Rusty Russell
2015-Feb-10 06:35 UTC
[PATCH] 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 at rustcorp.com.au> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index f16e462cb4ef..2aa38e59db2e 100644 --- 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;
Michael S. Tsirkin
2015-Feb-10 06:57 UTC
[PATCH] virtio_pci: use 16-bit accessor for queue_enable.
On Tue, Feb 10, 2015 at 05:05:01PM +1030, Rusty Russell wrote:> 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 at rustcorp.com.au>Acked-by: Michael S. Tsirkin <mst at redhat.com>> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c > index f16e462cb4ef..2aa38e59db2e 100644 > --- 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;
Maybe Matching Threads
- [PATCH] virtio_pci: use 16-bit accessor for queue_enable.
- [PATCH 1/2] virtio_pci_modern: type-safe io accessors
- [PATCH 1/2] virtio_pci_modern: type-safe io accessors
- [RFC 7/11] virtio_pci: new, capability-aware driver.
- [RFC 0/2] virtio_pci: patches never to apply.