Re: [Xen-devel] [Patch v11 3/3] vt-d: fix vt-d Device-TLB flush timeout issue (+ crash logic )

["Xu, Quan" <quan.xu@xxxxxxxxx>]

On June 18, 2016 5:54 PM, Xu, Quan <quan.xu@xxxxxxxxx> wrote:
> On June 17, 2016 9:35 PM, Julien Grall <julien.grall@xxxxxxx> wrote:
> > On 17/06/16 09:51, Xu, Quan wrote:
> > > + arm/amd maintainers..
> > >
> > > On June 01, 2016 5:05 PM, Xu, Quan <quan.xu@xxxxxxxxx> wrote:
> > >> If Device-TLB flush timed out, we hide the target ATS device
> > >> immediately and crash the domain owning this ATS device. If
> > >> impacted domain is hardware domain, just throw out a warning.
> > >>
> > >> By hiding the device, we make sure it can't be assigned to any
> > >> domain any longer (see device_assigned).
> > >
> > > DomU (other than Dom0) gets crashed when a device IOTLB flush times
> out.
> > I suppose that's what you will want on ARM/AMD then too.
> >
> > Correct it is what we want for ARM :).
> >
> 
> 
> That's good :):)..
> Julien, thanks.
> 
> > > We need to move up the crash logic , as similar as iommu_map_page()
> > > /
> > iommu_unmap_page().
> > >
> > >      - add the crash logic to iommu_iotlb_flush() / 
> > > iommu_iotlb_flush_all().
> > >
> > >      - when IOMMU/MMU share page tables, we need to fix it one by one.
> > >          -- on amd, we need to add the crash logic to
> > amd_iommu_flush_pages().
> > >          -- on intel, we need to add the crash logic to iommu_pte_flush().
> > >          -- on arm, we benefit that we add the crash logic to
> > iommu_iotlb_flush().
> >
> > Right.
> >
> 
> :):)
> 
> > >
> > >
> > > Taken together, we need to add crash logic to
> > >                           iommu_iotlb_flush() /
> > > iommu_iotlb_flush_all() /
> > iommu_pte_flush() / amd_iommu_flush_pages().
> >




Think twice,  now I am inclined to leave amd_iommu_flush_pages() as is,
As the IOTLB flush error has not been yet bubbled up on AMD platform, it is 
pointless to  add
domain crash logic there.

Quan




> > For iommu_iotlb_* yes as it is common code. I don't know for the others.
> >
> IMO, that's is enough. I hope the other maintainers can give some comments.
> Thanks!!
> 

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