Re: [Xen-devel] [PATCH] domctl: fix IRQ permission granting/revocation

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 10.12.14 at 10:53, <Ian.Campbell@xxxxxxxxxxxxx> wrote:
> On Wed, 2014-12-10 at 08:07 +0000, Jan Beulich wrote:
>> Commit 545607eb3c ("x86: fix various issues with handling guest IRQs")
>> wasn't really consistent in one respect: The granting of access to an
>> IRQ shouldn't assume the pIRQ->IRQ translation to be the same in both
>> domains. In fact it is wrong to assume that a translation is already/
>> still in place at the time access is being granted/revoked.
> 
> Specifically you need to do the translation using the mapping of the
> domain doing the granting, not the domain being granted too, correct?
> 
> It takes a little bit of thought to figure out which domain to check
> here, it would be worth a sentence or two explaining why this is the
> right one.

Would

"What is wanted is to translate the incoming pIRQ to an IRQ for
 the invoking domain (as the pIRQ is the only notion the invoking
 domain has of the IRQ), and grant the subject domain access to
 the resulting IRQ."

make this more clear without being purely redundant with the code?

Jan


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