Commit 36b64ccd authored by Stefano Garzarella's avatar Stefano Garzarella Committed by Pengyuan Zhao
Browse files

vdpa: add driver_override support 

stable inclusion
from stable-v5.17
commit 539fec78
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5WXCZ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=539fec78edb4e084e7c532affc56cc42d4ceea4b



----------------------------------------------------------------------

`driver_override` allows to control which of the vDPA bus drivers
binds to a vDPA device.

If `driver_override` is not set, the previous behaviour is followed:
devices use the first vDPA bus driver loaded (unless auto binding
is disabled).

Tested on Fedora 34 with driverctl(8):
  $ modprobe virtio-vdpa
  $ modprobe vhost-vdpa
  $ modprobe vdpa-sim-net

  $ vdpa dev add mgmtdev vdpasim_net name dev1

  # dev1 is attached to the first vDPA bus driver loaded
  $ driverctl -b vdpa list-devices
    dev1 virtio_vdpa

  $ driverctl -b vdpa set-override dev1 vhost_vdpa

  $ driverctl -b vdpa list-devices
    dev1 vhost_vdpa [*]

  Note: driverctl(8) integrates with udev so the binding is
  preserved.

Suggested-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20211126164753.181829-3-sgarzare@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarPengyuan Zhao <zhaopengyuan@hisilicon.com>
parent d3bb2019

drivers/vdpa/vdpa.c

+75 −0
Original line number Diff line number Diff line
@@ -45,8 +45,82 @@ static int vdpa_dev_remove(struct device *d) 
	return 0;

}



static int vdpa_dev_match(struct device *dev, struct device_driver *drv)

{

	   struct vdpa_device *vdev = dev_to_vdpa(dev);



	   /* Check override first, and if set, only use the named driver */

	   if (vdev->driver_override)

			   return strcmp(vdev->driver_override, drv->name) == 0;



	   /* Currently devices must be supported by all vDPA bus drivers */

	   return 1;

}



static ssize_t driver_override_store(struct device *dev,

									struct device_attribute *attr,

									const char *buf, size_t count)

{

	   struct vdpa_device *vdev = dev_to_vdpa(dev);

	   const char *driver_override, *old;

	   char *cp;



	   /* We need to keep extra room for a newline */

	   if (count >= (PAGE_SIZE - 1))

			   return -EINVAL;



	   driver_override = kstrndup(buf, count, GFP_KERNEL);

	   if (!driver_override)

			   return -ENOMEM;



	   cp = strchr(driver_override, '\n');

	   if (cp)

			   *cp = '\0';



	   device_lock(dev);

	   old = vdev->driver_override;

	   if (strlen(driver_override)) {

			   vdev->driver_override = driver_override;

	   } else {

			   kfree(driver_override);

			   vdev->driver_override = NULL;

	   }

	   device_unlock(dev);



	   kfree(old);



	   return count;

}



static ssize_t driver_override_show(struct device *dev,

								   struct device_attribute *attr, char *buf)

{

	   struct vdpa_device *vdev = dev_to_vdpa(dev);

	   ssize_t len;



	   device_lock(dev);

	   len = snprintf(buf, PAGE_SIZE, "%s\n", vdev->driver_override);

	   device_unlock(dev);



	   return len;

}

static DEVICE_ATTR_RW(driver_override);



static struct attribute *vdpa_dev_attrs[] = {

	   &dev_attr_driver_override.attr,

	   NULL,

};



static const struct attribute_group vdpa_dev_group = {

	   .attrs  = vdpa_dev_attrs,

};

__ATTRIBUTE_GROUPS(vdpa_dev);





static struct bus_type vdpa_bus = {

	.name  = "vdpa",

	.dev_groups = vdpa_dev_groups,

	.match = vdpa_dev_match,

	.probe = vdpa_dev_probe,

	.remove = vdpa_dev_remove,

};
@@ -60,6 +134,7 @@ static void vdpa_release_dev(struct device *d) 
		ops->free(vdev);



	ida_simple_remove(&vdpa_index_ida, vdev->index);

	kfree(vdev->driver_override);

	kfree(vdev);

}

include/linux/vdpa.h

+2 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ struct vdpa_mgmt_dev; 
 * vDPA device - representation of a vDPA device

 * @dev: underlying device

 * @dma_dev: the actual device that is performing DMA

 * @driver_override: driver name to force a match

 * @config: the configuration ops for this device.

 * @index: device index

 * @features_valid: were features initialized? for legacy guests
@@ -51,6 +52,7 @@ struct vdpa_mgmt_dev; 
struct vdpa_device {

	struct device dev;

	struct device *dma_dev;

	const char *driver_override;

	const struct vdpa_config_ops *config;

	unsigned int index;

	bool features_valid;