Re: [PATCH v3 5/5] conf: nodedev: Fill active_config at XML parse time

On Wed, Apr 17, 2024 at 09:58:10AM -0400, Cole Robinson wrote: > On 4/9/24 11:20 AM, Boris Fiuczynski wrote: >> On 4/9/24 16:56, Cole Robinson wrote: >>> Commit v10.0.0-265-ge67bca23e4 added a `active_config` and >>> `defined_config` to nodedev mdev internal XML handling. >>> `defined_config` can be filled at XML parse time, but `active_config` >>> must be filled in by nodedev driver. This wasn't implemented for the >>> test driver however, which caused virt-manager test suite regressions. >>> >>> Example before: >>> >>> ``` >>> $ virsh --connect >>> test:///home/crobinso/src/virt-manager/tests/data/testdriver/testdriver.xml nodedev-dumpxml mdev_8e37ee90_2b51_45e3_9b25_bf8283c03110 >>> <device> >>>    <name>mdev_8e37ee90_2b51_45e3_9b25_bf8283c03110</name> >>>    >>> <path>/sys/devices/css0/0.0.0023/8e37ee90-2b51-45e3-9b25-bf8283c03110</path> >>>    <parent>css_0_0_0023</parent> >>>    <capability type='mdev'> >>>      <type id='vfio_ccw-io'/> >>>      <iommuGroup number='0'/> >>>    </capability> >>> </device> >>> ``` >>> >>> Example after: >>> >>> ``` >>> $ virsh --connect >>> test:///home/crobinso/src/virt-manager/tests/data/testdriver/testdriver.xml nodedev-dumpxml mdev_8e37ee90_2b51_45e3_9b25_bf8283c03110 >>> <device> >>>    <name>mdev_8e37ee90_2b51_45e3_9b25_bf8283c03110</name> >>>    >>> <path>/sys/devices/css0/0.0.0023/8e37ee90-2b51-45e3-9b25-bf8283c03110</path> >>>    <parent>css_0_0_0023</parent> >>>    <capability type='mdev'> >>>      <iommuGroup number='0'/> >>>    </capability> >>> </device> >>> ``` >>> >>> Simplest solution is to fill in `active_config` at XML define time >>> as well. The real node_device driver already takes care to free any >>> `active_config` when it live updates this info, so we are safe there. >> >> I do not think that it is a good idea to hack the general code which >> creates in the real environments fake data. >> > > I can't tell how this affects real environments. Is there a place in the > udev driver where XML is parsed, and then active_config isn't explicitly > updated? > > If not, do you object to me pushing this with Michal's ACK? This is > causing some pain with virt-manager dev workflow > >> If your tests require active mdevs than the mocking code should set >> these active and also do the config copy. >> > > Obviously this can work but IMO it sets a bad precedent. If this > active/inactive_config structure is extended in the future, the test > driver syncing needs to be extended to match, or we need more plumbing > to share more of this > > > Personally I would have rather seen this implemented using ->newDef > pattern used by domain, network, storage. That's the closest thing to an > internal standard for handling differences between inactive config and > runtime config. ->def is copied to ->newDef at object startup time, and > the drivers change newDef as needed to reflect runtime state of the object. Yes, if we need to store both active and inactive config information then I would strongly prefer to have the normal def+newDef pattern, so we can expose this difference in the APIs with an "INACTIVE" flag and --inactive virsh opt.