/*
* Locking order is always:
- * vgic_cpu->ap_list_lock
- * vgic_irq->irq_lock
+ * its->cmd_lock (mutex)
+ * its->its_lock (mutex)
+ * vgic_cpu->ap_list_lock
+ * kvm->lpi_list_lock
+ * vgic_irq->irq_lock
*
- * (that is, always take the ap_list_lock before the struct vgic_irq lock).
+ * If you need to take multiple locks, always take the upper lock first,
+ * then the lower ones, e.g. first take the its_lock, then the irq_lock.
+ * If you are already holding a lock and need to take a higher one, you
+ * have to drop the lower ranking lock first and re-aquire it after having
+ * taken the upper one.
*
* When taking more than one ap_list_lock at the same time, always take the
* lowest numbered VCPU's ap_list_lock first, so:
* spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);
*/
+/*
+ * Iterate over the VM's list of mapped LPIs to find the one with a
+ * matching interrupt ID and return a reference to the IRQ structure.
+ */
+static struct vgic_irq *vgic_get_lpi(struct kvm *kvm, u32 intid)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct vgic_irq *irq = NULL;
+
+ spin_lock(&dist->lpi_list_lock);
+
+ list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+ if (irq->intid != intid)
+ continue;
+
+ /*
+ * This increases the refcount, the caller is expected to
+ * call vgic_put_irq() later once it's finished with the IRQ.
+ */
+ vgic_get_irq_kref(irq);
+ goto out_unlock;
+ }
+ irq = NULL;
+
+out_unlock:
+ spin_unlock(&dist->lpi_list_lock);
+
+ return irq;
+}
+
+/*
+ * This looks up the virtual interrupt ID to get the corresponding
+ * struct vgic_irq. It also increases the refcount, so any caller is expected
+ * to call vgic_put_irq() once it's finished with this IRQ.
+ */
struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
u32 intid)
{
if (intid <= VGIC_MAX_SPI)
return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS];
- /* LPIs are not yet covered */
+ /* LPIs */
if (intid >= VGIC_MIN_LPI)
- return NULL;
+ return vgic_get_lpi(kvm, intid);
WARN(1, "Looking up struct vgic_irq for reserved INTID");
return NULL;
}
+/*
+ * We can't do anything in here, because we lack the kvm pointer to
+ * lock and remove the item from the lpi_list. So we keep this function
+ * empty and use the return value of kref_put() to trigger the freeing.
+ */
+static void vgic_irq_release(struct kref *ref)
+{
+}
+
+void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
+{
+ struct vgic_dist *dist;
+
+ if (irq->intid < VGIC_MIN_LPI)
+ return;
+
+ if (!kref_put(&irq->refcount, vgic_irq_release))
+ return;
+
+ dist = &kvm->arch.vgic;
+
+ spin_lock(&dist->lpi_list_lock);
+ list_del(&irq->lpi_list);
+ dist->lpi_list_count--;
+ spin_unlock(&dist->lpi_list_lock);
+
+ kfree(irq);
+}
+
/**
* kvm_vgic_target_oracle - compute the target vcpu for an irq
*
goto retry;
}
+ /*
+ * Grab a reference to the irq to reflect the fact that it is
+ * now in the ap_list.
+ */
+ vgic_get_irq_kref(irq);
list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head);
irq->vcpu = vcpu;
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;
}
}
vgic_queue_irq_unlock(kvm, irq);
+ vgic_put_irq(kvm, irq);
return 0;
}
irq->hwintid = phys_irq;
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
return 0;
}
int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
{
- struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
-
- BUG_ON(!irq);
+ struct vgic_irq *irq;
if (!vgic_initialized(vcpu->kvm))
return -EAGAIN;
+ irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
+ BUG_ON(!irq);
+
spin_lock(&irq->irq_lock);
irq->hw = false;
irq->hwintid = 0;
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
return 0;
}
list_del(&irq->ap_list);
irq->vcpu = NULL;
spin_unlock(&irq->irq_lock);
+
+ /*
+ * This vgic_put_irq call matches the
+ * vgic_get_irq_kref in vgic_queue_irq_unlock,
+ * where we added the LPI to the ap_list. As
+ * we remove the irq from the list, we drop
+ * also drop the refcount.
+ */
+ vgic_put_irq(vcpu->kvm, irq);
continue;
}
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;
}
+
+int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
+{
+ if (vgic_has_its(kvm))
+ return vgic_its_inject_msi(kvm, msi);
+ else
+ return -ENODEV;
+}
projects / cascardo / linux.git / blobdiff