[PATCH v2 09/36] KVM: arm64: gic-v5: Detect implemented PPIs on boot

[Jonathan Cameron]

On Fri, 19 Dec 2025 15:52:38 +0000
Sascha Bischoff <Sascha.Bischoff at arm.com> wrote:

> It is expected that most GICv5 implementations will only implement a
> subset of the PPIs. GICv5 supports up to 128 PPIs in total, where the
> first 64 are architecturally defined, and the second 64 are
> implementation defined. This limitation applies to both physical and
> virtual PPIs as the same set is implemented in each case, and
> therefore KVM needs to determine a mask of implemented PPIs during
> early KVM init.
> 
> The check involves writing all of the ICH_PPI_ENABLERx_EL2 bits and
> reading those back again to determine which are stateful. If the bits
> are stateful, the PPIs are implemented. Else, they are not.
> 
> Signed-off-by: Sascha Bischoff <sascha.bischoff at arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron at huawei.com>