KVM: arm/arm64: GICv4: Add init/teardown of the per-VM vPE irq domain

In order to control the GICv4 view of virtual CPUs, we rely
on an irqdomain allocated for that purpose. Let's add a couple
of helpers to that effect.

At the same time, the vgic data structures gain new fields to
track all this... erm... wonderful stuff.

The way we hook into the vgic init is slightly convoluted. We
need the vgic to be initialized (in order to guarantee that
the number of vcpus is now fixed), and we must have a vITS
(otherwise this is all very pointless). So we end-up calling
the init from both vgic_init and vgic_its_create.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

4 files changed, 102 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 5801261f3add..40be908da238 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -285,6 +285,12 @@ int vgic_init(struct kvm *kvm)
         if (ret)
                 goto out;
 
+        if (vgic_supports_direct_msis(kvm)) {
+                ret = vgic_v4_init(kvm);
+                if (ret)
+                        goto out;
+        }
+
         kvm_for_each_vcpu(i, vcpu, kvm)
                 kvm_vgic_vcpu_enable(vcpu);
 
@@ -320,6 +326,9 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm)
 
         kfree(dist->spis);
         dist->nr_spis = 0;
+
+        if (vgic_supports_direct_msis(kvm))
+                vgic_v4_teardown(kvm);
 }
 
 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 09accdfed189..54f81eb24a07 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1638,6 +1638,14 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
         if (!its)
                 return -ENOMEM;
 
+        if (vgic_initialized(dev->kvm)) {
+                int ret = vgic_v4_init(dev->kvm);
+                if (ret) {
+                        kfree(its);
+                        return ret;
+                }
+        }
+
         mutex_init(&its->its_lock);
         mutex_init(&its->cmd_lock);
 
diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
new file mode 100644
index 000000000000..c794f0cef09e
--- /dev/null
+++ b/virt/kvm/arm/vgic/vgic-v4.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2017 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/kvm_host.h>
+
+#include "vgic.h"
+
+/**
+ * vgic_v4_init - Initialize the GICv4 data structures
+ * @kvm:        Pointer to the VM being initialized
+ *
+ * We may be called each time a vITS is created, or when the
+ * vgic is initialized. This relies on kvm->lock to be
+ * held. In both cases, the number of vcpus should now be
+ * fixed.
+ */
+int vgic_v4_init(struct kvm *kvm)
+{
+        struct vgic_dist *dist = &kvm->arch.vgic;
+        struct kvm_vcpu *vcpu;
+        int i, nr_vcpus, ret;
+
+        if (dist->its_vm.vpes)
+                return 0;
+
+        nr_vcpus = atomic_read(&kvm->online_vcpus);
+
+        dist->its_vm.vpes = kzalloc(sizeof(*dist->its_vm.vpes) * nr_vcpus,
+                                    GFP_KERNEL);
+        if (!dist->its_vm.vpes)
+                return -ENOMEM;
+
+        dist->its_vm.nr_vpes = nr_vcpus;
+
+        kvm_for_each_vcpu(i, vcpu, kvm)
+                dist->its_vm.vpes[i] = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
+
+        ret = its_alloc_vcpu_irqs(&dist->its_vm);
+        if (ret < 0) {
+                kvm_err("VPE IRQ allocation failure\n");
+                kfree(dist->its_vm.vpes);
+                dist->its_vm.nr_vpes = 0;
+                dist->its_vm.vpes = NULL;
+                return ret;
+        }
+
+        return ret;
+}
+
+/**
+ * vgic_v4_teardown - Free the GICv4 data structures
+ * @kvm:        Pointer to the VM being destroyed
+ *
+ * Relies on kvm->lock to be held.
+ */
+void vgic_v4_teardown(struct kvm *kvm)
+{
+        struct its_vm *its_vm = &kvm->arch.vgic.its_vm;
+
+        if (!its_vm->vpes)
+                return;
+
+        its_free_vcpu_irqs(its_vm);
+        kfree(its_vm->vpes);
+        its_vm->nr_vpes = 0;
+        its_vm->vpes = NULL;
+}
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 67509b203cf5..bf03a9648fbb 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -242,5 +242,7 @@ int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
 struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);
 
 bool vgic_supports_direct_msis(struct kvm *kvm);
+int vgic_v4_init(struct kvm *kvm);
+void vgic_v4_teardown(struct kvm *kvm);
 
 #endif