[RFC PATCH v2 02/32] x86: Secure Encrypted Virtualization (SEV) support

[Brijesh Singh]

From: Tom Lendacky <thomas.lendacky@xxxxxxx>

Provide support for Secure Encyrpted Virtualization (SEV). This initial
support defines a flag that is used by the kernel to determine if it is
running with SEV active.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
 arch/x86/include/asm/mem_encrypt.h |   14 +++++++++++++-
 arch/x86/mm/mem_encrypt.c          |    3 +++
 include/linux/mem_encrypt.h        |    6 ++++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 1fd5426..9799835 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -20,10 +20,16 @@
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 
 extern unsigned long sme_me_mask;
+extern unsigned int sev_enabled;
 
 static inline bool sme_active(void)
 {
-	return (sme_me_mask) ? true : false;
+	return (sme_me_mask && !sev_enabled) ? true : false;
+}
+
+static inline bool sev_active(void)
+{
+	return (sme_me_mask && sev_enabled) ? true : false;
 }
 
 static inline u64 sme_dma_mask(void)
@@ -53,6 +59,7 @@ void swiotlb_set_mem_attributes(void *vaddr, unsigned long size);
 
 #ifndef sme_me_mask
 #define sme_me_mask	0UL
+#define sev_enabled	0
 
 static inline bool sme_active(void)
 {
@@ -64,6 +71,11 @@ static inline u64 sme_dma_mask(void)
 	return 0ULL;
 }
 
+static inline bool sev_active(void)
+{
+	return false;
+}
+
 static inline int set_memory_encrypted(unsigned long vaddr, int numpages)
 {
 	return 0;
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index c5062e1..090419b 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -34,6 +34,9 @@ void __init __early_pgtable_flush(void);
 unsigned long sme_me_mask __section(.data) = 0;
 EXPORT_SYMBOL_GPL(sme_me_mask);
 
+unsigned int sev_enabled __section(.data) = 0;
+EXPORT_SYMBOL_GPL(sev_enabled);
+
 /* Buffer used for early in-place encryption by BSP, no locking needed */
 static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE);
 
diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
index 913cf80..4b47c73 100644
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -23,6 +23,7 @@
 
 #ifndef sme_me_mask
 #define sme_me_mask	0UL
+#define sev_enabled	0
 
 static inline bool sme_active(void)
 {
@@ -34,6 +35,11 @@ static inline u64 sme_dma_mask(void)
 	return 0ULL;
 }
 
+static inline bool sev_active(void)
+{
+	return false;
+}
+
 static inline int set_memory_encrypted(unsigned long vaddr, int numpages)
 {
 	return 0;