x86/sev: Dump SEV_STATUS

It is, and will be even more useful in the future, to dump the SEV
features enabled according to SEV_STATUS. Do so:

  [    0.542753] Memory Encryption Features active: AMD SEV SEV-ES SEV-SNP
  [    0.544425] SEV: Status: SEV SEV-ES SEV-SNP DebugSwap
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://lore.kernel.org/r/20240219094216.GAZdMieDHKiI8aaP3n@fat_crate.local

arch/x86/boot/compressed/sev.c

@@ -369,7 +369,7 @@ static void enforce_vmpl0(void)
 				 MSR_AMD64_SNP_VMPL_SSS |		\
 				 MSR_AMD64_SNP_SECURE_TSC |		\
 				 MSR_AMD64_SNP_VMGEXIT_PARAM |		\
-				 MSR_AMD64_SNP_VMSA_REG_PROTECTION |	\
+				 MSR_AMD64_SNP_VMSA_REG_PROT |		\
 				 MSR_AMD64_SNP_RESERVED_BIT13 |		\
 				 MSR_AMD64_SNP_RESERVED_BIT15 |		\
 				 MSR_AMD64_SNP_RESERVED_MASK)

arch/x86/include/asm/msr-index.h

@@ -594,36 +594,47 @@
 #define MSR_AMD64_SEV_ES_GHCB		0xc0010130
 #define MSR_AMD64_SEV			0xc0010131
 #define MSR_AMD64_SEV_ENABLED_BIT	0
-#define MSR_AMD64_SEV_ES_ENABLED_BIT	1
-#define MSR_AMD64_SEV_SNP_ENABLED_BIT	2
 #define MSR_AMD64_SEV_ENABLED		BIT_ULL(MSR_AMD64_SEV_ENABLED_BIT)
+#define MSR_AMD64_SEV_ES_ENABLED_BIT	1
 #define MSR_AMD64_SEV_ES_ENABLED	BIT_ULL(MSR_AMD64_SEV_ES_ENABLED_BIT)
+#define MSR_AMD64_SEV_SNP_ENABLED_BIT	2
 #define MSR_AMD64_SEV_SNP_ENABLED	BIT_ULL(MSR_AMD64_SEV_SNP_ENABLED_BIT)
-#define MSR_AMD64_RMP_BASE		0xc0010132
-#define MSR_AMD64_RMP_END		0xc0010133
-
-/* SNP feature bits enabled by the hypervisor */
-#define MSR_AMD64_SNP_VTOM			BIT_ULL(3)
-#define MSR_AMD64_SNP_REFLECT_VC		BIT_ULL(4)
-#define MSR_AMD64_SNP_RESTRICTED_INJ		BIT_ULL(5)
-#define MSR_AMD64_SNP_ALT_INJ			BIT_ULL(6)
-#define MSR_AMD64_SNP_DEBUG_SWAP		BIT_ULL(7)
-#define MSR_AMD64_SNP_PREVENT_HOST_IBS		BIT_ULL(8)
-#define MSR_AMD64_SNP_BTB_ISOLATION		BIT_ULL(9)
-#define MSR_AMD64_SNP_VMPL_SSS			BIT_ULL(10)
-#define MSR_AMD64_SNP_SECURE_TSC		BIT_ULL(11)
-#define MSR_AMD64_SNP_VMGEXIT_PARAM		BIT_ULL(12)
-#define MSR_AMD64_SNP_IBS_VIRT			BIT_ULL(14)
