From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id D489937A6 for ; Wed, 2 Dec 2015 17:26:40 +0100 (CET) Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id F326812048F; Wed, 2 Dec 2015 16:26:39 +0000 (UTC) Received: from redhat.com (vpn1-4-19.ams2.redhat.com [10.36.4.19]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id tB2GQb0j026429; Wed, 2 Dec 2015 11:26:38 -0500 Date: Wed, 2 Dec 2015 18:26:37 +0200 From: "Michael S. Tsirkin" To: Victor Kaplansky Message-ID: <20151202180824-mutt-send-email-mst@redhat.com> References: <1449027793-30975-1-git-send-email-yuanhan.liu@linux.intel.com> <1449027793-30975-4-git-send-email-yuanhan.liu@linux.intel.com> <20151202155405-mutt-send-email-victork@redhat.com> <20151202143802.GT2325@yliu-dev.sh.intel.com> <20151202170233-mutt-send-email-victork@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151202170233-mutt-send-email-victork@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [PATCH 3/4] vhost: log vring changes X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Dec 2015 16:26:41 -0000 On Wed, Dec 02, 2015 at 05:58:24PM +0200, Victor Kaplansky wrote: > On Wed, Dec 02, 2015 at 10:38:02PM +0800, Yuanhan Liu wrote: > > On Wed, Dec 02, 2015 at 04:07:02PM +0200, Victor Kaplansky wrote: > > > On Wed, Dec 02, 2015 at 11:43:12AM +0800, Yuanhan Liu wrote: > > > > Invoking vhost_log_write() to mark corresponding page as dirty while > > > > updating used vring. > > > > > > Looks good, thanks! > > > > > > I didn't find where you log the dirty pages in result of data > > > written to the buffers pointed by the descriptors in RX vring. > > > AFAIU, the buffers of RX queue reside in guest's memory and have > > > to be marked as dirty if they are written. What do you say? > > > > Yeah, we should. I got a question then: why log_guest_addr is set > > to the physical address of used vring in guest? I mean, apparently, > > we need log more changes other than used vring only. > > The physical address of used vring sent to the back-end, since > otherwise back-end has to perform virtual to physical > translation, and we want to avoid this. The dirty buffers has to > be marked as well, but their guest's physical address is known > directly from the descriptors. Yes, people wanted to be able to do multiple physical addresses to one virtual so you do not want to translate virt to phys. > > > > --yliu