From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16DD9C433DF for ; Wed, 15 Jul 2020 14:02:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E53BB2065D for ; Wed, 15 Jul 2020 14:02:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MB781OHZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729911AbgGOOCp (ORCPT ); Wed, 15 Jul 2020 10:02:45 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:54842 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727822AbgGOOCp (ORCPT ); Wed, 15 Jul 2020 10:02:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594821764; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZvHDwOoLbdSaOIDbTqIso84H/Gr3/SW89Du8SzMSm1c=; b=MB781OHZ2jB0ROJWdNwp4VMIUZlnqcWNnFT/x0wbwCeFytwG2f8+4HgAVXtcELhNivIluD 5jhxpUwpLY0wG1zG9SuK0R2rknXVKKkLxG8AHJWMf89bfMPxr1qYN/ZIAk1bMG7FzdxblL TpXm4p8YkcrbtR4pYcZd9Y3Ituq1m9g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-411-X7wHNdWnOBqDZp5sCk_oAw-1; Wed, 15 Jul 2020 10:02:42 -0400 X-MC-Unique: X7wHNdWnOBqDZp5sCk_oAw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3334880572E; Wed, 15 Jul 2020 14:02:41 +0000 (UTC) Received: from [10.72.13.230] (ovpn-13-230.pek2.redhat.com [10.72.13.230]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4900B19C4F; Wed, 15 Jul 2020 14:02:35 +0000 (UTC) Subject: Re: [PATCH RFC don't apply] vdpa_sim: endian-ness for config space To: "Michael S. Tsirkin" , linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org References: <20200715135540.22832-1-mst@redhat.com> From: Jason Wang Message-ID: <8f39dcc1-0899-7ed8-8a6e-75672417b9e3@redhat.com> Date: Wed, 15 Jul 2020 22:02:32 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200715135540.22832-1-mst@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/7/15 下午9:58, Michael S. Tsirkin wrote: > VDPA sim stores config space as native endian, but that > is wrong: modern guests expect LE. > I coded up the following to fix it up, but it is wrong too: > vdpasim_create is called before guest features are known. > > So what should we do? New ioctl to specify the interface used? > More ideas? > > Signed-off-by: Michael S. Tsirkin Can we do the endian conversion in set_config/get_config()? Thanks > > > --- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 22 ++++++++++++++++++++-- > 1 file changed, 20 insertions(+), 2 deletions(-) > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c > index a9bc5e0fb353..cc754ae0ec15 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c > @@ -24,6 +24,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -72,6 +73,23 @@ struct vdpasim { > u64 features; > }; > > +/* TODO: cross-endian support */ > +static inline bool vdpasim_is_little_endian(struct vdpasim *vdpasim) > +{ > + return virtio_legacy_is_little_endian() || > + (vdpasim->features & (1ULL << VIRTIO_F_VERSION_1)); > +} > + > +static inline u16 vdpasim16_to_cpu(struct vdpasim *vdpasim, __virtio16 val) > +{ > + return __virtio16_to_cpu(vdpasim_is_little_endian(vdpasim), val); > +} > + > +static inline __virtio16 cpu_to_vdpasim16(struct vdpasim *vdpasim, u16 val) > +{ > + return __cpu_to_virtio16(vdpasim_is_little_endian(vdpasim), val); > +} > + > static struct vdpasim *vdpasim_dev; > > static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa) > @@ -332,8 +350,8 @@ static struct vdpasim *vdpasim_create(void) > goto err_iommu; > > config = &vdpasim->config; > - config->mtu = 1500; > - config->status = VIRTIO_NET_S_LINK_UP; > + config->mtu = cpu_to_vdpasim16(vdpasim, 1500); > + config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP); > eth_random_addr(config->mac); > > vringh_set_iotlb(&vdpasim->vqs[0].vring, vdpasim->iommu);