Subject: Re: [PATCH v4 10/36] KVM: arm64: gic-v5: Detect implemented PPIs on boot

From: Jonathan Cameron <[email-masked]>
Date: Thu, 29 Jan 2026 12:15:34 +0000

On Wed, 28 Jan 2026 18:01:54 +0000
Sascha Bischoff <[email-masked]> wrote:

> As part of booting the system and initialising KVM, create and
> populate a mask of the implemented PPIs. This mask allows future PPI
> operations (such as save/restore or state, or syncing back into the
> shadow state) to only consider PPIs that are actually implemented on
> the host.
> 
> The set of implemented virtual PPIs matches the set of implemented
> physical PPIs for a GICv5 host. Therefore, this mask represents all
> PPIs that could ever by used by a GICv5-based guest on a specific
> host.
> 
> Only architected PPIs are currently supported in KVM with
> GICv5. Moreover, as KVM only supports a subset of all possible PPIS
> (Timers, PMU, GICv5 SW_PPI) the PPI mask only includes these PPIs, if
> present. The timers are always assumed to be present; if we have KVM
> we have EL2, which means that we have the EL1 & EL2 Timer PPIs. If we
> have a PMU (v3), then the PMUIRQ is present. The GICv5 SW_PPI is
> always assumed to be present.
> 
> Signed-off-by: Sascha Bischoff <[email-masked]>
Reviewed-by: Jonathan Cameron <[email-masked]>