Re: [PATCH 06/16] virtio-pci: support queue reset

[Jason Wang <jasowang@redhat.com>]

在 2022/7/18 19:17, Kangjie Xu 写道:
> From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
>
> PCI devices support vq reset.
>
> Based on this function, the driver can adjust the size of the ring, and
> quickly recycle the buffer in the ring.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
>   hw/virtio/virtio-pci.c         | 16 ++++++++++++++++
>   include/hw/virtio/virtio-pci.h |  1 +
>   2 files changed, 17 insertions(+)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 45327f0b31..35e8a5101a 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -1246,6 +1246,9 @@ static uint64_t virtio_pci_common_read(void *opaque, hwaddr addr,
>       case VIRTIO_PCI_COMMON_Q_USEDHI:
>           val = proxy->vqs[vdev->queue_sel].used[1];
>           break;
> +    case VIRTIO_PCI_COMMON_Q_RESET:
> +        val = proxy->vqs[vdev->queue_sel].reset;
> +        break;
>       default:
>           val = 0;
>       }
> @@ -1333,6 +1336,7 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
>                          ((uint64_t)proxy->vqs[vdev->queue_sel].used[1]) << 32 |
>                          proxy->vqs[vdev->queue_sel].used[0]);
>               proxy->vqs[vdev->queue_sel].enabled = 1;
> +            proxy->vqs[vdev->queue_sel].reset = 0;
>           } else {
>               virtio_error(vdev, "wrong value for queue_enable %"PRIx64, val);
>           }
> @@ -1355,6 +1359,17 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
>       case VIRTIO_PCI_COMMON_Q_USEDHI:
>           proxy->vqs[vdev->queue_sel].used[1] = val;
>           break;
> +    case VIRTIO_PCI_COMMON_Q_RESET:
> +        if (val == 1) {
> +            proxy->vqs[vdev->queue_sel].reset = 1;
> +
> +            virtio_queue_reset(vdev, vdev->queue_sel);
> +
> +            /* mark reset complete */


The code explain itself, so the comment could be removed.


> +            proxy->vqs[vdev->queue_sel].reset = 0;
> +            proxy->vqs[vdev->queue_sel].enabled = 0;
> +        }
> +        break;
>       default:
>           break;
>       }
> @@ -1950,6 +1965,7 @@ static void virtio_pci_reset(DeviceState *qdev)
>   
>       for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
>           proxy->vqs[i].enabled = 0;
> +        proxy->vqs[i].reset = 0;
>           proxy->vqs[i].num = 0;
>           proxy->vqs[i].desc[0] = proxy->vqs[i].desc[1] = 0;
>           proxy->vqs[i].avail[0] = proxy->vqs[i].avail[1] = 0;
> diff --git a/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
> index 2446dcd9ae..e9290e2b94 100644
> --- a/include/hw/virtio/virtio-pci.h
> +++ b/include/hw/virtio/virtio-pci.h
> @@ -117,6 +117,7 @@ typedef struct VirtIOPCIRegion {
>   typedef struct VirtIOPCIQueue {
>     uint16_t num;
>     bool enabled;
> +  bool reset;


How is this migrated?

Thanks


>     uint32_t desc[2];
>     uint32_t avail[2];
>     uint32_t used[2];