* [PATCH] virtio: virtio 1.0 cs04 spec compliance for reset
@ 2016-04-03 12:26 Michael S. Tsirkin
2016-04-05 2:53 ` Jason Wang
0 siblings, 1 reply; 2+ messages in thread
From: Michael S. Tsirkin @ 2016-04-03 12:26 UTC (permalink / raw)
To: linux-kernel; +Cc: stable, virtualization, Jason Wang, Bandan Das
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);
}
--
MST
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] virtio: virtio 1.0 cs04 spec compliance for reset
2016-04-03 12:26 [PATCH] virtio: virtio 1.0 cs04 spec compliance for reset Michael S. Tsirkin
@ 2016-04-05 2:53 ` Jason Wang
0 siblings, 0 replies; 2+ messages in thread
From: Jason Wang @ 2016-04-05 2:53 UTC (permalink / raw)
To: Michael S. Tsirkin, linux-kernel; +Cc: stable, virtualization, Bandan Das
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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