KVM: x86: Add return value to kvm_cpuid().
Return false in kvm_cpuid() when it fails to find the cpuid
entry. Also, this routine(and its caller) is optimized with
a new argument - check_limit, so that the check_cpuid_limit()
fall back can be avoided.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 59ca2ee..1450547 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -853,16 +853,24 @@ static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
}
-void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
+bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
+ u32 *ecx, u32 *edx, bool check_limit)
{
u32 function = *eax, index = *ecx;
struct kvm_cpuid_entry2 *best;
+ bool entry_found = true;
best = kvm_find_cpuid_entry(vcpu, function, index);
- if (!best)
- best = check_cpuid_limit(vcpu, function, index);
+ if (!best) {
+ entry_found = false;
+ if (!check_limit)
+ goto out;
+ best = check_cpuid_limit(vcpu, function, index);
+ }
+
+out:
if (best) {
*eax = best->eax;
*ebx = best->ebx;
@@ -870,7 +878,8 @@ void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
*edx = best->edx;
} else
*eax = *ebx = *ecx = *edx = 0;
- trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx);
+ trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx, entry_found);
+ return entry_found;
}
EXPORT_SYMBOL_GPL(kvm_cpuid);
@@ -883,7 +892,7 @@ int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
- kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
+ kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, true);
kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);