[PATCH 1/7] vfio: Include optional device match in vfio_device_ops callbacks

Alex Williamson
2020-02-11T23:05:37Z

Allow bus drivers to provide their own callback to match a device to
the user provided string.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
drivers/vfio/vfio.c | 20 ++++++++++++++++----
include/linux/vfio.h | 4 ++++
2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index c8482624ca34..0bd77d6ea691 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -875,11 +875,23 @@ EXPORT_SYMBOL_GPL(vfio_device_get_from_dev);
static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group,
char *buf)
{
- struct vfio_device *it, *device = NULL;
+ struct vfio_device *it, *device = ERR_PTR(-ENODEV);

mutex_lock(&group->device_lock);
list_for_each_entry(it, &group->device_list, group_next) {
- if (!strcmp(dev_name(it->dev), buf)) {
+ int ret;
+
+ if (it->ops->match) {
+ ret = it->ops->match(it->device_data, buf);
+ if (ret < 0) {
+ device = ERR_PTR(ret);
+ break;
+ }
+ } else {
+ ret = !strcmp(dev_name(it->dev), buf);
+ }
+
+ if (ret) {
device = it;
vfio_device_get(device);
break;
@@ -1430,8 +1442,8 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
return -EPERM;

device = vfio_device_get_from_name(group, buf);
- if (!device)
- return -ENODEV;
+ if (IS_ERR(device))
+ return PTR_ERR(device);

ret = device->ops->open(device->device_data);
if (ret) {
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index e42a711a2800..029694b977f2 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -26,6 +26,9 @@
* operations documented below
* @mmap: Perform mmap(2) on a region of the device file descriptor
* @request: Request for the bus driver to release the device
+ * @match: Optional device name match callback (return: 0 for no-match, >0 for
+ * match, -errno for abort (ex. match with insufficient or incorrect
+ * additional args)
*/
struct vfio_device_ops {
char *name;
@@ -39,6 +42,7 @@ struct vfio_device_ops {
unsigned long arg);
int (*mmap)(void *device_data, struct vm_area_struct *vma);
void (*request)(void *device_data, unsigned int count);
+ int (*match)(void *device_data, char *buf);
};

extern struct iommu_group *vfio_iommu_group_get(struct device *dev);