In the moment our struct vgic_irq's are statically allocated at guest creation time. So getting a pointer to an IRQ structure is trivial and safe. LPIs are more dynamic, they can be mapped and unmapped at any time during the guest's _runtime_. In preparation for supporting LPIs we introduce reference counting for those structures using the kernel's kref infrastructure. Since private IRQs and SPIs are statically allocated, the reqcount never drops to 0 at the moment, but we increase it when an IRQ gets onto a VCPU list and decrease it when it gets removed. This introduces vgic_put_irq(), which wraps kref_put and hides the release function from the callers. Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> --- include/kvm/vgic/vgic.h | 1 + virt/kvm/arm/vgic/vgic-init.c | 2 ++ virt/kvm/arm/vgic/vgic-mmio-v2.c | 8 ++++++++ virt/kvm/arm/vgic/vgic-mmio-v3.c | 10 +++++++--- virt/kvm/arm/vgic/vgic-mmio.c | 22 +++++++++++++++++++++ virt/kvm/arm/vgic/vgic-v2.c | 1 + virt/kvm/arm/vgic/vgic-v3.c | 1 + virt/kvm/arm/vgic/vgic.c | 41 +++++++++++++++++++++++++++++++++------- virt/kvm/arm/vgic/vgic.h | 1 + 9 files changed, 77 insertions(+), 10 deletions(-) diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h index 2f26f37..a296d94 100644 --- a/include/kvm/vgic/vgic.h +++ b/include/kvm/vgic/vgic.h @@ -96,6 +96,7 @@ struct vgic_irq { bool active; /* not used for LPIs */ bool enabled; bool hw; /* Tied to HW IRQ */ + struct kref refcount; /* Used for LPIs */ u32 hwintid; /* HW INTID number */ union { u8 targets; /* GICv2 target VCPUs mask */ diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c index 90cae48..ac3c1a5 100644 --- a/virt/kvm/arm/vgic/vgic-init.c +++ b/virt/kvm/arm/vgic/vgic-init.c @@ -177,6 +177,7 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis) spin_lock_init(&irq->irq_lock); irq->vcpu = NULL; irq->target_vcpu = vcpu0; + kref_init(&irq->refcount); if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2) irq->targets = 0; else @@ -211,6 +212,7 @@ static void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu) irq->vcpu = NULL; irq->target_vcpu = vcpu; irq->targets = 1U << vcpu->vcpu_id; + kref_init(&irq->refcount); if (vgic_irq_is_sgi(i)) { /* SGIs */ irq->enabled = 1; diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c index a213936..4152348 100644 --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c @@ -102,6 +102,7 @@ static void vgic_mmio_write_sgir(struct kvm_vcpu *source_vcpu, irq->source |= 1U << source_vcpu->vcpu_id; vgic_queue_irq_unlock(source_vcpu->kvm, irq); + vgic_put_irq(source_vcpu->kvm, irq); } } @@ -116,6 +117,8 @@ static unsigned long vgic_mmio_read_target(struct kvm_vcpu *vcpu, struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i); val |= (u64)irq->targets << (i * 8); + + vgic_put_irq(vcpu->kvm, irq); } return val; @@ -143,6 +146,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu, irq->target_vcpu = kvm_get_vcpu(vcpu->kvm, target); spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); } } @@ -157,6 +161,8 @@ static unsigned long vgic_mmio_read_sgipend(struct kvm_vcpu *vcpu, struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i); val |= (u64)irq->source << (i * 8); + + vgic_put_irq(vcpu->kvm, irq); } return val; } @@ -178,6 +184,7 @@ static void vgic_mmio_write_sgipendc(struct kvm_vcpu *vcpu, irq->pending = false; spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); } } @@ -201,6 +208,7 @@ static void vgic_mmio_write_sgipends(struct kvm_vcpu *vcpu, } else { spin_unlock(&irq->irq_lock); } + vgic_put_irq(vcpu->kvm, irq); } } diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c index fc7b6c9..829909e 100644 --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c @@ -80,15 +80,17 @@ static unsigned long vgic_mmio_read_irouter(struct kvm_vcpu *vcpu, { int intid = VGIC_ADDR_TO_INTID(addr, 64); struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, NULL, intid); + unsigned long ret = 0; if (!irq) return 0; /* The upper word is RAZ for us. */ - if (addr & 4) - return 0; + if (!