From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39257) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WiNQU-0007TF-1Y for qemu-devel@nongnu.org; Thu, 08 May 2014 08:27:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WiNQK-0006xz-3G for qemu-devel@nongnu.org; Thu, 08 May 2014 08:27:50 -0400 Message-ID: <536B783B.5030902@suse.de> Date: Thu, 08 May 2014 14:27:39 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1398940629-26415-1-git-send-email-aik@ozlabs.ru> <5368F6C3.8000307@ozlabs.ru> In-Reply-To: <5368F6C3.8000307@ozlabs.ru> Content-Type: text/plain; charset=KOI8-R; format=flowed 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: Alexey Kardashevskiy Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org 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 :) Alex