From e079ef0b1c40c7a4a1be0c1ac5dbff95685c3beb Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 29 Sep 2026 10:35:44 +0100 Subject: [PATCH] KVM: arm64: vgic: Allow last_lr_irq to be NULL when LRs are not overflowing last_lr_irq is always populated when there is any interrupt populated in the AP list. Not only this is not necessary (it is only useful when we completely fill the LRs), but this is in the way of further fixes. Make sure last_lr_irq is kept to NULL when we LRs are not completely full. Fixes: 6da5e537f5afe ("KVM: arm64: vgic: Pick EOIcount deactivations from AP-list tail") Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Signed-off-by: Marc Zyngier Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260929093548.3598547-4-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/vgic/vgic-v2.c | 6 ++++-- arch/arm64/kvm/vgic/vgic-v3.c | 6 ++++-- arch/arm64/kvm/vgic/vgic.c | 8 +++----- 3 files changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-v2.c b/arch/arm64/kvm/vgic/vgic-v2.c index 7182f63fc938..70cc53ba810a 100644 --- a/arch/arm64/kvm/vgic/vgic-v2.c +++ b/arch/arm64/kvm/vgic/vgic-v2.c @@ -122,6 +122,10 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu) for (int lr = 0; lr < vgic_cpu->vgic_v2.used_lrs; lr++) vgic_v2_fold_lr(vcpu, cpuif->vgic_lr[lr]); + cpuif->used_lrs = 0; + if (!irq) + return; + /* See the GICv3 equivalent for the EOIcount handling rationale */ list_for_each_entry_continue(irq, &vgic_cpu->ap_list_head, ap_list) { u32 lr; @@ -144,8 +148,6 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu) vgic_v2_fold_lr(vcpu, lr); eoicount--; } - - cpuif->used_lrs = 0; } void vgic_v2_deactivate(struct kvm_vcpu *vcpu, u32 val) diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c index 726e20a1da6e..346bacb3198f 100644 --- a/arch/arm64/kvm/vgic/vgic-v3.c +++ b/arch/arm64/kvm/vgic/vgic-v3.c @@ -155,6 +155,10 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu) for (int lr = 0; lr < cpuif->used_lrs; lr++) vgic_v3_fold_lr(vcpu, cpuif->vgic_lr[lr]); + cpuif->used_lrs = 0; + if (!irq) + return; + /* * EOIMode=0: use EOIcount to emulate deactivation. We are * guaranteed to deactivate in reverse order of the activation, so @@ -188,8 +192,6 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu) vgic_v3_fold_lr(vcpu, lr); eoicount--; } - - cpuif->used_lrs = 0; } void vgic_v3_deactivate(struct kvm_vcpu *vcpu, u64 val) diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c index b25303d9919f..425503e0c582 100644 --- a/arch/arm64/kvm/vgic/vgic.c +++ b/arch/arm64/kvm/vgic/vgic.c @@ -866,9 +866,6 @@ static void vgic_fold_state(struct kvm_vcpu *vcpu) return; } - if (!*host_data_ptr(last_lr_irq)) - return; - if (kvm_vgic_global_state.type == VGIC_V2) vgic_v2_fold_lr_state(vcpu); else @@ -1021,11 +1018,12 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu) scoped_guard(raw_spinlock, &irq->irq_lock) { if (likely(vgic_target_oracle(irq) == vcpu)) { vgic_populate_lr(vcpu, irq, count++); - *host_data_ptr(last_lr_irq) = irq; + if (count == kvm_vgic_global_state.nr_lr) + *host_data_ptr(last_lr_irq) = irq; } } - if (count == kvm_vgic_global_state.nr_lr) + if (*host_data_ptr(last_lr_irq)) break; }