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Diffstat (limited to 'virt/kvm/arm/vgic/vgic-mmio.c')
-rw-r--r--virt/kvm/arm/vgic/vgic-mmio.c105
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,