1 files changed, 37 insertions, 12 deletions

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index b6bc867dfc61..94294c3efb91 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1576,6 +1576,20 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
 	return r;
 }
 
+/*
+ * On POWER9, threads are independent and can be in different partitions.
+ * Therefore we consider each thread to be a subcore.
+ * There is a restriction that all threads have to be in the same
+ * MMU mode (radix or HPT), unfortunately, but since we only support
+ * HPT guests on a HPT host so far, that isn't an impediment yet.
+ */
+static int threads_per_vcore(void)
+{
+	if (cpu_has_feature(CPU_FTR_ARCH_300))
+		return 1;
+	return threads_per_subcore;
+}
+
 static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int core)
 {
 	struct kvmppc_vcore *vcore;
@@ -1590,7 +1604,7 @@ static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int core)
 	init_swait_queue_head(&vcore->wq);
 	vcore->preempt_tb = TB_NIL;
 	vcore->lpcr = kvm->arch.lpcr;
-	vcore->first_vcpuid = core * threads_per_subcore;
+	vcore->first_vcpuid = core * threads_per_vcore();
 	vcore->kvm = kvm;
 	INIT_LIST_HEAD(&vcore->preempt_list);
 
@@ -1753,7 +1767,7 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm,
 	int core;
 	struct kvmppc_vcore *vcore;
 
-	core = id / threads_per_subcore;
+	core = id / threads_per_vcore();
 	if (core >= KVM_MAX_VCORES)
 		goto out;
 
@@ -1971,7 +1985,10 @@ static void kvmppc_wait_for_nap(void)
 {
 	int cpu = smp_processor_id();
 	int i, loops;
+	int n_threads = threads_per_vcore();
 
+	if (n_threads <= 1)
+		return;
 	for (loops = 0; loops < 1000000; ++loops) {
 		/*
 		 * Check if all threads are finished.
@@ -1979,17 +1996,17 @@ static void kvmppc_wait_for_nap(void)
 		 * and the thread clears it when finished, so we look
 		 * for any threads that still have a non-NULL vcore ptr.
 		 */
-		for (i = 1; i < threads_per_subcore; ++i)
+		for (i = 1; i < n_threads; ++i)
 			if (paca[cpu + i].kvm_hstate.kvm_vcore)
 				break;
-		if (i == threads_per_subcore) {
+		if (i == n_threads) {
 			HMT_medium();
 			return;
 		}
 		HMT_low();
 	}
 	HMT_medium();
-	for (i = 1; i < threads_per_subcore; ++i)
+	for (i = 1; i < n_threads; ++i)
 		if (paca[cpu + i].kvm_hstate.kvm_vcore)
 			pr_err("KVM: CPU %d seems to be stuck\n", cpu + i);
 }
@@ -2055,7 +2072,7 @@ static void kvmppc_vcore_preempt(struct kvmppc_vcore *vc)
 
 	vc->vcore_state = VCORE_PREEMPT;
 	vc->pcpu = smp_processor_id();
-	if (vc->num_threads < threads_per_subcore) {
+	if (vc->num_threads < threads_per_vcore()) {
 		spin_lock(&lp->lock);
 		list_add_tail(&vc->preempt_list, &lp->list);
 		spin_unlock(&lp->lock);
@@ -2342,6 +2359,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 	unsigned long cmd_bit, stat_bit;
 	int pcpu, thr;
 	int target_threads;
+	int controlled_threads;
 
 	/*
 	 * Remove from the list any threads that have a signal pending
@@ -2360,11 +2378,18 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 	vc->preempt_tb = TB_NIL;
 
 	/*
+	 * Number of threads that we will be controlling: the same as
+	 * the number of threads per subcore, except on POWER9,
+	 * where it's 1 because the threads are (mostly) independent.
+	 */
+	controlled_threads = threads_per_vcore();
+
+	/*
 	 * Make sure we are running on primary threads, and that secondary
 	 * threads are offline.  Also check if the number of threads in this
 	 * guest are greater than the current system threads per guest.
 	 */
-	if ((threads_per_core > 1) &&
+	if ((controlled_threads > 1) &&
 	    ((vc->num_threads > threads_per_subcore) || !on_primary_thread())) {
 		for_each_runnable_thread(i, vcpu, vc) {
 			vcpu->arch.ret = -EBUSY;
@@ -2380,7 +2405,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 	 */
 	init_core_info(&core_info, vc);
 	pcpu = smp_processor_id();
-	target_threads = threads_per_subcore;
+	target_threads = controlled_threads;
 	if (target_smt_mode && target_smt_mode < target_threads)
 		target_threads = target_smt_mode;
 	if (vc->num_threads < target_threads)
@@ -2416,7 +2441,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 		smp_wmb();
 	}
 	pcpu = smp_processor_id();
-	for (thr = 0; thr < threads_per_subcore; ++thr)
+	for (thr = 0; thr < controlled_threads; ++thr)
 		paca[pcpu + thr].kvm_hstate.kvm_split_mode = sip;
 
 	/* Initiate micro-threading (split-core) if required */
@@ -2526,7 +2551,7 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 	}
 
 	/* Let secondaries go back to the offline loop */
-	for (i = 0; i < threads_per_subcore; ++i) {
+	for (i = 0; i < controlled_threads; ++i) {
 		kvmppc_release_hwthread(pcpu + i);
 		if (sip && sip->napped[i])
 			kvmppc_ipi_thread(pcpu + i);
@@ -3392,9 +3417,9 @@ static int kvmppc_core_check_processor_compat_hv(void)
 	    !cpu_has_feature(CPU_FTR_ARCH_206))
 		return -EIO;
 	/*
-	 * Disable KVM for Power9, untill the required bits merged.
+	 * Disable KVM for Power9 in radix mode.
 	 */
-	if (cpu_has_feature(CPU_FTR_ARCH_300))
+	if (cpu_has_feature(CPU_FTR_ARCH_300) && radix_enabled())
 		return -EIO;
 
 	return 0;