Re: [PATCH] irq/gic-its: gicv4: set VPENDING table as inner-shareable

From: Marc Zyngier
Date: Sat Mar 21 2020 - 05:54:36 EST


Hi Heyi,

On 2020-02-24 02:22, Heyi Guo wrote:
Hi Marc,

On 2019/12/2 2:04, Marc Zyngier wrote:
On Sat, 30 Nov 2019 15:38:49 +0800
Heyi Guo <guoheyi@xxxxxxxxxx> wrote:

There is no special reason to set virtual LPI pending table as
non-shareable. If we choose to hard code the shareability without
probing, inner-shareable will be a better choice, for all the other
ITS/GICR tables prefer to be inner-shareable.
One of the issues is that we have strictly no idea what the caches are
Inner Shareable with (I've been asking for such clarification for years
without getting anywhere). You can have as many disconnected inner
shareable domains as you want!

I suspect that in the grand scheme of things, the redistributors
ought to be in the same inner shareable domain, and that with a bit of
luck, the CPUs are there as well. Still, that's a massive guess.

What's more, on Hisilicon hip08 it will trigger some kind of bus
warning when mixing use of different shareabilities.
Do you have more information about what the bus is complaining about?
Is that because the CPUs have these pages mapped as inner shareable?

I'll give it a go on D05 (HIP07) to find out what changes there.

How's your go on D05? Did you see any issues?

Sorry it took so long. I've given it a go on my D05, and didn't notice
anything bad (or rather, nothing worse than usual, since GICv4 on this
machine is pretty... funky).

I've now take this into the 5.7 queue.

Thanks,

M.
--
Jazz is not dead. It just smells funny...