From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM timekeeping fixes, V2 Date: Sun, 18 Jul 2010 17:22:27 +0300 Message-ID: <4C430E23.9070707@redhat.com> References: <1278987938-23873-1-git-send-email-zamsden@redhat.com> <20100716131907.GJ23755@8bytes.org> <4C4094E0.7000403@redhat.com> <20100716192637.GK23755@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Zachary Amsden , KVM , Marcelo Tosatti , Glauber Costa , Linux-kernel To: Joerg Roedel Return-path: Received: from mx1.redhat.com ([209.132.183.28]:29582 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755240Ab0GROWb (ORCPT ); Sun, 18 Jul 2010 10:22:31 -0400 In-Reply-To: <20100716192637.GK23755@8bytes.org> Sender: kvm-owner@vger.kernel.org List-ID: On 07/16/2010 10:26 PM, Joerg Roedel wrote: > On Fri, Jul 16, 2010 at 07:20:32AM -1000, Zachary Amsden wrote: > > >> I've been very careful to keep nested SVM safe, but I've not got a good >> test for that. Is there any test suite for the nested case? >> > To test this you can boot a nested Linux guest and let both, L1 and L2 > guest use kvm_clock. Then put some load into the L2 guest and see if the > L2 or the L1 freezes hard (which happens with kvm_clock when the TSC > went backwards for one of them). > > With recent guests, they won't freeze any more, since we detect the tsc going backwards and compensate (in a brute-force way, nothing clever). But you can printk the maximum compensation and see if it's something unreasonable. -- error compiling committee.c: too many arguments to function