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path: root/drivers/vfio/vfio.c
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Diffstat (limited to 'drivers/vfio/vfio.c')
-rw-r--r--drivers/vfio/vfio.c86
1 files changed, 46 insertions, 40 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 561084ab387f..330d50582f40 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -382,7 +382,7 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
if (IS_ERR(dev)) {
vfio_free_group_minor(minor);
vfio_group_unlock_and_free(group);
- return (struct vfio_group *)dev; /* ERR_PTR */
+ return ERR_CAST(dev);
}
group->minor = minor;
@@ -423,6 +423,34 @@ static void vfio_group_put(struct vfio_group *group)
kref_put_mutex(&group->kref, vfio_group_release, &vfio.group_lock);
}
+struct vfio_group_put_work {
+ struct work_struct work;
+ struct vfio_group *group;
+};
+
+static void vfio_group_put_bg(struct work_struct *work)
+{
+ struct vfio_group_put_work *do_work;
+
+ do_work = container_of(work, struct vfio_group_put_work, work);
+
+ vfio_group_put(do_work->group);
+ kfree(do_work);
+}
+
+static void vfio_group_schedule_put(struct vfio_group *group)
+{
+ struct vfio_group_put_work *do_work;
+
+ do_work = kmalloc(sizeof(*do_work), GFP_KERNEL);
+ if (WARN_ON(!do_work))
+ return;
+
+ INIT_WORK(&do_work->work, vfio_group_put_bg);
+ do_work->group = group;
+ schedule_work(&do_work->work);
+}
+
/* Assume group_lock or group reference is held */
static void vfio_group_get(struct vfio_group *group)
{
@@ -762,7 +790,14 @@ static int vfio_iommu_group_notifier(struct notifier_block *nb,
break;
}
- vfio_group_put(group);
+ /*
+ * If we're the last reference to the group, the group will be
+ * released, which includes unregistering the iommu group notifier.
+ * We hold a read-lock on that notifier list, unregistering needs
+ * a write-lock... deadlock. Release our reference asynchronously
+ * to avoid that situation.
+ */
+ vfio_group_schedule_put(group);
return NOTIFY_OK;
}
@@ -1140,15 +1175,11 @@ static long vfio_fops_unl_ioctl(struct file *filep,
ret = vfio_ioctl_set_iommu(container, arg);
break;
default:
- down_read(&container->group_lock);
-
driver = container->iommu_driver;
data = container->iommu_data;
if (driver) /* passthrough all unrecognized ioctls */
ret = driver->ops->ioctl(data, cmd, arg);
-
- up_read(&container->group_lock);
}
return ret;
@@ -1202,15 +1233,11 @@ static ssize_t vfio_fops_read(struct file *filep, char __user *buf,
struct vfio_iommu_driver *driver;
ssize_t ret = -EINVAL;
- down_read(&container->group_lock);
-
driver = container->iommu_driver;
if (likely(driver && driver->ops->read))
ret = driver->ops->read(container->iommu_data,
buf, count, ppos);
- up_read(&container->group_lock);
-
return ret;
}
@@ -1221,15 +1248,11 @@ static ssize_t vfio_fops_write(struct file *filep, const char __user *buf,
struct vfio_iommu_driver *driver;
ssize_t ret = -EINVAL;
- down_read(&container->group_lock);
-
driver = container->iommu_driver;
if (likely(driver && driver->ops->write))
ret = driver->ops->write(container->iommu_data,
buf, count, ppos);
- up_read(&container->group_lock);
-
return ret;
}
@@ -1239,14 +1262,10 @@ static int vfio_fops_mmap(struct file *filep, struct vm_area_struct *vma)
struct vfio_iommu_driver *driver;
int ret = -EINVAL;
- down_read(&container->group_lock);
-
driver = container->iommu_driver;
if (likely(driver && driver->ops->mmap))
ret = driver->ops->mmap(container->iommu_data, vma);
- up_read(&container->group_lock);
-
return ret;
}
@@ -1741,6 +1760,15 @@ void vfio_group_put_external_user(struct vfio_group *group)
}
EXPORT_SYMBOL_GPL(vfio_group_put_external_user);
+bool vfio_external_group_match_file(struct vfio_group *test_group,
