KVM: x86: announce KVM_FEATURE_ASYNC_PF_INT

Introduce new capability to indicate that KVM supports interrupt based
delivery of 'page ready' APF events. This includes support for both
MSR_KVM_ASYNC_PF_INT and MSR_KVM_ASYNC_PF_ACK.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200525144125.143875-8-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -3446,6 +3446,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_X86_ROBUST_SINGLESTEP:
 	case KVM_CAP_XSAVE:
 	case KVM_CAP_ASYNC_PF:
+	case KVM_CAP_ASYNC_PF_INT:
 	case KVM_CAP_GET_TSC_KHZ:
 	case KVM_CAP_KVMCLOCK_CTRL:
 	case KVM_CAP_READONLY_MEM: