From: Kashyap Chamarthy <kchamart@redhat.com>
To: Stefan Bader <stefan.bader@canonical.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, Anthoine Bourgeois <bourgeois@bertin.fr>
Subject: Re: nVMX regression v3.13+, bisected
Date: Thu, 27 Feb 2014 02:14:23 +0530 [thread overview]
Message-ID: <20140226204423.GA25995@tesla.redhat.com> (raw)
In-Reply-To: <530E4E25.4050508@canonical.com>
On Wed, Feb 26, 2014 at 09:27:17PM +0100, Stefan Bader wrote:
> On 26.02.2014 21:25, Paolo Bonzini wrote:
[. . .]
> >>
> >> I bisected this and ended up on the following commit which, when reverted made
> >> the launch work again:
> >>
> >> Author: Anthoine Bourgeois <bourgeois@bertin.fr>
> >> Date: Wed Nov 13 11:45:37 2013 +0100
> >>
> >> kvm, vmx: Fix lazy FPU on nested guest
> >>
> >> If a nested guest does a NM fault but its CR0 doesn't contain the TS
> >> flag (because it was already cleared by the guest with L1 aid) then we
> >> have to activate FPU ourselves in L0 and then continue to L2. If TS flag
> >> is set then we fallback on the previous behavior, forward the fault to
> >> L1 if it asked for.
> >>
> >> Signed-off-by: Anthoine Bourgeois <bourgeois@bertin.fr>
> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> >>
> >> The condition to exit to L0 seems to be according to what the description says.
> >> Could it be that the handling in L0 is doing something wrong?
> >
> > Thanks, I'll look at it tomorrow or Friday.
> >
> > Paolo
> >
> Great thanks. And maybe it helps if I actually add the link to the bug report as
> I had intended... :-P
>
> [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1278531
Yes, I'm seeing something similar[*] in a consistent manner with minimal
Fedora installs on L0, L1 and L2, but couldn't manage time to do the
bisecting. I thought this would be my first bisecting exercise, but you
already beat me to it.
[*] https://bugzilla.kernel.org/show_bug.cgi?id=69491#c7
--
/kashyap
next prev parent reply other threads:[~2014-02-26 20:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-26 19:43 nVMX regression v3.13+, bisected Stefan Bader
2014-02-26 20:25 ` Paolo Bonzini
2014-02-26 20:27 ` Stefan Bader
2014-02-26 20:44 ` Kashyap Chamarthy [this message]
2014-02-27 12:10 ` Kashyap Chamarthy
2014-02-27 15:55 ` Kashyap Chamarthy
2014-02-27 10:51 ` Paolo Bonzini
2014-02-27 13:41 ` anthoine.bourgeois
2014-02-27 17:01 ` anthoine.bourgeois
2014-02-27 16:58 ` Paolo Bonzini
2014-02-27 21:34 ` Kashyap Chamarthy
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