On Thu, 13 Aug 2020 15:02:53 -0400 Eric Farman <farman@xxxxxxxxxxxxx> wrote: > On 8/13/20 11:33 AM, Cornelia Huck wrote: > > On Fri, 7 Aug 2020 13:59:42 +0200 > > Cornelia Huck <cohuck@xxxxxxxxxx> wrote: > > > >> On Wed, 05 Aug 2020 12:35:01 +0100 > >> Sean Mooney <smooney@xxxxxxxxxx> wrote: > >> > >>> On Wed, 2020-08-05 at 12:53 +0200, Jiri Pirko wrote: > >>>> Wed, Aug 05, 2020 at 11:33:38AM CEST, yan.y.zhao@xxxxxxxxx wrote: > >> > >> (...) > >> > >>>>> software_version: device driver's version. > >>>>> in <major>.<minor>[.bugfix] scheme, where there is no > >>>>> compatibility across major versions, minor versions have > >>>>> forward compatibility (ex. 1-> 2 is ok, 2 -> 1 is not) and > >>>>> bugfix version number indicates some degree of internal > >>>>> improvement that is not visible to the user in terms of > >>>>> features or compatibility, > >>>>> > >>>>> vendor specific attributes: each vendor may define different attributes > >>>>> device id : device id of a physical devices or mdev's parent pci device. > >>>>> it could be equal to pci id for pci devices > >>>>> aggregator: used together with mdev_type. e.g. aggregator=2 together > >>>>> with i915-GVTg_V5_4 means 2*1/4=1/2 of a gen9 Intel > >>>>> graphics device. > >>>>> remote_url: for a local NVMe VF, it may be configured with a remote > >>>>> url of a remote storage and all data is stored in the > >>>>> remote side specified by the remote url. > >>>>> ... > >>> just a minor not that i find ^ much more simmple to understand then > >>> the current proposal with self and compatiable. > >>> if i have well defiend attibute that i can parse and understand that allow > >>> me to calulate the what is and is not compatible that is likely going to > >>> more useful as you wont have to keep maintianing a list of other compatible > >>> devices every time a new sku is released. > >>> > >>> in anycase thank for actully shareing ^ as it make it simpler to reson about what > >>> you have previously proposed. > >> > >> So, what would be the most helpful format? A 'software_version' field > >> that follows the conventions outlined above, and other (possibly > >> optional) fields that have to match? > > > > Just to get a different perspective, I've been trying to come up with > > what would be useful for a very different kind of device, namely > > vfio-ccw. (Adding Eric to cc: for that.) > > > > software_version makes sense for everybody, so it should be a standard > > attribute. > > > > For the vfio-ccw type, we have only one vendor driver (vfio-ccw_IO). > > > > Given a subchannel A, we want to make sure that subchannel B has a > > reasonable chance of being compatible. I guess that means: > > > > - same subchannel type (I/O) > > - same chpid type (e.g. all FICON; I assume there are no 'mixed' setups > > -- Eric?) > > Correct. > > > - same number of chpids? Maybe we can live without that and just inject > > some machine checks, I don't know. Same chpid numbers is something we > > cannot guarantee, especially if we want to migrate cross-CEC (to > > another machine.) > > I think we'd live without it, because I wouldn't expect it to be > consistent between systems. Yes, and the guest needs to be able to deal with changing path configurations anyway. > > > > > Other possibly interesting information is not available at the > > subchannel level (vfio-ccw is a subchannel driver.) > > I presume you're alluding to the DASD uid (dasdinfo -x) here? Yes, or the even more basic Sense ID information. > > > > > So, looking at a concrete subchannel on one of my machines, it would > > look something like the following: > > > > <common> > > software_version=1.0.0 > > type=vfio-ccw <-- would be vfio-pci on the example above > > <vfio-ccw specific> > > subchannel_type=0 > > <vfio-ccw_IO specific> > > chpid_type=0x1a > > chpid_mask=0xf0 <-- not sure if needed/wanted Let's just drop the chpid_mask here. > > > > Does that make sense? Would be interesting if someone could come up with some possible information for a third type of device.
