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=-6.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 A44BAC433E1 for ; Thu, 13 Aug 2020 09:29:13 +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 6CDB920781 for ; Thu, 13 Aug 2020 09:29:13 +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="QFnog3nP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6CDB920781 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]:45884 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k69Xs-0004aR-OD for qemu-devel@archiver.kernel.org; Thu, 13 Aug 2020 05:29:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36768) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k69XJ-0004B5-Q8 for qemu-devel@nongnu.org; Thu, 13 Aug 2020 05:28:37 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:58368 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 1k69XI-0007Vu-5o for qemu-devel@nongnu.org; Thu, 13 Aug 2020 05:28:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597310914; 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=oB1us60SuqICitT/tyF2n/qmRSAuv/0+rqTp92vPYnM=; b=QFnog3nPybkL8JCl1veEALlAjT1QjZrKy8vKwf4nQoGGC0tJy1Zh12v1w1nWrFKSjUeAqE CLw3pyNgTmoG/71qfcElYKM9JubHL9PaL5NGhvgNdgnT5LxATPyyqCn/18YQbsEWFIXWoF ErJt7Bg/0ZXzE7L9HikjTEJC/6ghy7U= 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-319-yXfwezbqNBagg-eFmpcuaw-1; Thu, 13 Aug 2020 05:28:31 -0400 X-MC-Unique: yXfwezbqNBagg-eFmpcuaw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2851180183C; Thu, 13 Aug 2020 09:28:30 +0000 (UTC) Received: from gondolin (ovpn-112-216.ams2.redhat.com [10.36.112.216]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3F9AB600C5; Thu, 13 Aug 2020 09:28:23 +0000 (UTC) Date: Thu, 13 Aug 2020 11:28:20 +0200 From: Cornelia Huck To: Stefano Garzarella Subject: Re: virtio-vsock requires 'disable-legacy=on' in QEMU 5.1 Message-ID: <20200813112820.62ffd63e.cohuck@redhat.com> In-Reply-To: References: Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=cohuck@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=207.211.31.120; envelope-from=cohuck@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/13 03:45:42 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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: Halil Pasic , Qinghua Cheng , qemu devel list , Stefan Hajnoczi , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 13 Aug 2020 11:16:56 +0200 Stefano Garzarella wrote: > Hi, > > Qinghua discovered that virtio-vsock-pci requires 'disable-legacy=on' in > QEMU 5.1: > $ ./qemu-system-x86_64 ... -device vhost-vsock-pci,guest-cid=5 > qemu-system-x86_64: -device vhost-vsock-pci,guest-cid=5: > device is modern-only, use disable-legacy=on > > Bisecting I found that this behaviour starts from this commit: > 9b3a35ec82 ("virtio: verify that legacy support is not accidentally on") Oh, I had heard that from others already, was still trying to figure out what to do. > > IIUC virtio-vsock is modern-only, so I tried this patch and it works: > > diff --git a/hw/virtio/vhost-user-vsock-pci.c b/hw/virtio/vhost-user-vsock-pci.c > index f4cf95873d..6e4cc874cd 100644 > --- a/hw/virtio/vhost-user-vsock-pci.c > +++ b/hw/virtio/vhost-user-vsock-pci.c > @@ -40,6 +40,7 @@ static void vhost_user_vsock_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp) > VHostUserVSockPCI *dev = VHOST_USER_VSOCK_PCI(vpci_dev); > DeviceState *vdev = DEVICE(&dev->vdev); > > + virtio_pci_force_virtio_1(vpci_dev); > qdev_realize(vdev, BUS(&vpci_dev->bus), errp); > } > > diff --git a/hw/virtio/vhost-vsock-pci.c b/hw/virtio/vhost-vsock-pci.c > index a815278e69..f641b974e9 100644 > --- a/hw/virtio/vhost-vsock-pci.c > +++ b/hw/virtio/vhost-vsock-pci.c > @@ -44,6 +44,7 @@ static void vhost_vsock_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp) > VHostVSockPCI *dev = VHOST_VSOCK_PCI(vpci_dev); > DeviceState *vdev = DEVICE(&dev->vdev); > > + virtio_pci_force_virtio_1(vpci_dev); > qdev_realize(vdev, BUS(&vpci_dev->bus), errp); > } > > > Do you think this is the right approach or is there a better way to > solve this issue? We basically have three possible ways to deal with this: - Force it to modern (i.e., what you have been doing; would need the equivalent changes in ccw as well.) Pro: looks like the cleanest approach. Con: not sure if we would need backwards compatibility support, which looks hairy. - Add vsock to the list of devices with legacy support. Pro: Existing setups continue to work. Con: If vsock is really virtio-1-only, we still carry around possibly broken legacy support. - Do nothing, have users force legacy off. Bad idea, as ccw has no way to do that on the command line. The first option is probably best.