KVM: arm64: vgic-v5: Make the effective priority mask a strict limit

The way the effective priority mask is compared to the priority of
an interrupt to decide whether to wake-up or not, is slightly odd,
and breaks at the limits.

This could result in spurious wake-ups that are undesirable.

Make the computed priority mask comparison a strict inequality, so
that interrupts that have the same priority as the mask are not
signalled.

Fixes: 933e5288fa971 ("KVM: arm64: gic-v5: Check for pending PPIs")
Link: https://sashiko.dev/#/patchset/20260319154937.3619520-1-sascha.bischoff%40arm.com
Link: https://patch.msgid.link/20260401103611.357092-10-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/vgic/vgic-v5.c b/arch/arm64/kvm/vgic/vgic-v5.c
index 0f269321ece4b1cd457e38c4bdec31ad24677bdb..31040cfb61fc7a01693f029f25dda43f734be36a 100644 (file)
--- a/arch/arm64/kvm/vgic/vgic-v5.c
+++ b/arch/arm64/kvm/vgic/vgic-v5.c
@@ -367,7 +367,7 @@ bool vgic_v5_has_pending_ppi(struct kvm_vcpu *vcpu)
 
                scoped_guard(raw_spinlock_irqsave, &irq->irq_lock)
                        has_pending = (irq->enabled && irq_is_pending(irq) &&
-                                      irq->priority <= priority_mask);
+                                      irq->priority < priority_mask);
 
                vgic_put_irq(vcpu->kvm, irq);