-#define MSR_AMD64_SNP_VMSA_REG_PROTECTION	BIT_ULL(16)
-#define MSR_AMD64_SNP_SMT_PROTECTION		BIT_ULL(17)
-
-/* SNP feature bits reserved for future use. */
-#define MSR_AMD64_SNP_RESERVED_BIT13		BIT_ULL(13)
-#define MSR_AMD64_SNP_RESERVED_BIT15		BIT_ULL(15)
-#define MSR_AMD64_SNP_RESERVED_MASK		GENMASK_ULL(63, 18)
+#define MSR_AMD64_SNP_VTOM_BIT		3
+#define MSR_AMD64_SNP_VTOM		BIT_ULL(MSR_AMD64_SNP_VTOM_BIT)
+#define MSR_AMD64_SNP_REFLECT_VC_BIT	4
+#define MSR_AMD64_SNP_REFLECT_VC	BIT_ULL(MSR_AMD64_SNP_REFLECT_VC_BIT)
+#define MSR_AMD64_SNP_RESTRICTED_INJ_BIT 5
+#define MSR_AMD64_SNP_RESTRICTED_INJ	BIT_ULL(MSR_AMD64_SNP_RESTRICTED_INJ_BIT)
+#define MSR_AMD64_SNP_ALT_INJ_BIT	6
+#define MSR_AMD64_SNP_ALT_INJ		BIT_ULL(MSR_AMD64_SNP_ALT_INJ_BIT)
+#define MSR_AMD64_SNP_DEBUG_SWAP_BIT	7
+#define MSR_AMD64_SNP_DEBUG_SWAP	BIT_ULL(MSR_AMD64_SNP_DEBUG_SWAP_BIT)
+#define MSR_AMD64_SNP_PREVENT_HOST_IBS_BIT 8
+#define MSR_AMD64_SNP_PREVENT_HOST_IBS	BIT_ULL(MSR_AMD64_SNP_PREVENT_HOST_IBS_BIT)
+#define MSR_AMD64_SNP_BTB_ISOLATION_BIT	9
+#define MSR_AMD64_SNP_BTB_ISOLATION	BIT_ULL(MSR_AMD64_SNP_BTB_ISOLATION_BIT)
+#define MSR_AMD64_SNP_VMPL_SSS_BIT	10
+#define MSR_AMD64_SNP_VMPL_SSS		BIT_ULL(MSR_AMD64_SNP_VMPL_SSS_BIT)
+#define MSR_AMD64_SNP_SECURE_TSC_BIT	11
+#define MSR_AMD64_SNP_SECURE_TSC	BIT_ULL(MSR_AMD64_SNP_SECURE_TSC_BIT)
+#define MSR_AMD64_SNP_VMGEXIT_PARAM_BIT	12
+#define MSR_AMD64_SNP_VMGEXIT_PARAM	BIT_ULL(MSR_AMD64_SNP_VMGEXIT_PARAM_BIT)
+#define MSR_AMD64_SNP_RESERVED_BIT13	BIT_ULL(13)
+#define MSR_AMD64_SNP_IBS_VIRT_BIT	14
+#define MSR_AMD64_SNP_IBS_VIRT		BIT_ULL(MSR_AMD64_SNP_IBS_VIRT_BIT)
+#define MSR_AMD64_SNP_RESERVED_BIT15	BIT_ULL(15)
+#define MSR_AMD64_SNP_VMSA_REG_PROT_BIT	16
+#define MSR_AMD64_SNP_VMSA_REG_PROT	BIT_ULL(MSR_AMD64_SNP_VMSA_REG_PROT_BIT)
+#define MSR_AMD64_SNP_SMT_PROT_BIT	17
+#define MSR_AMD64_SNP_SMT_PROT		BIT_ULL(MSR_AMD64_SNP_SMT_PROT_BIT)
+#define MSR_AMD64_SNP_RESV_BIT		18
+#define MSR_AMD64_SNP_RESERVED_MASK	GENMASK_ULL(63, MSR_AMD64_SNP_RESV_BIT)
 
