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authorTom Lendacky <thomas.lendacky@amd.com>2017-10-20 17:30:44 +0300
committerThomas Gleixner <tglx@linutronix.de>2017-11-07 17:35:54 +0300
commitd8aa7eea78a1401cce39b3bb61ead0150044a3df (patch)
tree8578eb975c77968db7003b83d1c670ff27b35451 /arch/x86/mm
parent33e63acc119d15c2fac3e3775f32d1ce7a01021b (diff)
downloadlinux-d8aa7eea78a1401cce39b3bb61ead0150044a3df.tar.xz
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
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/mem_encrypt.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 16c5f37933a2..add836d3d174 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -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)
{