powerpc/64s: guard optional TIDR SPR with CPU ftr test

The TIDR SPR only exists on POWER9. Avoid accessing it when the
feature bit for it is not set.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211123095231.1036501-3-npiggin@gmail.com

arch/powerpc/kvm/book3s_hv.c

@@ -3780,7 +3780,8 @@ static void load_spr_state(struct kvm_vcpu *vcpu)
 	mtspr(SPRN_EBBHR, vcpu->arch.ebbhr);
 	mtspr(SPRN_EBBRR, vcpu->arch.ebbrr);
 	mtspr(SPRN_BESCR, vcpu->arch.bescr);
-	mtspr(SPRN_TIDR, vcpu->arch.tid);
+	if (cpu_has_feature(CPU_FTR_P9_TIDR))
+		mtspr(SPRN_TIDR, vcpu->arch.tid);
 	mtspr(SPRN_AMR, vcpu->arch.amr);
 	mtspr(SPRN_UAMOR, vcpu->arch.uamor);
 
@@ -3806,7 +3807,8 @@ static void store_spr_state(struct kvm_vcpu *vcpu)
 	vcpu->arch.ebbhr = mfspr(SPRN_EBBHR);
 	vcpu->arch.ebbrr = mfspr(SPRN_EBBRR);
 	vcpu->arch.bescr = mfspr(SPRN_BESCR);
-	vcpu->arch.tid = mfspr(SPRN_TIDR);
+	if (cpu_has_feature(CPU_FTR_P9_TIDR))
+		vcpu->arch.tid = mfspr(SPRN_TIDR);
 	vcpu->arch.amr = mfspr(SPRN_AMR);
 	vcpu->arch.uamor = mfspr(SPRN_UAMOR);
 	vcpu->arch.dscr = mfspr(SPRN_DSCR);
@@ -3826,7 +3828,8 @@ struct p9_host_os_sprs {
 static void save_p9_host_os_sprs(struct p9_host_os_sprs *host_os_sprs)
 {
 	host_os_sprs->dscr = mfspr(SPRN_DSCR);
-	host_os_sprs->tidr = mfspr(SPRN_TIDR);
+	if (cpu_has_feature(CPU_FTR_P9_TIDR))
+		host_os_sprs->tidr = mfspr(SPRN_TIDR);
 	host_os_sprs->iamr = mfspr(SPRN_IAMR);
 	host_os_sprs->amr = mfspr(SPRN_AMR);
 	host_os_sprs->fscr = mfspr(SPRN_FSCR);
@@ -3840,7 +3843,8 @@ static void restore_p9_host_os_sprs(struct kvm_vcpu *vcpu,
 	mtspr(SPRN_UAMOR, 0);
 
 	mtspr(SPRN_DSCR, host_os_sprs->dscr);
-	mtspr(SPRN_TIDR, host_os_sprs->tidr);
+	if (cpu_has_feature(CPU_FTR_P9_TIDR))
+		mtspr(SPRN_TIDR, host_os_sprs->tidr);
 	mtspr(SPRN_IAMR, host_os_sprs->iamr);
 
 	if (host_os_sprs->amr != vcpu->arch.amr)

arch/powerpc/xmon/xmon.c

@@ -2107,8 +2107,14 @@ static void dump_300_sprs(void)
 	if (!cpu_has_feature(CPU_FTR_ARCH_300))
 		return;
 
-	printf("pidr   = %.16lx  tidr  = %.16lx\n",
-		mfspr(SPRN_PID), mfspr(SPRN_TIDR));
+	if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
+		printf("pidr   = %.16lx  tidr  = %.16lx\n",
+			mfspr(SPRN_PID), mfspr(SPRN_TIDR));
+	} else {
+		printf("pidr   = %.16lx\n",
+			mfspr(SPRN_PID));
+	}
+
 	printf("psscr  = %.16lx\n",
 		hv ? mfspr(SPRN_PSSCR) : mfspr(SPRN_PSSCR_PR));