Re: [Xen-devel] [PATCH v4 26/33] xen/passthrough: Extend XEN_DOMCTL_*assign_device to support DT device

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Tue, 2015-03-31 at 13:30 +0100, Julien Grall wrote:
> >> +    /* TODO: Do we need to check is_dying? Mostly to protect against
> >> +     * hypercall trying to passthrough a device while we are
> >> +     * dying.
> > 
> > iommu_do_pci_domctl does in specific casses (i.e. assign device). I
> > guess you should follow that lead.
> 
> I'm not sure to fully understand when is_dying should be used or not.
> 
> Looking to the PCI code, the is_dying has been added when we add code to
> deal with page.
> 
> I would be inclined to say it's only necessary when deadling with page.
> Can someone confirm me?
> 
> Otherwise, I don't why is_dying should be check here and not in other call.

it makes little sense to add a device to a domain which is dying, but
it's just about plausible you might want to remove it (e.g. to unwedge
something which has gone wrong).

Overall I think being consistent with other similar cases (e.g. PCI) is
the way to go.



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