On Wed, Aug 19, 2020 at 02:57:34PM +0800, Jason Wang wrote: > > On 2020/8/19 上午11:30, Yan Zhao wrote: > > hi All, > > could we decide that sysfs is the interface that every VFIO vendor driver > > needs to provide in order to support vfio live migration, otherwise the > > userspace management tool would not list the device into the compatible > > list? > > > > if that's true, let's move to the standardizing of the sysfs interface. > > (1) content > > common part: (must) > > - software_version: (in major.minor.bugfix scheme) > > > This can not work for devices whose features can be negotiated/advertised > independently. (E.g virtio devices) > sorry, I don't understand here, why virtio devices need to use vfio interface? I think this thread is discussing about vfio related devices.
> > > - device_api: vfio-pci or vfio-ccw ... > > - type: mdev type for mdev device or > > a signature for physical device which is a counterpart for > > mdev type. > > > > device api specific part: (must) > > - pci id: pci id of mdev parent device or pci id of physical pci > > device (device_api is vfio-pci)API here. > > > So this assumes a PCI device which is probably not true. > for device_api of vfio-pci, why it's not true? for vfio-ccw, it's subchannel_type. > > > - subchannel_type (device_api is vfio-ccw) > > vendor driver specific part: (optional) > > - aggregator > > - chpid_type > > - remote_url > > > For "remote_url", just wonder if it's better to integrate or reuse the > existing NVME management interface instead of duplicating it here. Otherwise > it could be a burden for mgmt to learn. E.g vendor A may use "remote_url" > but vendor B may use a different attribute. > it's vendor driver specific. vendor specific attributes are inevitable, and that's why we are discussing here of a way to standardizing of it. our goal is that mgmt can use it without understanding the meaning of vendor specific attributes. > > > > > NOTE: vendors are free to add attributes in this part with a > > restriction that this attribute is able to be configured with the same > > name in sysfs too. e.g. > > > Sysfs works well for common attributes belongs to a class, but I'm not sure > it can work well for device/vendor specific attributes. Does this mean mgmt > need to iterate all the attributes in both src and dst? > no. just attributes under migration directory. > > > for aggregator, there must be a sysfs attribute in device node > > /sys/devices/pci0000:00/0000:00:02.0/882cc4da-dede-11e7-9180-078a62063ab1/intel_vgpu/aggregator, > > so that the userspace tool is able to configure the target device > > according to source device's aggregator attribute. > > > > > > (2) where and structure > > proposal 1: > > |- [path to device] > > |--- migration > > | |--- self > > | | |-software_version > > | | |-device_api > > | | |-type > > | | |-[pci_id or subchannel_type] > > | | |-<aggregator or chpid_type> > > | |--- compatible > > | | |-software_version > > | | |-device_api > > | | |-type > > | | |-[pci_id or subchannel_type] > > | | |-<aggregator or chpid_type> > > multiple compatible is allowed. > > attributes should be ASCII text files, preferably with only one value > > per file. > > > > > > proposal 2: use bin_attribute. > > |- [path to device] > > |--- migration > > | |--- self > > | |--- compatible > > > > so we can continue use multiline format. e.g. > > cat compatible > > software_version=0.1.0 > > device_api=vfio_pci > > type=i915-GVTg_V5_{val1:int:1,2,4,8} > > pci_id=80865963 > > aggregator={val1}/2 > > > So basically two questions: > > - how hard to standardize sysfs API for dealing with compatibility check (to > make it work for most types of devices) sorry, I just know we are in the process of standardizing of it :) > - how hard for the mgmt to learn with a vendor specific attributes (vs > existing management API) what is existing management API? Thanks _______________________________________________ Devel mailing list -- devel@ovirt.org To unsubscribe send an email to devel-le...@ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/devel@ovirt.org/message/QPOL2YB5QS3QDJ442JHSWWM4P7PTIUC3/