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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 E398CC433DF for ; Mon, 29 Jun 2020 18:46:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C719A2065D for ; Mon, 29 Jun 2020 18:46:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="jELQEPaT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729215AbgF2Sqp (ORCPT ); Mon, 29 Jun 2020 14:46:45 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:38690 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729306AbgF2Sqm (ORCPT ); Mon, 29 Jun 2020 14:46:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593456401; 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=lmeklZemL80Q7lsiy/DTnr9n71S9umll3AkykzC+jhc=; b=jELQEPaTByRF52JD1NkVF/HAlxaFMnoUqkxDJHCmhrUgyJv37/aFjMB0ZrMBV/C8A5FGbg 77ERASuOjnxp0ZtdN362hVpw7foWi1msxVMBPwgbh+YnlcTnQV8MwSaGWLBRODWZ7lW2Ks B4kgBLLhV/M9bniIF/RPvkHLTgqofYA= 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-39-qTZ19pRuPo682yuNxSFHLQ-1; Mon, 29 Jun 2020 09:44:50 -0400 X-MC-Unique: qTZ19pRuPo682yuNxSFHLQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 99FC6107ACF9; Mon, 29 Jun 2020 13:44:48 +0000 (UTC) Received: from gondolin (ovpn-113-61.ams2.redhat.com [10.36.113.61]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6FDB35C1D4; Mon, 29 Jun 2020 13:44:42 +0000 (UTC) Date: Mon, 29 Jun 2020 15:44:39 +0200 From: Cornelia Huck To: Pierre Morel Cc: Halil Pasic , linux-kernel@vger.kernel.org, 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, 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: <20200629154439.14cc5ae7.cohuck@redhat.com> In-Reply-To: <7fe6e9ab-fd5a-3f92-1f3a-f9e6805d3730@linux.ibm.com> References: <1592390637-17441-1-git-send-email-pmorel@linux.ibm.com> <1592390637-17441-2-git-send-email-pmorel@linux.ibm.com> <20200618002956.5f179de4.pasic@linux.ibm.com> <20200619112051.74babdb1.cohuck@redhat.com> <7fe6e9ab-fd5a-3f92-1f3a-f9e6805d3730@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 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 29 Jun 2020 15:14:04 +0200 Pierre Morel wrote: > On 2020-06-19 11:20, Cornelia Huck wrote: > > On Thu, 18 Jun 2020 00:29:56 +0200 > > Halil Pasic wrote: > > > >> On Wed, 17 Jun 2020 12:43:57 +0200 > >> Pierre Morel wrote: > >>> @@ -179,6 +194,13 @@ int virtio_finalize_features(struct virtio_device *dev) > >>> if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) > >>> return 0; > >>> > >>> + if (arch_needs_virtio_iommu_platform(dev) && > >>> + !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { > >>> + dev_warn(&dev->dev, > >>> + "virtio: device must provide VIRTIO_F_IOMMU_PLATFORM\n"); [Side note: wasn't there a patch renaming this bit on the list? I think this name is only kept for userspace compat.] > >> > >> I'm not sure, divulging the current Linux name of this feature bit is a > >> good idea, but if everybody else is fine with this, I don't care that > > > > Not sure if that feature name will ever change, as it is exported in > > headers. At most, we might want to add the new ACCESS_PLATFORM define > > and keep the old one, but that would still mean some churn. > > > >> much. An alternative would be: > >> "virtio: device falsely claims to have full access to the memory, > >> aborting the device" > > > > "virtio: device does not work with limited memory access" ? > > > > But no issue with keeping the current message. > > > > If it is OK, I would like to specify that the arch is responsible to > accept or not the device. > The reason why the device is not accepted without IOMMU_PLATFORM is arch > specific. Hm, I'd think the reason is always the same (the device cannot access the memory directly), just the way to figure out whether that is the case or not is arch-specific, as with so many other things. No real need to go into detail here, I think.