[PATCH v3 20/27] KVM: x86: Allow WRMSRNS to be advertised to guests

Xin Li (Intel) posted 27 patches 1 month, 4 weeks ago
[PATCH v3 20/27] KVM: x86: Allow WRMSRNS to be advertised to guests
Posted by Xin Li (Intel) 1 month, 4 weeks ago
From: Xin Li <xin3.li@intel.com>

Allow WRMSRNS to be advertised to guests.

WRMSRNS behaves exactly like WRMSR with the only difference being
that it is not a serializing instruction by default.  It improves
performance when being used in a hot path, e.g., setting FRED RSP0.

Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Tested-by: Shan Kang <shan.kang@intel.com>
---
 arch/x86/kvm/cpuid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index c55d150ece8d..63a78ebf9482 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -700,7 +700,7 @@ void kvm_set_cpu_caps(void)
 	kvm_cpu_cap_mask(CPUID_7_1_EAX,
 		F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) |
 		F(FZRM) | F(FSRS) | F(FSRC) | F(FRED) | F(LKGS) |
-		F(AMX_FP16) | F(AVX_IFMA) | F(LAM)
+		F(WRMSRNS) | F(AMX_FP16) | F(AVX_IFMA) | F(LAM)
 	);
 
 	kvm_cpu_cap_init_kvm_defined(CPUID_7_1_EDX,
-- 
2.46.2