From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57588) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xr67F-0000bg-0B for qemu-devel@nongnu.org; Wed, 19 Nov 2014 09:20:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xr678-0004Fy-R8 for qemu-devel@nongnu.org; Wed, 19 Nov 2014 09:20:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52043) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xr678-0004Fg-DR for qemu-devel@nongnu.org; Wed, 19 Nov 2014 09:20:10 -0500 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sAJEK868029278 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Wed, 19 Nov 2014 09:20:09 -0500 From: Juan Quintela In-Reply-To: <546CA4F5.2080202@redhat.com> (Paolo Bonzini's message of "Wed, 19 Nov 2014 15:11:01 +0100") 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> <546CA4F5.2080202@redhat.com> Date: Wed, 19 Nov 2014 15:20:07 +0100 Message-ID: <871tozmfvs.fsf@elfo.elfo> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH 2/5] exec: qemu_ram_alloc_device, qemu_ram_resize Reply-To: quintela@redhat.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, "Michael S. Tsirkin" Paolo Bonzini wrote: > 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. I am not an expert of cpu microcode, but I would assume that changes there tend to be minimal, no? And anyways, I wouldn't expect to introduce/remove features like NX (i.e. visible by the guest) on a microcode update? Later, Juan. > Paolo