[PATCH v3 41/59] KVM: arm/arm64: GICv4: Wire mapping/unmapping of VLPIs in VFIO irq bypass

Marc Zyngier
2017-07-31T17:27:04Z

Let's use the irq bypass mechanism introduced for platform device
interrupts to intercept the virtual PCIe endpoint configuration
and establish our LPI->VLPI mapping.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
include/kvm/arm_vgic.h | 8 ++++
virt/kvm/arm/arm.c | 27 ++++++++----
virt/kvm/arm/vgic/vgic-v4.c | 103 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 130 insertions(+), 8 deletions(-)

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 359eeffe9857..050f78d4fb42 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -367,4 +367,12 @@ int kvm_vgic_set_forwarding(struct kvm *kvm, unsigned int host_irq,
void kvm_vgic_unset_forwarding(struct kvm *kvm, unsigned int host_irq,
unsigned int vintid);

+struct kvm_kernel_irq_routing_entry;
+
+int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int irq,
+ struct kvm_kernel_irq_routing_entry *irq_entry);
+
+int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int irq,
+ struct kvm_kernel_irq_routing_entry *irq_entry);
+
#endif /* __KVM_ARM_VGIC_H */
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index ebab6c29e3be..6803ea27c47d 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -1457,11 +1457,16 @@ int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
struct kvm_kernel_irqfd *irqfd =
container_of(cons, struct kvm_kernel_irqfd, consumer);

- if (prod->type != IRQ_BYPASS_VFIO_PLATFORM)
+ switch (prod->type) {
+ case IRQ_BYPASS_VFIO_PLATFORM:
+ return kvm_vgic_set_forwarding(irqfd->kvm, prod->irq,
+ irqfd->gsi + VGIC_NR_PRIVATE_IRQS);
+ case IRQ_BYPASS_VFIO_PCI_MSI:
+ return kvm_vgic_v4_set_forwarding(irqfd->kvm, prod->irq,
+ &irqfd->irq_entry);
+ default:
return 0;
-
- return kvm_vgic_set_forwarding(irqfd->kvm, prod->irq,
- irqfd->gsi + VGIC_NR_PRIVATE_IRQS);
+ }
}
void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
struct irq_bypass_producer *prod)
@@ -1469,11 +1474,17 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
struct kvm_kernel_irqfd *irqfd =
container_of(cons, struct kvm_kernel_irqfd, consumer);

- if (prod->type != IRQ_BYPASS_VFIO_PLATFORM)
- return;
+ switch (prod->type) {
+ case IRQ_BYPASS_VFIO_PLATFORM:
+ kvm_vgic_unset_forwarding(irqfd->kvm, prod->irq,
+ irqfd->gsi + VGIC_NR_PRIVATE_IRQS);
+ break;

- kvm_vgic_unset_forwarding(irqfd->kvm, prod->irq,
- irqfd->gsi + VGIC_NR_PRIVATE_IRQS);
+ case IRQ_BYPASS_VFIO_PCI_MSI:
+ kvm_vgic_v4_unset_forwarding(irqfd->kvm, prod->irq,
+ &irqfd->irq_entry);
+ break;
+ }
}

void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *cons)
diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
index 207e1fda0dcd..338c86c5159f 100644
--- a/virt/kvm/arm/vgic/vgic-v4.c
+++ b/virt/kvm/arm/vgic/vgic-v4.c
@@ -72,3 +72,106 @@ void vgic_v4_teardown(struct kvm *kvm)
its_vm->nr_vpes = 0;
its_vm->vpes = NULL;
}
+
+static struct vgic_its *vgic_get_its(struct kvm *kvm,
+ struct kvm_kernel_irq_routing_entry *irq_entry)
+{
+ struct kvm_msi msi = (struct kvm_msi) {
+ .address_lo = irq_entry->msi.address_lo,
+ .address_hi = irq_entry->msi.address_hi,
+ .data = irq_entry->msi.data,
+ .flags = irq_entry->msi.flags,
+ .devid = irq_entry->msi.devid,
+ };
+
+ /*
+ * Get a reference on the LPI. If NULL, this is not a valid
+ * translation for any of our vITSs.
+ */
+ return vgic_msi_to_its(kvm, &msi);
+}
+
+int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
+ struct kvm_kernel_irq_routing_entry *irq_entry)
+{
+ struct vgic_its *its;
+ struct vgic_irq *irq;
+ struct its_vlpi_map map;
+ int ret;
+
+ if (!vgic_is_v4_capable(kvm))
+ return 0;
+
+ /*
+ * Get the ITS, and escape early on error (not a valid
+ * doorbell for any of our vITSs).
+ */
+ its = vgic_get_its(kvm, irq_entry);
+ if (IS_ERR(its))
+ return 0;
+
+ mutex_lock(&its->its_lock);
+
+ /* Perform then actual DevID/EventID -> LPI translation. */
+ ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
+ irq_entry->msi.data, &irq);
+ if (ret)
+ goto out;
+
+ /*
+ * Emit the mapping request. If it fails, the ITS probably
+ * isn't v4 compatible, so let's silently bail out. Holding
+ * the ITS lock should ensure that nothing can modify the
+ * target vcpu.
+ */
+ map = (struct its_vlpi_map) {
+ .vm = &kvm->arch.vgic.its_vm,
+ .vintid = irq->intid,
+ .db_enabled = true,
+ .vpe_idx = irq->target_vcpu->vcpu_id,
+ };
+
+ if (its_map_vlpi(virq, &map))
+ goto out;
+
+ irq->hw = true;
+ irq->host_irq = virq;
+
+out:
+ mutex_unlock(&its->its_lock);
+ return 0;
+}
+
+int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
+ struct kvm_kernel_irq_routing_entry *irq_entry)
+{
+ struct vgic_its *its;
+ struct vgic_irq *irq;
+ int ret;
+
+ if (!vgic_is_v4_capable(kvm))
+ return 0;
+
+ /*
+ * Get the ITS, and escape early on error (not a valid
+ * doorbell for any of our vITSs).
+ */
+ its = vgic_get_its(kvm, irq_entry);
+ if (IS_ERR(its))
+ return 0;
+
+ mutex_lock(&its->its_lock);
+
+ ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
+ irq_entry->msi.data, &irq);
+ if (ret)
+ goto out;
+
+ WARN_ON(!(irq->hw && irq->host_irq == virq));
+ irq->hw = false;
+ ret = its_unmap_vlpi(virq);
+
+out:
+ mutex_unlock(&its->its_lock);
+ return ret;
+}
--
2.11.0