Re: [PATCH 0/5] virtio: introduce SUSPEND bit and vq state

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Sep 06, 2023 at 04:16:32PM +0800, Zhu Lingshan wrote:
> This series introduces
> 1)a new SUSPEND bit in the device status
> Which is used to suspend the device, so that the device states
> and virtqueue states are stabilized.
> 
> 2)virtqueue state and its accessor, to get and set last_avail_idx
> and last_used_idx of virtqueues.
> 
> The main usecase of these new facilities is Live Migration.
> 
> Future work: dirty page tracking and in-flight descriptors.
> 
> This series addresses many comments from Jason, Stefan and Eugenio
> from RFC series.


after going over this in detail, it is like I worried: this
tries to do too much through a single register and
the ownership is muddied significantly.

I feel a separate capability for suspend/resume that would
be independent of device status would be preferable.

> Zhu Lingshan (5):
>   virtio: introduce vq state as basic facility
>   virtio: introduce SUSPEND bit in device status
>   virtqueue: constraints for virtqueue state
>   virtqueue: ignore resetting vqs when SUSPEND
>   virtio-pci: implement VIRTIO_F_QUEUE_STATE
> 
>  content.tex       | 118 ++++++++++++++++++++++++++++++++++++++++++++++
>  transport-pci.tex |  18 +++++++
>  2 files changed, 136 insertions(+)
> 
> -- 
> 2.35.3