Userspace can set the timer PPI numbers way before a GIC has been created, leading to odd behaviours on GICv5 as we'd accept non architectural PPI numbers. Move the v5 check into timer_irqs_are_valid(), which aligns the behaviour with the pre-v5 GICs, and is also guaranteed to run only once a GIC has been configured. Reviewed-by: Sascha Bischoff Fixes: 9491c63b6cd7b ("KVM: arm64: gic-v5: Enlighten arch timer for GICv5") Link: https://sashiko.dev/#/patchset/20260319154937.3619520-1-sascha.bischoff%40arm.com Signed-off-by: Marc Zyngier --- arch/arm64/kvm/arch_timer.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c index 6608c47d1f628..cbea4d9ee9552 100644 --- a/arch/arm64/kvm/arch_timer.c +++ b/arch/arm64/kvm/arch_timer.c @@ -1543,6 +1543,10 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu) if (kvm_vgic_set_owner(vcpu, irq, ctx)) break; + /* With GICv5, the default PPI is what you get -- nothing else */ + if (vgic_is_v5(vcpu->kvm) && irq != get_vgic_ppi(vcpu->kvm, default_ppi[i])) + break; + /* * We know by construction that we only have PPIs, so all values * are less than 32 for non-GICv5 VGICs. On GICv5, they are @@ -1678,13 +1682,6 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) return -ENXIO; } - /* - * The PPIs for the Arch Timers are architecturally defined for - * GICv5. Reject anything that changes them from the specified value. - */ - if (vgic_is_v5(vcpu->kvm) && vcpu->kvm->arch.timer_data.ppi[idx] != irq) - return -EINVAL; - /* * We cannot validate the IRQ unicity before we run, so take it at * face value. The verdict will be given on first vcpu run, for each -- 2.47.3