From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56018) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Up0wj-0007Ar-8r for qemu-devel@nongnu.org; Tue, 18 Jun 2013 14:48:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Up0wh-0003CP-V7 for qemu-devel@nongnu.org; Tue, 18 Jun 2013 14:48:01 -0400 From: Juan Quintela In-Reply-To: <20130618180727.GC12685@vm> (mdroth@linux.vnet.ibm.com's message of "Tue, 18 Jun 2013 13:07:27 -0500") References: <1369240371-21253-1-git-send-email-mdroth@linux.vnet.ibm.com> <20130611215351.GA12585@vm> <20130618180727.GC12685@vm> Date: Tue, 18 Jun 2013 20:47:12 +0200 Message-ID: <87ppvjntn3.fsf@elfo.elfo> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH v2] wdt_i6300esb: fix vmstate versioning Reply-To: quintela@redhat.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: mdroth Cc: peter.maydell@linaro.org, aliguori@us.ibm.com, qemu-devel@nongnu.org, qemu-stable@nongnu.org, nick@bytemark.co.uk, lersek@redhat.com mdroth wrote: > On Tue, Jun 11, 2013 at 04:53:51PM -0500, mdroth wrote: >> On Wed, May 22, 2013 at 11:32:51AM -0500, Michael Roth wrote: >> > When this VMSD was introduced it's version fields were set to >> > sizeof(I6300State), making them essentially random from build to build, >> > version to version. >> > >> > To fix this, we lock in a high version id and low minimum version id to >> > support old->new migration from all prior versions of this device's >> > state. This should work since the device state has not changed since >> > its introduction. >> > >> > The potentially breaks migration from 1.5+ to 1.5, but since the >> > versioning was essentially random prior to this patch, new->old >> > migration was not consistently functional to begin with. >> > >> > Reported-by: Nicholas Thomas >> > Suggested-by: Peter Maydell >> > Cc: qemu-stable@nongnu.org >> > Signed-off-by: Michael Roth >> >> Ping, looking to pull this in for 1.5.1 > > Anthony, Juan? Not sure if this is on your radar. Looking to get it > applied prior to stable freeze tomorrow. Reviewed-by: Juan Quintela I guess that the value was already there, not that the version field hasn't been abused lot of times. I agree that sizeof() makes for an interesting version number, especially if padding enter the equation.