Re: [PATCH] vmx: Parse vm.genid

On Mon, Aug 02, 2021 at 12:04:49PM +0100, Richard W.M. Jones wrote: > On Mon, Aug 02, 2021 at 01:00:15PM +0200, Michal Prívozník wrote: > > On 7/30/21 2:02 PM, Richard W.M. Jones wrote: > > > On Thu, Jul 29, 2021 at 10:30:30AM +0200, Michal Privoznik wrote: > > >> The VMware metadata file contains genid but we are not parsing > > >> and thus reporting it in domain XML. However, it's not as > > >> straightforward as one might think. The UUID reported by VMware > > >> is not in its usual string form, but split into two signed long > > >> longs. That means, we have to do a bit of trickery when parsing. > > >> But looking around it's the same magic that libguestfs does: > > >> > > >> https://github.com/libguestfs/virt-v2v/blob/master/v2v/input_vmx.ml#L421 > > >> > > >> It's also explained by Rich on qemu-devel: > > >> > > >> https://lists.nongnu.org/archive/html/qemu-devel/2018-07/msg02019.html > > >> > > >> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1598348 > > >> Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; > > >> --- > > >> > > >> I've successfully ran vmx2xmltest on an s390x machine which means that > > >> there shouldn't be any endiandness problem. > > >> > > >> src/vmx/vmx.c | 30 +++++++++++++++++++ > > >> .../vmx2xml-esx-in-the-wild-10.xml | 1 + > > >> 2 files changed, 31 insertions(+) > > >> > > > > > > > > Looked reasonable and seems to match the description here: > > > > > > https://lists.nongnu.org/archive/html/qemu-devel/2018-07/msg02019.html > > > > > > Reviewed-by: Richard W.M. Jones <rjones(a)redhat.com&gt; > > > > Pushed, thanks. > > > > > > > > Out of interest, what is this being consumed by? I will add this to > > > virt-v2v when it goes upstream. > > > > I don't recall all the specifics (it was John who implemented it), but > > IIRC it was needed for Windows guests. Something about identifying them > > uniquely. John? > > Sure, I understand what it's used for. I was just wondering if there > are other consumers who want to pull the genID from VMware VMX files > using libvirt. Seems like something quite specific to V2V scenarios. Could there even be a a case to be made for V2V to *not* preserve the the genID value. eg If you see a genID in the existing config, then write a /different/ genID value in the new VM, to indicate that this new VM is a fork of the original VM ?