From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53834) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xr5yT-00024y-IA for qemu-devel@nongnu.org; Wed, 19 Nov 2014 09:11:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xr5yN-0000iE-6X for qemu-devel@nongnu.org; Wed, 19 Nov 2014 09:11:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36537) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xr5yM-0000hl-UC for qemu-devel@nongnu.org; Wed, 19 Nov 2014 09:11:07 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sAJEB6uV018213 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Wed, 19 Nov 2014 09:11:06 -0500 Message-ID: <546CA4F5.2080202@redhat.com> Date: Wed, 19 Nov 2014 15:11:01 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1416254843-16859-1-git-send-email-mst@redhat.com> <1416254843-16859-3-git-send-email-mst@redhat.com> <546AE14E.7060606@redhat.com> <20141118074904.GA19745@redhat.com> <87y4r7o8dh.fsf@elfo.elfo> <20141119093320.GA26119@redhat.com> <87d28jo5yp.fsf@elfo.elfo> <20141119102136.GC26395@redhat.com> <878uj7o4ec.fsf@elfo.elfo> <20141119132851.GA27435@redhat.com> <87vbmbmhaj.fsf@elfo.elfo> <546CA051.4050803@redhat.com> <87egszmgn4.fsf@elfo.elfo> In-Reply-To: <87egszmgn4.fsf@elfo.elfo> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH 2/5] exec: qemu_ram_alloc_device, qemu_ram_resize List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: quintela@redhat.com Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, "Michael S. Tsirkin" On 19/11/2014 15:03, Juan Quintela wrote: > Paolo Bonzini wrote: >> On 19/11/2014 14:49, Juan Quintela wrote: >>>>> Real hardware lets users update firmware and so should virtual hardware. >>> But you can hibernate your laptop, update the firmware, and reboot? >>> Where the change can be anyting, like moving from traditional BIOS to >>> UEFI? >> >> Wait wait wait. I totally cannot follow. What would be the equivalent >> in QEMU? > > qemu-2.0 -M pc-2.0 > > migrate to disk/s3/s4 > > upgrade qemu > > qemu-2.2 -M pc-2.0 > > try interesting variation of s3/s4/migration to disk. Migration to disk > should work (we migrate BIOS ROM blocks, enphasis on ROM), s3 perhaps > (machine needs to be saved to disk), s4 ..... depends how it ends being > done. Ok, got it. S3 + migrate to disk should work. S4 probably would work, but I think it would work on a real system too as long as you update software and not hardware (e.g. changing the motherboard would change the MAC address of the on-board NIC, for example). Consider the similar case on real hardware: boot update microcode RPM s4 turn on CPU microcode is installed early by the kernel, before looking for a hibernation image to resume from, so the CPU microcode after resume from S4 is different from the microcode at the time you suspended to disk. This probably would work. Paolo