Re: [PATCH v1 0/8] Add IO page table replacement support

[Jason Gunthorpe]

On Mon, Feb 06, 2023 at 06:39:29AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> > Sent: Friday, February 3, 2023 11:04 PM
> > 
> > On Fri, Feb 03, 2023 at 08:09:30AM +0000, Tian, Kevin wrote:
> > > > From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> > > > Sent: Thursday, February 2, 2023 3:05 PM
> > > >
> > > > QEMU with this feature should have the vIOMMU maintain a cache of the
> > > > guest io page table addresses and assign a unique IOAS to each unique
> > > > guest page table.
> > >
> > > I didn't get why we impose such requirement to userspace.
> > 
> > I read this as implementation guidance for qemu. qemu can do what it
> > wants of course
> > 
> 
> sure but I still didn't get why this is a guidance specific to the
> new replace cmd...

I think the guidance is about the change to VFIO uAPI where it is now
possible to change the domain attached, previously that was not
possible

Jason