From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Virtio Queries Date: Mon, 13 Apr 2009 14:07:27 +0300 Message-ID: <49E31CEF.30904@redhat.com> References: <3D9CB4061D1EB3408D4A0B910433453C030298EEC8@inbmail01.lsi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "kvm@vger.kernel.org" To: "Kumar, Venkat" Return-path: Received: from mx2.redhat.com ([66.187.237.31]:60244 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752158AbZDMLHb (ORCPT ); Mon, 13 Apr 2009 07:07:31 -0400 In-Reply-To: <3D9CB4061D1EB3408D4A0B910433453C030298EEC8@inbmail01.lsi.com> Sender: kvm-owner@vger.kernel.org List-ID: Kumar, Venkat wrote: > Hi, I am a few questions on Virtio, Hope somebody clarifies them > > 1. What is the address type that is put inside the vring descriptor in the virt queue while placing a request? Is it the guest virtual address or guest physical address? > Guest physical address. Guest virtual addresses change meanings from time to time. > 2. If it is Guest physical address, how qemu converts it to its virtual address before processing the buffer? > See the logic in cpu_physical_memory_rw() and cpu_physical_memory_map(). > 3. How does qemu interact with guest once it receives the buffers from the virt queue for doing the IO? > qemu advanced the ring indexes, and notifies the guest by sending an interrupt when the requests are completed. -- error compiling committee.c: too many arguments to function