From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: Re: kvm-tools: can't seem to set guest_mac and KVM_GET_SUPPORTED_CPUID failed. Date: Thu, 17 Nov 2011 12:08:30 +0200 Message-ID: <1321524510.4221.9.camel@lappy> References: <20111117004246.GA1694@dancer.ca.sandia.gov> <1321510055.4221.5.camel@lappy> <1321512998.4221.7.camel@lappy> <4EC4CE05.6000607@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Pekka Enberg , David Evensky , kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mail-ww0-f42.google.com ([74.125.82.42]:35943 "EHLO mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751243Ab1KQKKd (ORCPT ); Thu, 17 Nov 2011 05:10:33 -0500 Received: by wwe3 with SMTP id 3so2961214wwe.1 for ; Thu, 17 Nov 2011 02:10:32 -0800 (PST) In-Reply-To: <4EC4CE05.6000607@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: 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 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.