Re: [Xen-devel] [PATCH v3 18/24] xen/passthrough: iommu_deassign_device_dt: By default reassign device to nobody

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 20/02/2015 17:04, Ian Campbell wrote:
> On Tue, 2015-01-13 at 14:25 +0000, Julien Grall wrote:
> > Currently, when the device is deassigned from a domain, we directly reassign
> > to DOM0.
> >
> > As the device may not have been correctly reset, this may lead to corruption or
> > expose some part of DOM0 memory. Also, we may have no way to reset some
> > platform devices.
> >
> > If Xen reassigns the device to "nobody", it may receive some global/context
> > fault because the transaction has failed (indeed the context has been
> > marked invalid). Unfortunately there is no simple way to quiesce a buggy
> > hardware. I think we could live with that for a first version of platform
> > device passthrough.
> >
> > DOM0 will have to issue an hypercall to assign the device to itself if it
> > wants to use it.
> Does this behaviour differ from x86? If so then it is worth calling that
> out explicitly (even if not, good to know I think!)
What do you mean by "calling that out explicitly"?

Regards,

--
Julien Grall

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