From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH 2/2] Remove -tdf Date: Wed, 23 Jul 2008 08:58:25 +0300 Message-ID: <20080723055825.GA3196@minantech.com> References: <1216756217-21888-1-git-send-email-aliguori@us.ibm.com> <1216756217-21888-2-git-send-email-aliguori@us.ibm.com> <48865934.8070007@qumranet.com> <48868769.7050307@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dor Laor , kvm@vger.kernel.org, Avi Kivity To: Anthony Liguori Return-path: Received: from il.qumranet.com ([212.179.150.194]:17857 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750877AbYGWF61 (ORCPT ); Wed, 23 Jul 2008 01:58:27 -0400 Content-Disposition: inline In-Reply-To: <48868769.7050307@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Jul 22, 2008 at 08:20:41PM -0500, Anthony Liguori wrote: >> Currently both in-kernel PIT and even the in kernel irqchips are not >> 100% bullet proof. >> Of course this code is a hack, Gleb Natapov has send better fix for >> PIT/RTC to qemu list. >> Can you look into them: >> http://www.mail-archive.com/kvm@vger.kernel.org/msg01181.html > > Paul Brook's initial feedback is still valid. It causes quite a lot of > churn and may not jive well with a virtual time base. An advantage to > the current -tdf patch is that it's more contained. I don't think > either approach is going to get past Paul in it's current form. Yes, my patch causes a lot of churn because it changes widely used API. But the time drift fix itself is contained to PIT/RTC code only. The last patch series I've sent disables time drift fix if virtual time base is enabled as Paul requested. There was no further feedback from him. As Jan Kiszka wrote in one of his mails may be Paul's virtual time base can be adopted to work with KVM too. BTW how virtual time base handles SMP guest? > Also, it's important that this is reproducible in upstream QEMU and not > just in KVM. If we can make a compelling case for the importance of > this, we can possibly work out a compromise. > I developed and tested my patch with upstream QEMU. -- Gleb.