KVM: Disable vapic support on Intel machines with FlexPriority

FlexPriority accelerates the tpr without any patching.

Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/svm.c

@@ -1653,6 +1653,11 @@ static void svm_check_processor_compat(void *rtn)
 	*(int *)rtn = 0;
 }
 
+static bool svm_cpu_has_accelerated_tpr(void)
+{
+	return false;
+}
+
 static struct kvm_x86_ops svm_x86_ops = {
 	.cpu_has_kvm_support = has_svm,
 	.disabled_by_bios = is_disabled,
@@ -1661,6 +1666,7 @@ static struct kvm_x86_ops svm_x86_ops = {
 	.check_processor_compatibility = svm_check_processor_compat,
 	.hardware_enable = svm_hardware_enable,
 	.hardware_disable = svm_hardware_disable,
+	.cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr,
 
 	.vcpu_create = svm_create_vcpu,
 	.vcpu_free = svm_free_vcpu,

arch/x86/kvm/vmx.c

@@ -192,7 +192,7 @@ static inline int cpu_has_secondary_exec_ctrls(void)
 		CPU_BASED_ACTIVATE_SECONDARY_CONTROLS);
 }
 
-static inline int cpu_has_vmx_virtualize_apic_accesses(void)
+static inline bool cpu_has_vmx_virtualize_apic_accesses(void)
 {
 	return (vmcs_config.cpu_based_2nd_exec_ctrl &
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES);
@@ -2565,6 +2565,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.check_processor_compatibility = vmx_check_processor_compat,
 	.hardware_enable = hardware_enable,
 	.hardware_disable = hardware_disable,
+	.cpu_has_accelerated_tpr = cpu_has_vmx_virtualize_apic_accesses,
 
 	.vcpu_create = vmx_create_vcpu,
 	.vcpu_free = vmx_free_vcpu,

arch/x86/kvm/x86.c

@@ -684,9 +684,11 @@ int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_SET_TSS_ADDR:
 	case KVM_CAP_EXT_CPUID:
-	case KVM_CAP_VAPIC:
 		r = 1;
 		break;
+	case KVM_CAP_VAPIC:
+		r = !kvm_x86_ops->cpu_has_accelerated_tpr();
+		break;
 	default:
 		r = 0;
 		break;

include/asm-x86/kvm_host.h

@@ -329,6 +329,7 @@ struct kvm_x86_ops {
 	void (*check_processor_compatibility)(void *rtn);
 	int (*hardware_setup)(void);               /* __init */
 	void (*hardware_unsetup)(void);            /* __exit */
+	bool (*cpu_has_accelerated_tpr)(void);
 
 	/* Create, but do not attach this VCPU */
 	struct kvm_vcpu *(*vcpu_create)(struct kvm *kvm, unsigned id);