KVM: PPC: Book3S PR: Implement RFID TM behavior to suppress change from S0 to N0

According to ISA specification for RFID, in MSR TM disabled and TS
suspended state (S0), if the target MSR is TM disabled and TS state is
inactive (N0), rfid should suppress this update.

This patch makes the RFID emulation of PR KVM consistent with this.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/book3s_emulate.c

@@ -117,11 +117,28 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	case 19:
 		switch (get_xop(inst)) {
 		case OP_19_XOP_RFID:
-		case OP_19_XOP_RFI:
+		case OP_19_XOP_RFI: {
+			unsigned long srr1 = kvmppc_get_srr1(vcpu);
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+			unsigned long cur_msr = kvmppc_get_msr(vcpu);
+
+			/*
+			 * add rules to fit in ISA specification regarding TM
+			 * state transistion in TM disable/Suspended state,
+			 * and target TM state is TM inactive(00) state. (the
+			 * change should be suppressed).
+			 */
+			if (((cur_msr & MSR_TM) == 0) &&
+				((srr1 & MSR_TM) == 0) &&
+				MSR_TM_SUSPENDED(cur_msr) &&
+				!MSR_TM_ACTIVE(srr1))
+				srr1 |= MSR_TS_S;
+#endif
 			kvmppc_set_pc(vcpu, kvmppc_get_srr0(vcpu));
-			kvmppc_set_msr(vcpu, kvmppc_get_srr1(vcpu));
+			kvmppc_set_msr(vcpu, srr1);
 			*advance = 0;
 			break;
+		}
 
 		default:
 			emulated = EMULATE_FAIL;