[PATCH v4 37/49] KVM: arm64: GICv2: Handle LR overflow when EOImode==0

Marc Zyngier
2025-11-20T17:26:04Z

Similarly to the GICv3 version, handle the EOIcount-driven deactivation
by walking the overflow list.

Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/vgic/vgic-v2.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic-v2.c b/arch/arm64/kvm/vgic/vgic-v2.c
index 9a2de03f74c30..bbd4d003fde86 100644
--- a/arch/arm64/kvm/vgic/vgic-v2.c
+++ b/arch/arm64/kvm/vgic/vgic-v2.c
@@ -100,6 +100,8 @@ static void vgic_v2_fold_lr(struct kvm_vcpu *vcpu, u32 val)
vgic_put_irq(vcpu->kvm, irq);
}

+static u32 vgic_v2_compute_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq);
+
/*
* transfer the content of the LRs back into the corresponding ap_list:
* - active bit is transferred as is
@@ -111,12 +113,37 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_v2_cpu_if *cpuif = &vgic_cpu->vgic_v2;
+ u32 eoicount = FIELD_GET(GICH_HCR_EOICOUNT, cpuif->vgic_hcr);
+ struct vgic_irq *irq;

DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());

for (int lr = 0; lr < vgic_cpu->vgic_v2.used_lrs; lr++)
vgic_v2_fold_lr(vcpu, cpuif->vgic_lr[lr]);

+ /* See the GICv3 equivalent for the EOIcount handling rationale */
+ list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
+ u32 lr;
+
+ if (!eoicount) {
+ break;
+ } else {
+ guard(raw_spinlock)(&irq->irq_lock);
+
+ if (!(likely(vgic_target_oracle(irq) == vcpu) &&
+ irq->active))
+ continue;
+
+ lr = vgic_v2_compute_lr(vcpu, irq) & ~GICH_LR_ACTIVE_BIT;
+ }
+
+ if (lr & GICH_LR_HW)
+ writel_relaxed(FIELD_GET(GICH_LR_PHYSID_CPUID, lr),
+ kvm_vgic_global_state.gicc_base + GIC_CPU_DEACTIVATE);
+ vgic_v2_fold_lr(vcpu, lr);
+ eoicount--;
+ }
+
cpuif->used_lrs = 0;
}

--
2.47.3