Re: [PATCH V2 0/5] Fix UNMAP notifier for intel-iommu

[Jason Wang]

On Thu, Feb 23, 2023 at 11:47 PM Peter Xu <peterx@redhat.com> wrote:
>
> On Thu, Feb 23, 2023 at 02:59:19PM +0800, Jason Wang wrote:
> > Hi All:
> >
> > According to ATS, device should work if ATS is disabled. This is not
> > correctly implemented in the current intel-iommu since it doesn't
> > handle the UNMAP notifier correctly. This breaks the vhost-net +
> > vIOMMU without dt.
> >
> > The root casue is that the when there's a device IOTLB miss (note that
> > it's not specific to PCI so it can work without ATS), Qemu doesn't
> > build the IOVA tree, so when guest start an IOTLB invalidation, Qemu
> > won't trigger the UNMAP notifier.
> >
> > Fixing this by triggering UNMAP notifier in those cases.
>
> Maybe someday we should start merging different places where we used the
> same IOMMU_NOTIFIER_UNMAP event and also taking care of truncation of
> notifier ranges within memory.c, but that can definitely be done later.

Yes, probably.

>
> Reviewed-by: Peter Xu <peterx@redhat.com>
>
> Thanks, Jason!

You're welcome :)

Thanks

>
> --
> Peter Xu
>