From 539fec78edb4e084e7c532affc56cc42d4ceea4b Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Fri, 26 Nov 2021 17:47:53 +0100 Subject: vdpa: add driver_override support `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 Acked-by: Jason Wang Signed-off-by: Stefano Garzarella Link: https://lore.kernel.org/r/20211126164753.181829-3-sgarzare@redhat.com Signed-off-by: Michael S. Tsirkin --- Documentation/ABI/testing/sysfs-bus-vdpa | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-bus-vdpa b/Documentation/ABI/testing/sysfs-bus-vdpa index 4e55761a39df..28a6111202ba 100644 --- a/Documentation/ABI/testing/sysfs-bus-vdpa +++ b/Documentation/ABI/testing/sysfs-bus-vdpa @@ -35,3 +35,23 @@ 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. -- cgit v1.3-14-g43fede