KVM: PPC: Correctly report KVM_CAP_PPC_ALLOC_HTAB

At present KVM on powerpc always reports KVM_CAP_PPC_ALLOC_HTAB as enabled.
However, the ioctl() it advertises (KVM_PPC_ALLOCATE_HTAB) only actually
works on KVM HV.  On KVM PR it will fail with ENOTTY.

QEMU already has a workaround for this, so it's not breaking things in
practice, but it would be better to advertise this correctly.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/powerpc.c

@@ -536,7 +536,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 #ifdef CONFIG_PPC_BOOK3S_64
 	case KVM_CAP_SPAPR_TCE:
 	case KVM_CAP_SPAPR_TCE_64:
-	case KVM_CAP_PPC_ALLOC_HTAB:
 	case KVM_CAP_PPC_RTAS:
 	case KVM_CAP_PPC_FIXUP_HCALL:
 	case KVM_CAP_PPC_ENABLE_HCALL:
@@ -545,6 +544,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 #endif
 		r = 1;
 		break;
+
+	case KVM_CAP_PPC_ALLOC_HTAB:
+		r = hv_enabled;
+		break;
 #endif /* CONFIG_PPC_BOOK3S_64 */
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 	case KVM_CAP_PPC_SMT: