From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jason J. Herne" Subject: Re: [[RFC] KVM-S390: Provide guest TOD Clock Get/Set Controls Date: Wed, 08 Oct 2014 10:22:25 -0400 Message-ID: <543548A1.9000905@linux.vnet.ibm.com> Reply-To: jjherne@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org, Christian Borntraeger , Alexander Graf , aik@ozlabs.ru, Cornelia Huck Return-path: Received: from e36.co.us.ibm.com ([32.97.110.154]:56824 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753787AbaJHOWb (ORCPT ); Wed, 8 Oct 2014 10:22:31 -0400 Received: from /spool/local by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 8 Oct 2014 08:22:31 -0600 Received: from b03cxnp08025.gho.boulder.ibm.com (b03cxnp08025.gho.boulder.ibm.com [9.17.130.17]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 426221FF003B for ; Wed, 8 Oct 2014 08:11:13 -0600 (MDT) Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id s98EMREB48365686 for ; Wed, 8 Oct 2014 16:22:27 +0200 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id s98ER47x026394 for ; Wed, 8 Oct 2014 08:27:05 -0600 Sender: kvm-owner@vger.kernel.org List-ID: This is a reply to the following thread: http://www.spinics.net/lists/kvm/msg108448.html I'm sending it in this fashion because my normal mail client is not allowing me to send it in plain text and the html is getting rejected by the mailing list. Sorry to those of you who received both this and the original. Ping. Does anyone feel strongly about this issue? I'm interested in opinions so we can get s390 TOD clock migration working :). We need to decide which interface to use, s390 specific ioctl or KVM_SET_CLOCK. Then we need to decide if we're going to snap a guest clock forward on the resume of a "suspend to disk" type operation. The alternative is to fix up the guest TOD value such that the guest notices no change of time, which as Christian points out, seems wrong. Unless we really want to show no time change and force the guest to use ntp to figure out that he is behind. -- -- Jason J. Herne (jjherne@linux.vnet.ibm.com)