Re: [libvirt] [PATCH v4 3/3] qemu: Automatically create NVRAM store

On Fri, Aug 22, 2014 at 12:12:52PM +0200, Laszlo Ersek wrote: > On 08/22/14 11:56, Daniel P. Berrange wrote: >> On Fri, Aug 22, 2014 at 11:38:06AM +0200, Laszlo Ersek wrote: >>> On 08/22/14 10:54, Daniel P. Berrange wrote: >>>> On Fri, Aug 22, 2014 at 10:27:29AM +0200, Laszlo Ersek wrote: >>>>> On 08/21/14 11:05, Daniel P. Berrange wrote: >>>>>> So the user has the ability to specify a arbitrary BIOS in the XML, >>>>>> but unless it matches one of the ones listed in the libvirt config >>>>>> they aren't going to be able to start the guest. What can we do >>>>>> about this, as it doesn't really seem like a great position to be >>>>>> in. >>>>> >>>>> I disagree. Users who use virt-manager (for which patches still have to >>>>> be written, to expose this feature) won't put arbitrary strings in the >>>>> <loader> element; virt-manager should offer a minimal choice between >>>>> "BIOS" vs. "UEFI". >>>>> >>>>> Users who are hard-core enough to hack the domain XML by hand are >>>>> expected to provide good values. >>>> >>>> The problem I'm raising is that it is *not* sufficient to merely >>>> provide good values in the XML here. You can't simply deploy a >>>> custom OVMF file and update your XML, because this code is relying >>>> on values in the libvirtd.conf configuration file. >>> >>> If the domain XML spells out both <loader> and <nvram>, then both should >>> be updated manually by the user (if the VM's old nvram is not compatible >>> with the new loader). This would include the user either instantiating >>> the new varstore for the VM, or removing the <nvram> element (so that >>> the new default template can take effect). >>> >>> If the domain XML doesn't spell out <nvram> (either genuinely, or >>> because the user removed that element, see above), then yes, you need to >>> edit /etc/libvirt/qemu.conf. >>> >>> I don't see a problem with that. You won't keep installing OVMF_CODE.fd >>> files in random locations in the host filesystem. You might be >>> developing OVMF and install various ad-hoc builds, but those would go to >>> the same location (same pathname), hence it would have to be added only >>> once to the qemu.conf file. >> >> Well I do see a problem with editing qemu.conf for this, particularly >> when there is a very straightforward way to avoid that need which I >> have outlined here. It is crazy to force these extra hoops onto people > > OK. > > But, if you don't provide a default map in some central config file, for > at least the system-wide OVMF installation(s), how do you save people > from the exact same burden (== manual varstore instantiation), when they > try to create a brand new UEFI virtual machine that uses one of the > system-wide OVMF filesets? Libvirt won't know where to copy the varstore > from. Having a default map in libvirt and in qemu.conf is still acceptable for the common case. I just want to make sure that if the user wants to provide a non-default BIOS in <loader> they can still get the NVRAM automatically created from a template, without having to edit qemu.conf and restart libvirtd.