From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754002Ab2APKSV (ORCPT ); Mon, 16 Jan 2012 05:18:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:7139 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751195Ab2APKSU (ORCPT ); Mon, 16 Jan 2012 05:18:20 -0500 Message-ID: <4F13F967.5000007@redhat.com> Date: Mon, 16 Jan 2012 12:18:15 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0 MIME-Version: 1.0 To: Xiao Guangrong CC: Marcelo Tosatti , LKML , KVM Subject: Re: [PATCH 1/3] KVM: trace mmio read event properly References: <4F13EE3D.2070602@linux.vnet.ibm.com> <4F13EE73.1080504@linux.vnet.ibm.com> In-Reply-To: <4F13EE73.1080504@linux.vnet.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/16/2012 11:31 AM, Xiao Guangrong wrote: > In current code, we use KVM_TRACE_MMIO_READ to trace mmio read event which > only can be completed immediately, instead of it, we trace the time when > read event occur, then cooperate with then later patch, we can know the time > of mmio read emulation > > @@ -3744,6 +3740,8 @@ mmio: > /* > * Is this MMIO handled locally? > */ > + trace_kvm_mmio(write ? KVM_TRACE_MMIO_WRITE : KVM_TRACE_MMIO_READ, It's better to push the conditional to the trace event itself, so it's only evaluated if tracing is enabled. > + bytes, gpa, *(u64 *)val); We get the wrong value for reads here, no? Can't we leave the code as is, and infer the start of the event from the last kvm_exit trace? > handled = ops->read_write_mmio(vcpu, gpa, bytes, val); > if (handled == bytes) > return X86EMUL_CONTINUE; -- error compiling committee.c: too many arguments to function