Re: [Xen-devel] [PATCH RFC 4/4] x86/dom0: re-order DMA remapping enabling for PVH Dom0

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, Jun 30, 2017 at 05:52:33AM -0600, Jan Beulich wrote:
> >>> Roger Pau Monne <roger.pau@xxxxxxxxxx> 04/24/17 1:52 PM >>>
> >Make sure the reserved regions are setup before enabling the DMA remapping in
> >the IOMMU, by calling dom0_setup_permissions before iommu_hwdom_init. Also, 
> >in
> >order to workaround IOMMU issues seen on pre-Haswell Intel hardware, make 
> >sure
> >the DMA remapping is enabled after populating Dom0 p2m.
> 
> Looks reasonable (especially considering that iommu_hwdom_init() is being 
> called
> fairly late in the PV case as well), but please explain the "IOMMU issues 
> seen on
> pre-Haswell Intel hardware" a little here (or if it all is mean to refer to 
> what patch 3
> does, refer to it).

Yes, it's the same issue as described in patch #3, I will add a
reference to the title of the patch if that's fine.

Thanks, Roger.

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