From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54704) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WkxxZ-0006eo-QV for qemu-devel@nongnu.org; Thu, 15 May 2014 11:52:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WkxxN-0005Yn-TY for qemu-devel@nongnu.org; Thu, 15 May 2014 11:52:41 -0400 Received: from mail-pb0-f42.google.com ([209.85.160.42]:44850) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WkxxN-0005YY-O1 for qemu-devel@nongnu.org; Thu, 15 May 2014 11:52:29 -0400 Received: by mail-pb0-f42.google.com with SMTP id md12so1279010pbc.1 for ; Thu, 15 May 2014 08:52:28 -0700 (PDT) Message-ID: <5374E2B9.20508@ozlabs.ru> Date: Fri, 16 May 2014 01:52:25 +1000 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <1398940629-26415-1-git-send-email-aik@ozlabs.ru> <5368F6C3.8000307@ozlabs.ru> <536B783B.5030902@suse.de> In-Reply-To: <536B783B.5030902@suse.de> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v7] spapr: Add support for time base offset migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org On 05/08/2014 10:27 PM, Alexander Graf wrote: > On 05/06/2014 04:50 PM, Alexey Kardashevskiy wrote: >> On 05/01/2014 08:37 PM, Alexey Kardashevskiy wrote: >>> This allows guests to have a different timebase origin from the host. >>> >>> This is needed for migration, where a guest can migrate from one host >>> to another and the two hosts might have a different timebase origin. >>> However, the timebase seen by the guest must not go backwards, and >>> should go forwards only by a small amount corresponding to the time >>> taken for the migration. >>> >>> This is only supported for recent POWER hardware which has the TBU40 >>> (timebase upper 40 bits) register. That includes POWER6, 7, 8 but not >>> 970. >>> >>> This adds kvm_access_one_reg() to access a special register which is not >>> in env->spr. This requires kvm_set_one_reg/kvm_get_one_reg patch. >>> >>> The feature must be present in the host kernel. >>> >>> This bumps vmstate_spapr::version_id and enables new vmstate_ppc_timebase >>> only for it. Since the vmstate_spapr::minimum_version_id remains >>> unchanged, migration from older QEMU is supported but without >>> vmstate_ppc_timebase. >>> >>> Signed-off-by: Alexey Kardashevskiy >>> --- >>> Changes: >>> v7: >>> * migration_duration_ns forced to be between [0...1s] >>> * s/tb/tb_remote/ >>> * time_of_the_day_ns is int64_t now as this is what get_clock_realtime() >>> returns >> Still bad? :) > > The dependency isn't fulfilled yet :) Thanks to Cornelia, it is now! -- Alexey