From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: [PATCH] tsc: use kvmclock for calibration Date: Thu, 09 Aug 2012 16:12:18 +0200 Message-ID: <5023C542.5050004@redhat.com> References: <1344513463-7329-1-git-send-email-kraxel@redhat.com> <5023B2C4.90302@redhat.com> <5023C1D2.5090103@redhat.com> <5023C2BE.5070702@redhat.com> <5023C395.40900@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: seabios@seabios.org, kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:44955 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030179Ab2HIOMg (ORCPT ); Thu, 9 Aug 2012 10:12:36 -0400 In-Reply-To: <5023C395.40900@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Hi, >> er, the documentation says 4 bytes (so stack alignment works). I >> distinctly remember having a large alignment requirement so we don't >> cross a page or slot boundary... something's wrong here. > > case MSR_KVM_SYSTEM_TIME: { [ ... ] > So your tests worked by pure luck, but the bug is in kvm. We need to > grab two pages here. Ok, so better use memalign(32,32) to make sure the struct doesn't cross a page border ... cheers, Gerd