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authorScott Wood <scottwood@freescale.com>2013-04-12 14:08:42 +0000
committerAlexander Graf <agraf@suse.de>2013-04-26 20:27:20 +0200
commit852b6d57dc7fa378019786fa84727036e56839ea (patch)
tree4d617ba91f6fc5de3fddac349e695d914e626a49 /virt/kvm
parent7df35f549606e8a9004a77ef31dc80dfa893a590 (diff)
downloadlinux-linaro-stable-852b6d57dc7fa378019786fa84727036e56839ea.tar.gz
kvm: add device control API
Currently, devices that are emulated inside KVM are configured in a hardcoded manner based on an assumption that any given architecture only has one way to do it. If there's any need to access device state, it is done through inflexible one-purpose-only IOCTLs (e.g. KVM_GET/SET_LAPIC). Defining new IOCTLs for every little thing is cumbersome and depletes a limited numberspace. This API provides a mechanism to instantiate a device of a certain type, returning an ID that can be used to set/get attributes of the device. Attributes may include configuration parameters (e.g. register base address), device state, operational commands, etc. It is similar to the ONE_REG API, except that it acts on devices rather than vcpus. Both device types and individual attributes can be tested without having to create the device or get/set the attribute, without the need for separately managing enumerated capabilities. Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'virt/kvm')
-rw-r--r--virt/kvm/kvm_main.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f9492f3847d6..5f0d78c2537b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2159,6 +2159,117 @@ out:
}
#endif
+static int kvm_device_ioctl_attr(struct kvm_device *dev,
+ int (*accessor)(struct kvm_device *dev,
+ struct kvm_device_attr *attr),
+ unsigned long arg)
+{
+ struct kvm_device_attr attr;
+
+ if (!accessor)
+ return -EPERM;
+
+ if (copy_from_user(&attr, (void __user *)arg, sizeof(attr)))
+ return -EFAULT;
+
+ return accessor(dev, &attr);
+}
+
+static long kvm_device_ioctl(struct file *filp, unsigned int ioctl,
+ unsigned long arg)
+{
+ struct kvm_device *dev = filp->private_data;
+
+ switch (ioctl) {
+ case KVM_SET_DEVICE_ATTR:
+ return kvm_device_ioctl_attr(dev, dev->ops->set_attr, arg);
+ case KVM_GET_DEVICE_ATTR:
+ return kvm_device_ioctl_attr(dev, dev->ops->get_attr, arg);
+ case KVM_HAS_DEVICE_ATTR:
+ return kvm_device_ioctl_attr(dev, dev->ops->has_attr, arg);
+ default:
+ if (dev->ops->ioctl)
+ return dev->ops->ioctl(dev, ioctl, arg);
+
+ return -ENOTTY;
+ }
+}
+
+void kvm_device_get(struct kvm_device *dev)
+{
+ atomic_inc(&dev->users);
+}
+
+void kvm_device_put(struct kvm_device *dev)
+{
+ if (atomic_dec_and_test(&dev->users))
+ dev->ops->destroy(dev);
+}
+
+static int kvm_device_release(struct inode *inode, struct file *filp)
+{
+ struct kvm_device *dev = filp->private_data;
+ struct kvm *kvm = dev->kvm;
+
+ kvm_device_put(dev);
+ kvm_put_kvm(kvm);
+ return 0;
+}
+
+static const struct file_operations kvm_device_fops = {
+ .unlocked_ioctl = kvm_device_ioctl,
+ .release = kvm_device_release,
+};
+
+struct kvm_device *kvm_device_from_filp(struct file *filp)
+{
+ if (filp->f_op != &kvm_device_fops)
+ return NULL;
+
+ return filp->private_data;
+}
+
+static int kvm_ioctl_create_device(struct kvm *kvm,
+ struct kvm_create_device *cd)
+{
+ struct kvm_device_ops *ops = NULL;
+ struct kvm_device *dev;
+ bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
+ int ret;
+
+ switch (cd->type) {
+ default:
+ return -ENODEV;
+ }
+
+ if (test)
+ return 0;
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return -ENOMEM;
+
+ dev->ops = ops;
+ dev->kvm = kvm;
+ atomic_set(&dev->users, 1);
+
+ ret = ops->create(dev, cd->type);
+ if (ret < 0) {
+ kfree(dev);
+ return ret;
+ }
+
+ ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR);
+ if (ret < 0) {
+ ops->destroy(dev);
+ return ret;
+ }
+
+ kvm_get_kvm(kvm);
+ cd->fd = ret;
+ return 0;
+}
+
static long kvm_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -2304,6 +2415,24 @@ static long kvm_vm_ioctl(struct file *filp,
break;
}
#endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */
+ case KVM_CREATE_DEVICE: {
+ struct kvm_create_device cd;
+
+ r = -EFAULT;
+ if (copy_from_user(&cd, argp, sizeof(cd)))
+ goto out;
+
+ r = kvm_ioctl_create_device(kvm, &cd);
+ if (r)
+ goto out;
+
+ r = -EFAULT;
+ if (copy_to_user(argp, &cd, sizeof(cd)))
+ goto out;
+
+ r = 0;
+ break;
+ }
default:
r = kvm_arch_vm_ioctl(filp, ioctl, arg);
if (r == -ENOTTY)