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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable 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 B8E5BC433DF for ; Tue, 21 Jul 2020 16:46:35 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8BC892065E for ; Tue, 21 Jul 2020 16:46:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8BC892065E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33794 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jxvPW-00062O-Rv for qemu-devel@archiver.kernel.org; Tue, 21 Jul 2020 12:46:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46128) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jxvO8-0005R0-34 for qemu-devel@nongnu.org; Tue, 21 Jul 2020 12:45:08 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:39496) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jxvO6-0001U4-Cc for qemu-devel@nongnu.org; Tue, 21 Jul 2020 12:45:07 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06LGhbxG184174 for ; Tue, 21 Jul 2020 12:45:03 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 32dn6xuga1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 21 Jul 2020 12:45:03 -0400 Received: from m0098399.ppops.net (m0098399.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 06LGi5MW185885 for ; Tue, 21 Jul 2020 12:45:03 -0400 Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com with ESMTP id 32dn6xug8e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 21 Jul 2020 12:45:02 -0400 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06LGLic1021954; Tue, 21 Jul 2020 16:45:00 GMT Received: from b06avi18878370.portsmouth.uk.ibm.com (b06avi18878370.portsmouth.uk.ibm.com [9.149.26.194]) by ppma06ams.nl.ibm.com with ESMTP id 32brbh41fk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 21 Jul 2020 16:45:00 +0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06LGiwGc62980572 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Jul 2020 16:44:58 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 76FB511C04C; Tue, 21 Jul 2020 16:44:58 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E995411C05C; Tue, 21 Jul 2020 16:44:57 +0000 (GMT) Received: from oc2783563651 (unknown [9.145.95.222]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 21 Jul 2020 16:44:57 +0000 (GMT) Date: Tue, 21 Jul 2020 18:44:56 +0200 From: Halil Pasic To: "Michael S. Tsirkin" Subject: Re: [RFC v2 2/3] libvhost-user: handle endianness as mandated by the spec Message-ID: <20200721184456.1305ca0b.pasic@linux.ibm.com> In-Reply-To: <20200721093942-mutt-send-email-mst@kernel.org> References: <20200717092929.19453-1-mhartmay@linux.ibm.com> <20200717092929.19453-3-mhartmay@linux.ibm.com> <20200721093942-mutt-send-email-mst@kernel.org> Organization: IBM X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-07-21_09:2020-07-21, 2020-07-21 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 impostorscore=0 mlxscore=0 malwarescore=0 clxscore=1015 bulkscore=0 priorityscore=1501 lowpriorityscore=0 mlxlogscore=861 adultscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007210114 Received-SPF: pass client-ip=148.163.156.1; envelope-from=pasic@linux.ibm.com; helo=mx0a-001b2d01.pphosted.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/21 11:41:50 X-ACL-Warn: Detected OS = Linux 3.x [generic] [fuzzy] X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Daniel P. =?UTF-8?B?QmVycmFu?= =?UTF-8?B?Z8Op?=" , Cornelia Huck , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , Marc Hartmayer , Stefan Hajnoczi , =?UTF-8?B?TWFyYy1BbmRyw6k=?= Lureau Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 21 Jul 2020 09:40:10 -0400 "Michael S. Tsirkin" wrote: > On Fri, Jul 17, 2020 at 11:29:28AM +0200, Marc Hartmayer wrote: > > Since virtio existed even before it got standardized, the virtio > > standard defines the following types of virtio devices: > > > > + legacy device (pre-virtio 1.0) > > + non-legacy or VIRTIO 1.0 device > > + transitional device (which can act both as legacy and non-legacy) > > > > Virtio 1.0 defines the fields of the virtqueues as little endian, > > while legacy uses guest's native endian [1]. Currently libvhost-user > > does not handle virtio endianness at all, i.e. it works only if the > > native endianness matches with whatever is actually needed. That means > > things break spectacularly on big-endian targets. Let us handle virtio > > endianness for non-legacy as required by the virtio specification > > [1]. We will fence non-legacy virtio devices with the upcoming patch. > > > > [1] https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-210003 > > > > Signed-off-by: Marc Hartmayer > > > > --- > > Note: As we don't support legacy virtio devices > > Who's "we" in this sentence? vhost user supports legacy generally ... In that sentence "we" is the library "libvhost-user". I would like to avoid s390x being an oddball regarding this. Marc's previous version made an attempt at correct endianness handling for legacy and non-legacy. That spawned a discussion on how we don't want legacy devices in this context. This series makes what seemed to be the consensus reached in that discussion explicit: namely that libvhost-user does not support legacy-virtio. Regards, Halil