Re: [ovirt-devel] rethinking fake-kvm and faqemu

On Oct 3, 2015, at 20:48 , Martin Polednik <mpolednik(a)redhat.com&gt; wrote: > Hello everyone, > > I've been reworking the fake_kvm and faqemu VDSM hook to make them > somewhat more usable and mostly to allow testing of ppc64le on x86_64 > based hosts. > > TL;DR version: checkout [1], enable fake_kvm and happy ppc64le hacking :) > > Current fake_kvm isn't really a hook and is contained within 'caps' > module. This is wrong for multiple reasons, the most important one > being mixing optional with mainline code. Another issue appears when > one tries to move the fake_kvm code into a hook: the whole notion of > architectures within VDSM is contained within the 'caps' module. > > The patch series, which git tip is at [1], introduces new cpuinfo > module that moves information related to architecture to 'cpuinfo' > module of the VDSM library. Intermediate benefit is that current hooks > and library code can access the information related to host's cpu. > > This allows for moving fake_kvm code into a hook that I've called > fakearch. Fakearch is, in my opinion, more suitable name - there is > barely any KVM faking, but the host 'fakes' selected architecture. > > Faqemu is, on the other hand, a hook. Unfortunately it wasn't really > updated and doesn't allow running VMs under fake architecture. The > series therefore try to refactor it to allow cross-arch VMs to be > started (the VM actually uses host architecture, but from engine's > point of view it's running on the faked arch). so it will run in full emulation, or?

> > So far tested cross-arch runs are * x86_64->x86_64 (faqemu functionality), > * x86_64->ppc64le (the most important one), > * ppc64le->x86_64, > * ppc64le->ppc64le (faqemu for Power). > > I'm interested in your reviews and comments regarding this effort! > > [1] https://gerrit.ovirt.org/#/c/46962/ > > Best regards, > mpolednik