diff options
| author | Tom Lendacky <thomas.lendacky@amd.com> | 2020-12-10 11:09:36 -0600 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-12-14 11:09:30 -0500 |
| commit | 69372cf01290b9587d2cee8fbe161d75d55c3adc (patch) | |
| tree | 4a60a68a95a4d45ea4b68f1680a8644d142b7ce6 /arch/x86/kernel/cpu/scattered.c | |
| parent | 3f1a18b9fa1c294802d2750d1ef6a1221b10b76b (diff) | |
x86/cpu: Add VM page flush MSR availablility as a CPUID feature
On systems that do not have hardware enforced cache coherency between
encrypted and unencrypted mappings of the same physical page, the
hypervisor can use the VM page flush MSR (0xc001011e) to flush the cache
contents of an SEV guest page. When a small number of pages are being
flushed, this can be used in place of issuing a WBINVD across all CPUs.
CPUID 0x8000001f_eax[2] is used to determine if the VM page flush MSR is
available. Add a CPUID feature to indicate it is supported and define the
MSR.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <f1966379e31f9b208db5257509c4a089a87d33d0.1607620209.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kernel/cpu/scattered.c')
| -rw-r--r-- | arch/x86/kernel/cpu/scattered.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c index 866c9a9bcdee..236924930bf0 100644 --- a/arch/x86/kernel/cpu/scattered.c +++ b/arch/x86/kernel/cpu/scattered.c @@ -44,6 +44,7 @@ static const struct cpuid_bit cpuid_bits[] = { { X86_FEATURE_SEV, CPUID_EAX, 1, 0x8000001f, 0 }, { X86_FEATURE_SEV_ES, CPUID_EAX, 3, 0x8000001f, 0 }, { X86_FEATURE_SME_COHERENT, CPUID_EAX, 10, 0x8000001f, 0 }, + { X86_FEATURE_VM_PAGE_FLUSH, CPUID_EAX, 2, 0x8000001f, 0 }, { 0, 0, 0, 0, 0 } }; |