2 files changed, 35 insertions, 14 deletions

diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index e9693a29d00..4c403750360 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -73,14 +73,13 @@ static int kvm_iommu_map_memslots(struct kvm *kvm)
 {
         int i, r = 0;
 
-        down_read(&kvm->slots_lock);
         for (i = 0; i < kvm->nmemslots; i++) {
                 r = kvm_iommu_map_pages(kvm, kvm->memslots[i].base_gfn,
                                         kvm->memslots[i].npages);
                 if (r)
                         break;
         }
-        up_read(&kvm->slots_lock);
+
         return r;
 }
 
@@ -190,12 +189,11 @@ static void kvm_iommu_put_pages(struct kvm *kvm,
 static int kvm_iommu_unmap_memslots(struct kvm *kvm)
 {
         int i;
-        down_read(&kvm->slots_lock);
+
         for (i = 0; i < kvm->nmemslots; i++) {
                 kvm_iommu_put_pages(kvm, kvm->memslots[i].base_gfn,
                                     kvm->memslots[i].npages);
         }
-        up_read(&kvm->slots_lock);
 
         return 0;
 }
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3a5a08298aa..29a667ce35b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -173,7 +173,6 @@ static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work)
                 assigned_dev->host_irq_disabled = false;
         }
         mutex_unlock(&assigned_dev->kvm->lock);
-        kvm_put_kvm(assigned_dev->kvm);
 }
 
 static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id)
@@ -181,8 +180,6 @@ static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id)
         struct kvm_assigned_dev_kernel *assigned_dev =
                 (struct kvm_assigned_dev_kernel *) dev_id;
 
-        kvm_get_kvm(assigned_dev->kvm);
-
         schedule_work(&assigned_dev->interrupt_work);
 
         disable_irq_nosync(irq);
@@ -213,6 +210,7 @@ static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)
         }
 }
 
+/* The function implicit hold kvm->lock mutex due to cancel_work_sync() */
 static void kvm_free_assigned_irq(struct kvm *kvm,
                                   struct kvm_assigned_dev_kernel *assigned_dev)
 {
@@ -228,11 +226,24 @@ static void kvm_free_assigned_irq(struct kvm *kvm,
         if (!assigned_dev->irq_requested_type)
                 return;
 
-        if (cancel_work_sync(&assigned_dev->interrupt_work))
-                /* We had pending work. That means we will have to take
-                 * care of kvm_put_kvm.
-                 */
-                kvm_put_kvm(kvm);
+        /*
+         * In kvm_free_device_irq, cancel_work_sync return true if:
+         * 1. work is scheduled, and then cancelled.
+         * 2. work callback is executed.
+         *
+         * The first one ensured that the irq is disabled and no more events
+         * would happen. But for the second one, the irq may be enabled (e.g.
+         * for MSI). So we disable irq here to prevent further events.
+         *
+         * Notice this maybe result in nested disable if the interrupt type is
+         * INTx, but it's OK for we are going to free it.
+         *
+         * If this function is a part of VM destroy, please ensure that till
+         * now, the kvm state is still legal for probably we also have to wait
+         * interrupt_work done.
+         */
+        disable_irq_nosync(assigned_dev->host_irq);
+        cancel_work_sync(&assigned_dev->interrupt_work);
 
         free_irq(assigned_dev->host_irq, (void *)assigned_dev);
 
@@ -285,8 +296,8 @@ static int assigned_device_update_intx(struct kvm *kvm,
 
         if (irqchip_in_kernel(kvm)) {
                 if (!msi2intx &&
-                    adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI) {
-                        free_irq(adev->host_irq, (void *)kvm);
+                    (adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI)) {
+                        free_irq(adev->host_irq, (void *)adev);
                         pci_disable_msi(adev->dev);
                 }
 
@@ -455,6 +466,7 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
         struct kvm_assigned_dev_kernel *match;
         struct pci_dev *dev;
 
+        down_read(&kvm->slots_lock);
         mutex_lock(&kvm->lock);
 
         match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
@@ -516,6 +528,7 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
 
 out:
         mutex_unlock(&kvm->lock);
+        up_read(&kvm->slots_lock);
         return r;
 out_list_del:
         list_del(&match->list);
@@ -527,6 +540,7 @@ out_put:
 out_free:
         kfree(match);
         mutex_unlock(&kvm->lock);
+        up_read(&kvm->slots_lock);
         return r;
 }
 #endif
@@ -789,11 +803,19 @@ static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
         return young;
 }
 
+static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
+                                     struct mm_struct *mm)
+{
+        struct kvm *kvm = mmu_notifier_to_kvm(mn);
+        kvm_arch_flush_shadow(kvm);
+}
+
 static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
         .invalidate_page        = kvm_mmu_notifier_invalidate_page,
         .invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
         .invalidate_range_end   = kvm_mmu_notifier_invalidate_range_end,
         .clear_flush_young      = kvm_mmu_notifier_clear_flush_young,
+        .release                = kvm_mmu_notifier_release,
 };
 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
 
@@ -883,6 +905,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
 {
         struct mm_struct *mm = kvm->mm;
 
+        kvm_arch_sync_events(kvm);
         spin_lock(&kvm_lock);
         list_del(&kvm->vm_list);
         spin_unlock(&kvm_lock);