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-rw-r--r--arch/x86/coco/core.c4
-rw-r--r--arch/x86/coco/sev/core.c107
-rw-r--r--arch/x86/include/asm/sev-common.h1
-rw-r--r--arch/x86/include/asm/sev.h21
-rw-r--r--arch/x86/include/asm/svm.h6
-rw-r--r--arch/x86/mm/mem_encrypt.c2
-rw-r--r--include/linux/cc_platform.h8
7 files changed, 146 insertions, 3 deletions
diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
index 0f81f70aca822..9a0ddda3aa697 100644
--- a/arch/x86/coco/core.c
+++ b/arch/x86/coco/core.c
@@ -65,7 +65,6 @@ static __maybe_unused __always_inline bool amd_cc_platform_vtom(enum cc_attr att
* up under SME the trampoline area cannot be encrypted, whereas under SEV
* the trampoline area must be encrypted.
*/
-
static bool noinstr amd_cc_platform_has(enum cc_attr attr)
{
#ifdef CONFIG_AMD_MEM_ENCRYPT
@@ -97,6 +96,9 @@ static bool noinstr amd_cc_platform_has(enum cc_attr attr)
case CC_ATTR_GUEST_SEV_SNP:
return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
+ case CC_ATTR_GUEST_SNP_SECURE_TSC:
+ return sev_status & MSR_AMD64_SNP_SECURE_TSC;
+
case CC_ATTR_HOST_SEV_SNP:
return cc_flags.host_sev_snp;
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index ad3a28845817f..7458805b8f0e5 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -96,6 +96,14 @@ static u64 sev_hv_features __ro_after_init;
/* Secrets page physical address from the CC blob */
static u64 secrets_pa __ro_after_init;
+/*
+ * For Secure TSC guests, the BSP fetches TSC_INFO using SNP guest messaging and
+ * initializes snp_tsc_scale and snp_tsc_offset. These values are replicated
+ * across the APs VMSA fields (TSC_SCALE and TSC_OFFSET).
+ */
+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;
@@ -1277,6 +1285,12 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
vmsa->vmpl = snp_vmpl;
vmsa->sev_features = sev_status >> 2;
+ /* Populate AP's TSC scale/offset to get accurate TSC values. */
+ 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) {
@@ -3126,3 +3140,96 @@ 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)
+{
+ 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 = -ENOMEM;
+
+ tsc_req = kzalloc(sizeof(*tsc_req), GFP_KERNEL);
+ if (!tsc_req)
+ return rc;
+
+ /*
+ * The intermediate response buffer is used while decrypting the
+ * response payload. Make sure that it has enough space to cover
+ * the authtag.
+ */
+ tsc_resp = kzalloc(sizeof(*tsc_resp) + AUTHTAG_LEN, GFP_KERNEL);
+ if (!tsc_resp)
+ goto e_free_tsc_req;
+
+ req = kzalloc(sizeof(*req), GFP_KERNEL);
+ if (!req)
+ goto e_free_tsc_resp;
+
+ rio = kzalloc(sizeof(*rio), GFP_KERNEL);
+ if (!rio)
+ goto e_free_req;
+
+ mdesc = snp_msg_alloc();
+ if (IS_ERR_OR_NULL(mdesc))
+ goto e_free_rio;
+
+ rc = snp_msg_init(mdesc, snp_vmpl);
+ if (rc)
+ goto e_free_mdesc;
+
+ 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 = (void *)tsc_resp;
+ 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 e_request;
+
+ pr_debug("%s: response status 0x%x scale 0x%llx offset 0x%llx factor 0x%x\n",
+ __func__, tsc_resp->status, tsc_resp->tsc_scale, tsc_resp->tsc_offset,
+ tsc_resp->tsc_factor);
+
+ if (!tsc_resp->status) {
+ snp_tsc_scale = tsc_resp->tsc_scale;
+ snp_tsc_offset = tsc_resp->tsc_offset;
+ } else {
+ pr_err("Failed to get TSC info, response status 0x%x\n", tsc_resp->status);
+ rc = -EIO;
+ }
+
+e_request:
+ /* The response buffer contains sensitive data, explicitly clear it. */
+ memzero_explicit(tsc_resp, sizeof(*tsc_resp) + AUTHTAG_LEN);
+e_free_mdesc:
+ snp_msg_free(mdesc);
+e_free_rio:
+ kfree(rio);
+e_free_req:
+ kfree(req);
+ e_free_tsc_resp:
+ kfree(tsc_resp);
+e_free_tsc_req:
+ kfree(tsc_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");
+}
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 50f5666938c09..6ef92432a5cef 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -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)
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 0937ac7a96db0..bdcdaac4df1c5 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -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 +177,21 @@ struct snp_guest_msg {
u8 payload[PAGE_SIZE - sizeof(struct snp_guest_msg_hdr)];
} __packed;
+#define SNP_TSC_INFO_REQ_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;
@@ -463,6 +481,8 @@ void snp_msg_free(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);
+void __init snp_secure_tsc_prepare(void);
+
#else /* !CONFIG_AMD_MEM_ENCRYPT */
#define snp_vmpl 0
@@ -503,6 +523,7 @@ static inline struct snp_msg_desc *snp_msg_alloc(void) { return NULL; }
static inline void snp_msg_free(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 void __init snp_secure_tsc_prepare(void) { }
#endif /* CONFIG_AMD_MEM_ENCRYPT */
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 2b59b9951c90e..92e18798f1977 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -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);
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 0a120d85d7bba..95bae74fdab23 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -94,6 +94,8 @@ void __init mem_encrypt_init(void)
/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
swiotlb_update_mem_attributes();
+ snp_secure_tsc_prepare();
+
print_mem_encrypt_feature_info();
}
diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h
index caa4b44306346..0bf7d33a1048c 100644
--- a/include/linux/cc_platform.h
+++ b/include/linux/cc_platform.h
@@ -82,6 +82,14 @@ enum cc_attr {
CC_ATTR_GUEST_SEV_SNP,
/**
+ * @CC_ATTR_GUEST_SNP_SECURE_TSC: SNP Secure TSC is active.
+ *
+ * The platform/OS is running as a guest/virtual machine and actively
+ * using AMD SEV-SNP Secure TSC feature.
+ */
+ CC_ATTR_GUEST_SNP_SECURE_TSC,
+
+ /**
* @CC_ATTR_HOST_SEV_SNP: AMD SNP enabled on the host.
*
* The host kernel is running with the necessary features
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-29 13:53:59 +0000