diff options
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/arm/vgic/vgic-mmio.c | 105 |
1 files changed, 66 insertions, 39 deletions
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c index 4ef35719fcbe..059595ec3da0 100644 --- a/virt/kvm/arm/vgic/vgic-mmio.c +++ b/virt/kvm/arm/vgic/vgic-mmio.c @@ -173,6 +173,66 @@ unsigned long vgic_mmio_read_active(struct kvm_vcpu *vcpu, return value; } +static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq, + bool new_active_state) +{ + spin_lock(&irq->irq_lock); + /* + * If this virtual IRQ was written into a list register, we + * have to make sure the CPU that runs the VCPU thread has + * synced back LR state to the struct vgic_irq. We can only + * know this for sure, when either this irq is not assigned to + * anyone's AP list anymore, or the VCPU thread is not + * running on any CPUs. + * + * In the opposite case, we know the VCPU thread may be on its + * way back from the guest and still has to sync back this + * 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 */ + BUG_ON(irq->intid < VGIC_NR_PRIVATE_IRQS); + cond_resched_lock(&irq->irq_lock); + } + + irq->active = new_active_state; + if (new_active_state) + vgic_queue_irq_unlock(vcpu->kvm, irq); + else + spin_unlock(&irq->irq_lock); +} + +/* + * If we are fiddling with an IRQ's active state, we have to make sure the IRQ + * is not queued on some running VCPU's LRs, because then the change to the + * active state can be overwritten when the VCPU's state is synced coming back + * from the guest. + * + * For shared interrupts, we have to stop all the VCPUs because interrupts can + * be migrated while we don't hold the IRQ locks and we don't want to be + * chasing moving targets. + * + * For private interrupts, we only have to make sure the single and only VCPU + * that can potentially queue the IRQ is stopped. + */ +static void vgic_change_active_prepare(struct kvm_vcpu *vcpu, u32 intid) +{ + if (intid < VGIC_NR_PRIVATE_IRQS) + kvm_arm_halt_vcpu(vcpu); + else + kvm_arm_halt_guest(vcpu->kvm); +} + +/* See vgic_change_active_prepare */ +static void vgic_change_active_finish(struct kvm_vcpu *vcpu, u32 intid) +{ + if (intid < VGIC_NR_PRIVATE_IRQS) + kvm_arm_resume_vcpu(vcpu); + else + kvm_arm_resume_guest(vcpu->kvm); +} + void vgic_mmio_write_cactive(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len, unsigned long val) @@ -180,32 +240,12 @@ void vgic_mmio_write_cactive(struct kvm_vcpu *vcpu, u32 intid = VGIC_ADDR_TO_INTID(addr, 1); int i; - kvm_arm_halt_guest(vcpu->kvm); + vgic_change_active_prepare(vcpu, intid); for_each_set_bit(i, &val, len * 8) { struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i); - - spin_lock(&irq->irq_lock); - /* - * If this virtual IRQ was written into a list register, we - * have to make sure the CPU that runs the VCPU thread has - * synced back LR state to the struct vgic_irq. We can only - * know this for sure, when either this irq is not assigned to - * anyone's AP list anymore, or the VCPU thread is not - * running on any CPUs. - * - * In the opposite case, we know the VCPU thread may be on its - * way back from the guest and still has to sync back this - * 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); - - irq->active = false; - spin_unlock(&irq->irq_lock); + vgic_mmio_change_active(vcpu, irq, false); } - kvm_arm_resume_guest(vcpu->kvm); + vgic_change_active_finish(vcpu, intid); } void vgic_mmio_write_sactive(struct kvm_vcpu *vcpu, @@ -215,25 +255,12 @@ void vgic_mmio_write_sactive(struct kvm_vcpu *vcpu, u32 intid = VGIC_ADDR_TO_INTID(addr, 1); int i; + vgic_change_active_prepare(vcpu, intid); for_each_set_bit(i, &val, len * 8) { struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i); - - spin_lock(&irq->irq_lock); - - /* - * If the IRQ was already active or there is no target VCPU - * assigned at the moment, then just proceed. - */ - if (irq->active || !irq->target_vcpu) { - irq->active = true; - - spin_unlock(&irq->irq_lock); - continue; - } - - irq->active = true; - vgic_queue_irq_unlock(vcpu->kvm, irq); + vgic_mmio_change_active(vcpu, irq, true); } + vgic_change_active_finish(vcpu, intid); } unsigned long vgic_mmio_read_priority(struct kvm_vcpu *vcpu, |