From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36553) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T6fXA-0001xs-Rt for qemu-devel@nongnu.org; Wed, 29 Aug 2012 06:30:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T6fX6-0004yv-DG for qemu-devel@nongnu.org; Wed, 29 Aug 2012 06:30:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53022) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T6fX6-0004yp-55 for qemu-devel@nongnu.org; Wed, 29 Aug 2012 06:30:00 -0400 Date: Wed, 29 Aug 2012 13:31:13 +0300 From: "Michael S. Tsirkin" Message-ID: <20120829103113.GA5825@redhat.com> References: <20120828191338.GE6223@otherpad.lan.raisama.net> <20120828213527.GB5817@redhat.com> <20120828220242.GW2886@otherpad.lan.raisama.net> <20120828222113.GA5970@redhat.com> <20120829095903.GB32031@amt.cnet> <20120829102324.GC5225@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120829102324.GC5225@redhat.com> Subject: Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcelo Tosatti Cc: gleb@redhat.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, Blue Swirl , Jan Kiszka , avi@redhat.com, Anthony Liguori , Eduardo Habkost On Wed, Aug 29, 2012 at 01:23:24PM +0300, Michael S. Tsirkin wrote: > > Michael, not migrating the PVEOI MSR actually crashes the guest? > > > Not at all. migration currently simply disables PV EOI, so > each EOI triggers exits after migration. I would like to add: without this patch guest will crash. But what will crash guest is *not* the fact we do not migrate the PV EOI MSR. It is the fact that PV EOI bit is set in CPUID. If guest reads CPUID before migration and then writes the MSR after migration, it will crash. > -- > MST