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

On 4/18/24 8:52 AM, Cole Robinson wrote: > On 4/17/24 10:12 AM, Daniel P. Berrangé wrote: > > 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. > > That is already implemented in git, by Boris. But it's implemented > without the newDef pattern > > - Cole I can try to adapt the current implementation to use the def/newDef pattern. I didn't think to suggest this when the patch was originally submitted.