Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Radim Krčmář:
 "ARM:
   - Fix handling of the 32bit cycle counter
   - Fix cycle counter filtering

  x86:
   - Fix a race leading to double unregistering of user notifiers
   - Amend oversight in kvm_arch_set_irq that turned Hyper-V code dead
   - Use SRCU around kvm_lapic_set_vapic_addr
   - Avoid recursive flushing of asynchronous page faults
   - Do not rely on deferred update in KVM_GET_CLOCK, which fixes #GP
   - Let userspace know that KVM_GET_CLOCK is useful with master clock;
     4.9 changed the return value to better match the guest clock, but
     didn't provide means to let guests take advantage of it"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: x86: merge kvm_arch_set_irq and kvm_arch_set_irq_inatomic
  KVM: x86: fix missed SRCU usage in kvm_lapic_set_vapic_addr
  KVM: async_pf: avoid recursive flushing of work items
  kvm: kvmclock: let KVM_GET_CLOCK return whether the master clock is in use
  KVM: Disable irq while unregistering user notifier
  KVM: x86: do not go through vcpu in __get_kvmclock_ns
  KVM: arm64: Fix the issues when guest PMCCFILTR is configured
  arm64: KVM: pmu: Fix AArch32 cycle counter access

1 files changed, 12 insertions, 1 deletions

diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 8035cc1eb955..efeceb0a222d 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -91,6 +91,7 @@ static void async_pf_execute(struct work_struct *work)
 
 	spin_lock(&vcpu->async_pf.lock);
 	list_add_tail(&apf->link, &vcpu->async_pf.done);
+	apf->vcpu = NULL;
 	spin_unlock(&vcpu->async_pf.lock);
 
 	/*
@@ -113,6 +114,8 @@ static void async_pf_execute(struct work_struct *work)
 
 void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 {
+	spin_lock(&vcpu->async_pf.lock);
+
 	/* cancel outstanding work queue item */
 	while (!list_empty(&vcpu->async_pf.queue)) {
 		struct kvm_async_pf *work =
@@ -120,6 +123,14 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 					 typeof(*work), queue);
 		list_del(&work->queue);
 
+		/*
+		 * We know it's present in vcpu->async_pf.done, do
+		 * nothing here.
+		 */
+		if (!work->vcpu)
+			continue;
+
+		spin_unlock(&vcpu->async_pf.lock);
 #ifdef CONFIG_KVM_ASYNC_PF_SYNC
 		flush_work(&work->work);
 #else
@@ -129,9 +140,9 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 			kmem_cache_free(async_pf_cache, work);
 		}
 #endif
+		spin_lock(&vcpu->async_pf.lock);
 	}
 
-	spin_lock(&vcpu->async_pf.lock);
 	while (!list_empty(&vcpu->async_pf.done)) {
 		struct kvm_async_pf *work =
 			list_first_entry(&vcpu->async_pf.done,