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=-6.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 B0590C433E1 for ; Mon, 27 Jul 2020 12:45:39 +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 7E94E2064B for ; Mon, 27 Jul 2020 12:45:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WLzs4JQr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E94E2064B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:38890 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k02Ve-0004va-Qs for qemu-devel@archiver.kernel.org; Mon, 27 Jul 2020 08:45:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41780) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k02US-00040q-I7 for qemu-devel@nongnu.org; Mon, 27 Jul 2020 08:44:24 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:44495 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1k02UQ-0000ix-IJ for qemu-devel@nongnu.org; Mon, 27 Jul 2020 08:44:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595853861; 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=ZTKlWMpmhIUZff9L44QS4QC9XHhVKm4Fq5T1+XOt4UI=; b=WLzs4JQrj+hnvnte+iIgKKmfs7KpJif6NUxurDe7UgQk/uuwUOcBsBxkCYtS9hb2tZNBz+ udm5zv4PzuNvSBxiIZBs2HsjYE4LxSkEv1J0GgADREwn8jrxuFC9vUAMiKy6D5LyPzsJmx GZI6O7k3pcrkfd/QFVkjx7gG/tizp6A= 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-418-Al_cwpiZNE-0uM4UZUhUaw-1; Mon, 27 Jul 2020 08:44:18 -0400 X-MC-Unique: Al_cwpiZNE-0uM4UZUhUaw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C76A61DE5; Mon, 27 Jul 2020 12:44:17 +0000 (UTC) Received: from [10.72.12.71] (ovpn-12-71.pek2.redhat.com [10.72.12.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id E177E60BF4; Mon, 27 Jul 2020 12:44:11 +0000 (UTC) Subject: Re: [BUG] vhost-vdpa: qemu-system-s390x crashes with second virtio-net-ccw device To: "Michael S. Tsirkin" References: <20200724152718.4e1cbc9e.cohuck@redhat.com> <20200724092906-mutt-send-email-mst@kernel.org> <20200724165627.70c6dfd6.cohuck@redhat.com> <20200724111512-mutt-send-email-mst@kernel.org> <20200724173448.18773aec.cohuck@redhat.com> <5a0dfa0b-5a1d-e7d2-1785-8cca6ddb9db8@redhat.com> <20200727084310.7d29ec6d.cohuck@redhat.com> <676ce079-adf6-a279-c2ea-68f43146e2ac@redhat.com> <20200727104148.4ae49715.cohuck@redhat.com> <20200727074221-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: Date: Mon, 27 Jul 2020 20:44:09 +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: <20200727074221-mutt-send-email-mst@kernel.org> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=jasowang@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/27 01:44:14 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-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: qemu-s390x@nongnu.org, Cornelia Huck , qemu-devel@nongnu.org, Cindy Lu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/7/27 下午7:43, Michael S. Tsirkin wrote: > On Mon, Jul 27, 2020 at 04:51:23PM +0800, Jason Wang wrote: >> On 2020/7/27 下午4:41, Cornelia Huck wrote: >>> On Mon, 27 Jul 2020 15:38:12 +0800 >>> Jason Wang wrote: >>> >>>> On 2020/7/27 下午2:43, Cornelia Huck wrote: >>>>> On Sat, 25 Jul 2020 08:40:07 +0800 >>>>> Jason Wang wrote: >>>>>> On 2020/7/24 下午11:34, Cornelia Huck wrote: >>>>>>> On Fri, 24 Jul 2020 11:17:57 -0400 >>>>>>> "Michael S. Tsirkin" wrote: >>>>>>>> On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: >>>>>>>>> On Fri, 24 Jul 2020 09:30:58 -0400 >>>>>>>>> "Michael S. Tsirkin" wrote: >>>>>>>>>> On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: >>>>>>>>>>> When I start qemu with a second virtio-net-ccw device (i.e. adding >>>>>>>>>>> -device virtio-net-ccw in addition to the autogenerated device), I get >>>>>>>>>>> a segfault. gdb points to >>>>>>>>>>> >>>>>>>>>>> #0 0x000055d6ab52681d in virtio_net_get_config (vdev=, >>>>>>>>>>> config=0x55d6ad9e3f80 "RT") at /home/cohuck/git/qemu/hw/net/virtio-net.c:146 >>>>>>>>>>> 146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { >>>>>>>>>>> >>>>>>>>>>> (backtrace doesn't go further) >>>>>>>>> The core was incomplete, but running under gdb directly shows that it >>>>>>>>> is just a bog-standard config space access (first for that device). >>>>>>>>> >>>>>>>>> The cause of the crash is that nc->peer is not set... no idea how that >>>>>>>>> can happen, not that familiar with that part of QEMU. (Should the code >>>>>>>>> check, or is that really something that should not happen?) >>>>>>>>> >>>>>>>>> What I don't understand is why it is set correctly for the first, >>>>>>>>> autogenerated virtio-net-ccw device, but not for the second one, and >>>>>>>>> why virtio-net-pci doesn't show these problems. The only difference >>>>>>>>> between -ccw and -pci that comes to my mind here is that config space >>>>>>>>> accesses for ccw are done via an asynchronous operation, so timing >>>>>>>>> might be different. >>>>>>>> Hopefully Jason has an idea. Could you post a full command line >>>>>>>> please? Do you need a working guest to trigger this? Does this trigger >>>>>>>> on an x86 host? >>>>>>> Yes, it does trigger with tcg-on-x86 as well. I've been using >>>>>>> >>>>>>> s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu qemu,zpci=on >>>>>>> -m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 >>>>>>> -drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 >>>>>>> -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 >>>>>>> -device virtio-net-ccw >>>>>>> >>>>>>> It seems it needs the guest actually doing something with the nics; I >>>>>>> cannot reproduce the crash if I use the old advent calendar moon buggy >>>>>>> image and just add a virtio-net-ccw device. >>>>>>> >>>>>>> (I don't think it's a problem with my local build, as I see the problem >>>>>>> both on my laptop and on an LPAR.) >>>>>> It looks to me we forget the check the existence of peer. >>>>>> >>>>>> Please try the attached patch to see if it works. >>>>> Thanks, that patch gets my guest up and running again. So, FWIW, >>>>> >>>>> Tested-by: Cornelia Huck >>>>> >>>>> Any idea why this did not hit with virtio-net-pci (or the autogenerated >>>>> virtio-net-ccw device)? >>>> It can be hit with virtio-net-pci as well (just start without peer). >>> Hm, I had not been able to reproduce the crash with a 'naked' -device >>> virtio-net-pci. But checking seems to be the right idea anyway. >> Sorry for being unclear, I meant for networking part, you just need start >> without peer, and you need a real guest (any Linux) that is trying to access >> the config space of virtio-net. >> >> Thanks > A pxe guest will do it, but that doesn't support ccw, right? Yes, it depends on the cli actually. > > I'm still unclear why this triggers with ccw but not pci - > any idea? I don't test pxe but I can reproduce this with pci (just start a linux guest without a peer). Thanks