Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751004AbaJUECX (ORCPT ); Tue, 21 Oct 2014 00:02:23 -0400 Received: from rrcs-76-79-27-186.west.biz.rr.com ([76.79.27.186]:62931 "EHLO rrcs-76-79-27-186.west.biz.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750730AbaJUECW (ORCPT ); Tue, 21 Oct 2014 00:02:22 -0400 Date: Mon, 20 Oct 2014 23:02:13 -0500 From: Jeff Epler To: Thomas Shao Cc: Thomas Gleixner , "gregkh@linuxfoundation.org" , LKML , "devel@linuxdriverproject.org" , "olaf@aepfle.de" , "apw@canonical.com" , "jasowang@redhat.com" , KY Srinivasan , John Stultz , Richard Cochran Subject: Re: [PATCH v2 1/2] timekeeping: add EXPORT_SYMBOL_GPL for do_adjtimex() Message-ID: <20141021040212.GA6278@unpythonic.net> References: <1413362372-16236-1-git-send-email-huishao@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 21, 2014 at 03:18:58AM +0000, Thomas Shao wrote: > In some situation, the user is not able to enable guest VM to sync with external > time source, like NTP. But the host is still synced with a trusted time source. > In this case, host-guest time synchronization is useful. It's interesting to imagine that a virtualization host could present a time service to the guest *userspace*, even when the guest is not otherwise exposed to the internet at large. This could take the form of an NTP server on a private network, or as an implementation of a time source directly usable by ntpd in the guest, for instance as an emulated serial port with synthetic NEMA GPS signal + PPS signal, for instance. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/