diff options
Diffstat (limited to 'virt/kvm')
| -rw-r--r-- | virt/kvm/arm/vgic/vgic.c | 211 | ||||
| -rw-r--r-- | virt/kvm/arm/vgic/vgic.h | 1 |
2 files changed, 212 insertions, 0 deletions
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c index fb45537451b2..ada1d02a02b4 100644 --- a/virt/kvm/arm/vgic/vgic.c +++ b/virt/kvm/arm/vgic/vgic.c @@ -19,8 +19,31 @@ #include "vgic.h" +#define CREATE_TRACE_POINTS +#include "../trace.h" + +#ifdef CONFIG_DEBUG_SPINLOCK +#define DEBUG_SPINLOCK_BUG_ON(p) BUG_ON(p) +#else +#define DEBUG_SPINLOCK_BUG_ON(p) +#endif + struct vgic_global __section(.hyp.text) kvm_vgic_global_state; +/* + * Locking order is always: + * vgic_cpu->ap_list_lock + * vgic_irq->irq_lock + * + * (that is, always take the ap_list_lock before the struct vgic_irq lock). + * + * When taking more than one ap_list_lock at the same time, always take the + * lowest numbered VCPU's ap_list_lock first, so: + * vcpuX->vcpu_id < vcpuY->vcpu_id: + * spin_lock(vcpuX->arch.vgic_cpu.ap_list_lock); + * spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock); + */ + struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 intid) { @@ -39,3 +62,191 @@ struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu, WARN(1, "Looking up struct vgic_irq for reserved INTID"); return NULL; } + +/** + * kvm_vgic_target_oracle - compute the target vcpu for an irq + * + * @irq: The irq to route. Must be already locked. + * + * Based on the current state of the interrupt (enabled, pending, + * active, vcpu and target_vcpu), compute the next vcpu this should be + * given to. Return NULL if this shouldn't be injected at all. + * + * Requires the IRQ lock to be held. + */ +static struct kvm_vcpu *vgic_target_oracle(struct vgic_irq *irq) +{ + DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock)); + + /* If the interrupt is active, it must stay on the current vcpu */ + if (irq->active) + return irq->vcpu ? : irq->target_vcpu; + + /* + * If the IRQ is not active but enabled and pending, we should direct + * it to its configured target VCPU. + * If the distributor is disabled, pending interrupts shouldn't be + * forwarded. + */ + if (irq->enabled && irq->pending) { + if (unlikely(irq->target_vcpu && + !irq->target_vcpu->kvm->arch.vgic.enabled)) + return NULL; + + return irq->target_vcpu; + } + + /* If neither active nor pending and enabled, then this IRQ should not + * be queued to any VCPU. + */ + return NULL; +} + +/* + * Only valid injection if changing level for level-triggered IRQs or for a + * rising edge. + */ +static bool vgic_validate_injection(struct vgic_irq *irq, bool level) +{ + switch (irq->config) { + case VGIC_CONFIG_LEVEL: + return irq->line_level != level; + case VGIC_CONFIG_EDGE: + return level; + } + + return false; +} + +/* + * Check whether an IRQ needs to (and can) be queued to a VCPU's ap list. + * Do the queuing if necessary, taking the right locks in the right order. + * Returns true when the IRQ was queued, false otherwise. + * + * Needs to be entered with the IRQ lock already held, but will return + * with all locks dropped. + */ +bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq) +{ + struct kvm_vcpu *vcpu; + + DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock)); + +retry: + vcpu = vgic_target_oracle(irq); + if (irq->vcpu || !vcpu) { + /* + * If this IRQ is already on a VCPU's ap_list, then it + * cannot be moved or modified and there is no more work for + * us to do. + * + * Otherwise, if the irq is not pending and enabled, it does + * not need to be inserted into an ap_list and there is also + * no more work for us to do. + */ + spin_unlock(&irq->irq_lock); + return false; + } + + /* + * We must unlock the irq lock to take the ap_list_lock where + * we are going to insert this new pending interrupt. + */ + spin_unlock(&irq->irq_lock); + + /* someone can do stuff here, which we re-check below */ + + spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock); + spin_lock(&irq->irq_lock); + + /* + * Did something change behind our backs? + * + * There are two cases: + * 1) The irq lost its pending state or was disabled behind our + * backs and/or it was queued to another VCPU's ap_list. + * 2) Someone changed the affinity on this irq behind our + * backs and we are now holding the wrong ap_list_lock. + * + * In both cases, drop the locks and retry. + */ + + if (unlikely(irq->vcpu || vcpu != vgic_target_oracle(irq))) { + spin_unlock(&irq->irq_lock); + spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock); + + spin_lock(&irq->irq_lock); + goto retry; + } + + list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head); + irq->vcpu = vcpu; + + spin_unlock(&irq->irq_lock); + spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock); + + kvm_vcpu_kick(vcpu); + + return true; +} + +static int vgic_update_irq_pending(struct kvm *kvm, int cpuid, + unsigned int intid, bool level, + bool mapped_irq) +{ + struct kvm_vcpu *vcpu; + struct vgic_irq *irq; + int ret; + + trace_vgic_update_irq_pending(cpuid, intid, level); + + vcpu = kvm_get_vcpu(kvm, cpuid); + if (!vcpu && intid < VGIC_NR_PRIVATE_IRQS) + return -EINVAL; + + irq = vgic_get_irq(kvm, vcpu, intid); + if (!irq) + return -EINVAL; + + if (irq->hw != mapped_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); + return 0; + } + + if (irq->config == VGIC_CONFIG_LEVEL) { + irq->line_level = level; + irq->pending = level || irq->soft_pending; + } else { + irq->pending = true; + } + + vgic_queue_irq_unlock(kvm, irq); + + return 0; +} + +/** + * kvm_vgic_inject_irq - Inject an IRQ from a device to the vgic + * @kvm: The VM structure pointer + * @cpuid: The CPU for PPIs + * @intid: The INTID to inject a new state to. + * @level: Edge-triggered: true: to trigger the interrupt + * false: to ignore the call + * Level-sensitive true: raise the input signal + * false: lower the input signal + * + * The VGIC is not concerned with devices being active-LOW or active-HIGH for + * level-sensitive interrupts. You can think of the level parameter as 1 + * being HIGH and 0 being LOW and all devices being active-HIGH. + */ +int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid, + bool level) +{ + return vgic_update_irq_pending(kvm, cpuid, intid, level, false); +} diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h index 61b8d226081b..c6257679e091 100644 --- a/virt/kvm/arm/vgic/vgic.h +++ b/virt/kvm/arm/vgic/vgic.h @@ -18,5 +18,6 @@ struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 intid); +bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq); #endif |