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 --- drivers/vdpa/vdpa.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) (limited to 'drivers') diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index 09bbe53c3ac4..59d0b8bbb79c 100644 --- a/drivers/vdpa/vdpa.c +++ b/drivers/vdpa/vdpa.c @@ -52,8 +52,81 @@ static void vdpa_dev_remove(struct device *d) drv->remove(vdev); } +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, }; @@ -68,6 +141,7 @@ static void vdpa_release_dev(struct device *d) ida_simple_remove(&vdpa_index_ida, vdev->index); mutex_destroy(&vdev->cf_mutex); + kfree(vdev->driver_override); kfree(vdev); } -- cgit v1.2.3