[PATCH v5 10/26] KVM: arm/arm64: GICv4: Wire mapping/unmapping of VLPIs in VFIO irq bypass

Marc Zyngier
2017-10-27T14:28:12Z

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.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
include/kvm/arm_vgic.h | 8 ++++
virt/kvm/arm/arm.c | 6 ++-
virt/kvm/arm/vgic/vgic-v4.c | 108 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 120 insertions(+), 2 deletions(-)

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 7eeb6c2a2f9c..2f750c770bf2 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -373,4 +373,12 @@ int kvm_vgic_setup_default_irq_routing(struct kvm *kvm);

int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner);

+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 5d5218ecd547..8388c1cc23f6 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -1462,7 +1462,8 @@ 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);

- return 0;
+ return kvm_vgic_v4_set_forwarding(irqfd->kvm, prod->irq,
+ &irqfd->irq_entry);
}
void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
struct irq_bypass_producer *prod)
@@ -1470,7 +1471,8 @@ 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);

- return;
+ kvm_vgic_v4_unset_forwarding(irqfd->kvm, prod->irq,
+ &irqfd->irq_entry);
}

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 c794f0cef09e..01a2889b7b7c 100644
--- a/virt/kvm/arm/vgic/vgic-v4.c
+++ b/virt/kvm/arm/vgic/vgic-v4.c
@@ -18,6 +18,7 @@
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/kvm_host.h>
+#include <linux/irqchip/arm-gic-v3.h>

#include "vgic.h"

@@ -81,3 +82,110 @@ 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_supports_direct_msis(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,
+ .vpe = &irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe,
+ .vintid = irq->intid,
+ .properties = ((irq->priority & 0xfc) |
+ (irq->enabled ? LPI_PROP_ENABLED : 0) |
+ LPI_PROP_GROUP1),
+ .db_enabled = true,
+ };
+
+ ret = its_map_vlpi(virq, &map);
+ if (ret)
+ goto out;
+
+ irq->hw = true;
+ irq->host_irq = virq;
+
+out:
+ mutex_unlock(&its->its_lock);
+ return ret;
+}
+
+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_supports_direct_msis(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