[RFC Part1 PATCH v3 03/17] x86/mm: Secure Encrypted Virtualization (SEV) support

Brijesh Singh
2017-07-24T19:07:43Z

From: Tom Lendacky <thomas.lendacky@amd.com>

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@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
arch/x86/include/asm/mem_encrypt.h | 2 ++
arch/x86/mm/mem_encrypt.c | 3 +++
include/linux/mem_encrypt.h | 8 +++++++-
3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 8e618fc..9274ec7 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -22,6 +22,7 @@
#ifdef CONFIG_AMD_MEM_ENCRYPT

extern unsigned long sme_me_mask;
+extern unsigned int sev_enabled;

void sme_encrypt_execute(unsigned long encrypted_kernel_vaddr,
unsigned long decrypted_kernel_vaddr,
@@ -50,6 +51,7 @@ void swiotlb_set_mem_attributes(void *vaddr, unsigned long size);
#else /* !CONFIG_AMD_MEM_ENCRYPT */

#define sme_me_mask 0UL
+#define sev_enabled 0

static inline void __init sme_early_encrypt(resource_size_t paddr,
unsigned long size) { }
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 0fbd092..1e4643e 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -40,6 +40,9 @@ static char sme_cmdline_off[] __initdata = "off";
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 1255f09..ea0831a 100644
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -22,12 +22,18 @@
#else /* !CONFIG_ARCH_HAS_MEM_ENCRYPT */

#define sme_me_mask 0UL
+#define sev_enabled 0

#endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */

static inline bool sme_active(void)
{
- return !!sme_me_mask;
+ return (sme_me_mask && !sev_enabled);
+}
+
+static inline bool sev_active(void)
+{
+ return (sme_me_mask && sev_enabled);
}

static inline unsigned long sme_get_me_mask(void)
--
2.9.4