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

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.