linux-kernel - [PATCH 43/61] KVM: x86: Use KVM cpu caps to mark CR4.LA57 as not-reserved

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Date:   Sat,  1 Feb 2020 10:52:00 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 43/61] KVM: x86: Use KVM cpu caps to mark CR4.LA57 as not-reserved

Add accessor(s) for KVM cpu caps and use said accessor to detect
hardware support for LA57 instead of manually querying CPUID.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/cpuid.h | 13 +++++++++++++
 arch/x86/kvm/x86.c   |  2 +-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 7b71ae0ca05e..5ce4219d465f 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -274,6 +274,19 @@ static __always_inline void kvm_cpu_cap_set(unsigned x86_feature)
 	kvm_cpu_caps[x86_leaf] |= __feature_bit(x86_feature);
 }
 
+static __always_inline u32 kvm_cpu_cap_get(unsigned x86_feature)
+{
+	unsigned x86_leaf = x86_feature / 32;
+
+	reverse_cpuid_check(x86_leaf);
+	return kvm_cpu_caps[x86_leaf] & __feature_bit(x86_feature);
+}
+
+static __always_inline bool kvm_cpu_cap_has(unsigned x86_feature)
+{
+	return kvm_cpu_cap_get(x86_feature);
+}
+
 static __always_inline void kvm_cpu_cap_check_and_set(unsigned x86_feature)
 {
 	if (boot_cpu_has(x86_feature))
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c5ed199d6cd9..cb40737187a1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -912,7 +912,7 @@ static u64 kvm_host_cr4_reserved_bits(struct cpuinfo_x86 *c)
 {
 	u64 reserved_bits = __cr4_reserved_bits(cpu_has, c);
 
-	if (cpuid_ecx(0x7) & feature_bit(LA57))
+	if (kvm_cpu_cap_has(X86_FEATURE_LA57))
 		reserved_bits &= ~X86_CR4_LA57;
 
 	if (kvm_x86_ops->umip_emulated())
-- 
2.24.1