[PATCH -v2] x86/sev: Dump SEV_STATUS

From: Borislav Petkov
Date: Mon Feb 19 2024 - 04:42:47 EST

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From: "Borislav Petkov (AMD)" <bp@xxxxxxxxx>

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@xxxxxxxxx>
Reviewed-by: Nikunj A Dadhania <nikunj@xxxxxxx>
---
arch/x86/boot/compressed/sev.c | 2 +-
arch/x86/include/asm/msr-index.h | 59 +++++++++++++++++++-------------
arch/x86/include/asm/sev.h | 2 ++
arch/x86/kernel/sev.c | 35 +++++++++++++++++++
arch/x86/mm/mem_encrypt.c | 5 +++
5 files changed, 78 insertions(+), 25 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index fffdba4ae806..97561eabfbef 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -370,7 +370,7 @@ 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)
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 237c50cc1c72..24c575cdd6b9 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -605,36 +605,47 @@
#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
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index d7b27cb34c2b..10f9f1b259c3 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -229,6 +229,7 @@ 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) { }
@@ -258,6 +259,7 @@ 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
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 1ef7ae806a01..7d242898852f 100644
--- a/arch/x86/kernel/sev.c
+++ b/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");
+}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index d035bce3a2b0..6f3b3e028718 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/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");
--
2.43.0

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Next message: neil . armstrong: "Re: [PATCH v5 00/18] power: sequencing: implement the subsystem and add first users"
Previous message: Mikhail Gavrilov: "Re: This is the fourth time I’ve tried to find what led to the regression of outgoing network speed and each time I find the merge commit 8c94ccc7cd691472461448f98e2372c75849406c"
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