Re: [PATCH 0/4] USB hostdev: allow addressing by port

Am 23.06.2025 um 16:50 schrieb Daniel P. Berrangé: > On Mon, Apr 21, 2025 at 09:38:34PM +0200, Maximilian Martin via Devel wrote: > > This resubmission splits up the previous patch into multiple patches and > > incorporates review comments from Michal Prívozník. > > > > Currently, only vendor/product and bus/device matching are supported for USB host > > devices. Neither of these provide a stable and persistent way of assigning a guest > > a specific host device. Vendor/product can be ambiguous. Device numbers change on > > every enumeration. > > > > This patch adds a bus/port matching, which allows a specific port on the host to be > > specified using the dotted notation found in Linux's "devpath" sysfs attribute. > In terms of our API, we're expecting people to use the > 'node device' APIs to identify what devices are available > on the host and their attributes, rather than queryin > Linux directly. This gives us a platform independant > usage model, which also works when the mgmt app has no > login to the virt host. > > > Currently for USB devices we report bus, dev, vendor & product, > but don't report the port: > > # virsh nodedev-dumpxml usb_1_10_4 > <device> > <name>usb_1_10_4</name> > <path>/sys/devices/pci0000:00/0000:00:14.0/usb1/1-10/1-10.4</path> > <devnode type='dev'>/dev/bus/usb/001/004</devnode> > <parent>usb_1_10</parent> > <driver> > <name>usb</name> > </driver> > <capability type='usb_device'> > <bus>1</bus> > <device>4</device> > <product id='0x10c0'>Dell Integrated Hub</product> > <vendor id='0x1604'>Tascam</vendor> > </capability> > </device> > > we need to add 'port' to this xml document under the 'usb_device' > capability. > Well, the port is included in the path (everything after last '-'). udev does not report it explicitly. Do you think this is enough or should I parse the path and add the port to capabilites?