On Tue, Jun 18, 2019 at 03:04:40PM -0300, Daniel Henrique Barboza wrote: > Hi, > > This is labeled as RFC but it's more like a FYI to let people know and > comment beforehand. Shiva sent a 28 patch series last year that implements > hotplug/unplug support for PCI multifunction devices [1]. The design > motivation of his work was based in a RFC sent to this mailing list back > in 2016 [2]. > > I'll briefly summarize the goals and motivations here. What we have today > in Libvirt: > > - no hotplug/unplug support for multifunction PCI devices > > This is explained in details in [2]. When hotplugging a multifunction > device, QEMU will queue the hotplug operation of all non-zero functions and, > when function 0 is hotplugged, all functions are hotplugged together. This > is true for all archs that supports PCI multifunction devices in QEMU. For > unplug it varies: x86 will unplug all functions if any function is > unplugged, ppc64 needs to unplug each one. Do you know anything about why ppc64 & x86 are different in this respect in QEMU. I think it would be desirable to fix QEMU so that unplug works consistently across architectures. These kind of behavioural differences are a cause of pain as x86 gets all the day to day testing & leaving ppc64 to bitrot if it behaves differently. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
