Re: [virtio-comment] Re: [PATCH 0/2] Selective queue enabling

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

On Tue, Jun 13, 2023 at 03:46:35AM -0400, Michael S. Tsirkin wrote:
> On Mon, Jun 12, 2023 at 09:56:57AM +0200, Eugenio Perez Martin wrote:
> > > > Another drawback of that is the long time a device can spend to
> > > > reconfigure its memory maps.
> > >
> > > The map is already used for cvq though, I don't see why it would take
> > > much more with this.
> > >
> > 
> > In the case of vDPA HW, CVQ maps may not need to reach the device's or
> > platform IOMMU, so the modification of that mapping is way cheaper.
> 
> Oh, I get it. It's setup time, but you are right.
> 
> > > > taking that into account, does it make
> > > > sense to send a new version with the bit 1 on enable?
> > > >
> > > > Thanks!
> > >
> > > Current hardware won't support the extra bit though.


Thinking more about this, I think the following works:

- enable all queues before DRIVER_OK
- reset all data queues before DRIVER_OK
- DRIVER_OK
- CVQ commands
- re-enable data queues


No?



> -- 
> MST