2 files changed, 20 insertions, 0 deletions

diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 3d1bf41e8892..03d1984bd363 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -169,11 +169,29 @@ static void vp_set_status(struct virtio_device *vdev, u8 status)
         iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 }
 
+/* wait for pending irq handlers */
+static void vp_synchronize_vectors(struct virtio_device *vdev)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        int i;
+
+        if (vp_dev->intx_enabled)
+                synchronize_irq(vp_dev->pci_dev->irq);
+
+        for (i = 0; i < vp_dev->msix_vectors; ++i)
+                synchronize_irq(vp_dev->msix_entries[i].vector);
+}
+
 static void vp_reset(struct virtio_device *vdev)
 {
         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
         /* 0 status means a reset. */
         iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
+        /* Flush out the status write, and flush in device writes,
+         * including MSi-X interrupts, if any. */
+        ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
+        /* Flush pending VQ/configuration callbacks. */
+        vp_synchronize_vectors(vdev);
 }
 
 /* the notify function used when creating a virt queue */
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index add4790b21fe..e9e72bda1b72 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -85,6 +85,8 @@
  * @reset: reset the device
  *      vdev: the virtio device
  *      After this, status and feature negotiation must be done again
+ *      Device must not be reset from its vq/config callbacks, or in
+ *      parallel with being added/removed.
  * @find_vqs: find virtqueues and instantiate them.
  *      vdev: the virtio_device
  *      nvqs: the number of virtqueues to find