KVM: PPC: Add emulation for dcba

Mac OS X uses the dcba instruction. According to the specification it doesn't
guarantee any functionality, so let's just emulate it as nop.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/kvm/book3s_64_emulate.c

@@ -37,6 +37,7 @@
 #define OP_31_XOP_SLBIA		498
 #define OP_31_XOP_MFSR		595
 #define OP_31_XOP_MFSRIN	659
+#define OP_31_XOP_DCBA		758
 #define OP_31_XOP_SLBMFEV	851
 #define OP_31_XOP_EIOIO		854
 #define OP_31_XOP_SLBMFEE	915
@@ -183,6 +184,9 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
 				kvmppc_set_gpr(vcpu, get_rt(inst), t);
 			}
 			break;
+		case OP_31_XOP_DCBA:
+			/* Gets treated as NOP */
+			break;
 		case OP_31_XOP_DCBZ:
 		{
 			ulong rb = kvmppc_get_gpr(vcpu, get_rb(inst));