[bug report] GICv4.1: vSGI remains pending across the guest reset

Oliver Upton oliver.upton at linux.dev
Sun Dec 17 09:34:38 PST 2023


On Sun, Dec 17, 2023 at 05:33:16PM +0000, Oliver Upton wrote:
> On Sun, Dec 17, 2023 at 11:26:15AM +0000, Marc Zyngier wrote:
> 
> [...]
> 
> > But this has *nothing* to do with the guest. This is the *host*
> > userspace performing a write to the redistributor view, which has
> > different semantics. Which is why your earlier description made no
> > sense to me.
> > 
> > I think the problem is slightly larger than what you describe. A write
> > to ISPENDR0 should be propagated to the ITS for any values of the
> > latch, just like this happens on enabling HW-backed SGIs.
> > 
> > Can you please give this a go?
> 
> What do you think about using this as an opportunity for a bit of
> cleanup? It'd be nice unify the various MMIO and uaccess handlers for
> SPENDING + CPENDING while being careful about the arch_timer interrupt.

Cut myself off... Meant to say that user writes to SPENDING for GICv3
can then be treated as:

> 	clear = ~val;
> 	vgic_uaccess_write_spending(val);
> 	vgic_uaccess_write_cpending(clear);

-- 
Thanks,
Oliver



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