From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753103AbeBUJLK (ORCPT ); Wed, 21 Feb 2018 04:11:10 -0500 Received: from mail-lf0-f68.google.com ([209.85.215.68]:37955 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752473AbeBUJLI (ORCPT ); Wed, 21 Feb 2018 04:11:08 -0500 X-Google-Smtp-Source: AH8x226PgYhrD1+9l+LmxcQf0HpM9KHMr8LaS7bpbBivdJySxwWUmvdEnjVI6eLBAbJRGuPcn8Sx0w== Subject: Re: [PATCH 1/9] drm/xen-front: Introduce Xen para-virtualized frontend driver To: Juergen Gross , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, airlied@linux.ie, daniel.vetter@intel.com, seanpaul@chromium.org, gustavo@padovan.org, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com Cc: Oleksandr Andrushchenko References: <1519200222-20623-1-git-send-email-andr2000@gmail.com> <1519200222-20623-2-git-send-email-andr2000@gmail.com> <91386840-c34a-31a4-2bb3-14a27ececa9c@gmail.com> <4b20fcdd-2618-71a8-d94e-37c802973a02@suse.com> From: Oleksandr Andrushchenko Message-ID: <95653e33-b0a0-e061-ba9e-35552b5a8037@gmail.com> Date: Wed, 21 Feb 2018 11:11:05 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <4b20fcdd-2618-71a8-d94e-37c802973a02@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/21/2018 11:09 AM, Juergen Gross wrote: > On 21/02/18 09:47, Oleksandr Andrushchenko wrote: >> On 02/21/2018 10:19 AM, Juergen Gross wrote: >>> On 21/02/18 09:03, Oleksandr Andrushchenko wrote: >>>> From: Oleksandr Andrushchenko >>>> >>>> Introduce skeleton of the para-virtualized Xen display >>>> frontend driver. This patch only adds required >>>> essential stubs. >>>> >>>> Signed-off-by: Oleksandr Andrushchenko >>>> >>>> --- >>>>   drivers/gpu/drm/Kconfig             |  2 + >>>>   drivers/gpu/drm/Makefile            |  1 + >>>>   drivers/gpu/drm/xen/Kconfig         | 17 ++++++++ >>>>   drivers/gpu/drm/xen/Makefile        |  5 +++ >>>>   drivers/gpu/drm/xen/xen_drm_front.c | 83 >>>> +++++++++++++++++++++++++++++++++++++ >>>>   5 files changed, 108 insertions(+) >>>>   create mode 100644 drivers/gpu/drm/xen/Kconfig >>>>   create mode 100644 drivers/gpu/drm/xen/Makefile >>>>   create mode 100644 drivers/gpu/drm/xen/xen_drm_front.c >>>> >>>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig >>>> index deeefa7a1773..757825ac60df 100644 >>>> --- a/drivers/gpu/drm/Kconfig >>>> +++ b/drivers/gpu/drm/Kconfig >>>> @@ -289,6 +289,8 @@ source "drivers/gpu/drm/pl111/Kconfig" >>>>     source "drivers/gpu/drm/tve200/Kconfig" >>>>   +source "drivers/gpu/drm/xen/Kconfig" >>>> + >>>>   # Keep legacy drivers last >>>>     menuconfig DRM_LEGACY >>>> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile >>>> index 50093ff4479b..9d66657ea117 100644 >>>> --- a/drivers/gpu/drm/Makefile >>>> +++ b/drivers/gpu/drm/Makefile >>>> @@ -103,3 +103,4 @@ obj-$(CONFIG_DRM_MXSFB)    += mxsfb/ >>>>   obj-$(CONFIG_DRM_TINYDRM) += tinydrm/ >>>>   obj-$(CONFIG_DRM_PL111) += pl111/ >>>>   obj-$(CONFIG_DRM_TVE200) += tve200/ >>>> +obj-$(CONFIG_DRM_XEN) += xen/ >>>> diff --git a/drivers/gpu/drm/xen/Kconfig b/drivers/gpu/drm/xen/Kconfig >>>> new file mode 100644 >>>> index 000000000000..4cca160782ab >>>> --- /dev/null >>>> +++ b/drivers/gpu/drm/xen/Kconfig >>>> @@ -0,0 +1,17 @@ >>>> +config DRM_XEN >>>> +    bool "DRM Support for Xen guest OS" >>>> +    depends on XEN >>>> +    help >>>> +      Choose this option if you want to enable DRM support >>>> +      for Xen. >>>> + >>>> +config DRM_XEN_FRONTEND >>>> +    