Received: by 2002:a25:b323:0:0:0:0:0 with SMTP id l35csp612814ybj; Sat, 21 Sep 2019 08:15:45 -0700 (PDT) X-Google-Smtp-Source: APXvYqzZy7EFguMYvcN8GHtdjEzlrtZ6a0+7TPV6ZVms6qLi+7Lpt+3vxwKiI06H5hOmujPmZc8F X-Received: by 2002:aa7:d844:: with SMTP id f4mr19072736eds.269.1569078945587; Sat, 21 Sep 2019 08:15:45 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1569078945; cv=none; d=google.com; s=arc-20160816; b=e17zcI/LCKdPN94zuipixb9bCtyZZ5PqKgRifFPNO2IMGp1Sx1wzplvDSD3YfsLYuU Jvip+UNcFUySoi7yYg/FdWrsrL8xEPSdnCdCFLZ08MVWKcuzf35Wu8SpjyCoDyG30OoU fqgz4dZUGAagjxeovpGZpemYuT6uxEyJhhYdggRY2NyGlnWh2gE/x9rIkACUBteisEg/ 9LoiJ9FB80lzDrUtjc4vIJK0F9Na1e1OxAuGBZ6ApVfqq2mONyjgmz0NZ43X4Q3f4cWV 6Fl4REnZAOiwbxAUJqzqjGiL5YhEeRNXWb0CMsdEjXlWXKj2cLUc8HY1i8blY74r+2OB ZBvw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:user-agent:references :message-id:in-reply-to:subject:cc:to:from:date; bh=UkkuaDH+fqEVpAA2X2kW6iUlpOPQzv0XWcfHEqYvPG0=; b=uWPUJ9FkDOCj05QrZSI6tttDYHc/T89BIJzti7k+QL9Zhj1RJkXiCs5KHGypczlYEM G9D34+OpeAMRW6nns7EI6vELIVufRh6PSHpogs5Q5Cc5QQmUyeuIEb6dbs0E9x4TCvLd MSUjD4ap5jGKB928U0IK6UXKuvpnmqefARR5sqQc3Q4BfdittLgueZT6o/oT2fpeV8sw QnR6hFByeqZC0+WRdO4Na/XBzqxtPQaDTDV++eqfhtmP5+TYC7GJwtXtGPan7JY6IHDI 0CyapJlp26PJYs/jczF98/DtKanxxpnNtzeS9szGd1P85gMlgNBpcMIFM/UJk/DR68Oj av0w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p10si2480660ejz.391.2019.09.21.08.14.22; Sat, 21 Sep 2019 08:15:45 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408654AbfITKXY (ORCPT + 99 others); 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