linux-kernel - [PATCH 26/61] KVM: x86: Introduce cpuid_entry

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Message-Id: <20200201185218.24473-27-sean.j.christopherson@intel.com>
Date:   Sat,  1 Feb 2020 10:51:43 -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 26/61] KVM: x86: Introduce cpuid_entry_{get,has}() accessors

Introduce accessors to retrieve feature bits from CPUID entries and use
the new accessors where applicable.  Using the accessors eliminates the
need to manually specify the register to be queried at no extra cost
(binary output is identical) and will allow adding runtime consistency
checks on the function and index in a future patch.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/cpuid.c |  9 +++++----
 arch/x86/kvm/cpuid.h | 46 +++++++++++++++++++++++++++++++++++---------
 2 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index e3026fe638aa..3316963dad3d 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -68,7 +68,7 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
 		best->edx |= F(APIC);
 
 	if (apic) {
-		if (best->ecx & F(TSC_DEADLINE_TIMER))
+		if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER))
 			apic->lapic_timer.timer_mode_mask = 3 << 17;
 		else
 			apic->lapic_timer.timer_mode_mask = 1 << 17;
@@ -96,7 +96,8 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
 	}
 
 	best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
-	if (best && (best->eax & (F(XSAVES) | F(XSAVEC))))
+	if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
+		     cpuid_entry_has(best, X86_FEATURE_XSAVEC)))
 		best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
 
 	/*
@@ -155,7 +156,7 @@ static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
 			break;
 		}
 	}
-	if (entry && (entry->edx & F(NX)) && !is_efer_nx()) {
+	if (entry && cpuid_entry_has(entry, X86_FEATURE_NX) && !is_efer_nx()) {
 		entry->edx &= ~F(NX);
 		printk(KERN_INFO "kvm: guest NX capability removed\n");
 	}
@@ -387,7 +388,7 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry)
 		entry->ebx |= F(TSC_ADJUST);
 
 		entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;
-		f_la57 = entry->ecx & F(LA57);
+		f_la57 = cpuid_entry_get(entry, X86_FEATURE_LA57);
 		cpuid_mask(&entry->ecx, CPUID_7_ECX);
 		/* Set LA57 based on hardware capability. */
 		entry->ecx |= f_la57;
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 72a79bdfed6b..64e96e4086e2 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -95,16 +95,10 @@ static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned x86_feature)
 	return reverse_cpuid[x86_leaf];
 }
 
-static __always_inline u32 *guest_cpuid_get_register(struct kvm_vcpu *vcpu, unsigned x86_feature)
+static __always_inline u32 *__cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry,
+						  const struct cpuid_reg *cpuid)
 {
-	struct kvm_cpuid_entry2 *entry;
-	const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature);
-
-	entry = kvm_find_cpuid_entry(vcpu, cpuid.function, cpuid.index);
-	if (!entry)
-		return NULL;
-
-	switch (cpuid.reg) {
+	switch (cpuid->reg) {
 	case CPUID_EAX:
 		return &entry->eax;
 	case CPUID_EBX:
@@ -119,6 +113,40 @@ static __always_inline u32 *guest_cpuid_get_register(struct kvm_vcpu *vcpu, unsi
 	}
 }
 
+static __always_inline u32 *cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry,
+						unsigned x86_feature)
+{
+	const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature);
+
+	return __cpuid_entry_get_reg(entry, &cpuid);
+}
+
+static __always_inline u32 cpuid_entry_get(struct kvm_cpuid_entry2 *entry,
+					   unsigned x86_feature)
+{
+	u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
+
+	return *reg & __feature_bit(x86_feature);
+}
+
+static __always_inline bool cpuid_entry_has(struct kvm_cpuid_entry2 *entry,
+					    unsigned x86_feature)
+{
+	return cpuid_entry_get(entry, x86_feature);
+}
+
+static __always_inline int *guest_cpuid_get_register(struct kvm_vcpu *vcpu, unsigned x86_feature)
+{
+	struct kvm_cpuid_entry2 *entry;
+	const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature);
+
+	entry = kvm_find_cpuid_entry(vcpu, cpuid.function, cpuid.index);
+	if (!entry)
+		return NULL;
+
+	return __cpuid_entry_get_reg(entry, &cpuid);
+}
+
 static __always_inline bool guest_cpuid_has(struct kvm_vcpu *vcpu, unsigned x86_feature)
 {
 	u32 *reg;
-- 
2.24.1