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=-6.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 1E8BFC433DF for ; Wed, 19 Aug 2020 09:35:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECB80206FA for ; Wed, 19 Aug 2020 09:35:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NWvsaX6K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727076AbgHSJfF (ORCPT ); Wed, 19 Aug 2020 05:35:05 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:59912 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726919AbgHSJfE (ORCPT ); Wed, 19 Aug 2020 05:35:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597829702; 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=zgtCTigZDuhIGcxkV1+kVI09BLaRJYOiJT5Qj4JZMc0=; b=NWvsaX6KxcaVKWeczrmsQADFybabdpeFcVkuRdoN8LjbRbO1DT3tvmrFn+hIWDsvwVLVo9 KGUo3oHPWy8toallB6PBAcF9GnVl2dMTO0OtKDVOrf8Z/kiaAjnQMdfbH/llWzzw7f1yCb 2dWrPuV95P1QQjU7VytBuaE+C5wRzck= 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-13-ZetAcgeqN7WK8fydIu2eWQ-1; Wed, 19 Aug 2020 05:34:58 -0400 X-MC-Unique: ZetAcgeqN7WK8fydIu2eWQ-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 F1ED41084C8A; Wed, 19 Aug 2020 09:34:55 +0000 (UTC) Received: from gondolin (ovpn-112-216.ams2.redhat.com [10.36.112.216]) by smtp.corp.redhat.com (Postfix) with ESMTP id 62AFA59; Wed, 19 Aug 2020 09:34:49 +0000 (UTC) Date: Wed, 19 Aug 2020 11:34:46 +0200 From: Cornelia Huck To: Pierre Morel Cc: linux-kernel@vger.kernel.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.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, hca@linux.ibm.com, gor@linux.ibm.com Subject: Re: [PATCH v8 1/2] virtio: let arch validate VIRTIO features Message-ID: <20200819113446.3f098d1e.cohuck@redhat.com> In-Reply-To: <64acd55a-8a22-4b84-0f9e-e13196c1520d@linux.ibm.com> References: <1597762711-3550-1-git-send-email-pmorel@linux.ibm.com> <1597762711-3550-2-git-send-email-pmorel@linux.ibm.com> <20200818191910.1fc300f2.cohuck@redhat.com> <64acd55a-8a22-4b84-0f9e-e13196c1520d@linux.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 19 Aug 2020 10:50:18 +0200 Pierre Morel wrote: > On 2020-08-18 19:19, Cornelia Huck wrote: > > On Tue, 18 Aug 2020 16:58:30 +0200 > > Pierre Morel wrote: > > > ... > >> +config ARCH_HAS_RESTRICTED_MEMORY_ACCESS > >> + bool > >> + help > >> + This option is selected by any architecture enforcing > >> + VIRTIO_F_IOMMU_PLATFORM > > > > This option is only for a very specific case of "restricted memory > > access", namely the kind that requires IOMMU_PLATFORM for virtio > > devices. ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS? Or is this intended > > to cover cases outside of virtio as well? > > AFAIK we did not identify other restrictions so adding VIRTIO in the > name should be the best thing to do. > > If new restrictions appear they also may be orthogonal. > > I will change to ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS if no one > complains. > > > > >> + > >> menuconfig VIRTIO_MENU > >> bool "Virtio drivers" > >> default y > >> diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c > >> index a977e32a88f2..1471db7d6510 100644 > >> --- a/drivers/virtio/virtio.c > >> +++ b/drivers/virtio/virtio.c > >> @@ -176,6 +176,10 @@ int virtio_finalize_features(struct virtio_device *dev) > >> if (ret) > >> return ret; > >> > >> + ret = arch_has_restricted_memory_access(dev); > >> + if (ret) > >> + return ret; > > > > Hm, I'd rather have expected something like > > > > if (arch_has_restricted_memory_access(dev)) { > > may be also change the callback name to > arch_has_restricted_virtio_memory_access() ? Yes, why not. > > > // enforce VERSION_1 and IOMMU_PLATFORM > > } > > > > Otherwise, you're duplicating the checks in the individual architecture > > callbacks again. > > Yes, I agree and go back this way. > > > > > [Not sure whether the device argument would be needed here; are there > > architectures where we'd only require IOMMU_PLATFORM for a subset of > > virtio devices?] > > I don't think so and since we do the checks locally, we do not need the > device argument anymore. Yes, that would also remove some layering entanglement.