Re: [PATCH V2] amd iommu: re-enable iommu msi if dom0 disabled it

[Keir Fraser <keir.xen@gmail.com>]

On 21/06/2012 16:49, "Jan Beulich" <JBeulich@suse.com> wrote:

> the question now arises whether we really want this, and
> particularly this late before 4.2. The Linux folks don't seem to
> be willing to take the strait forward workaround for the
> problem introduced at their end, so we will likely need
> something (the more that the questionable fix already made
> it into various stable trees) before 4.2 goes out (and even
> the older trees would be affected, just that putting a change
> like this there is even more questionable).

I'd be okay seeing the proposed patch go in ahead of 4.2.0-rc1.

 -- Keir

> There are obviously more potential problems in this area: If
> any of the MMIO addresses used by AMD's IOMMU is
> configurable through one of the BARs, and if Dom0 decides to
> re-assign MMIO space, neither allowing the writes nor simply
> dropping them as done here will work. Whether that's a real
> problem I don't know - Wei? And there might be other issues
> arising from dropping all writes - we might just currently not be
> aware of them.