RE: [PATCH V2 6/6] virtio-pci: implement dirty page tracking

[Parav Pandit <parav@nvidia.com>]

> From: Michael S. Tsirkin <mst@redhat.com>
> Sent: Monday, November 6, 2023 4:58 PM
> 
> On Mon, Nov 06, 2023 at 11:21:12AM +0000, Parav Pandit wrote:
> >
> > > From: Michael S. Tsirkin <mst@redhat.com>
> > > Sent: Monday, November 6, 2023 4:00 PM
> > >
> > > On Mon, Nov 06, 2023 at 04:34:44AM +0000, Parav Pandit wrote:
> > > > > Do you know there are locked transaction and atomic operations in
> PCI???
> > > > Can you explain how PCI does RMW locked transaction?
> > > > Is it one TLP or multiple?
> > >
> > > Parav what are you asking about here?
> >
> > > pcie supports CAS and Swap which likely can work for this use-case -
> > > these are non posted writes. It's in the pcie spec.
> > PCI spec do not have atomic OR operation.
> > Lingshan in above comment suggested some unknown locked transaction and
> atomic operation.
> > So I was asking him which is that atomic operation and how PCI does it?
> > I don't know if any that can do PCI atomic OR without a workaround.
> 
> Well this is not what you wrote - you asked about RMW and that's exactly what
> CAS does.
> Maybe you should take a bit more care writing then. Generally this discussion
> would benefit a lot if people stop shooting from the hip.

Yes. I will take more care. Thanks.