KVM: x86: Add dedicated helper to get CPUID entry with significant index

Add a second CPUID helper, kvm_find_cpuid_entry_index(), to handle KVM
queries for CPUID leaves whose index _may_ be significant, and drop the
index param from the existing kvm_find_cpuid_entry().  Add a WARN in the
inner helper, cpuid_entry2_find(), to detect attempts to retrieve a CPUID
entry whose index is significant without explicitly providing an index.

Using an explicit magic number and letting callers omit the index avoids
confusion by eliminating the myriad cases where KVM specifies '0' as a
dummy value.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 9 insertions, 9 deletions

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 53ccba896e77..4bc098fbec31 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -531,7 +531,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 	pmu->pebs_enable_mask = ~0ull;
 	pmu->pebs_data_cfg_mask = ~0ull;
 
-	entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
+	entry = kvm_find_cpuid_entry(vcpu, 0xa);
 	if (!entry || !vcpu->kvm->arch.enable_pmu)
 		return;
 	eax.full = entry->eax;
@@ -577,7 +577,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 		pmu->global_ovf_ctrl_mask &=
 				~MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI;
 
-	entry = kvm_find_cpuid_entry(vcpu, 7, 0);
+	entry = kvm_find_cpuid_entry_index(vcpu, 7, 0);
 	if (entry &&
 	    (boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
 	    (entry->ebx & (X86_FEATURE_HLE|X86_FEATURE_RTM))) {
diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index 7ae8aa73724c..aba8cebdc587 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -148,8 +148,8 @@ static int __handle_encls_ecreate(struct kvm_vcpu *vcpu,
 	u8 max_size_log2;
 	int trapnr, ret;
 
-	sgx_12_0 = kvm_find_cpuid_entry(vcpu, 0x12, 0);
-	sgx_12_1 = kvm_find_cpuid_entry(vcpu, 0x12, 1);
+	sgx_12_0 = kvm_find_cpuid_entry_index(vcpu, 0x12, 0);
+	sgx_12_1 = kvm_find_cpuid_entry_index(vcpu, 0x12, 1);
 	if (!sgx_12_0 || !sgx_12_1) {
 		kvm_prepare_emulation_failure_exit(vcpu);
 		return 0;
@@ -431,7 +431,7 @@ static bool sgx_intercept_encls_ecreate(struct kvm_vcpu *vcpu)
 	if (!vcpu->kvm->arch.sgx_provisioning_allowed)
 		return true;
 
-	guest_cpuid = kvm_find_cpuid_entry(vcpu, 0x12, 0);
+	guest_cpuid = kvm_find_cpuid_entry_index(vcpu, 0x12, 0);
 	if (!guest_cpuid)
 		return true;
 
@@ -439,7 +439,7 @@ static bool sgx_intercept_encls_ecreate(struct kvm_vcpu *vcpu)
 	if (guest_cpuid->ebx != ebx || guest_cpuid->edx != edx)
 		return true;
 
-	guest_cpuid = kvm_find_cpuid_entry(vcpu, 0x12, 1);
+	guest_cpuid = kvm_find_cpuid_entry_index(vcpu, 0x12, 1);
 	if (!guest_cpuid)
 		return true;
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 3842e121070a..e6ab2c2c4d3b 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7430,7 +7430,7 @@ static void nested_vmx_cr_fixed1_bits_update(struct kvm_vcpu *vcpu)
 		vmx->nested.msrs.cr4_fixed1 |= (_cr4_mask);	\
 } while (0)
 
-	entry = kvm_find_cpuid_entry(vcpu, 0x1, 0);
+	entry = kvm_find_cpuid_entry(vcpu, 0x1);
 	cr4_fixed1_update(X86_CR4_VME,        edx, feature_bit(VME));
 	cr4_fixed1_update(X86_CR4_PVI,        edx, feature_bit(VME));
 	cr4_fixed1_update(X86_CR4_TSD,        edx, feature_bit(TSC));
@@ -7446,7 +7446,7 @@ static void nested_vmx_cr_fixed1_bits_update(struct kvm_vcpu *vcpu)
 	cr4_fixed1_update(X86_CR4_PCIDE,      ecx, feature_bit(PCID));
 	cr4_fixed1_update(X86_CR4_OSXSAVE,    ecx, feature_bit(XSAVE));
 
-	entry = kvm_find_cpuid_entry(vcpu, 0x7, 0);
+	entry = kvm_find_cpuid_entry_index(vcpu, 0x7, 0);
 	cr4_fixed1_update(X86_CR4_FSGSBASE,   ebx, feature_bit(FSGSBASE));
 	cr4_fixed1_update(X86_CR4_SMEP,       ebx, feature_bit(SMEP));
 	cr4_fixed1_update(X86_CR4_SMAP,       ebx, feature_bit(SMAP));
@@ -7481,7 +7481,7 @@ static void update_intel_pt_cfg(struct kvm_vcpu *vcpu)
 	int i;
 
 	for (i = 0; i < PT_CPUID_LEAVES; i++) {
-		best = kvm_find_cpuid_entry(vcpu, 0x14, i);
+		best = kvm_find_cpuid_entry_index(vcpu, 0x14, i);
 		if (!best)
 			return;
 		vmx->pt_desc.caps[CPUID_EAX + i*PT_CPUID_REGS_NUM] = best->eax;