539fec78ed
`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: Jason Wang <jasowang@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20211126164753.181829-3-sgarzare@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2.3 KiB
What: /sys/bus/vdpa/driver_autoprobe Date: March 2020 Contact: virtualization@lists.linux-foundation.org Description: This file determines whether new devices are immediately bound to a driver after the creation. It initially contains 1, which means the kernel automatically binds devices to a compatible driver immediately after they are created.
Writing "0" to this file disable this feature, any other string
enable it.
What: /sys/bus/vdpa/driver_probe Date: March 2020 Contact: virtualization@lists.linux-foundation.org Description: Writing a device name to this file will cause the kernel binds devices to a compatible driver.
This can be useful when /sys/bus/vdpa/driver_autoprobe is
disabled.
What: /sys/bus/vdpa/drivers/.../bind Date: March 2020 Contact: virtualization@lists.linux-foundation.org Description: Writing a device name to this file will cause the driver to attempt to bind to the device. This is useful for overriding default bindings.
What: /sys/bus/vdpa/drivers/.../unbind Date: March 2020 Contact: virtualization@lists.linux-foundation.org Description: Writing a device name to this file will cause the driver to attempt to unbind from the device. This may be useful when overriding default bindings.
What: /sys/bus/vdpa/devices/.../driver_override Date: November 2021 Contact: virtualization@lists.linux-foundation.org Description: This file allows the driver for a device to be specified. When specified, only a driver with a name matching the value written to driver_override will have an opportunity to bind to the device. The override is specified by writing a string to the driver_override file (echo vhost-vdpa > driver_override) and may be cleared with an empty string (echo > driver_override). This returns the device to standard matching rules binding. Writing to driver_override does not automatically unbind the device from its current driver or make any attempt to automatically load the specified driver. If no driver with a matching name is currently loaded in the kernel, the device will not bind to any driver. This also allows devices to opt-out of driver binding using a driver_override name such as "none". Only a single driver may be specified in the override, there is no support for parsing delimiters.