+ struct file *filep)
+{
+ struct vfio_group *group = filep->private_data;
+
+ return (filep->f_op == &vfio_group_fops) && (group == test_group);
+}
+EXPORT_SYMBOL_GPL(vfio_external_group_match_file);
+
int vfio_external_user_iommu_id(struct vfio_group *group)
{
return iommu_group_id(group->iommu_group);
@@ -1949,8 +1977,6 @@ int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, int npage,
goto err_pin_pages;
container = group->container;
- down_read(&container->group_lock);
-
driver = container->iommu_driver;
if (likely(driver && driver->ops->pin_pages))
ret = driver->ops->pin_pages(container->iommu_data, user_pfn,
@@ -1958,7 +1984,6 @@ int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, int npage,
else
ret = -ENOTTY;
- up_read(&container->group_lock);
vfio_group_try_dissolve_container(group);
err_pin_pages:
@@ -1998,8 +2023,6 @@ int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage)
goto err_unpin_pages;
container = group->container;
- down_read(&container->group_lock);
-
driver = container->iommu_driver;
if (likely(driver && driver->ops->unpin_pages))
ret = driver->ops->unpin_pages(container->iommu_data, user_pfn,
@@ -2007,7 +2030,6 @@ int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage)
else
ret = -ENOTTY;
- up_read(&container->group_lock);
vfio_group_try_dissolve_container(group);
err_unpin_pages:
@@ -2029,8 +2051,6 @@ static int vfio_register_iommu_notifier(struct vfio_group *group,
return -EINVAL;
container = group->container;
- down_read(&container->group_lock);
-
driver = container->iommu_driver;
if (likely(driver && driver->ops->register_notifier))
ret = driver->ops->register_notifier(container->iommu_data,
@@ -2038,7 +2058,6 @@ static int vfio_register_iommu_notifier(struct vfio_group *group,
else
ret = -ENOTTY;
- up_read(&container->group_lock);
vfio_group_try_dissolve_container(group);
return ret;
@@ -2056,8 +2075,6 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group,
return -EINVAL;
container = group->container;
- down_read(&container->group_lock);
-
driver = container->iommu_driver;
if (likely(driver && driver->ops->unregister_notifier))
ret = driver->ops->unregister_notifier(container->iommu_data,
@@ -2065,7 +2082,6 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group,
else
ret = -ENOTTY;
- up_read(&container->group_lock);
vfio_group_try_dissolve_container(group);
return ret;
@@ -2083,7 +2099,6 @@ static int vfio_register_group_notifier(struct vfio_group *group,
unsigned long *events,
struct notifier_block *nb)
{
- struct vfio_container *container;
int ret;
bool set_kvm = false;
@@ -2101,9 +2116,6 @@ static int vfio_register_group_notifier(struct vfio_group *group,
if (ret)
return -EINVAL;
- container = group->container;
- down_read(&container->group_lock);
-
ret = blocking_notifier_chain_register(&group->notifier, nb);
/*
@@ -2114,7 +2126,6 @@ static int vfio_register_group_notifier(struct vfio_group *group,
blocking_notifier_call_chain(&group->notifier,
VFIO_GROUP_NOTIFY_SET_KVM, group->kvm);
- up_read(&container->group_lock);
vfio_group_try_dissolve_container(group);
return ret;
@@ -2123,19 +2134,14 @@ static int vfio_register_group_notifier(struct vfio_group *group,
static int vfio_unregister_group_notifier(struct vfio_group *group,
struct notifier_block *nb)
{
- struct vfio_container *container;
int ret;
ret = vfio_group_add_container_user(group);
if (ret)
return -EINVAL;
- container = group->container;
- down_read(&container->group_lock);
-
ret = blocking_notifier_chain_unregister(&group->notifier, nb);
- up_read(&container->group_lock);
vfio_group_try_dissolve_container(group);
return ret;
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-22 12:58:21 +0300