RE: [virtio-comment] [PATCH 5/5] virtio-pci: implement VIRTIO_F_QUEUE_STATE

[Parav Pandit <parav@nvidia.com>]

> From: Zhu, Lingshan <lingshan.zhu@intel.com>
> Sent: Tuesday, September 12, 2023 2:38 PM

> supplementary: As Jason ever pointed out: the two solution can co-exist for
> sure, I am implementing basic facilities, admin vq can free feel to reuse them like
> forwarding messages to them, and this can help support nested.

Sure. Sounds good.

At lest two device vendors + other industry bodies including led by Intel are moving away from the register-based implementation in virtualization area.
And registers that you expose are not supporting device reset and FLR sequence. So please add some text for that in PCI transport section about violation.
And guideline for driver on how it should not touch them to make this usable.
This will make the nested solution more clear.

Do you find the administration commands we proposed in [1] useful for nested case?
If not, both will likely diverge.

We would like to avoid suspending individual VQs in the passthrough case, as things are controlled at the device level.
It also reduces driver -> device interaction for large queue count ranging from 1 to 32K.

So at present I see very little overlap between the two. I will look more again on 9/13 if passthrough proposal can utilize anything from your series.