Re: kvm-tools: can't seem to set guest_mac and KVM_GET_SUPPORTED_CPUID failed.

Sasha Levin
2011-11-17T10:10:33Z

On Thu, 2011-11-17 at 11:04 +0200, Avi Kivity wrote:
> On 11/17/2011 08:56 AM, Sasha Levin wrote:
> > On Thu, 2011-11-17 at 08:53 +0200, Pekka Enberg wrote:
> > > On Thu, Nov 17, 2011 at 8:07 AM, Sasha Levin <levinsasha928@gmail.com> wrote:
> > > >> Also, when I start the guest I sometimes get the following error message:
> > > >>
> > > >> # kvm run -k /path/to/bzImage-3.0.8 -m 256 -c 1 --name guest-15757
> > > >> KVM_GET_SUPPORTED_CPUID failed: Argument list too long
> > > >
> > > > Heh, we were talking about it couple of weeks ago, but since I couldn't
> > > > reproduce it here (it was happening to me before, but now it's gone) the
> > > > discussing died.
> > > >
> > > > Could you please provide some statistics on how often it happens to you?
> > > > Also, can you try wrapping the ioctl with a 'while (1)' (theres only 1
> > > > ioctl call to KVM_GET_SUPPORTED_CPUID) and see if it would happen at
> > > > some point?
> > >
> > > I'm no longer able to reproduce it here with 3.2-rc1. We could just
> > > try the easy way out and do what Qemu does and retry for E2BIG...
> >
> > Let's not do that :)
>
> Right :)
>
> > It'll just get uncovered again when someone decides to use
> > KVM_GET_SUPPORTED_CPUID somewhere else (like in Avi's cpuid patch).
> >
> > I'll try going back to <3.0 later today and see if it comes back.
>
> It might be worthwhile to write a small program that only does
> KVM_GET_SUPPORTED_CPUID, to rule out issues in userspace (though there
> isn't much of a window for such issues).

Heh... It actually discovered a different (minor) issue there, and a
documentation error as well.

I'll send patches in a bit.

--

Sasha.