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

Zhu, Lingshan
2023-09-06T08:39:11Z

On 9/6/2023 4:29 PM, Michael S. Tsirkin wrote:
> 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.
> oh that answers my question - it's not covered.
> I don't think we can merge this without in-flight descriptor
> support.
When SUSPEND, we require the device wait until all descriptors that
being processed to finish and mark them as used.(In patch 2)

at this point there may be no in-flight descriptors, so this is still
self-consistent. The tracker for in-flight descriptors is excluded to
make this series small and focus.
>
>
>
>> This series addresses many comments from Jason, Stefan and Eugenio
>> from RFC series.
>>
>> 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
>>
>>
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