Re: [patch 21/32] NTB/msi: Convert to msi_on_each_desc()

[Dave Jiang]

On 12/1/2021 3:03 PM, Thomas Gleixner wrote:
> On Wed, Dec 01 2021 at 14:49, Dave Jiang wrote:
> > On 12/1/2021 2:44 PM, Thomas Gleixner wrote:
> > > How that is backed on the host does not really matter. You can expose
> > > MSI-X to the guest with a INTx backing as well.
> > >
> > > I'm still failing to see the connection between the 9 MSIX vectors and
> > > the 2048 IMS vectors which I assume that this is the limitation of the
> > > physical device, right?
> > I think I was confused with what you were asking and was thinking you
> > are saying why can't we just have MSIX on guest backed by the MSIX on
> > the physical device and thought there would not be enough vectors to
> > service the many guests. I think I understand what your position is now
> > with the clarification above.
> This still depends on how this overall discussion about representation
> of all of this stuff is resolved.
>
> > > What needs a subdevice to expose?
> Can you answer that too please?

Sorry. So initial version of the IDXD sub-device is represented with a 
single queue. It needs a command irq (emulated) and a completion irq 
that is backed by a device vector (currently IMS).


> Thanks,
>
>          tglx