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Diffstat (limited to 'arch/powerpc/kvm/book3s_hv.c')
-rw-r--r--arch/powerpc/kvm/book3s_hv.c41
1 files changed, 33 insertions, 8 deletions
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index c886557638a1..6fa518f6501d 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -225,6 +225,13 @@ static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu)
int cpu;
struct rcuwait *waitp;
+ /*
+ * rcuwait_wake_up contains smp_mb() which orders prior stores that
+ * create pending work vs below loads of cpu fields. The other side
+ * is the barrier in vcpu run that orders setting the cpu fields vs
+ * testing for pending work.
+ */
+
waitp = kvm_arch_vcpu_get_wait(vcpu);
if (rcuwait_wake_up(waitp))
++vcpu->stat.generic.halt_wakeup;
@@ -1089,7 +1096,7 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
break;
}
tvcpu->arch.prodded = 1;
- smp_mb();
+ smp_mb(); /* This orders prodded store vs ceded load */
if (tvcpu->arch.ceded)
kvmppc_fast_vcpu_kick_hv(tvcpu);
break;
@@ -3766,6 +3773,14 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
pvc = core_info.vc[sub];
pvc->pcpu = pcpu + thr;
for_each_runnable_thread(i, vcpu, pvc) {
+ /*
+ * XXX: is kvmppc_start_thread called too late here?
+ * It updates vcpu->cpu and vcpu->arch.thread_cpu
+ * which are used by kvmppc_fast_vcpu_kick_hv(), but
+ * kick is called after new exceptions become available
+ * and exceptions are checked earlier than here, by
+ * kvmppc_core_prepare_to_enter.
+ */
kvmppc_start_thread(vcpu, pvc);
kvmppc_create_dtl_entry(vcpu, pvc);
trace_kvm_guest_enter(vcpu);
@@ -4487,6 +4502,21 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
if (need_resched() || !kvm->arch.mmu_ready)
goto out;
+ vcpu->cpu = pcpu;
+ vcpu->arch.thread_cpu = pcpu;
+ vc->pcpu = pcpu;
+ local_paca->kvm_hstate.kvm_vcpu = vcpu;
+ local_paca->kvm_hstate.ptid = 0;
+ local_paca->kvm_hstate.fake_suspend = 0;
+
+ /*
+ * Orders set cpu/thread_cpu vs testing for pending interrupts and
+ * doorbells below. The other side is when these fields are set vs
+ * kvmppc_fast_vcpu_kick_hv reading the cpu/thread_cpu fields to
+ * kick a vCPU to notice the pending interrupt.
+ */
+ smp_mb();
+
if (!nested) {
kvmppc_core_prepare_to_enter(vcpu);
if (test_bit(BOOK3S_IRQPRIO_EXTERNAL,
@@ -4506,13 +4536,6 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
tb = mftb();
- vcpu->cpu = pcpu;
- vcpu->arch.thread_cpu = pcpu;
- vc->pcpu = pcpu;
- local_paca->kvm_hstate.kvm_vcpu = vcpu;
- local_paca->kvm_hstate.ptid = 0;
- local_paca->kvm_hstate.fake_suspend = 0;
-
__kvmppc_create_dtl_entry(vcpu, pcpu, tb + vc->tb_offset, 0);
trace_kvm_guest_enter(vcpu);
@@ -4614,6 +4637,8 @@ int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu, u64 time_limit,
run->exit_reason = KVM_EXIT_INTR;
vcpu->arch.ret = -EINTR;
out:
+ vcpu->cpu = -1;
+ vcpu->arch.thread_cpu = -1;
powerpc_local_irq_pmu_restore(flags);
preempt_enable();
goto done;