From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B786C49ED7 for ; Fri, 20 Sep 2019 10:23:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 580862086A for ; Fri, 20 Sep 2019 10:23:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408658AbfITKXY (ORCPT ); Fri, 20 Sep 2019 06:23:24 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:51967 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405917AbfITKXY (ORCPT ); Fri, 20 Sep 2019 06:23:24 -0400 Received: from [5.158.153.55] (helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iBG4M-0006uo-Ru; Fri, 20 Sep 2019 12:23:19 +0200 Date: Fri, 20 Sep 2019 12:23:12 +0200 (CEST) From: Thomas Gleixner To: Paolo Bonzini cc: Suleiman Souhlal , rkrcmar@redhat.com, john.stultz@linaro.org, sboyd@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [RFC 0/2] kvm: Use host timekeeping in guest. In-Reply-To: <1ec0b238-61a7-8353-026e-3a2ee23e6240@redhat.com> Message-ID: References: <20190920062713.78503-1-suleiman@google.com> <1ec0b238-61a7-8353-026e-3a2ee23e6240@redhat.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Sep 2019, Paolo Bonzini wrote: > On 20/09/19 08:27, Suleiman Souhlal wrote: > > To do that, I am changing kvmclock to request to the host to copy > > its timekeeping parameters (mult, base, cycle_last, etc), so that > > the guest timekeeper can use the same values, so that time can > > be synchronized between the guest and the host. > > > > Any suggestions or feedback would be highly appreciated. > > I'm not a timekeeping maintainer, but I don't think the > kernel/time/timekeeping.c changes are acceptable. Indeed. #ifdef WHATEVERTHEHECK does not go anywhere. If at all this needs to be a runtime switch, but I have yet to understand the whole picture of this. Thanks, tglx