Re: [Xen-devel] [PATCH 09/28] ARM: GICv3 ITS: map device and LPIs to the ITS on physdev_op hypercall

[Julien Grall <julien.grall@xxxxxxx>]

On 31/01/17 16:02, Jaggi, Manish wrote:
> On 1/31/2017 8:47 PM, Julien Grall wrote:
> > On 31/01/17 14:08, Jaggi, Manish wrote:
> > > Hi Julien,
> > >
> > > On 1/31/2017 7:16 PM, Julien Grall wrote:
> > > > On 31/01/17 13:19, Jaggi, Manish wrote:
> > > > > On 1/31/2017 6:13 PM, Julien Grall wrote:
> > > > > > On 31/01/17 10:29, Jaggi, Manish wrote:
> > > If you please go back to your comment where you wrote "we need to find another way 
> > > to get the DeviceID", I was referring that we should add that another way in this 
> > > series so that correct DeviceID is programmed in ITS.
> > This is not the first time I am saying this, just saying "we should add that another 
> > way..." is not helpful. You should also provide some details on what you would do.
> Julien, As you suggested we need to find another way, I assumed you had 
> something in mind.
I gave suggestions on my e-mail but you may have missed it...

> Since we both agree that sbdf!=deviceID, the current series of ITS patches will 
> program the incorrect deviceID so there is a need to
> have a way to map sbdf with deviceID in xen.
>
> One option could be to add a new hypercall to supply sbdf and deviceID to xen.
... as well as the part where I am saying that I am not in favor to 
implement an hypercall temporarily, and against adding a new hypercall 
for only a couple of weeks. As you may know PHYSDEV hypercall are part 
of the stable ABI and once they are added they cannot be removed.
So we need to be sure the hypercall is necessary. In this case, the 
hypercall is not necessary as all the information can be found in the 
firmware tables. However this is not implemented yet and part of the 
discussion on PCI Passthrough (see [1]).
We need a temporary solution that does not involve any commitment on the 
ABI until Xen is able to discover PCI.
Regards,

[1] <5cf9128e-e845-2a89-f7c7-ac8616941ab9@xxxxxxxxxx>
>
--
Julien Grall

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