From patchwork Tue Sep 3 21:02:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eduardo Habkost X-Patchwork-Id: 11129019 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6775614F7 for ; Tue, 3 Sep 2019 21:37:53 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 475012087E for ; Tue, 3 Sep 2019 21:37:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 475012087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:51890 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i5GUp-0003AT-Gf for patchwork-qemu-devel@patchwork.kernel.org; Tue, 03 Sep 2019 17:37:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57033) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i5Fwj-0004Ua-OF for qemu-devel@nongnu.org; Tue, 03 Sep 2019 17:02:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i5Fwi-0001UQ-IG for qemu-devel@nongnu.org; Tue, 03 Sep 2019 17:02:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52452) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i5Fwi-0001U3-DC for qemu-devel@nongnu.org; Tue, 03 Sep 2019 17:02:36 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B088510C6352; Tue, 3 Sep 2019 21:02:35 +0000 (UTC) Received: from localhost (ovpn-116-55.gru2.redhat.com [10.97.116.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 485D11001956; Tue, 3 Sep 2019 21:02:35 +0000 (UTC) From: Eduardo Habkost To: Paolo Bonzini , Igor Mammedov , Peter Maydell , Richard Henderson , Marcel Apfelbaum , qemu-devel@nongnu.org Date: Tue, 3 Sep 2019 18:02:01 -0300 Message-Id: <20190903210201.14627-14-ehabkost@redhat.com> In-Reply-To: <20190903210201.14627-1-ehabkost@redhat.com> References: <20190903210201.14627-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.64]); Tue, 03 Sep 2019 21:02:35 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL v2 13/13] migration: Do not re-read the clock on pre_save in case of paused guest X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marcelo Tosatti , "Maxiwell S. Garcia" Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: "Maxiwell S. Garcia" The clock move makes the guest knows about the paused time between the 'stop' and 'migrate' commands. This is an issue in an already-paused VM because some side effects, like process stalls, could happen after migration. So, this patch checks the runstate of guest in the pre_save handler and do not re-reads the clock in case of paused state (cold migration). Signed-off-by: Maxiwell S. Garcia Message-Id: <20190829210711.6570-1-maxiwell@linux.ibm.com> Reviewed-by: Marcelo Tosatti Signed-off-by: Eduardo Habkost --- hw/i386/kvm/clock.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c index 80c133a724..2c59b6894b 100644 --- a/hw/i386/kvm/clock.c +++ b/hw/i386/kvm/clock.c @@ -41,6 +41,9 @@ typedef struct KVMClockState { uint64_t clock; bool clock_valid; + /* whether the 'clock' value was obtained in the 'paused' state */ + bool runstate_paused; + /* whether machine type supports reliable KVM_GET_CLOCK */ bool mach_use_reliable_get_clock; @@ -202,6 +205,8 @@ static void kvmclock_vm_state_change(void *opaque, int running, return; } + s->runstate_paused = runstate_check(RUN_STATE_PAUSED); + kvm_synchronize_all_tsc(); kvm_update_clock(s); @@ -260,9 +265,9 @@ static int kvmclock_pre_load(void *opaque) } /* - * When migrating, read the clock just before migration, - * so that the guest clock counts during the events - * between: + * When migrating a running guest, read the clock just + * before migration, so that the guest clock counts + * during the events between: * * * vm_stop() * * @@ -277,7 +282,9 @@ static int kvmclock_pre_save(void *opaque) { KVMClockState *s = opaque; - kvm_update_clock(s); + if (!s->runstate_paused) { + kvm_update_clock(s); + } return 0; }