From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51004) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y1xKr-0005kF-Q9 for qemu-devel@nongnu.org; Fri, 19 Dec 2014 08:11:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y1xKl-0005MU-GK for qemu-devel@nongnu.org; Fri, 19 Dec 2014 08:11:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51316) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y1xKl-0005MH-8p for qemu-devel@nongnu.org; Fri, 19 Dec 2014 08:11:07 -0500 Message-ID: <549423E2.6020806@redhat.com> Date: Fri, 19 Dec 2014 14:10:58 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <20141219120340.3416948b@nial.brq.redhat.com> <549408C8.70107@redhat.com> <20141219123252.7dc36ea5@nial.brq.redhat.com> <549413D0.7090109@redhat.com> <20141219134237.224005b6@nial.brq.redhat.com> In-Reply-To: <20141219134237.224005b6@nial.brq.redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] broken backward migration due to commit 461a275 "parallel: adding vmstate for save/restore" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: quintela@redhat.com, dgilbert@redhat.com, Pavel.Dovgaluk@ispras.ru, qemu-devel@nongnu.org On 19/12/2014 13:42, Igor Mammedov wrote: > On Fri, 19 Dec 2014 13:02:24 +0100 > Paolo Bonzini wrote: > >> >> >> On 19/12/2014 12:32, Igor Mammedov wrote: >>> There is one more commit that breaks it, this time with subsection >>> 6c3bff0 "exec: Save CPUState::exception_index field" >>> >>> qemu: warning: error while loading state for instance 0x0 of device 'cpu_common' >>> the same reproducer with -parallel none >> >> Patch sent, thanks. >> >> Paolo > > one more breakage: > a28fe7e pckbd: adding new fields to vmstate > > source: > qemu-system-x86_64 -monitor stdio -M pc-i440fx-1.7 -parallel none xpsp3x86.qcow2 > > switch to text screen where you could select Safe Mode and stop/migrate at this point > > target: > qemu-system-x86_64-1.7 -monitor stdio -M pc-i440fx-1.7 -incoming "exec: gzip -c -d STATEFILE.gz" xpsp3x86.qcow2 > > qemu: warning: error while loading state for instance 0x0 of device 'pckbd' Looks like Windows (all versions) writes 0xDD and 0xDF to the outport port of the keyboard controller when it enables/disables the A20 line. There are two possibilities: 1) disable this if you care about backwards-migration 2) apply upstream a patch like this: diff --git a/hw/input/pckbd.c b/hw/input/pckbd.c index 2b0cd3d..cb4a8be 100644 --- a/hw/input/pckbd.c +++ b/hw/input/pckbd.c @@ -373,7 +373,7 @@ static void kbd_reset(void *opaque) static uint8_t kbd_outport_default(KBDState *s) { - return KBD_OUT_RESET | KBD_OUT_A20 + return (0xdf & ~KBD_OUT_OBF & ~KBD_OUT_MOUSE_OBF) | (s->status & KBD_STAT_OBF ? KBD_OUT_OBF : 0) | (s->status & KBD_STAT_MOUSE_OBF ? KBD_OUT_MOUSE_OBF : 0); } 3) do both, so upstream works better Paolo