
+ u64 tsc_offset;
+ u32 tsc_factor;
+ u8 rsvd2[100];
+} __packed;
+
struct snp_guest_req {
void *req_buf;
size_t req_sz;
@@ -497,6 +516,27 @@ static inline void snp_msg_cleanup(struct snp_msg_desc *mdesc)
int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req,
struct snp_guest_request_ioctl *rio);
+static inline int handle_guest_request(struct snp_msg_desc *mdesc, u64 exit_code,
+ struct snp_guest_request_ioctl *rio, u8 type,
+ void *req_buf, size_t req_sz, void *resp_buf,
+ u32 resp_sz)
+{
+ struct snp_guest_req req = {
+ .msg_version = rio->msg_version,
+ .msg_type = type,
+ .vmpck_id = mdesc->vmpck_id,
+ .req_buf = req_buf,
+ .req_sz = req_sz,
+ .resp_buf = resp_buf,
+ .resp_sz = resp_sz,
+ .exit_code = exit_code,
+ };
+
+ return snp_send_guest_request(mdesc, &req, rio);
+}
+
+void __init snp_secure_tsc_prepare(void);
+
#else /* !CONFIG_AMD_MEM_ENCRYPT */
#define snp_vmpl 0
@@ -538,6 +578,12 @@ static inline struct snp_msg_desc *snp_msg_alloc(void) { return NULL; }
static inline void snp_msg_cleanup(struct snp_msg_desc *mdesc) { }
static inline int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req,
struct snp_guest_request_ioctl *rio) { return -ENODEV; }
+static inline int handle_guest_request(struct snp_msg_desc *mdesc, u64 exit_code,
+ struct snp_guest_request_ioctl *rio, u8 type,
+ void *req_buf, size_t req_sz, void *resp_buf,
+ u32 resp_sz) { return -ENODEV; }
+
+static inline void __init snp_secure_tsc_prepare(void) { }
#endif /* CONFIG_AMD_MEM_ENCRYPT */
@@ -417,7 +417,9 @@ struct sev_es_save_area {
u8 reserved_0x298[80];
u32 pkru;
u32 tsc_aux;
- u8 reserved_0x2f0[24];
+ u64 tsc_scale;
+ u64 tsc_offset;
+ u8 reserved_0x300[8];
u64 rcx;
u64 rdx;
u64 rbx;
@@ -564,7 +566,7 @@ static inline void __unused_size_checks(void)
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298);
- BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2f0);
+ BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x300);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x3f0);
@@ -98,6 +98,10 @@ static u64 secrets_pa __ro_after_init;
static struct snp_msg_desc *snp_mdesc;
+/* Secure TSC values read using TSC_INFO SNP Guest request */
+static u64 snp_tsc_scale __ro_after_init;
+static u64 snp_tsc_offset __ro_after_init;
+
/* #VC handler runtime per-CPU data */
struct sev_es_runtime_data {
struct ghcb ghcb_page;
@@ -1175,6 +1179,12 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
vmsa->vmpl = snp_vmpl;
vmsa->sev_features = sev_status >> 2;
+ /* Set Secure TSC parameters */
+ if (cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) {
+ vmsa->tsc_scale = snp_tsc_scale;
+ vmsa->tsc_offset = snp_tsc_offset;
+ }
+
/* Switch the page over to a VMSA page now that it is initialized */
ret = snp_set_vmsa(vmsa, caa, apic_id, true);
if (ret) {
@@ -2985,3 +2995,84 @@ int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req
return 0;
}
EXPORT_SYMBOL_GPL(snp_send_guest_request);
+
+static int __init snp_get_tsc_info(void)
+{
+ static u8 buf[SNP_TSC_INFO_RESP_SZ + AUTHTAG_LEN];
+ struct snp_guest_request_ioctl rio;
+ struct snp_tsc_info_resp tsc_resp;
+ struct snp_tsc_info_req *tsc_req;
+ struct snp_msg_desc *mdesc;
+ struct snp_guest_req req;
+ int rc;
+
+ /*
+ * The intermediate response buffer is used while decrypting the
+ * response payload. Make sure that it has enough space to cover the
+ * authtag.
+ */
+ BUILD_BUG_ON(sizeof(buf) < (sizeof(tsc_resp) + AUTHTAG_LEN));
+
+ mdesc = snp_msg_alloc();
+ if (IS_ERR_OR_NULL(mdesc))
+ return -ENOMEM;
+
+ rc = snp_msg_init(mdesc, snp_vmpl);
+ if (rc)
+ return rc;
+
+ tsc_req = kzalloc(sizeof(struct snp_tsc_info_req), GFP_KERNEL);
+ if (!tsc_req)
+ return -ENOMEM;
+
+ memset(&req, 0, sizeof(req));
+ memset(&rio, 0, sizeof(rio));
+ memset(buf, 0, sizeof(buf));
+
+ req.msg_version = MSG_HDR_VER;
+ req.msg_type = SNP_MSG_TSC_INFO_REQ;
+ req.vmpck_id = snp_vmpl;
+ req.req_buf = tsc_req;
+ req.req_sz = sizeof(*tsc_req);
+ req.resp_buf = buf;
+ req.resp_sz = sizeof(tsc_resp) + AUTHTAG_LEN;
+ req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ rc = snp_send_guest_request(mdesc, &req, &rio);
+ if (rc)
+ goto err_req;
+
+ memcpy(&tsc_resp, buf, sizeof(tsc_resp));
+ pr_debug("%s: response status %x scale %llx offset %llx factor %x\n",
+ __func__, tsc_resp.status, tsc_resp.tsc_scale, tsc_resp.tsc_offset,
+ tsc_resp.tsc_factor);
+
+ if (tsc_resp.status == 0) {
+ snp_tsc_scale = tsc_resp.tsc_scale;
+ snp_tsc_offset = tsc_resp.tsc_offset;
+ } else {
+ pr_err("Failed to get TSC info, response status %x\n", tsc_resp.status);
+ rc = -EIO;
+ }
+
+err_req:
+ /* The response buffer contains the sensitive data, explicitly clear it. */
+ memzero_explicit(buf, sizeof(buf));
+ memzero_explicit(&tsc_resp, sizeof(tsc_resp));
+ memzero_explicit(&req, sizeof(req));
+
+ return rc;
+}
+
+void __init snp_secure_tsc_prepare(void)
+{
+ if (!cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC))
+ return;
+
+ if (snp_get_tsc_info()) {
+ pr_alert("Unable to retrieve Secure TSC info from ASP\n");
+ sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC);
+ }
+
+ pr_debug("SecureTSC enabled");
+}
@@ -94,6 +94,10 @@ void __init mem_encrypt_init(void)
/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
swiotlb_update_mem_attributes();
+ /* Initialize SNP Secure TSC */
+ if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+ snp_secure_tsc_prepare();
+
print_mem_encrypt_feature_info();
}