From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 1/3] KVM: trace mmio read event properly Date: Mon, 16 Jan 2012 12:18:15 +0200 Message-ID: <4F13F967.5000007@redhat.com> References: <4F13EE3D.2070602@linux.vnet.ibm.com> <4F13EE73.1080504@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , LKML , KVM To: Xiao Guangrong Return-path: In-Reply-To: <4F13EE73.1080504@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.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