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authorAlex Williamson <alex.williamson@redhat.com>2013-12-19 10:17:13 -0700
committerAlex Williamson <alex.williamson@redhat.com>2013-12-19 10:17:13 -0700
commitd10999016f4164e9b80f1b3dece3842087cfa3bb (patch)
tree8c739c70480d451e1c0e62c1cf1f8f695f4071ce
parent8dcf94bcff5bf3b54380ae2a17b034fb3b9d58e5 (diff)
downloadlwn-d10999016f4164e9b80f1b3dece3842087cfa3bb.tar.gz
lwn-d10999016f4164e9b80f1b3dece3842087cfa3bb.zip
vfio: Convert control interface to misc driver
This change allows us to support module auto loading using devname support in userspace tools. With this, /dev/vfio/vfio will always be present and opening it will cause the vfio module to load. This should avoid needing to configure the system to statically load vfio in order to get libvirt to correctly detect support for it. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
-rw-r--r--drivers/vfio/vfio.c70
1 files changed, 33 insertions, 37 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 1eab4ace0671..21271d8df023 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -22,6 +22,7 @@
#include <linux/idr.h>
#include <linux/iommu.h>
#include <linux/list.h>
+#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
@@ -45,9 +46,7 @@ static struct vfio {
struct idr group_idr;
struct mutex group_lock;
struct cdev group_cdev;
- struct device *dev;
- dev_t devt;
- struct cdev cdev;
+ dev_t group_devt;
wait_queue_head_t release_q;
} vfio;
@@ -142,8 +141,7 @@ EXPORT_SYMBOL_GPL(vfio_unregister_iommu_driver);
*/
static int vfio_alloc_group_minor(struct vfio_group *group)
{
- /* index 0 is used by /dev/vfio/vfio */
- return idr_alloc(&vfio.group_idr, group, 1, MINORMASK + 1, GFP_KERNEL);
+ return idr_alloc(&vfio.group_idr, group, 0, MINORMASK + 1, GFP_KERNEL);
}
static void vfio_free_group_minor(int minor)
@@ -243,7 +241,8 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
}
}
- dev = device_create(vfio.class, NULL, MKDEV(MAJOR(vfio.devt), minor),
+ dev = device_create(vfio.class, NULL,
+ MKDEV(MAJOR(vfio.group_devt), minor),
group, "%d", iommu_group_id(iommu_group));
if (IS_ERR(dev)) {
vfio_free_group_minor(minor);
@@ -268,7 +267,7 @@ static void vfio_group_release(struct kref *kref)
WARN_ON(!list_empty(&group->device_list));
- device_destroy(vfio.class, MKDEV(MAJOR(vfio.devt), group->minor));
+ device_destroy(vfio.class, MKDEV(MAJOR(vfio.group_devt), group->minor));
list_del(&group->vfio_next);
vfio_free_group_minor(group->minor);
vfio_group_unlock_and_free(group);
@@ -1419,12 +1418,17 @@ EXPORT_SYMBOL_GPL(vfio_external_user_iommu_id);
*/
static char *vfio_devnode(struct device *dev, umode_t *mode)
{
- if (mode && (MINOR(dev->devt) == 0))
- *mode = S_IRUGO | S_IWUGO;
-
return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev));
}
+static struct miscdevice vfio_dev = {
+ .minor = VFIO_MINOR,
+ .name = "vfio",
+ .fops = &vfio_fops,
+ .nodename = "vfio/vfio",
+ .mode = S_IRUGO | S_IWUGO,
+};
+
static int __init vfio_init(void)
{
int ret;
@@ -1436,6 +1440,13 @@ static int __init vfio_init(void)
INIT_LIST_HEAD(&vfio.iommu_drivers_list);
init_waitqueue_head(&vfio.release_q);
+ ret = misc_register(&vfio_dev);
+ if (ret) {
+ pr_err("vfio: misc device register failed\n");
+ return ret;
+ }
+
+ /* /dev/vfio/$GROUP */
vfio.class = class_create(THIS_MODULE, "vfio");
if (IS_ERR(vfio.class)) {
ret = PTR_ERR(vfio.class);
@@ -1444,27 +1455,14 @@ static int __init vfio_init(void)
vfio.class->devnode = vfio_devnode;
- ret = alloc_chrdev_region(&vfio.devt, 0, MINORMASK, "vfio");
- if (ret)
- goto err_base_chrdev;
-
- cdev_init(&vfio.cdev, &vfio_fops);
- ret = cdev_add(&vfio.cdev, vfio.devt, 1);
+ ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK, "vfio");
if (ret)
- goto err_base_cdev;
+ goto err_alloc_chrdev;
- vfio.dev = device_create(vfio.class, NULL, vfio.devt, NULL, "vfio");
- if (IS_ERR(vfio.dev)) {
- ret = PTR_ERR(vfio.dev);
- goto err_base_dev;
- }
-
- /* /dev/vfio/$GROUP */
cdev_init(&vfio.group_cdev, &vfio_group_fops);
- ret = cdev_add(&vfio.group_cdev,
- MKDEV(MAJOR(vfio.devt), 1), MINORMASK - 1);
+ ret = cdev_add(&vfio.group_cdev, vfio.group_devt, MINORMASK);
if (ret)
- goto err_groups_cdev;
+ goto err_cdev_add;
pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
@@ -1478,16 +1476,13 @@ static int __init vfio_init(void)
return 0;
-err_groups_cdev:
- device_destroy(vfio.class, vfio.devt);
-err_base_dev:
- cdev_del(&vfio.cdev);
-err_base_cdev:
- unregister_chrdev_region(vfio.devt, MINORMASK);
-err_base_chrdev:
+err_cdev_add:
+ unregister_chrdev_region(vfio.group_devt, MINORMASK);
+err_alloc_chrdev:
class_destroy(vfio.class);
vfio.class = NULL;
err_class:
+ misc_deregister(&vfio_dev);
return ret;
}
@@ -1497,11 +1492,10 @@ static void __exit vfio_cleanup(void)
idr_destroy(&vfio.group_idr);
cdev_del(&vfio.group_cdev);
- device_destroy(vfio.class, vfio.devt);
- cdev_del(&vfio.cdev);
- unregister_chrdev_region(vfio.devt, MINORMASK);
+ unregister_chrdev_region(vfio.group_devt, MINORMASK);
class_destroy(vfio.class);
vfio.class = NULL;
+ misc_deregister(&vfio_dev);
}
module_init(vfio_init);
@@ -1511,3 +1505,5 @@ MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_ALIAS_MISCDEV(VFIO_MINOR);
+MODULE_ALIAS("devname:vfio/vfio");