diff options
Diffstat (limited to 'arch/x86/kernel/cpu')
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index a6f88ca1a6b4..5398db4dedb4 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -546,6 +546,23 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c) u64 msr; /* + * Mark using WBINVD is needed during kexec on processors that + * support SME. This provides support for performing a successful + * kexec when going from SME inactive to SME active (or vice-versa). + * + * The cache must be cleared so that if there are entries with the + * same physical address, both with and without the encryption bit, + * they don't race each other when flushed and potentially end up + * with the wrong entry being committed to memory. + * + * Test the CPUID bit directly because with mem_encrypt=off the + * BSP will clear the X86_FEATURE_SME bit and the APs will not + * see it set after that. + */ + if (c->extended_cpuid_level >= 0x8000001f && (cpuid_eax(0x8000001f) & BIT(0))) + __this_cpu_write(cache_state_incoherent, true); + + /* * BIOS support is required for SME and SEV. * For SME: If BIOS has enabled SME then adjust x86_phys_bits by * the SME physical address space reduction value. |