From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 2/2] KVM: Trace emulated instructions Date: Tue, 06 Apr 2010 00:38:00 +0300 Message-ID: <4BBA5838.6080603@redhat.com> References: <1269529376-17650-1-git-send-email-avi@redhat.com> <1269529376-17650-3-git-send-email-avi@redhat.com> <20100405184438.GA7141@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Gleb Natapov To: Marcelo Tosatti Return-path: Received: from mx1.redhat.com ([209.132.183.28]:25690 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756434Ab0DEViD (ORCPT ); Mon, 5 Apr 2010 17:38:03 -0400 Received: from int-mx04.intmail.prod.int.phx2.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.17]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o35Lc3MF011666 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 5 Apr 2010 17:38:03 -0400 In-Reply-To: <20100405184438.GA7141@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: On 04/05/2010 09:44 PM, Marcelo Tosatti wrote: > On Thu, Mar 25, 2010 at 05:02:56PM +0200, Avi Kivity wrote: > >> Log emulated instructions in ftrace, especially if they failed. >> > Why not log all emulated instructions? Seems useful to me. > > That was the intent, but it didn't pan out. I tried to avoid double-logging where an mmio read is dispatched to userspace, and the instruction is re-executed. Perhaps we should split it into a decode trace and execution result trace? Less easy to use but avoids confusion due to duplication. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.