Re: [Xen-devel] [PATCH v3 03/26] ARM: GICv3 ITS: allocate device and collection table

[Julien Grall <julien.grall@xxxxxxx>]

On 04/03/2017 08:39 PM, Andre Przywara wrote:
> Hi,
>
> On 03/04/17 18:22, Julien Grall wrote:
> > Hi Andre,
> >
> > On 03/04/17 16:38, Julien Grall wrote:
> > > On 31/03/17 19:05, Andre Przywara wrote:
> > > > Each ITS maps a pair of a DeviceID (for instance derived from a PCI
> > > > b/d/f triplet) and an EventID (the MSI payload or interrupt ID) to a
> > > > pair of LPI number and collection ID, which points to the target CPU.
> > > > This mapping is stored in the device and collection tables, which
> > > > software
> > > > has to provide for the ITS to use.
> > > > Allocate the required memory and hand it to the ITS.
> > > > The maximum number of devices is limited to a compile-time constant
> > > > exposed in Kconfig.
> > > >
> > > > Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> > > Reviewed-by: Julien Grall <julien.grall@xxxxxxx>
> > Actually I will withdraw my reviewed-by. I didn't spot you keep the
> > command line around which I clearly say no and gave some reasons why.
> > Sorry for the mess.
> `
> I thought we were talking about the Kconfig option to drop here (which
> the commit msg wrongly states as still being around)?
>
> For implementations that don't support indirect tables, but still
> advertise high numbers, I'd find it useful to have the possibility to
> limit this to avoid memory waste.
Again, how the user will know the magic numbers? If the platform 
advertises high device number, then it is none of our business. If the 
number needs to be reduced, this should be a platform specific code.
Cheers,

--
Julien Grall

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