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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 CB046C00449 for ; Wed, 3 Oct 2018 15:10:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 802962098A for ; Wed, 3 Oct 2018 15:10:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 802962098A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726989AbeJCV7E (ORCPT ); Wed, 3 Oct 2018 17:59:04 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:34033 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726797AbeJCV7E (ORCPT ); Wed, 3 Oct 2018 17:59:04 -0400 Received: from tmo-096-48.customers.d1-online.com ([80.187.96.48] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1g7imw-0005gw-2H; Wed, 03 Oct 2018 17:10:10 +0200 Date: Wed, 3 Oct 2018 17:10:08 +0200 (CEST) From: Thomas Gleixner To: Andy Lutomirski cc: Vitaly Kuznetsov , Andy Lutomirski , Marcelo Tosatti , Paolo Bonzini , Radim Krcmar , Wanpeng Li , LKML , X86 ML , Peter Zijlstra , Matt Rickard , Stephen Boyd , John Stultz , Florian Weimer , KY Srinivasan , devel@linuxdriverproject.org, Linux Virtualization , Arnd Bergmann , Juergen Gross Subject: Re: [patch 00/11] x86/vdso: Cleanups, simmplifications and CLOCK_TAI support In-Reply-To: <8C316427-8BEC-4979-8AB2-5E385066BB6F@amacapital.net> Message-ID: References: <20180914125006.349747096@linutronix.de> <87sh1ne64t.fsf@vitty.brq.redhat.com> <4B6A97E1-17E6-40F2-A7A0-87731668A07C@amacapital.net> <87murvdysd.fsf@vitty.brq.redhat.com> <8C316427-8BEC-4979-8AB2-5E385066BB6F@amacapital.net> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323329-391363870-1538579410=:23677" 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 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-391363870-1538579410=:23677 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT On Wed, 3 Oct 2018, Andy Lutomirski wrote: > > On Oct 3, 2018, at 5:01 AM, Vitaly Kuznetsov wrote: > > Not all Hyper-V hosts support reenlightenment notifications (and, if I'm > > not mistaken, you need to enable nesting for the VM to get the feature - > > and most VMs don't have this) so I think we'll have to keep Hyper-V > > vclock for the time being. > > > But this does suggest that the correct way to pass a clock through to an > L2 guest where L0 is HV is to make L1 use the “tsc” clock and L2 use > kvmclock (or something newer and better). This would require adding > support for atomic frequency changes all the way through the timekeeping > and arch code. > > John, tglx, would that be okay or crazy? Not sure what you mean. I think I lost you somewhere on the way. Thanks, tglx --8323329-391363870-1538579410=:23677--