Re: [PATCH v1 4/8] virtio-mmio: Lock ioeventfd state with VIRTIO_F_NOTIFICATION_DATA

[Eugenio Perez Martin]

On Mon, Mar 4, 2024 at 8:46 PM Jonah Palmer <jonah.palmer@oracle.com> wrote:
>
> Prevent ioeventfd from being enabled/disabled when a virtio-mmio device
> has negotiated the VIRTIO_F_NOTIFICATION_DATA transport feature.
>
> Due to ioeventfd not being able to carry the extra data associated with
> this feature, the ioeventfd should be left in a disabled state for
> emulated virtio-mmio devices using this feature.
>

Acked-by: Eugenio Pérez <eperezma@redhat.com>

> Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
> ---
>  hw/virtio/virtio-mmio.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
> index f99d5851a2..f42ed5c512 100644
> --- a/hw/virtio/virtio-mmio.c
> +++ b/hw/virtio/virtio-mmio.c
> @@ -421,7 +421,8 @@ static void virtio_mmio_write(void *opaque, hwaddr 
> offset, uint64_t value,
>          virtio_update_irq(vdev);
>          break;
>      case VIRTIO_MMIO_STATUS:
> -        if (!(value & VIRTIO_CONFIG_S_DRIVER_OK)) {
> +        if (!(value & VIRTIO_CONFIG_S_DRIVER_OK) &&
> +            !virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFICATION_DATA)) {
>              virtio_mmio_stop_ioeventfd(proxy);
>          }
>
> @@ -433,7 +434,8 @@ static void virtio_mmio_write(void *opaque, hwaddr 
> offset, uint64_t value,
>
>          virtio_set_status(vdev, value & 0xff);
>
> -        if (value & VIRTIO_CONFIG_S_DRIVER_OK) {
> +        if ((value & VIRTIO_CONFIG_S_DRIVER_OK) &&
> +            !virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFICATION_DATA)) {
>              virtio_mmio_start_ioeventfd(proxy);
>          }
>
> --
> 2.39.3
>