@@ -704,9 +704,13 @@ EXPORT_SYMBOL_GPL(vfio_del_group_dev);
static long vfio_ioctl_check_extension(struct vfio_container *container,
unsigned long arg)
{
- struct vfio_iommu_driver *driver = container->iommu_driver;
+ struct vfio_iommu_driver *driver;
long ret = 0;
+ down_read(&container->group_lock);
+
+ driver = container->iommu_driver;
+
switch (arg) {
/* No base extensions yet */
default:
@@ -736,6 +740,8 @@ static long vfio_ioctl_check_extension(struct vfio_container *container,
VFIO_CHECK_EXTENSION, arg);
}
+ up_read(&container->group_lock);
+
return ret;
}
@@ -844,9 +850,6 @@ static long vfio_fops_unl_ioctl(struct file *filep,
if (!container)
return ret;
- driver = container->iommu_driver;
- data = container->iommu_data;
-
switch (cmd) {
case VFIO_GET_API_VERSION:
ret = VFIO_API_VERSION;
@@ -858,8 +861,15 @@ 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;
@@ -910,35 +920,55 @@ static ssize_t vfio_fops_read(struct file *filep, char __user *buf,
size_t count, loff_t *ppos)
{
struct vfio_container *container = filep->private_data;
- struct vfio_iommu_driver *driver = container->iommu_driver;
+ struct vfio_iommu_driver *driver;
+ ssize_t ret = -EINVAL;
- if (unlikely(!driver || !driver->ops->read))
- return -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);
- return driver->ops->read(container->iommu_data, buf, count, ppos);
+ up_read(&container->group_lock);
+
+ return ret;
}
static ssize_t vfio_fops_write(struct file *filep, const char __user *buf,
size_t count, loff_t *ppos)
{
struct vfio_container *container = filep->private_data;
- struct vfio_iommu_driver *driver = container->iommu_driver;
+ struct vfio_iommu_driver *driver;
+ ssize_t ret = -EINVAL;
- if (unlikely(!driver || !driver->ops->write))
- return -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 driver->ops->write(container->iommu_data, buf, count, ppos);
+ return ret;
}
static int vfio_fops_mmap(struct file *filep, struct vm_area_struct *vma)
{
struct vfio_container *container = filep->private_data;
- struct vfio_iommu_driver *driver = container->iommu_driver;
+ struct vfio_iommu_driver *driver;
+ int ret = -EINVAL;
- if (unlikely(!driver || !driver->ops->mmap))
- return -EINVAL;
+ down_read(&container->group_lock);
- return driver->ops->mmap(container->iommu_data, vma);
+ 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;
}
static const struct file_operations vfio_fops = {
If a group or device is released or a container is unset from a group it can race against file ops on the container. Protect these with down_reads to allow concurrent users. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reported-by: Michael S. Tsirkin <mst@redhat.com> --- drivers/vfio/vfio.c | 62 ++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 46 insertions(+), 16 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html