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

Tian, Kevin
2021-12-11T07:44:14Z

> From: Thomas Gleixner <tglx@linutronix.de>
> Sent: Saturday, December 11, 2021 3:00 AM
>
> Jason,
>
> On Fri, Dec 10 2021 at 08:39, Jason Gunthorpe wrote:
>
> > On Fri, Dec 10, 2021 at 07:29:01AM +0000, Tian, Kevin wrote:
> >> > 5) It's not possible for the kernel to reliably detect whether it is
> >> > running on bare metal or not. Yes we talked about heuristics, but
> >> > that's something I really want to avoid.
> >>
> >> How would the hypercall mechanism avoid such heuristics?
> >
> > It is clever, we don't have an vIOMMU that supplies vIR today, so by
> > definition all guests are excluded and only bare metal works.
>
> Dammit. Now you spilled the beans. :)
>

Unfortunately we do have that today. Qemu supports IR for
both AMD and Intel vIOMMU.

Thanks
Kevin