tristate "Para-virtualized frontend driver for Xen guest OS" >>>> +    depends on DRM_XEN >>>> +    depends on DRM >>>> +    select DRM_KMS_HELPER >>>> +    select VIDEOMODE_HELPERS >>>> +    select XEN_XENBUS_FRONTEND >>>> +    help >>>> +      Choose this option if you want to enable a para-virtualized >>>> +      frontend DRM/KMS driver for Xen guest OSes. >>>> diff --git a/drivers/gpu/drm/xen/Makefile b/drivers/gpu/drm/xen/Makefile >>>> new file mode 100644 >>>> index 000000000000..967074d348f6 >>>> --- /dev/null >>>> +++ b/drivers/gpu/drm/xen/Makefile >>>> @@ -0,0 +1,5 @@ >>>> +# SPDX-License-Identifier: GPL-2.0 >>>> + >>>> +drm_xen_front-objs := xen_drm_front.o >>>> + >>>> +obj-$(CONFIG_DRM_XEN_FRONTEND) += drm_xen_front.o >>>> diff --git a/drivers/gpu/drm/xen/xen_drm_front.c >>>> b/drivers/gpu/drm/xen/xen_drm_front.c >>>> new file mode 100644 >>>> index 000000000000..fd372fb464a1 >>>> --- /dev/null >>>> +++ b/drivers/gpu/drm/xen/xen_drm_front.c >>>> @@ -0,0 +1,83 @@ >>>> +/* >>>> + *  Xen para-virtual DRM device >>>> + * >>>> + *   This program is free software; you can redistribute it and/or >>>> modify >>>> + *   it under the terms of the GNU General Public License as >>>> published by >>>> + *   the Free Software Foundation; either version 2 of the License, or >>>> + *   (at your option) any later version. >>>> + * >>>> + *   This program is distributed in the hope that it will be useful, >>>> + *   but WITHOUT ANY WARRANTY; without even the implied warranty of >>>> + *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the >>>> + *   GNU General Public License for more details. >>> Use SPDX identifier instead (same applies for all other new >>> sources): >>> >>> // SPDX-License-Identifier: GPL-2.0 >> Will update, thank you >>>> + * >>>> + * Copyright (C) 2016-2018 EPAM Systems Inc. >>>> + * >>>> + * Author: Oleksandr Andrushchenko >>>> + */ >>>> + >>>> +#include >>>> + >>>> +#include >>>> +#include >>>> +#include >>>> + >>>> +#include >>>> + >>>> +static void backend_on_changed(struct xenbus_device *xb_dev, >>>> +        enum xenbus_state backend_state) >>>> +{ >>>> +} >>>> + >>>> +static int xen_drv_probe(struct xenbus_device *xb_dev, >>>> +        const struct xenbus_device_id *id) >>>> +{ >>>> +    return 0; >>>> +} >>>> + >>>> +static int xen_drv_remove(struct xenbus_device *dev) >>>> +{ >>>> +    return 0; >>>> +} >>>> + >>>> +static const struct xenbus_device_id xen_drv_ids[] = { >>>> +    { XENDISPL_DRIVER_NAME }, >>>> +    { "" } >>>> +}; >>>> + >>>> +static struct xenbus_driver xen_driver = { >>>> +    .ids = xen_drv_ids, >>>> +    .probe = xen_drv_probe, >>>> +    .remove = xen_drv_remove, >>>> +    .otherend_changed = backend_on_changed, >>>> +}; >>>> + >>>> +static int __init xen_drv_init(void) >>>> +{ >>>> +    if (!xen_domain()) >>>> +        return -ENODEV; >>>> + >>>> +    if (xen_initial_domain()) { >>>> +        DRM_ERROR(XENDISPL_DRIVER_NAME " cannot run in initial >>>> domain\n"); >>>> +        return -ENODEV; >>>> +    } >>> Why not? Wouldn't that be possible in case of the backend living in a >>> driver domain? >> It is possible (and in my use-case backend indeed runs in >> a driver domain). I was just not sure if it is really a >> good idea to allow that. If you think this is ok, then >> I'll remove this check > I don't think the driver should decide that. This would be the job of > Xen tools IMO. Agree, will remove > > Juergen