linux-kernel - [PATCH v2 1/3] KVM: x86: X86_FEATURE

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Date:   Sat,  5 Aug 2017 00:12:48 +0200
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        David Hildenbrand <david@...hat.com>
Subject: [PATCH v2 1/3] KVM: x86: X86_FEATURE_NRIPS is not scattered anymore

bit(X86_FEATURE_NRIPS) is 3 since 2ccd71f1b278 ("x86/cpufeature: Move
some of the scattered feature bits to x86_capability"), so we can
simplify the code.

Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
---
v2: new, explain why it's ok to use X86_FEATURE_NRIPS (David)
---
 arch/x86/kvm/cpuid.h | 14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index da6728383052..c723d64657d0 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -160,25 +160,13 @@ static inline bool guest_cpuid_has_rdtscp(struct kvm_vcpu *vcpu)
 	return best && (best->edx & bit(X86_FEATURE_RDTSCP));
 }
 
-/*
- * NRIPS is provided through cpuidfn 0x8000000a.edx bit 3
- */
-#define BIT_NRIPS	3
-
 static inline bool guest_cpuid_has_nrips(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpuid_entry2 *best;
 
 	best = kvm_find_cpuid_entry(vcpu, 0x8000000a, 0);
-
-	/*
-	 * NRIPS is a scattered cpuid feature, so we can't use
-	 * X86_FEATURE_NRIPS here (X86_FEATURE_NRIPS would be bit
-	 * position 8, not 3).
-	 */
-	return best && (best->edx & bit(BIT_NRIPS));
+	return best && (best->edx & bit(X86_FEATURE_NRIPS));
 }
-#undef BIT_NRIPS
 
 static inline int guest_cpuid_family(struct kvm_vcpu *vcpu)
 {
-- 
2.13.3