From d8aa7eea78a1401cce39b3bb61ead0150044a3df Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Fri, 20 Oct 2017 09:30:44 -0500 Subject: 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 Signed-off-by: Brijesh Singh Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Tested-by: Borislav Petkov Cc: kvm@vger.kernel.org Cc: Borislav Petkov Cc: Andy Lutomirski Link: https://lkml.kernel.org/r/20171020143059.3291-3-brijesh.singh@amd.com --- arch/x86/mm/mem_encrypt.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'arch/x86/mm') 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) { -- cgit v1.2.3-59-g8ed1b