 #define MSR_AMD64_VIRT_SPEC_CTRL	0xc001011f
 
+#define MSR_AMD64_RMP_BASE		0xc0010132
+#define MSR_AMD64_RMP_END		0xc0010133
+
 /* AMD Collaborative Processor Performance Control MSRs */
 #define MSR_AMD_CPPC_CAP1		0xc00102b0
 #define MSR_AMD_CPPC_ENABLE		0xc00102b1

arch/x86/include/asm/sev.h

@@ -228,6 +228,7 @@ void snp_accept_memory(phys_addr_t start, phys_addr_t end);
 u64 snp_get_unsupported_features(u64 status);
 u64 sev_get_status(void);
 void kdump_sev_callback(void);
+void sev_show_status(void);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -257,6 +258,7 @@ static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
 static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
 static inline u64 sev_get_status(void) { return 0; }
 static inline void kdump_sev_callback(void) { }
+static inline void sev_show_status(void) { }
 #endif
 
 #ifdef CONFIG_KVM_AMD_SEV

arch/x86/kernel/sev.c

@@ -59,6 +59,25 @@
 #define AP_INIT_CR0_DEFAULT		0x60000010
 #define AP_INIT_MXCSR_DEFAULT		0x1f80
 
+static const char * const sev_status_feat_names[] = {
+	[MSR_AMD64_SEV_ENABLED_BIT]		= "SEV",
+	[MSR_AMD64_SEV_ES_ENABLED_BIT]		= "SEV-ES",
+	[MSR_AMD64_SEV_SNP_ENABLED_BIT]		= "SEV-SNP",
+	[MSR_AMD64_SNP_VTOM_BIT]		= "vTom",
+	[MSR_AMD64_SNP_REFLECT_VC_BIT]		= "ReflectVC",
+	[MSR_AMD64_SNP_RESTRICTED_INJ_BIT]	= "RI",
+	[MSR_AMD64_SNP_ALT_INJ_BIT]		= "AI",
+	[MSR_AMD64_SNP_DEBUG_SWAP_BIT]		= "DebugSwap",
+	[MSR_AMD64_SNP_PREVENT_HOST_IBS_BIT]	= "NoHostIBS",
+	[MSR_AMD64_SNP_BTB_ISOLATION_BIT]	= "BTBIsol",
+	[MSR_AMD64_SNP_VMPL_SSS_BIT]		= "VmplSSS",
+	[MSR_AMD64_SNP_SECURE_TSC_BIT]		= "SecureTSC",
+	[MSR_AMD64_SNP_VMGEXIT_PARAM_BIT]	= "VMGExitParam",
+	[MSR_AMD64_SNP_IBS_VIRT_BIT]		= "IBSVirt",
+	[MSR_AMD64_SNP_VMSA_REG_PROT_BIT]	= "VMSARegProt",
+	[MSR_AMD64_SNP_SMT_PROT_BIT]		= "SMTProt",
+};
+
 /* For early boot hypervisor communication in SEV-ES enabled guests */
 static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE);
 
@@ -2275,3 +2294,19 @@ void kdump_sev_callback(void)
 	if (cpu_feature_enabled(X86_FEATURE_SEV_SNP))
 		wbinvd();
 }
+
+void sev_show_status(void)
+{
+	int i;
+
+	pr_info("Status: ");
+	for (i = 0; i < MSR_AMD64_SNP_RESV_BIT; i++) {
+		if (sev_status & BIT_ULL(i)) {
+			if (!sev_status_feat_names[i])
+				continue;
+
+			pr_cont("%s ", sev_status_feat_names[i]);
+		}
+	}
+	pr_cont("\n");
+}

arch/x86/mm/mem_encrypt.c

@@ -14,6 +14,8 @@
 #include <linux/mem_encrypt.h>
 #include <linux/virtio_anchor.h>
 
+#include <asm/sev.h>
+
 /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
 bool force_dma_unencrypted(struct device *dev)
 {
@@ -74,6 +76,9 @@ static void print_mem_encrypt_feature_info(void)
 			pr_cont(" SEV-SNP");
 
 		pr_cont("\n");
+
+		sev_show_status();
+
 		break;
 	default:
 		pr_cont("Unknown\n");