Hi On Tue, Oct 10, 2017 at 10:31 AM, Daniel P. Berrange <berra...@redhat.com> wrote: > On Tue, Oct 10, 2017 at 12:44:26AM +0300, Michael S. Tsirkin wrote: >> On Mon, Oct 09, 2017 at 02:02:18PM +0100, Daniel P. Berrange wrote: >> > On Mon, Oct 09, 2017 at 02:43:44PM +0200, Igor Mammedov wrote: >> > > On Mon, 9 Oct 2017 12:03:36 +0100 >> > > "Daniel P. Berrange" <berra...@redhat.com> wrote: >> > > >> > > > On Mon, Sep 11, 2017 at 06:59:24PM +0200, Marc-André Lureau wrote: >> > > > > See docs/specs/vmcoreinfo.txt for details. >> > > > > >> > > > > "etc/vmcoreinfo" fw_cfg entry is added when using "-device >> > > > > vmcoreinfo". >> > > > >> > > > I'm wondering if you considered just adding the entry to fw_cfg by >> > > > default, without requiring any -device arg ? Unless I'm >> > > > misunderstanding, >> > > > this doesn't feel like a device to me - its just a well known bucket >> > > > in fw_cfg IIUC ? Obviously its existance would need to be tied to >> > > > the latest machine type for ABI reasons though. The benefit of this >> > > > is that it would "just work" without us having to plumb it through to >> > > > all the downstream applications that use QEMU for mgmt guest >> > > > (OpenStack, >> > > > oVirt, GNOME Boxes, virt-manager, and countless other mgmt apps). >> > > it follows model set by pvpanic device, it's easier to manage from >> > > migration >> > > POV, one could use it even for old machine types with new qemu (just by >> > > adding >> > > device, it makes instance not backwards migratable to old qemu but >> > > should work >> > > for forward migration) and if user doesn't need it, device could be just >> > > omitted >> > > from CLI. >> > >> > Sure but it means that in effect no one will have this functionality >> > enabled >> > for several years. pvpanic has been around a long time and I rarely see it >> > present in configured guests :-( >> > >> > >> > Regards, >> > Daniel >> >> libvirt runs with -nodefaults, right? I'd argue pretty strongly -nodefaults >> shouldn't add optional devices anyway. > > This isn't really adding a device though is it - it is just a well known > location in fw_cfg to receive data.
Enabling the device on some configurations by default can be done as a follow-up patch. Can we get this series reviewed & merged? thanks -- Marc-André Lureau