virtio_pci: use 16-bit accessor for queue_enable.

Since PCI is little endian, 8-bit access might work, but the spec section
is very clear on this:

  4.1.3.1 Driver Requirements: PCI Device Layout

  The driver MUST access each field using the “natural” access method,
  i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for 16-bit
  fields and 8-bit accesses for 8-bit fields.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index f16e462cb4ef35510c5022f56e1b3420582f9ceb..2aa38e59db2e0849a7cba101358d970a389b7f80 100644 (file)
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -294,7 +294,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 
        /* Check if queue is either not available or already active. */
        num = ioread16(&cfg->queue_size);
-       if (!num || ioread8(&cfg->queue_enable))
+       if (!num || ioread16(&cfg->queue_enable))
                return ERR_PTR(-ENOENT);
 
        if (num & (num - 1)) {
@@ -394,7 +394,7 @@ static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
         */
        list_for_each_entry(vq, &vdev->vqs, list) {
                iowrite16(vq->index, &vp_dev->common->queue_select);
-               iowrite8(1, &vp_dev->common->queue_enable);
+               iowrite16(1, &vp_dev->common->queue_enable);
        }
 
        return 0;