(addr & 4)) + ret = extract_bytes(READ_ONCE(irq->mpidr), addr & 7, len); - return extract_bytes(READ_ONCE(irq->mpidr), addr & 7, len); + vgic_put_irq(vcpu->kvm, irq); + return ret; } static void vgic_mmio_write_irouter(struct kvm_vcpu *vcpu, @@ -112,6 +114,7 @@ static void vgic_mmio_write_irouter(struct kvm_vcpu *vcpu, irq->target_vcpu = kvm_mpidr_to_vcpu(vcpu->kvm, irq->mpidr); spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); } static unsigned long vgic_mmio_read_v3r_typer(struct kvm_vcpu *vcpu, @@ -445,5 +448,6 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg) irq->pending = true; vgic_queue_irq_unlock(vcpu->kvm, irq); + vgic_put_irq(vcpu->kvm, irq); } } diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c index 9f6fab7..630d1c3 100644 --- a/virt/kvm/arm/vgic/vgic-mmio.c +++ b/virt/kvm/arm/vgic/vgic-mmio.c @@ -56,6 +56,8 @@ unsigned long vgic_mmio_read_enable(struct kvm_vcpu *vcpu, if (irq->enabled) value |= (1U << i); + + vgic_put_irq(vcpu->kvm, irq); } return value; @@ -74,6 +76,8 @@ void vgic_mmio_write_senable(struct kvm_vcpu *vcpu, spin_lock(&irq->irq_lock); irq->enabled = true; vgic_queue_irq_unlock(vcpu->kvm, irq); + + vgic_put_irq(vcpu->kvm, irq); } } @@ -92,6 +96,7 @@ void vgic_mmio_write_cenable(struct kvm_vcpu *vcpu, irq->enabled = false; spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); } } @@ -108,6 +113,8 @@ unsigned long vgic_mmio_read_pending(struct kvm_vcpu *vcpu, if (irq->pending) value |= (1U << i); + + vgic_put_irq(vcpu->kvm, irq); } return value; @@ -129,6 +136,7 @@ void vgic_mmio_write_spending(struct kvm_vcpu *vcpu, irq->soft_pending = true; vgic_queue_irq_unlock(vcpu->kvm, irq); + vgic_put_irq(vcpu->kvm, irq); } } @@ -152,6 +160,7 @@ void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu, } spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); } } @@ -168,6 +177,8 @@ unsigned long vgic_mmio_read_active(struct kvm_vcpu *vcpu, if (irq->active) value |= (1U << i); + + vgic_put_irq(vcpu->kvm, irq); } return value; @@ -190,6 +201,7 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq, * IRQ, so we release and re-acquire the spin_lock to let the * other thread sync back the IRQ. */ + while (irq->vcpu && /* IRQ may have state in an LR somewhere */ irq->vcpu->cpu != -1) /* VCPU thread is running */ cond_resched_lock(&irq->irq_lock); @@ -242,6 +254,7 @@ void vgic_mmio_write_cactive(struct kvm_vcpu *vcpu, for_each_set_bit(i, &val, len * 8) { struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i); vgic_mmio_change_active(vcpu, irq, false); + vgic_put_irq(vcpu->kvm, irq); } vgic_change_active_finish(vcpu, intid); } @@ -257,6 +270,7 @@ void vgic_mmio_write_sactive(struct kvm_vcpu *vcpu, for_each_set_bit(i, &val, len * 8) { struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i); vgic_mmio_change_active(vcpu, irq, true); + vgic_put_irq(vcpu->kvm, irq); } vgic_change_active_finish(vcpu, intid); } @@ -272,6 +286,8 @@ unsigned long vgic_mmio_read_priority(struct kvm_vcpu *vcpu, struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i); val |= (u64)irq->priority << (i * 8); + + vgic_put_irq(vcpu->kvm, irq); } return val; @@ -298,6 +314,8 @@ void vgic_mmio_write_priority(struct kvm_vcpu *vcpu, /* Narrow the priority range to what we actually support */ irq->priority = (val >> (i * 8)) & GENMASK(7, 8 - VGIC_PRI_BITS); spin_unlock(&irq->irq_lock); + + vgic_put_irq(vcpu->kvm, irq); } } @@ -313,6 +331,8 @@ unsigned long vgic_mmio_read_config(struct kvm_vcpu *vcpu, if (irq->config == VGIC_CONFIG_EDGE) value |= (2U << (i * 2)); + + vgic_put_irq(vcpu->kvm, irq); } return value; @@ -345,6 +365,8 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu, irq->pending = irq->line_level | irq->soft_pending; } spin_unlock(&irq->irq_lock); + + vgic_put_irq(vcpu->kvm, irq); } } diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c index 80313de..cedde7d 100644 --- a/virt/kvm/arm/vgic/vgic-v2.c +++ b/virt/kvm/arm/vgic/vgic-v2.c @@ -124,6 +124,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu) } spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); } } diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c index e48a22e..f0ac064 100644 --- a/virt/kvm/arm/vgic/vgic-v3.c +++ b/virt/kvm/arm/vgic/vgic-v3.c @@ -113,6 +113,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu) } spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); } } diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c index 69b61ab..b90705c 100644 --- a/virt/kvm/arm/vgic/vgic.c +++ b/virt/kvm/arm/vgic/vgic.c @@ -48,13 +48,20 @@ struct vgic_global __section(.hyp.text) kvm_vgic_global_state; struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 intid) { - /* SGIs and PPIs */ - if (intid <= VGIC_MAX_PRIVATE) - return &vcpu->arch.vgic_cpu.private_irqs[intid]; + struct vgic_dist *dist = &kvm->arch.vgic; + struct vgic_irq *irq; + + if (intid <= VGIC_MAX_PRIVATE) { /* SGIs and PPIs */ + irq = &vcpu->arch.vgic_cpu.private_irqs[intid]; + kref_get(&irq->refcount); + return irq; + } - /* SPIs */ - if (intid <= VGIC_MAX_SPI) - return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS]; + if (intid <= VGIC_MAX_SPI) { /* SPIs */ + irq = &dist->spis[intid - VGIC_NR_PRIVATE_IRQS]; + kref_get(&irq->refcount); + return irq; + } /* LPIs are not yet covered */ if (intid >= VGIC_MIN_LPI) @@ -64,6 +71,17 @@ struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu, return NULL; } +/* The refcount should never drop to 0 at the moment. */ +static void vgic_irq_release(struct kref *ref) +{ + WARN_ON(1); +} + +void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq) +{ + kref_put(&irq->refcount, vgic_irq_release); +} + /** * kvm_vgic_target_oracle - compute the target vcpu for an irq * @@ -236,6 +254,7 @@ retry: goto retry; } + kref_get(&irq->refcount); list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head); irq->vcpu = vcpu; @@ -269,14 +288,17 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid, if (!irq) return -EINVAL; - if (irq->hw != mapped_irq) + if (irq->hw != mapped_irq) { + vgic_put_irq(kvm, irq); return -EINVAL; + } spin_lock(&irq->irq_lock); if (!vgic_validate_injection(irq, level)) { /* Nothing to see here, move along... */ spin_unlock(&irq->irq_lock); + vgic_put_irq(kvm, irq); return 0; } @@ -288,6 +310,7 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid, } vgic_queue_irq_unlock(kvm, irq); + vgic_put_irq(kvm, irq); return 0; } @@ -330,6 +353,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq) irq->hwintid = phys_irq; spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); return 0; } @@ -349,6 +373,7 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq) irq->hwintid = 0; spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); return 0; } @@ -386,6 +411,7 @@ retry: list_del(&irq->ap_list); irq->vcpu = NULL; spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); continue; } @@ -614,6 +640,7 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq) spin_lock(&irq->irq_lock); map_is_active = irq->hw && irq->active; spin_unlock(&irq->irq_lock); + vgic_put_irq(vcpu->kvm, irq); return map_is_active; } diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h index c752152..5b79c34 100644 --- a/virt/kvm/arm/vgic/vgic.h +++ b/virt/kvm/arm/vgic/vgic.h @@ -38,6 +38,7 @@ struct vgic_vmcr { struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 intid); +void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq); bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq); void vgic_kick_vcpus(struct kvm *kvm); -- 2.9.0 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html