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=-9.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2C9F6C433E2 for ; Wed, 16 Sep 2020 09:09:50 +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 C8ABA2087D for ; Wed, 16 Sep 2020 09:09:49 +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="abkLQqNZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C8ABA2087D 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]:57108 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kITRl-0006s0-0v for qemu-devel@archiver.kernel.org; Wed, 16 Sep 2020 05:09:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42112) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kITQw-00060i-R0 for qemu-devel@nongnu.org; Wed, 16 Sep 2020 05:08:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:33484) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kITQu-0002zT-IH for qemu-devel@nongnu.org; Wed, 16 Sep 2020 05:08:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600247335; 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=4wbkAh16LTqbWTqdhsGvyV/tlBLCoQLY3QMWob8WvcY=; b=abkLQqNZx4VTqfr9TOocN5sVoK8X4DqIdcUrZlURnx3Yth5eVQngOObO8i03i2tdOodx7U q2WurBsuwzgPIzeNv29uhcN2FLOe9rQ6yGG0KOHG5gnFf2T+kZq2xK56j2xZ+LWNg59kWx gbdBApiSWf2YVDbrsvEy8DPNh43adFE= 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-45-OW6joycaPG-CBXxSk778hg-1; Wed, 16 Sep 2020 05:08:53 -0400 X-MC-Unique: OW6joycaPG-CBXxSk778hg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B7917ADC00; Wed, 16 Sep 2020 09:08:52 +0000 (UTC) Received: from gondolin (ovpn-112-252.ams2.redhat.com [10.36.112.252]) by smtp.corp.redhat.com (Postfix) with ESMTP id 54DC3614F5; Wed, 16 Sep 2020 09:08:51 +0000 (UTC) Date: Wed, 16 Sep 2020 11:08:48 +0200 From: Cornelia Huck To: Stefano Garzarella Subject: Re: [PATCH v2] virtio: skip legacy support check on machine types less than 5.1 Message-ID: <20200916110848.47395807.cohuck@redhat.com> In-Reply-To: <20200915130514.80989-1-sgarzare@redhat.com> References: <20200915130514.80989-1-sgarzare@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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=216.205.24.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/16 02:16:02 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -50 X-Spam_score: -5.1 X-Spam_bar: ----- X-Spam_report: (-5.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.999, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: Eduardo Habkost , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 15 Sep 2020 15:05:14 +0200 Stefano Garzarella wrote: > Commit 9b3a35ec82 ("virtio: verify that legacy support is not accidentally > on") added a check that returns an error if legacy support is on, but the > device is not legacy. > > Unfortunately some devices were wrongly declared legacy even if they > were not (e.g vhost-vsock). > > To avoid migration issues, we disable this error for machine types < 5.1, > but we print a warning. > > Cc: qemu-stable@nongnu.org > Fixes: 9b3a35ec82 ("virtio: verify that legacy support is not accidentally on") > Suggested-by: Dr. David Alan Gilbert > Suggested-by: Cornelia Huck > Signed-off-by: Stefano Garzarella > --- > v2: > - fixed Cornelia's e-mail address > --- > include/hw/virtio/virtio.h | 1 + > hw/core/machine.c | 1 + > hw/virtio/virtio.c | 18 ++++++++++++++++-- > 3 files changed, 18 insertions(+), 2 deletions(-) > > diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h > index 807280451b..ed7cee348b 100644 > --- a/include/hw/virtio/virtio.h > +++ b/include/hw/virtio/virtio.h > @@ -103,6 +103,7 @@ struct VirtIODevice > bool use_started; > bool started; > bool start_on_kick; /* when virtio 1.0 feature has not been negotiated */ > + bool disable_legacy_check; > VMChangeStateEntry *vmstate; > char *bus_name; > uint8_t device_endian; > diff --git a/hw/core/machine.c b/hw/core/machine.c > index ea26d61237..b686eab798 100644 > --- a/hw/core/machine.c > +++ b/hw/core/machine.c > @@ -44,6 +44,7 @@ GlobalProperty hw_compat_5_0[] = { > { "vmport", "x-signal-unsupported-cmd", "off" }, > { "vmport", "x-report-vmx-type", "off" }, > { "vmport", "x-cmds-v2", "off" }, > + { "virtio-device", "x-disable-legacy-check", "true" }, Hm... not sure if we actually should add a new device property for that. Maybe we can use a flag in the base machine type instead? > }; > const size_t hw_compat_5_0_len = G_N_ELEMENTS(hw_compat_5_0); > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index e983025217..30ccc43b8c 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -3287,6 +3287,8 @@ void virtio_init(VirtIODevice *vdev, const char *name, > */ > bool virtio_legacy_allowed(VirtIODevice *vdev) > { > + bool ret = false; > + > switch (vdev->device_id) { > case VIRTIO_ID_NET: > case VIRTIO_ID_BLOCK: > @@ -3298,10 +3300,20 @@ bool virtio_legacy_allowed(VirtIODevice *vdev) > case VIRTIO_ID_9P: > case VIRTIO_ID_RPROC_SERIAL: > case VIRTIO_ID_CAIF: > + ret = true; > + } > + > + /* > + * For backward compatibility, we allow legacy mode with old machine types > + * to get the migration working. > + */ > + if (!ret && vdev->disable_legacy_check) { > + warn_report("device is modern-only, but for backward compatibility " > + "legacy is allowed"); I don't think we should warn in the function that returns whether legacy is allowed or not. Future code might want to call this function for other purposes, and returning true with a warning is not that useful for code that wants to find out whether legacy is supported for a type in principle. So even though it is more work, I think we should move this warning to the code that is actively trying to fence off misconfigured devices. > return true; > - default: > - return false; > } > + > + return ret; > } > > hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n) > @@ -3713,6 +3725,8 @@ static Property virtio_properties[] = { > DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features), > DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true), > DEFINE_PROP_BOOL("use-disabled-flag", VirtIODevice, use_disabled_flag, true), > + DEFINE_PROP_BOOL("x-disable-legacy-check", VirtIODevice, > + disable_legacy_check, false), > DEFINE_PROP_END_OF_LIST(), > }; >