linux-kernel - [PATCH 10/10] KVM: x86: Bury guest_cpuid_is_amd_or

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Date: Fri,  5 Apr 2024 16:56:03 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Sandipan Das <sandipan.das@....com>, Jim Mattson <jmattson@...gle.com>, 
	Like Xu <like.xu.linux@...il.com>
Subject: [PATCH 10/10] KVM: x86: Bury guest_cpuid_is_amd_or_hygon() in cpuid.c

Move guest_cpuid_is_amd_or_hygon() into cpuid.c now that, except for one
Intel quirk in the emulator, KVM checks for AMD vs. Intel *compatible*
vCPUs, not exact vendors, i.e. now that there should not be any reason for
KVM at-large to care about the exact vendor.

Opportunistically refactor the guts of the helper to use "entry" instead
of "best", and short circuit the !entry path to make the common case more
readable.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/cpuid.c | 12 ++++++++++++
 arch/x86/kvm/cpuid.h | 10 ----------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 77352a4abd87..c5fb39930213 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -335,6 +335,18 @@ static bool kvm_cpuid_has_hyperv(struct kvm_cpuid_entry2 *entries, int nent)
 #endif
 }
 
+static bool guest_cpuid_is_amd_or_hygon(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpuid_entry2 *entry;
+
+	entry = kvm_find_cpuid_entry(vcpu, 0);
+	if (!entry)
+		return false;
+
+	return is_guest_vendor_amd(entry->ebx, entry->ecx, entry->edx) ||
+	       is_guest_vendor_hygon(entry->ebx, entry->ecx, entry->edx);
+}
+
 static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 03d015e9ce33..41697cca354e 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -102,16 +102,6 @@ static __always_inline void guest_cpuid_clear(struct kvm_vcpu *vcpu,
 		*reg &= ~__feature_bit(x86_feature);
 }
 
-static inline bool guest_cpuid_is_amd_or_hygon(struct kvm_vcpu *vcpu)
-{
-	struct kvm_cpuid_entry2 *best;
-
-	best = kvm_find_cpuid_entry(vcpu, 0);
-	return best &&
-	       (is_guest_vendor_amd(best->ebx, best->ecx, best->edx) ||
-		is_guest_vendor_hygon(best->ebx, best->ecx, best->edx));
-}
-
 static inline bool guest_cpuid_is_amd_compatible(struct kvm_vcpu *vcpu)
 {
 	return vcpu->arch.is_amd_compatible;
-- 
2.44.0.478.gd926399ef9-goog