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Date:   Thu, 3 Nov 2022 19:43:26 -0400
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Subject: Re: [PATCH v2 0/7] vfio-ccw parent rework
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To:     Alex Williamson <alex.williamson@redhat.com>,
        Eric Farman <farman@linux.ibm.com>
Cc:     Cornelia Huck <cohuck@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Kevin Tian <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>,
        Zhenyu Wang <zhenyuw@linux.intel.com>,
        Zhi Wang <zhi.a.wang@intel.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Halil Pasic <pasic@linux.ibm.com>,
        Vineeth Vijayan <vneethv@linux.ibm.com>,
        Peter Oberparleiter <oberpar@linux.ibm.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Sven Schnelle <svens@linux.ibm.com>,
        Tony Krowiak <akrowiak@linux.ibm.com>,
        Jason Herne <jjherne@linux.ibm.com>,
        Harald Freudenberger <freude@linux.ibm.com>,
        Diana Craciun <diana.craciun@oss.nxp.com>,
        Eric Auger <eric.auger@redhat.com>,
        Kirti Wankhede <kwankhede@nvidia.com>,
        Abhishek Sahu <abhsahu@nvidia.com>,
        Yishai Hadas <yishaih@nvidia.com>,
        intel-gvt-dev@lists.freedesktop.org,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
        kvm@vger.kernel.org
References: <20221102150152.2521475-1-farman@linux.ibm.com>
 <20221103155611.0008075f.alex.williamson@redhat.com>
From:   Matthew Rosato <mjrosato@linux.ibm.com>
In-Reply-To: <20221103155611.0008075f.alex.williamson@redhat.com>
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On 11/3/22 5:56 PM, Alex Williamson wrote:
> On Wed,  2 Nov 2022 16:01:45 +0100
> Eric Farman <farman@linux.ibm.com> wrote:
> 
>> Hi all,
>>
>> Here is an update to the vfio-ccw lifecycle changes that have been discussed
>> in various forms over the past year [1][2] or so, and which I dusted off
>> recently.
>>
>> Patches 1-5 rework the behavior of the vfio-ccw driver's private struct.
>> In summary, the mdev pieces are split out of vfio_ccw_private and into a
>> new vfio_ccw_parent struct that will continue to follow today's lifecycle.
>> The remainder (bulk) of the private struct moves to follow the mdev
>> probe/remove pair. There's opportunity for further separation of the
>> things in the private struct, which would simplify some of the vfio-ccw
>> code, but it got too hairy as I started that. Once vfio-ccw is no longer
>> considered unique, those cleanups can happen at our leisure. 
>>
>> Patch 6 removes the trickery where vfio-ccw uses vfio_init_device instead of
>> vfio_alloc_device, and thus removes vfio_init_device from the outside world.
>>
>> Patch 7 removes vfio_free_device from vfio-ccw and the other drivers (hello,
>> CC list!), letting it be handled by vfio_device_release directly.
> 
> Looks like another spin is pending, but the vfio core and collateral
> changes in 6 and 7 look good to me.  Would this go in through the vfio
> or s390 tree?  I'd be happy to merge or provide a branch, depending on
> the route.
> 
> For 6 & 7:
> Acked-by: Alex Williamson <alex.williamson@redhat.com>
> 
> Thanks,
> Alex

LGTM with those few comments addressed -- @Eric please send a v3 and I think it's ready.

I would suggest vfio tree to reduce the chance of conflicts; this touches various vfio drivers (and main) with the last patches while the s390 hits are at least all contained to the vfio-ccw driver code.