[PATCH v2 10/12] KVM: arm/arm64: prepare GICv3 emulation to use kvm_io_bus MMIO handling

[Andre Przywara <andre.przywara@arm.com>]

Using the framework provided by the recent vgic.c changes, we
register a kvm_io_bus device on mapping the virtual GICv3 resources.
The distributor mapping is pretty straight forward, but the
redistributors need some more love, since they need to be tagged with
the respective redistributor (read: VCPU) they are connected with.
We use the kvm_io_bus framework to register two devices per VCPU, as
each block is handled independently by the VGIC code.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 include/kvm/arm_vgic.h      |    1 +
 virt/kvm/arm/vgic-v3-emul.c |   34 +++++++++++++++++++++++++++++++++-
 virt/kvm/arm/vgic.c         |   18 ++++++++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 4523984..d6705f4 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -252,6 +252,7 @@ struct vgic_dist {
 
 	struct vgic_vm_ops	vm_ops;
 	struct vgic_io_device	dist_iodev;
+	struct vgic_io_device	*redist_iodevs;
 };
 
 struct vgic_v2_cpu_if {
diff --git a/virt/kvm/arm/vgic-v3-emul.c b/virt/kvm/arm/vgic-v3-emul.c
index 14943e3..35679d1 100644
--- a/virt/kvm/arm/vgic-v3-emul.c
+++ b/virt/kvm/arm/vgic-v3-emul.c
@@ -766,6 +766,9 @@ static int vgic_v3_map_resources(struct kvm *kvm,
 {
 	int ret = 0;
 	struct vgic_dist *dist = &kvm->arch.vgic;
+	gpa_t rdbase = dist->vgic_redist_base;
+	struct vgic_io_device *iodevs = NULL;
+	int i;
 
 	if (!irqchip_in_kernel(kvm))
 		return 0;
@@ -791,7 +794,36 @@ static int vgic_v3_map_resources(struct kvm *kvm,
 		goto out;
 	}
 
-	kvm->arch.vgic.ready = true;
+	ret = vgic_register_kvm_io_dev(kvm, dist->vgic_dist_base,
+				       GIC_V3_DIST_SIZE, vgic_v3_dist_ranges,
+				       -1, &dist->dist_iodev);
+	if (ret)
+		goto out;
+
+	iodevs = kcalloc(dist->nr_cpus * 2, sizeof(iodevs[0]), GFP_KERNEL);
+	if (!iodevs) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* kvm_vgic_destroy() will take care of destroying the devices later. */
+	for (i = 0; i < dist->nr_cpus; i++) {
+		ret = vgic_register_kvm_io_dev(kvm, rdbase,
+					       SZ_64K, vgic_redist_ranges,
+					       i, &iodevs[i * 2]);
+		if (ret)
+			goto out;
+		ret = vgic_register_kvm_io_dev(kvm, rdbase + SGI_BASE_OFFSET,
+					       SZ_64K, vgic_redist_sgi_ranges,
+					       i, &iodevs[i * 2 + 1]);
+		if (ret)
+			goto out;
+		rdbase += GIC_V3_REDIST_SIZE;
+	}
+
+	dist->redist_iodevs = iodevs;
+	dist->ready = true;
+
 out:
 	if (ret)
 		kvm_vgic_destroy(kvm);
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 9a732d0..9cbb55f4 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -992,6 +992,8 @@ int vgic_register_kvm_io_dev(struct kvm *kvm, gpa_t base, int len,
 static void vgic_unregister_kvm_io_dev(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct vgic_io_device *iodevs;
+	int i;
 
 	if (!dist || !kvm->buses[KVM_MMIO_BUS])
 		return;
@@ -1001,6 +1003,22 @@ static void vgic_unregister_kvm_io_dev(struct kvm *kvm)
 	if (dist->dist_iodev.dev.ops)
 		kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS,
 					  &dist->dist_iodev.dev);
+
+	iodevs = dist->redist_iodevs;
+	if (iodevs) {
+		for (i = 0; i < dist->nr_cpus * 2; i++) {
+			/*
+			 * Because of a failed initialization we could get here
+			 * without ever having registered a device.
+			 */
+			if (!iodevs[i].dev.ops)
+				continue;
+			kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS,
+						  &iodevs[i].dev);
+		}
+		kfree(iodevs);
+		dist->redist_iodevs = NULL;
+	}
 	mutex_unlock(&kvm->slots_lock);
 }
 
-- 
1.7.9.5