[PATCH Part1 RFC v4 04/36] x86/mm: Add sev_feature_enabled() helper
From: Brijesh Singh <hidden>
Date: 2021-07-07 18:15:56
Also in:
linux-coco, linux-crypto, linux-efi, linux-mm, lkml, platform-driver-x86
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
The sev_feature_enabled() helper can be used by the guest to query whether the SNP - Secure Nested Paging feature is active. Signed-off-by: Brijesh Singh <redacted> --- arch/x86/include/asm/mem_encrypt.h | 8 ++++++++ arch/x86/include/asm/msr-index.h | 2 ++ arch/x86/mm/mem_encrypt.c | 14 ++++++++++++++ 3 files changed, 24 insertions(+)
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 8cc2fd308f65..fb857f2e72cb 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h@@ -16,6 +16,12 @@ #include <asm/bootparam.h> +enum sev_feature_type { + SEV, + SEV_ES, + SEV_SNP +}; + #ifdef CONFIG_AMD_MEM_ENCRYPT extern u64 sme_me_mask;
@@ -54,6 +60,7 @@ void __init sev_es_init_vc_handling(void); bool sme_active(void); bool sev_active(void); bool sev_es_active(void); +bool sev_feature_enabled(unsigned int feature_type); #define __bss_decrypted __section(".bss..decrypted")
@@ -87,6 +94,7 @@ static inline int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0; } static inline void mem_encrypt_free_decrypted_mem(void) { } +static bool sev_feature_enabled(unsigned int feature_type) { return false; } #define __bss_decrypted
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index a7c413432b33..37589da0282e 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h@@ -481,8 +481,10 @@ #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_ULL(MSR_AMD64_SEV_ES_ENABLED_BIT) +#define MSR_AMD64_SEV_SNP_ENABLED BIT_ULL(MSR_AMD64_SEV_SNP_ENABLED_BIT) #define MSR_AMD64_VIRT_SPEC_CTRL 0xc001011f
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index ff08dc463634..63e7799a9a86 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c@@ -389,6 +389,16 @@ bool noinstr sev_es_active(void) return sev_status & MSR_AMD64_SEV_ES_ENABLED; } +bool sev_feature_enabled(unsigned int type) +{ + switch (type) { + case SEV: return sev_status & MSR_AMD64_SEV_ENABLED; + case SEV_ES: return sev_status & MSR_AMD64_SEV_ES_ENABLED; + case SEV_SNP: return sev_status & MSR_AMD64_SEV_SNP_ENABLED; + default: return false; + } +} + /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */ bool force_dma_unencrypted(struct device *dev) {
@@ -461,6 +471,10 @@ static void print_mem_encrypt_feature_info(void) if (sev_es_active()) pr_cont(" SEV-ES"); + /* Secure Nested Paging */ + if (sev_feature_enabled(SEV_SNP)) + pr_cont(" SEV-SNP"); + pr_cont("\n"); }
--
2.17.1