From 354920e79441c8a53ac73008b06d3b70ed06eb34 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 15 Mar 2021 13:11:58 +0000 Subject: [PATCH] KVM: arm64: vgic: Implement SW-driven deactivation In order to deal with these systems that do not offer HW-based deactivation of interrupts, let implement a SW-based approach: - When the irq is queued into a LR, treat it as a pure virtual interrupt and set the EOI flag in the LR. - When the interrupt state is read back from the LR, force a deactivation when the state is invalid (neither active nor pending) Interrupts requiring such treatment get the VGIC_SW_RESAMPLE flag. Signed-off-by: Marc Zyngier --- arch/arm64/kvm/vgic/vgic-v2.c | 19 +++++++++++++++---- arch/arm64/kvm/vgic/vgic-v3.c | 19 +++++++++++++++---- include/kvm/arm_vgic.h | 10 ++++++++++ 3 files changed, 40 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-v2.c b/arch/arm64/kvm/vgic/vgic-v2.c index 11934c2..2c58020 100644 --- a/arch/arm64/kvm/vgic/vgic-v2.c +++ b/arch/arm64/kvm/vgic/vgic-v2.c @@ -108,11 +108,22 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu) * If this causes us to lower the level, we have to also clear * the physical active state, since we will otherwise never be * told when the interrupt becomes asserted again. + * + * Another case is when the interrupt requires a helping hand + * on deactivation (no HW deactivation, for example). */ - if (vgic_irq_is_mapped_level(irq) && (val & GICH_LR_PENDING_BIT)) { - irq->line_level = vgic_get_phys_line_level(irq); + if (vgic_irq_is_mapped_level(irq)) { + bool resample = false; + + if (val & GICH_LR_PENDING_BIT) { + irq->line_level = vgic_get_phys_line_level(irq); + resample = !irq->line_level; + } else if (vgic_irq_needs_resampling(irq) && + !(irq->active || irq->pending_latch)) { + resample = true; + } - if (!irq->line_level) + if (resample) vgic_irq_set_phys_active(irq, false); } @@ -152,7 +163,7 @@ void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr) if (irq->group) val |= GICH_LR_GROUP1; - if (irq->hw) { + if (irq->hw && !vgic_irq_needs_resampling(irq)) { val |= GICH_LR_HW; val |= irq->hwintid << GICH_LR_PHYSID_CPUID_SHIFT; /* diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c index 41ecf21..66004f6 100644 --- a/arch/arm64/kvm/vgic/vgic-v3.c +++ b/arch/arm64/kvm/vgic/vgic-v3.c @@ -101,11 +101,22 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu) * If this causes us to lower the level, we have to also clear * the physical active state, since we will otherwise never be * told when the interrupt becomes asserted again. + * + * Another case is when the interrupt requires a helping hand + * on deactivation (no HW deactivation, for example). */ - if (vgic_irq_is_mapped_level(irq) && (val & ICH_LR_PENDING_BIT)) { - irq->line_level = vgic_get_phys_line_level(irq); + if (vgic_irq_is_mapped_level(irq)) { + bool resample = false; + + if (val & ICH_LR_PENDING_BIT) { + irq->line_level = vgic_get_phys_line_level(irq); + resample = !irq->line_level; + } else if (vgic_irq_needs_resampling(irq) && + !(irq->active || irq->pending_latch)) { + resample = true; + } - if (!irq->line_level) + if (resample) vgic_irq_set_phys_active(irq, false); } @@ -136,7 +147,7 @@ void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr) } } - if (irq->hw) { + if (irq->hw && !vgic_irq_needs_resampling(irq)) { val |= ICH_LR_HW; val |= ((u64)irq->hwintid) << ICH_LR_PHYS_ID_SHIFT; /* diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index e5f06df0..e602d84 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -99,6 +99,11 @@ enum vgic_irq_config { * kvm_arm_get_running_vcpu() to get the vcpu pointer for private IRQs. */ struct irq_ops { + /* Per interrupt flags for special-cased interrupts */ + unsigned long flags; + +#define VGIC_IRQ_SW_RESAMPLE BIT(0) /* Clear the active state for resampling */ + /* * Callback function pointer to in-kernel devices that can tell us the * state of the input level of mapped level-triggered IRQ faster than @@ -150,6 +155,11 @@ struct vgic_irq { for in-kernel devices. */ }; +static inline bool vgic_irq_needs_resampling(struct vgic_irq *irq) +{ + return irq->ops && (irq->ops->flags & VGIC_IRQ_SW_RESAMPLE); +} + struct vgic_register_region; struct vgic_its; -- 2.7.4