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x86/mm: Add Secure Encrypted Virtualization (SEV) support 

Provide support for Secure Encrypted 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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20171020143059.3291-3-brijesh.singh@amd.com
This commit is contained in:
Tom Lendacky 2017-10-20 09:30:44 -05:00 committed by Thomas Gleixner
parent 33e63acc11
commit d8aa7eea78
3 changed files with 37 additions and 2 deletions
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6
arch/x86/include/asm/mem_encrypt.h
View File

@ -47,6 +47,9 @@ void __init mem_encrypt_init(void);
void swiotlb_set_mem_attributes(void *vaddr, unsigned long size);
bool sme_active(void);
bool sev_active(void);
#else /* !CONFIG_AMD_MEM_ENCRYPT */
#define sme_me_mask 0ULL
@ -64,6 +67,9 @@ static inline void __init sme_early_init(void) { }
static inline void __init sme_encrypt_kernel(void) { }
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; }
#endif /* CONFIG_AMD_MEM_ENCRYPT */
/*

26
arch/x86/mm/mem_encrypt.c
View File

@ -42,6 +42,8 @@ static char sme_cmdline_off[] __initdata = "off";
u64 sme_me_mask __section(.data) = 0;
EXPORT_SYMBOL_GPL(sme_me_mask);
static bool sev_enabled __section(.data);
/* Buffer used for early in-place encryption by BSP, no locking needed */
static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE);
@ -192,6 +194,30 @@ void __init sme_early_init(void)
protection_map[i] = pgprot_encrypted(protection_map[i]);
}
/*
* SME and SEV are very similar but they are not the same, so there are
* times that the kernel will need to distinguish between SME and SEV. The
* sme_active() and sev_active() functions are used for this. When a
* distinction isn't needed, the mem_encrypt_active() function can be used.
*
* The trampoline code is a good example for this requirement. Before
* paging is activated, SME will access all memory as decrypted, but SEV
* will access all memory as encrypted. So, when APs are being brought
* up under SME the trampoline area cannot be encrypted, whereas under SEV
* the trampoline area must be encrypted.
*/
bool sme_active(void)
{
return sme_me_mask && !sev_enabled;
}
EXPORT_SYMBOL_GPL(sme_active);
bool sev_active(void)
{
return sme_me_mask && sev_enabled;
}
EXPORT_SYMBOL_GPL(sev_active);
/* Architecture __weak replacement functions */
void __init mem_encrypt_init(void)
{

7
include/linux/mem_encrypt.h
View File

@ -23,11 +23,14 @@
#define sme_me_mask 0ULL
static inline bool sme_active(void) { return false; }
static inline bool sev_active(void) { return false; }
#endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */
static inline bool sme_active(void)
static inline bool mem_encrypt_active(void)
{
return !!sme_me_mask;
return sme_me_mask;
}
static inline u64 sme_get_me_mask(void)