From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: 32-bit qemu + 64-bit kvm be a problem? Date: Wed, 02 Jun 2010 10:52:30 +0400 Message-ID: <4C05FFAE.4070209@msgid.tls.msk.ru> References: <5d649bdb1003100159i7edb6b62u24bf0e934d2a94bf@mail.gmail.com> <4B980B26.5080903@msgid.tls.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Neo Jia Return-path: Received: from isrv.corpit.ru ([81.13.33.159]:44535 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752056Ab0FBGwe (ORCPT ); Wed, 2 Jun 2010 02:52:34 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: 02.06.2010 09:44, Neo Jia wrote: > On Wed, Mar 10, 2010 at 2:12 PM, Michael Tokarev wrote: [] >> I use 32bit kvm on 64bit kernel since the day one. Nothing of interest >> since that, everything just works. > I just came back to this thread because I am seeing that I can't run > VISTA 64-bit inside 64/32 mode, which will crash with bugcheck 0x5D. > Is this a known issue? I haven't seen it myself, but I never tried vista. Win7 64bit installs and works just fine. STOP 0x0000005D, according to M$, means "there is a processor present that is not supported". I'd say try to experiment with different -cpu options. Also see if it works in native 64bit mode. >> Recently (this week) I come across a situation when something does not >> work in 64/32 mode. Namely it is linux aio (see the other thread in >> kvm@ a few days back) - but this is not due to kvm but due to other >> kernel subsystem (in this case aio) which lacks proper compat handlers >> in place. > > Could you tell me more about the AIO issue? Will this will slow down > the guest if it does a lot I/O? Will setting up coalescing help? You can search it yourself. In a nutshell it's an optimisation in kvm since version 0.12 to let raw devices be used a bit more efficient. /mjt