[PATCH 31/62] x86/sev-es: Add SEV-ES Feature Detection
From: Joerg Roedel <joro@8bytes.org>
Date: 2020-02-11 13:57:15
Also in:
kvm, lkml
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
From: Joerg Roedel <redacted> Add the sev_es_active function for checking whether SEV-ES is enabled. Also cache the value of MSR_AMD64_SEV at boot to speed up the feature checking in the running code. Signed-off-by: Joerg Roedel <redacted> --- arch/x86/include/asm/mem_encrypt.h | 3 +++ arch/x86/include/asm/msr-index.h | 2 ++ arch/x86/mm/mem_encrypt.c | 11 ++++++++++- arch/x86/mm/mem_encrypt_identity.c | 3 +++ 4 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 848ce43b9040..6f61bb93366a 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h@@ -19,6 +19,7 @@ #ifdef CONFIG_AMD_MEM_ENCRYPT extern u64 sme_me_mask; +extern u64 sev_status; extern bool sev_enabled; void sme_encrypt_execute(unsigned long encrypted_kernel_vaddr,
@@ -49,6 +50,7 @@ void __init mem_encrypt_free_decrypted_mem(void); bool sme_active(void); bool sev_active(void); +bool sev_es_active(void); #define __bss_decrypted __attribute__((__section__(".bss..decrypted")))
@@ -71,6 +73,7 @@ static inline void __init sme_enable(struct boot_params *bp) { } static inline bool sme_active(void) { return false; } static inline bool sev_active(void) { return false; } +static inline bool sev_es_active(void) { return false; } static inline int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index b6139b70db54..1411c37b6cd9 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h@@ -435,7 +435,9 @@ #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_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_VIRT_SPEC_CTRL 0xc001011f
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index a03614bd3e1a..a35fcba24866 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c@@ -38,7 +38,9 @@ * section is later cleared. */ u64 sme_me_mask __section(.data) = 0; +u64 sev_status __section(.data) = 0; EXPORT_SYMBOL(sme_me_mask); +EXPORT_SYMBOL(sev_status); DEFINE_STATIC_KEY_FALSE(sev_enable_key); EXPORT_SYMBOL_GPL(sev_enable_key);
@@ -347,9 +349,16 @@ bool sme_active(void) bool sev_active(void) { - return sme_me_mask && sev_enabled; + return !!(sev_status & MSR_AMD64_SEV_ENABLED); } +bool sev_es_active(void) +{ + return !!(sev_status & MSR_AMD64_SEV_ES_ENABLED); +} +EXPORT_SYMBOL_GPL(sev_es_active); + + /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */ bool force_dma_unencrypted(struct device *dev) {
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index e2b0e2ac07bb..68d75379e06a 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c@@ -540,6 +540,9 @@ void __init sme_enable(struct boot_params *bp) if (!(msr & MSR_AMD64_SEV_ENABLED)) return; + /* Save SEV_STATUS to avoid reading MSR again */ + sev_status = msr; + /* SEV state cannot be controlled by a command line option */ sme_me_mask = me_mask; sev_enabled = true;
--
2.17.1