5 files changed, 45 insertions, 0 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2a7f5d782c33..49ec9038ec14 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -604,6 +604,8 @@ struct kvm_arch {
 	bool iommu_noncoherent;
 #define __KVM_HAVE_ARCH_NONCOHERENT_DMA
 	atomic_t noncoherent_dma_count;
+#define __KVM_HAVE_ARCH_ASSIGNED_DEVICE
+	atomic_t assigned_device_count;
 	struct kvm_pic *vpic;
 	struct kvm_ioapic *vioapic;
 	struct kvm_pit *vpit;
diff --git a/arch/x86/kvm/iommu.c b/arch/x86/kvm/iommu.c
index 7dbced309ddb..5c520ebf6343 100644
--- a/arch/x86/kvm/iommu.c
+++ b/arch/x86/kvm/iommu.c
@@ -200,6 +200,7 @@ int kvm_assign_device(struct kvm *kvm, struct pci_dev *pdev)
 			goto out_unmap;
 	}
 
+	kvm_arch_start_assignment(kvm);
 	pci_set_dev_assigned(pdev);
 
 	dev_info(&pdev->dev, "kvm assign device\n");
@@ -224,6 +225,7 @@ int kvm_deassign_device(struct kvm *kvm, struct pci_dev *pdev)
 	iommu_detach_device(domain, &pdev->dev);
 
 	pci_clear_dev_assigned(pdev);
+	kvm_arch_end_assignment(kvm);
 
 	dev_info(&pdev->dev, "kvm deassign device\n");
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6bd19c7abc65..0024968b342d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8213,6 +8213,24 @@ bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu)
 			kvm_x86_ops->interrupt_allowed(vcpu);
 }
 
+void kvm_arch_start_assignment(struct kvm *kvm)
+{
+	atomic_inc(&kvm->arch.assigned_device_count);
+}
+EXPORT_SYMBOL_GPL(kvm_arch_start_assignment);
+
+void kvm_arch_end_assignment(struct kvm *kvm)
+{
+	atomic_dec(&kvm->arch.assigned_device_count);
+}
+EXPORT_SYMBOL_GPL(kvm_arch_end_assignment);
+
+bool kvm_arch_has_assigned_device(struct kvm *kvm)
+{
+	return atomic_read(&kvm->arch.assigned_device_count);
+}
+EXPORT_SYMBOL_GPL(kvm_arch_has_assigned_device);
+
 void kvm_arch_register_noncoherent_dma(struct kvm *kvm)
 {
 	atomic_inc(&kvm->arch.noncoherent_dma_count);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 9564fd78c547..05e99b8ef465 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -734,6 +734,24 @@ static inline bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
 	return false;
 }
 #endif
+#ifdef __KVM_HAVE_ARCH_ASSIGNED_DEVICE
+void kvm_arch_start_assignment(struct kvm *kvm);
+void kvm_arch_end_assignment(struct kvm *kvm);
+bool kvm_arch_has_assigned_device(struct kvm *kvm);
+#else
+static inline void kvm_arch_start_assignment(struct kvm *kvm)
+{
+}
+
+static inline void kvm_arch_end_assignment(struct kvm *kvm)
+{
+}
+
+static inline bool kvm_arch_has_assigned_device(struct kvm *kvm)
+{
+	return false;
+}
+#endif
 
 static inline wait_queue_head_t *kvm_arch_vcpu_wq(struct kvm_vcpu *vcpu)
 {
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 620e37f741b8..1dd087da6f31 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -155,6 +155,8 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 		list_add_tail(&kvg->node, &kv->group_list);
 		kvg->vfio_group = vfio_group;
 
+		kvm_arch_start_assignment(dev->kvm);
+
 		mutex_unlock(&kv->lock);
 
 		kvm_vfio_update_coherency(dev);
@@ -190,6 +192,8 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 			break;
 		}
 
+		kvm_arch_end_assignment(dev->kvm);
+
 		mutex_unlock(&kv->lock);
 
 		kvm_vfio_group_put_external_user(vfio_group);
@@ -239,6 +243,7 @@ static void kvm_vfio_destroy(struct kvm_device *dev)
 		kvm_vfio_group_put_external_user(kvg->vfio_group);
 		list_del(&kvg->node);
 		kfree(kvg);
+		kvm_arch_end_assignment(dev->kvm);
 	}
 
 	kvm_vfio_update_coherency(dev);