From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 3A68C21CEB0EA for ; Thu, 14 Sep 2017 12:09:20 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1D70680B29; Thu, 14 Sep 2017 19:12:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 1D70680B29 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lersek@redhat.com Received: from lacos-laptop-7.usersys.redhat.com (ovpn-121-80.rdu2.redhat.com [10.10.121.80]) by smtp.corp.redhat.com (Postfix) with ESMTP id EEB715D9C9; Thu, 14 Sep 2017 19:12:17 +0000 (UTC) To: Brijesh Singh , edk2-devel@lists.01.org Cc: Jordan Justen , Tom Lendacky , Ard Biesheuvel References: <20170914110822.112540-1-brijesh.singh@amd.com> <20170914110822.112540-5-brijesh.singh@amd.com> From: Laszlo Ersek Message-ID: <234fe938-6813-cbf7-6888-9d187a22d010@redhat.com> Date: Thu, 14 Sep 2017 21:12:16 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20170914110822.112540-5-brijesh.singh@amd.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 14 Sep 2017 19:12:19 +0000 (UTC) Subject: Re: [PATCH v3 4/8] OvmfPkg/VirtioNetDxe: dynamically alloc transmit header X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Sep 2017 19:09:20 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 09/14/17 13:08, Brijesh Singh wrote: > Each network packet is submitted for transmission by pushing the head > descriptor of a two-part descriptor chain to the Available Ring of the > TX queue. VirtioNetInitTx() sets up the the descriptor chains for all > queueable packets in advance, and points all the head descriptors to the > same shared, never modified, VIRTIO_1_0_NET_REQ header object (or its > initial VIRTIO_NET_REQ sub-object, dependent on virtio version). > VirtioNetInitTx() currently uses the header object's system physical > address for populating the head descriptors. > > When device is behind the IOMMU, VirtioNet driver is required to provide > the device address of VIRTIO_1_0_NET_REQ header. In this patch we > dynamically allocate the header using AllocateSharedPages() and map with > BusMasterCommonBuffer so that header can be accessed by both processor > and the device. > > We map the header object for CommonBuffer operation because, in order to > stick with the current code order, we populate the head descriptors with > the header's device address first, and fill in the header itself second. > > Cc: Ard Biesheuvel > Cc: Jordan Justen > Cc: Tom Lendacky > Cc: Laszlo Ersek > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Brijesh Singh > --- > OvmfPkg/VirtioNetDxe/VirtioNet.h | 3 +- > OvmfPkg/VirtioNetDxe/SnpInitialize.c | 64 +++++++++++++++++--- > OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c | 7 +++ > 3 files changed, 65 insertions(+), 9 deletions(-) Reviewed-by: Laszlo Ersek