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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 F2AC5C433DF for ; Mon, 6 Jul 2020 14:34:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD3592070B for ; Mon, 6 Jul 2020 14:34:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ipe82HpR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729316AbgGFOeU (ORCPT ); Mon, 6 Jul 2020 10:34:20 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:53777 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729201AbgGFOeU (ORCPT ); Mon, 6 Jul 2020 10:34:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594046058; 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=hBET4KTCF7VLtikUgOS5OyaCCHxUdfauUuYPMbcHgTI=; b=ipe82HpRb4vj7yLs1qxZw908pEIE8JWwwA+Fvm4bFH+0IUr7XE+vHh4qTe8YgVjOFfsfPE ZNCDihoFRcRrb4sIUYs8b+WgCOwyTctpuhqyeHdLUfFWlkzhvfXel2PuVm7E8MIrFvI1+J DdRKlya2mjKfe3tor/nkwkuGc3sw2A0= 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-381-8UAvHL0EOOKZDXFTB_A5Fw-1; Mon, 06 Jul 2020 10:34:16 -0400 X-MC-Unique: 8UAvHL0EOOKZDXFTB_A5Fw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D7F1B10506E1; Mon, 6 Jul 2020 14:33:49 +0000 (UTC) Received: from gondolin (ovpn-112-234.ams2.redhat.com [10.36.112.234]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2C3B41A914; Mon, 6 Jul 2020 14:33:43 +0000 (UTC) Date: Mon, 6 Jul 2020 16:33:40 +0200 From: Cornelia Huck To: Pierre Morel Cc: "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, jasowang@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org, thomas.lendacky@amd.com, david@gibson.dropbear.id.au, linuxram@us.ibm.com, heiko.carstens@de.ibm.com, gor@linux.ibm.com Subject: Re: [PATCH v3 1/1] s390: virtio: let arch accept devices without IOMMU feature Message-ID: <20200706163340.2ce7a5f2.cohuck@redhat.com> In-Reply-To: References: <1592390637-17441-1-git-send-email-pmorel@linux.ibm.com> <1592390637-17441-2-git-send-email-pmorel@linux.ibm.com> <20200629115651-mutt-send-email-mst@kernel.org> <20200629180526.41d0732b.cohuck@redhat.com> <26ecd4c6-837b-1ce6-170b-a0155e4dd4d4@linux.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 6 Jul 2020 15:37:37 +0200 Pierre Morel wrote: > On 2020-07-02 15:03, Pierre Morel wrote: > >=20 > >=20 > > On 2020-06-29 18:05, Cornelia Huck wrote: =20 > >> On Mon, 29 Jun 2020 11:57:14 -0400 > >> "Michael S. Tsirkin" wrote: > >> =20 > >>> On Wed, Jun 17, 2020 at 12:43:57PM +0200, Pierre Morel wrote: =20 > >>>> An architecture protecting the guest memory against unauthorized host > >>>> access may want to enforce VIRTIO I/O device protection through the > >>>> use of VIRTIO_F_IOMMU_PLATFORM. > >>>> > >>>> Let's give a chance to the architecture to accept or not devices > >>>> without VIRTIO_F_IOMMU_PLATFORM. > >>>> > >>>> Signed-off-by: Pierre Morel > >>>> Acked-by: Jason Wang > >>>> Acked-by: Christian Borntraeger > >>>> --- > >>>> =C2=A0 arch/s390/mm/init.c=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0 6 ++++++ > >>>> =C2=A0 drivers/virtio/virtio.c | 22 ++++++++++++++++++++++ > >>>> =C2=A0 include/linux/virtio.h=C2=A0 |=C2=A0 2 ++ > >>>> =C2=A0 3 files changed, 30 insertions(+) =20 > >> =20 > >>>> @@ -179,6 +194,13 @@ int virtio_finalize_features(struct=20 > >>>> virtio_device *dev) > >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (!virtio_has_feature(dev, VIRTIO_F= _VERSION_1)) > >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return 0; > >>>> +=C2=A0=C2=A0=C2=A0 if (arch_needs_virtio_iommu_platform(dev) && > >>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 !virtio_has_feature(dev,= VIRTIO_F_IOMMU_PLATFORM)) { > >>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 dev_warn(&dev->dev, > >>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 "virtio: device must provide VIRTIO_F_IOMMU_PLATFORM\n"); > >>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return -ENODEV; > >>>> +=C2=A0=C2=A0=C2=A0 } > >>>> + > >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 virtio_add_status(dev, VIRTIO_CONFIG_= S_FEATURES_OK); > >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 status =3D dev->config->get_status(de= v); > >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (!(status & VIRTIO_CONFIG_S_FEATUR= ES_OK)) { =20 > >>> > >>> Well don't you need to check it *before* VIRTIO_F_VERSION_1, not afte= r? =20 > >> > >> But it's only available with VERSION_1 anyway, isn't it? So it probably > >> also needs to fail when this feature is needed if VERSION_1 has not be= en > >> negotiated, I think. =20 >=20 >=20 > would be something like: >=20 > - if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) > - return 0; > + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { > + ret =3D arch_accept_virtio_features(dev); > + if (ret) > + dev_warn(&dev->dev, > + "virtio: device must provide=20 > VIRTIO_F_VERSION_1\n"); > + return ret; > + } That looks wrong; I think we want to validate in all cases. What about: ret =3D arch_accept_virtio_features(dev); // this can include checking for // older or newer features if (ret) // assume that the arch callback moaned already return ret; if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) return 0; // do the virtio-1 only FEATURES_OK dance >=20 >=20 > just a thought on the function name: > It becomes more general than just IOMMU_PLATFORM related. >=20 > What do you think of: >=20 > arch_accept_virtio_features() Or maybe arch_validate_virtio_features()? >=20 > ? >=20 > Regards, > Pierre >=20 >=20