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 A9B2CC00A89 for ; Thu, 5 Nov 2020 13:08:25 +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 D55D62065D for ; Thu, 5 Nov 2020 13:08:24 +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="GsFV9m4Z" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D55D62065D 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]:41880 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kaf02-0001Zj-E8 for qemu-devel@archiver.kernel.org; Thu, 05 Nov 2020 08:08:23 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:51418) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kaez7-0000oG-2f for qemu-devel@nongnu.org; Thu, 05 Nov 2020 08:07:25 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:43506) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kaez3-0000dA-Ln for qemu-devel@nongnu.org; Thu, 05 Nov 2020 08:07:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604581640; 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=3ZjvhQ+VyLDneEqqJ85vjkYZQugcXUEY1t8QBvzRR3g=; b=GsFV9m4ZGuz741kP3jHbv3GicY0wMESdSRnIUZiukcAz/bmdaGIkbn0wUmJzkPiGssaK2a M5nN82rdC6AdAr36z245YSMc/CHXfuanTjq/reGJ5F4FELhc1Dg2+zsnqAwQVxdBYRdWDF Vpps+/fow675n/5acbn2j4qyMLl7shw= 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-134-VY_XQ7BiMtesknmUbVTg6w-1; Thu, 05 Nov 2020 08:07:19 -0500 X-MC-Unique: VY_XQ7BiMtesknmUbVTg6w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AF9F980B71A; Thu, 5 Nov 2020 13:07:17 +0000 (UTC) Received: from gondolin (ovpn-112-138.ams2.redhat.com [10.36.112.138]) by smtp.corp.redhat.com (Postfix) with ESMTP id A8CD21002C31; Thu, 5 Nov 2020 13:06:55 +0000 (UTC) Date: Thu, 5 Nov 2020 14:06:52 +0100 From: Cornelia Huck To: Philippe =?UTF-8?B?TWF0aGlldS1EYXVkw6k=?= Subject: Re: [PATCH-for-6.0 1/3] hw/virtio: Add configure switch to disable legacy VIRTIO Message-ID: <20201105140652.6c975b9e.cohuck@redhat.com> In-Reply-To: <20201105124353.3680057-2-philmd@redhat.com> References: <20201105124353.3680057-1-philmd@redhat.com> <20201105124353.3680057-2-philmd@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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=UTF-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=63.128.21.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/04 22:46:30 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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: Elena Ufimtseva , Fam Zheng , Thomas Huth , Jagannathan Raman , qemu-block@nongnu.org, "Michael S. Tsirkin" , Jason Wang , Christian Schoenebeck , Greg Kurz , Wainer dos Santos Moschetta , qemu-devel@nongnu.org, Kevin Wolf , Stefan Hajnoczi , Paolo Bonzini , =?UTF-8?B?TWFyYy1BbmRyw6k=?= Lureau , Max Reitz , Alex =?UTF-8?B?QmVubsOpZQ==?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 5 Nov 2020 13:43:51 +0100 Philippe Mathieu-Daud=C3=A9 wrote: > Per [1] (Terminology): >=20 > Legacy interfaces are not required; ie. don=E2=80=99t implement them > unless you have a need for backwards compatibility! >=20 > [2] (Version 1.0): >=20 > The device configuration space uses the little-endian format > for multi-byte fields. >=20 > and [3] (Legacy Interface): >=20 > for legacy interfaces, device configuration space is generally > the guest=E2=80=99s native endian, rather than PCI=E2=80=99s little-end= ian. > The correct endian-ness is documented for each device. >=20 > Add the --disable-virtio-legacy configure flag to produce builds > with VIRTIO 1.0 only, and the --enable-virtio-legacy to include > legacy VIRTIO support (supporting legacy VIRTIO is the default). This is only dealing with endianess issues; there are other differences on the control plane as well. Currently, virtio-pci has the option to make devices non-transitional, but virtio-ccw has not (only for device types). For virtio-mmio, you need to select one of legacy or non-transitional, IIRC. >=20 > [1] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.h= tml#x1-60001 > [2] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.h= tml#x1-170003 > [3] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.h= tml#x1-200003 >=20 > Signed-off-by: Philippe Mathieu-Daud=C3=A9 > --- > configure | 10 ++++++++++ > meson.build | 1 + > include/hw/virtio/virtio-access.h | 19 +++++-------------- > hw/virtio/virtio-legacy.c | 29 +++++++++++++++++++++++++++++ > hw/virtio/meson.build | 1 + > 5 files changed, 46 insertions(+), 14 deletions(-) > create mode 100644 hw/virtio/virtio-legacy.c (...) > diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio= -access.h > index 6818a23a2d3..b6c060f8cc6 100644 > --- a/include/hw/virtio/virtio-access.h > +++ b/include/hw/virtio/virtio-access.h > @@ -20,24 +20,15 @@ > #include "hw/virtio/virtio.h" > #include "hw/virtio/virtio-bus.h" > =20 > -#if defined(TARGET_PPC64) || defined(TARGET_ARM) > -#define LEGACY_VIRTIO_IS_BIENDIAN 1 > -#endif > - > +#ifdef CONFIG_VIRTIO_LEGACY > +bool virtio_access_is_big_endian(VirtIODevice *vdev); > +#else > static inline bool virtio_access_is_big_endian(VirtIODevice *vdev) > { > -#if defined(LEGACY_VIRTIO_IS_BIENDIAN) > - return virtio_is_big_endian(vdev); > -#elif defined(TARGET_WORDS_BIGENDIAN) > - if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { > - /* Devices conforming to VIRTIO 1.0 or later are always LE. */ > - return false; > - } > - return true; > -#else > + /* Devices conforming to VIRTIO 1.0 or later are always LE. */ > return false; This will make migration from a QEMU that has devices for which 1.0 has not been negotiated fail. > -#endif > } > +#endif > =20 > static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa) > {