linux-kernel - [PATCH 2/3] KVM: x86: expose MOVDIRI CPU feature into VM.

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Date:   Tue, 10 Jul 2018 16:54:42 +0800
From:   Jingqi Liu <jingqi.liu@...el.com>
To:     pbonzini@...hat.com, rkrcmar@...hat.com, tglx@...utronix.de,
        mingo@...hat.com, hpa@...or.com
Cc:     x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        wei.w.wang@...el.com, Jingqi Liu <jingqi.liu@...el.com>
Subject: [PATCH 2/3] KVM: x86: expose MOVDIRI CPU feature into VM.

MOVDIRI moves doubleword or quadword from register to memory through
direct store which is implemented by using write combining (WC) for
writing data directly into memory without caching the data.

Availability of the MOVDIRI instruction is indicated by the presence of
the CPUID feature flag MOVDIRI(CPUID.0x07.0x0:ECX[bit 27]).

This patch exposes the movdiri feature to the guest.

The release document ref below link:
https://software.intel.com/sites/default/files/managed/c5/15/\
architecture-instruction-set-extensions-programming-reference.pdf
This patch has a dependency on https://lkml.org/lkml/2018/6/15/654.

Signed-off-by: Jingqi Liu <jingqi.liu@...el.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 e16c05e..456caf7 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -406,7 +406,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ |
 		F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
 		F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
-		F(CLDEMOTE) | F(WAITPKG);
+		F(CLDEMOTE) | F(WAITPKG) | F(MOVDIRI);

 	/* cpuid 7.0.edx*/
 	const u32 kvm_cpuid_7_0_edx_x86_features =
-- 
1.8.3.1