[ovirt-devel] rethinking fake-kvm and faqemu

[Michal Skrivanek]

On Oct 3, 2015, at 20:48 , Martin Polednik <mpolednik at redhat.com> 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