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Subject[PATCH 36/70] x86/sev-es: Add SEV-ES Feature Detection
Date
From: Joerg Roedel <jroedel@suse.de>

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 <jroedel@suse.de>
---
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 9eb279927fc2..e69743be869b 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
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