Recent QEMU versions added support for virtio SR-IOV emulation, allowing virtio devices to expose SR-IOV VFs to the guest. However, virtio_bus does not implement the num_vf callback of bus_type, causing dev_num_vf() to return 0 for virtio devices even when SR-IOV VFs are active.
net/core/rtnetlink.c calls dev_num_vf(dev->dev.parent) to populate IFLA_NUM_VF and IFLA_VFINFO_LIST in RTM_GETLINK responses. For a virtio-net device, dev.parent points to the virtio_device, whose bus is virtio_bus. Without num_vf, SR-IOV VF information is silently omitted from tools that rely on rtnetlink, such as 'ip link show'. Add a num_vf callback that delegates to dev_num_vf(dev->parent), which in turn reaches the underlying transport (pci_bus_type for virtio-pci) where the actual VF count is tracked. Non-PCI transports are unaffected as dev_num_vf() returns 0 when no num_vf callback is present. Signed-off-by: Yui Washizu <[email protected]> --- drivers/virtio/virtio.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 5bdc6b82b30b..299fa83be1d5 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -435,6 +435,14 @@ static void virtio_dev_shutdown(struct device *_d) dev->config->reset(dev); } +static int virtio_dev_num_vf(struct device *dev) +{ + struct virtio_device *vdev = dev_to_virtio(dev); + + return dev_num_vf(vdev->dev.parent); +} + + static const struct bus_type virtio_bus = { .name = "virtio", .match = virtio_dev_match, @@ -444,6 +452,7 @@ static const struct bus_type virtio_bus = { .remove = virtio_dev_remove, .irq_get_affinity = virtio_irq_get_affinity, .shutdown = virtio_dev_shutdown, + .num_vf = virtio_dev_num_vf, }; int __register_virtio_driver(struct virtio_driver *driver, struct module *owner) -- 2.47.3
