KVM: arm64: vgic-its: Introduce new KVM ITS device

Introduce a new KVM device that represents an ARM Interrupt Translation
Service (ITS) controller. Since there can be multiple of this per guest,
we can't piggy back on the existing GICv3 distributor device, but create
a new type of KVM device.
On the KVM_CREATE_DEVICE ioctl we allocate and initialize the ITS data
structure and store the pointer in the kvm_device data.
Upon an explicit init ioctl from userland (after having setup the MMIO
address) we register the handlers with the kvm_io_bus framework.
Any reference to an ITS thus has to go via this interface.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

4 files changed, 141 insertions, 3 deletions

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 4654d6edf6a6..6b47b3674690 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -21,6 +21,7 @@
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <linux/interrupt.h>
+#include <linux/uaccess.h>
 
 #include <linux/irqchip/arm-gic-v3.h>
 
@@ -84,6 +85,9 @@ static int vgic_its_init_its(struct kvm *kvm, struct vgic_its *its)
         struct vgic_io_device *iodev = &its->iodev;
         int ret;
 
+        if (its->initialized)
+                return 0;
+
         if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base))
                 return -ENXIO;
 
@@ -99,5 +103,136 @@ static int vgic_its_init_its(struct kvm *kvm, struct vgic_its *its)
                                       KVM_VGIC_V3_ITS_SIZE, &iodev->dev);
         mutex_unlock(&kvm->slots_lock);
 
+        if (!ret)
+                its->initialized = true;
+
         return ret;
 }
+
+static int vgic_its_create(struct kvm_device *dev, u32 type)
+{
+        struct vgic_its *its;
+
+        if (type != KVM_DEV_TYPE_ARM_VGIC_ITS)
+                return -ENODEV;
+
+        its = kzalloc(sizeof(struct vgic_its), GFP_KERNEL);
+        if (!its)
+                return -ENOMEM;
+
+        its->vgic_its_base = VGIC_ADDR_UNDEF;
+
+        dev->kvm->arch.vgic.has_its = true;
+        its->initialized = false;
+        its->enabled = false;
+
+        dev->private = its;
+
+        return 0;
+}
+
+static void vgic_its_destroy(struct kvm_device *kvm_dev)
+{
+        struct vgic_its *its = kvm_dev->private;
+
+        kfree(its);
+}
+
+static int vgic_its_has_attr(struct kvm_device *dev,
+                             struct kvm_device_attr *attr)
+{
+        switch (attr->group) {
+        case KVM_DEV_ARM_VGIC_GRP_ADDR:
+                switch (attr->attr) {
+                case KVM_VGIC_ITS_ADDR_TYPE:
+                        return 0;
+                }
+                break;
+        case KVM_DEV_ARM_VGIC_GRP_CTRL:
+                switch (attr->attr) {
+                case KVM_DEV_ARM_VGIC_CTRL_INIT:
+                        return 0;
+                }
+                break;
+        }
+        return -ENXIO;
+}
+
+static int vgic_its_set_attr(struct kvm_device *dev,
+                             struct kvm_device_attr *attr)
+{
+        struct vgic_its *its = dev->private;
+        int ret;
+
+        switch (attr->group) {
+        case KVM_DEV_ARM_VGIC_GRP_ADDR: {
+                u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+                unsigned long type = (unsigned long)attr->attr;
+                u64 addr;
+
+                if (type != KVM_VGIC_ITS_ADDR_TYPE)
+                        return -ENODEV;
+
+                if (its->initialized)
+                        return -EBUSY;
+
+                if (copy_from_user(&addr, uaddr, sizeof(addr)))
+                        return -EFAULT;
+
+                ret = vgic_check_ioaddr(dev->kvm, &its->vgic_its_base,
+                                        addr, SZ_64K);
+                if (ret)
+                        return ret;
+
+                its->vgic_its_base = addr;
+
+                return 0;
+        }
+        case KVM_DEV_ARM_VGIC_GRP_CTRL:
+                switch (attr->attr) {
+                case KVM_DEV_ARM_VGIC_CTRL_INIT:
+                        return vgic_its_init_its(dev->kvm, its);
+                }
+                break;
+        }
+        return -ENXIO;
+}
+
+static int vgic_its_get_attr(struct kvm_device *dev,
+                             struct kvm_device_attr *attr)
+{
+        switch (attr->group) {
+        case KVM_DEV_ARM_VGIC_GRP_ADDR: {
+                struct vgic_its *its = dev->private;
+                u64 addr = its->vgic_its_base;
+                u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+                unsigned long type = (unsigned long)attr->attr;
+
+                if (type != KVM_VGIC_ITS_ADDR_TYPE)
+                        return -ENODEV;
+
+                if (copy_to_user(uaddr, &addr, sizeof(addr)))
+                        return -EFAULT;
+                break;
+        default:
+                return -ENXIO;
+        }
+        }
+
+        return 0;
+}
+
+static struct kvm_device_ops kvm_arm_vgic_its_ops = {
+        .name = "kvm-arm-vgic-its",
+        .create = vgic_its_create,
+        .destroy = vgic_its_destroy,
+        .set_attr = vgic_its_set_attr,
+        .get_attr = vgic_its_get_attr,
+        .has_attr = vgic_its_has_attr,
+};
+
+int kvm_vgic_register_its_device(void)
+{
+        return kvm_register_device_ops(&kvm_arm_vgic_its_ops,
+                                       KVM_DEV_TYPE_ARM_VGIC_ITS);
+}
diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index 2f24f13c6c90..561d2ba96a4f 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -21,8 +21,8 @@
 
 /* common helpers */
 
-static int vgic_check_ioaddr(struct kvm *kvm, phys_addr_t *ioaddr,
-                             phys_addr_t addr, phys_addr_t alignment)
+int vgic_check_ioaddr(struct kvm *kvm, phys_addr_t *ioaddr,
+                      phys_addr_t addr, phys_addr_t alignment)
 {
         if (addr & ~KVM_PHYS_MASK)
                 return -E2BIG;
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index b92b7d6cabe6..a5c35050c786 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -49,7 +49,7 @@ bool vgic_has_its(struct kvm *kvm)
         if (dist->vgic_model != KVM_DEV_TYPE_ARM_VGIC_V3)
                 return false;
 
-        return false;
+        return dist->has_its;
 }
 
 static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 31807c166d2a..8192a293f119 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -42,6 +42,9 @@ void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq);
 bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq);
 void vgic_kick_vcpus(struct kvm *kvm);
 
+int vgic_check_ioaddr(struct kvm *kvm, phys_addr_t *ioaddr,
+                      phys_addr_t addr, phys_addr_t alignment);
+
 void vgic_v2_process_maintenance(struct kvm_vcpu *vcpu);
 void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu);
 void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr);