Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765843AbZDCOYY (ORCPT ); Fri, 3 Apr 2009 10:24:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761398AbZDCOYN (ORCPT ); Fri, 3 Apr 2009 10:24:13 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:33926 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758387AbZDCOYN (ORCPT ); Fri, 3 Apr 2009 10:24:13 -0400 Date: Fri, 3 Apr 2009 16:23:25 +0200 From: Ingo Molnar To: Masami Hiramatsu Cc: Avi Kivity , "H. Peter Anvin" , Frederic Weisbecker , Steven Rostedt , Ananth N Mavinakayanahalli , Andrew Morton , Andi Kleen , Jim Keniston , kvm@vger.kernel.org, systemtap-ml , LKML , Vegard Nossum Subject: Re: [PATCH -tip 0/6 V4] tracing: kprobe-based event tracer Message-ID: <20090403142325.GA14932@elte.hu> References: <49D4F4B5.9040107@redhat.com> <20090403112639.GC31399@elte.hu> <49D5F80B.7000305@redhat.com> <49D61B56.9020408@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49D61B56.9020408@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1170 Lines: 29 * Masami Hiramatsu wrote: > Hmm, I'd like to know actually kvm aims to emulate all kinds of > instructions. If so, I might find some bugs in x86_emulate.c. > However, I don't know all bugs. To find all of them, we have to > port x86_emulate.c to user-space, decode binaries with it, and > compare its output with another decoder, as Jim had done with > insn.c. > > https://www.redhat.com/archives/utrace-devel/2009-March/msg00031.html btw., i'd suggest we put a build time check for this into the kernel version as well. For example to decode the vmlinux via objdump, run it through your decoder as well and compare the results. Put under a CONFIG_DEBUG_X86_DECODER_TEST kind of (deault-off) build-time self-test. This would ensure that the kernel we are running is fully supported by the decoder - even as GCC/GAS starts using new instructions, etc. How does this sound to you? Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/