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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 DD739C43381 for ; Wed, 20 Feb 2019 09:27:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5A1D2147A for ; Wed, 20 Feb 2019 09:27:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726867AbfBTJ1h convert rfc822-to-8bit (ORCPT ); Wed, 20 Feb 2019 04:27:37 -0500 Received: from mx1.redhat.com ([209.132.183.28]:40606 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726142AbfBTJ1g (ORCPT ); Wed, 20 Feb 2019 04:27:36 -0500 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 mx1.redhat.com (Postfix) with ESMTPS id D1198EDE10; Wed, 20 Feb 2019 09:27:35 +0000 (UTC) Received: from gondolin (dhcp-192-187.str.redhat.com [10.33.192.187]) by smtp.corp.redhat.com (Postfix) with ESMTP id C929D19C57; Wed, 20 Feb 2019 09:27:33 +0000 (UTC) Date: Wed, 20 Feb 2019 10:27:31 +0100 From: Cornelia Huck To: Pierre Morel Cc: Tony Krowiak , borntraeger@de.ibm.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com Subject: Re: [PATCH v2 1/1] s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem Message-ID: <20190220102731.4fca4f91.cohuck@redhat.com> In-Reply-To: <6cc5b478-4678-9a82-b902-cc9aed22becf@linux.ibm.com> References: <1550513328-12646-1-git-send-email-pmorel@linux.ibm.com> <1550513328-12646-2-git-send-email-pmorel@linux.ibm.com> <8e6853ba-12ed-a4f3-1263-0e15f715b644@linux.ibm.com> <6cc5b478-4678-9a82-b902-cc9aed22becf@linux.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 20 Feb 2019 09:27:36 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 19 Feb 2019 22:31:17 +0100 Pierre Morel wrote: > On 19/02/2019 19:52, Tony Krowiak wrote: > > On 2/18/19 1:08 PM, Pierre Morel wrote: > >> Libudev relies on having a subsystem link for non-root devices. To > >> avoid libudev (and potentially other userspace tools) choking on the > >> matrix device let us introduce a vfio_ap bus and with that the vfio_ap > >> bus subsytem, and make the matrix device reside within it. > >> > >> Doing this we need to suppress the forced link from the matrix device to > >> the vfio_ap driver and we suppress the device_type we do not need > >> anymore. > >> > >> Since the associated matrix driver is not the vfio_ap driver any more, > >> we have to change the search for the devices on the vfio_ap driver in > >> the function vfio_ap_verify_queue_reserved. > >> > >> Reported-by: Marc Hartmayer > >> Reported-by: Christian Borntraeger > >> Signed-off-by: Pierre Morel > >> --- > >>   drivers/s390/crypto/vfio_ap_drv.c     | 48 > >> +++++++++++++++++++++++++++++------ > >>   drivers/s390/crypto/vfio_ap_ops.c     |  4 +-- > >>   drivers/s390/crypto/vfio_ap_private.h |  1 + > >>   3 files changed, 43 insertions(+), 10 deletions(-) > >> > >> diff --git a/drivers/s390/crypto/vfio_ap_drv.c > >> b/drivers/s390/crypto/vfio_ap_drv.c > >> index 31c6c84..8e45559 100644 > >> --- a/drivers/s390/crypto/vfio_ap_drv.c > >> +++ b/drivers/s390/crypto/vfio_ap_drv.c > >> @@ -24,10 +24,6 @@ MODULE_LICENSE("GPL v2"); > >>   static struct ap_driver vfio_ap_drv; > >> -static struct device_type vfio_ap_dev_type = { > >> -    .name = VFIO_AP_DEV_TYPE_NAME, > >> -}; > >> - > >>   struct ap_matrix_dev *matrix_dev; > >>   /* Only type 10 adapters (CEX4 and later) are supported > >> @@ -62,6 +58,27 @@ static void vfio_ap_matrix_dev_release(struct > >> device *dev) > >>       kfree(matrix_dev); > >>   } > >> +static int matrix_bus_match(struct device *dev, struct device_driver > >> *drv) > >> +{ > >> +    return 1; > > > > I think we should verify the following: > > > > * dev == matrix_dev->device > > * drv == &matrix_driver > > > > The model employed is for the matrix device to be a singleton, so I > > think we should verify that the matrix device and driver defined herein > > ought to be the only possible choices for a match. Of course, doing so > > will require some restructuring of this patch. > > I think Conny already answered this question. Not quite :), but I don't think we need any magic in there, as there's only one device and only one driver on that bus. No need to make this more complicated. > > > > >> +} > >> + > >> +static struct bus_type matrix_bus = { > >> +    .name = "vfio_ap", > >> +    .match = &matrix_bus_match, > >> +}; > >> + > >> +static int matrix_probe(struct device *dev) > >> +{ > >> +    return 0; > >> +} > >> + > >> +static struct device_driver matrix_driver = { > >> +    .name = "vfio_ap", > > > > This is the same name used for the original device driver. I think > > this driver ought to have a different name to avoid confusion. > > How about vfio_ap_matrix or some other name to differentiate the > > two. > > I would like too, but changing this will change the path to the mediated > device supported type. Yes, we don't want to change that. > > > > > >> +    .bus = &matrix_bus, > >> +    .probe = matrix_probe, > > > > I would add: > >     .suppress_bind_attrs = true; > > > > This will remove the sysfs bind/unbind interfaces. Since there is only > > one matrix device and it's lifecycle is controlled herein, there is no > > sense in allowing a root user to bind/unbind it. > > > > OTOH bind/unbind has no impact. > If no one else ask for this I will not change what has already been > reviewed by Conny and Christian. As we only have one driver, it does not really make sense anyway.