Re: [Xen-devel] [PATCH V5 10/10] xen/arm64: increase MAX_VIRT_CPUS to 128 on arm64

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Chen,

On 01/06/2015 01:56, Chen Baozi wrote:
> > For instance, with your series a cluster can use up to 16 cores but the
> > GIC-500 is only supporting up to 8 cores...
> Well, if 4096 is a acceptable value, it will cost 512M address space for GICR_*
> (We need to chagne patch #1 too). Although we do have enough space for GICR_*
> before it reaches the GNTTAB region, I don't think it is a good idea to
> increase MAX_VIRT_CPUS to such a big one.
4096 is the limitation of using only AFF1 and AFF0. That would be 
inevitable if one day we decide to support 4096 CPUs :).
> And I've also check the old value of MAX_VIRT_CPUS, it used to be 128 before
> aa25a61.
>
> Or do you have a better suggestion?
I'm not against to limit to 128 vCPUs. It's just the commit message is 
not true. You are limiting the number of VCPUs for practical reason
and not because we are implementing GIC-500.

Please update the commit message according to it.

Regards,

--
Julien Grall

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