diff options
| author | Jiaxi Chen <jiaxi.chen@linux.intel.com> | 2022-11-25 15:58:40 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-11-28 21:33:27 +0300 |
| commit | 6a19d7aa5821522eec528fd44f24fe774b875377 (patch) | |
| tree | 3fa3bf05fb75c98855d613a8cdd9cf47f511d6de /arch/x86/kvm/cpuid.c | |
| parent | 047c7229906152fb85c23dc18fd25a00cd7cb4de (diff) | |
| download | linux-6a19d7aa5821522eec528fd44f24fe774b875377.tar.xz | |
x86: KVM: Advertise CMPccXADD CPUID to user space
CMPccXADD is a new set of instructions in the latest Intel platform
Sierra Forest. This new instruction set includes a semaphore operation
that can compare and add the operands if condition is met, which can
improve database performance.
The bit definition:
CPUID.(EAX=7,ECX=1):EAX[bit 7]
CMPccXADD is on an expected-dense CPUID leaf and some other bits on this
leaf have kernel usages. Given that, define this feature bit like
X86_FEATURE_<name> in kernel. Considering CMPccXADD itself has no truly
kernel usages and /proc/cpuinfo has too much unreadable flags, hide this
one in /proc/cpuinfo.
Advertise CMPCCXADD to KVM userspace. This is safe because there are no
new VMX controls or additional host enabling required for guests to use
this feature.
Signed-off-by: Jiaxi Chen <jiaxi.chen@linux.intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Message-Id: <20221125125845.1182922-4-jiaxi.chen@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 73c3c6dc6e7b..2f263ff911d6 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -663,7 +663,7 @@ void kvm_set_cpu_caps(void) kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD); kvm_cpu_cap_mask(CPUID_7_1_EAX, - F(AVX_VNNI) | F(AVX512_BF16) + F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) ); kvm_cpu_cap_mask(CPUID_D_1_EAX, |