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SubjectRe: [PATCH] virtio: virtio 1.0 cs04 spec compliance for reset
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On 04/03/2016 08:26 PM, Michael S. Tsirkin wrote:
> The spec says: after writing 0 to device_status, the driver MUST wait
> for a read of device_status to return 0 before reinitializing the
> device.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> drivers/virtio/virtio_pci_modern.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index f6f28cc..e76bd91 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -17,6 +17,7 @@
> *
> */
>
> +#include <linux/delay.h>
> #define VIRTIO_PCI_NO_LEGACY
> #include "virtio_pci_common.h"
>
> @@ -271,9 +272,13 @@ static void vp_reset(struct virtio_device *vdev)
> struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> /* 0 status means a reset. */
> vp_iowrite8(0, &vp_dev->common->device_status);
> - /* Flush out the status write, and flush in device writes,
> - * including MSI-X interrupts, if any. */
> - vp_ioread8(&vp_dev->common->device_status);
> + /* After writing 0 to device_status, the driver MUST wait for a read of
> + * device_status to return 0 before reinitializing the device.
> + * This will flush out the status write, and flush in device writes,
> + * including MSI-X interrupts, if any.
> + */
> + while (vp_ioread8(&vp_dev->common->device_status))
> + msleep(1);
> /* Flush pending VQ/configuration callbacks. */
> vp_synchronize_vectors(vdev);
> }

Acked-by: Jason Wang <jasowang@redhat.com>

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