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From: David Stevens <stevensd@chromium.org>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: geoff@hostfission.com, virtio-dev@lists.oasis-open.org,
	"Alex Lau" <alexlau@chromium.org>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Alexandre Courbot" <acourbot@chromium.org>,
	qemu-devel@nongnu.org, "Tomasz Figa" <tfiga@chromium.org>,
	"Keiichi Watanabe" <keiichiw@chromium.org>,
	"Gerd Hoffmann" <kraxel@redhat.com>,
	"Hans Verkuil" <hverkuil@xs4all.nl>,
	"Stéphane Marchesin" <marcheu@chromium.org>,
	"Dylan Reid" <dgreid@chromium.org>,
	"Gurchetan Singh" <gurchetansingh@chromium.org>,
	"Dmitry Morozov" <dmitry.morozov@opensynergy.com>,
	"Pawel Osciak" <posciak@chromium.org>,
	"Linux Media Mailing List" <linux-media@vger.kernel.org>
Subject: Re: guest / host buffer sharing ...
Date: Mon, 11 Nov 2019 12:04:25 +0900
Message-ID: <CAD=HUj41r8wHZ2-By8tLftkoqC5r_Bw=pr=zX2aZ7GTs1ESWhg@mail.gmail.com> (raw)
In-Reply-To: <20191106084344.GB189998@stefanha-x1.localdomain>

> My question would be "what is the actual problem you are trying to
> solve?".

One problem that needs to be solved is sharing buffers between
devices. With the out-of-tree Wayland device, to share virtio-gpu
buffers we've been using the virtio resource id. However, that
approach isn't necessarily the right approach, especially once there
are more devices allocating/sharing buffers. Specifically, this issue
came up in the recent RFC about adding a virtio video decoder device.

Having a centralized buffer allocator device is one way to deal with
sharing buffers, since it gives a definitive buffer identifier that
can be used by all drivers/devices to refer to the buffer. That being
said, I think the device as proposed is insufficient, as such a
centralized buffer allocator should probably be responsible for
allocating all shared buffers, not just linear guest ram buffers.

-David


  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-05 10:54 Gerd Hoffmann
2019-11-05 11:35 ` Geoffrey McRae
2019-11-06  6:24   ` Gerd Hoffmann
2019-11-06  8:36 ` David Stevens
2019-11-06 12:41   ` Gerd Hoffmann
2019-11-06 22:28     ` Geoffrey McRae
2019-11-07  6:48       ` Gerd Hoffmann
2019-11-06  8:43 ` Stefan Hajnoczi
2019-11-06  9:51   ` Gerd Hoffmann
2019-11-06 10:10     ` [virtio-dev] " Dr. David Alan Gilbert
2019-11-07 11:11       ` Gerd Hoffmann
2019-11-07 11:16         ` Dr. David Alan Gilbert
2019-11-08  6:45           ` Gerd Hoffmann
2019-11-06 11:46     ` Stefan Hajnoczi
2019-11-06 12:50       ` Gerd Hoffmann
2019-11-07 12:10         ` Stefan Hajnoczi
2019-11-07 15:10           ` Frank Yang
2019-11-08  7:22           ` Gerd Hoffmann
2019-11-08  7:35             ` Stefan Hajnoczi
2019-11-09  1:41               ` Stéphane Marchesin
2019-11-09 10:12                 ` Stefan Hajnoczi
2019-11-09 11:16                   ` Tomasz Figa
2019-11-09 12:08                     ` Stefan Hajnoczi
2019-11-09 15:12                       ` Tomasz Figa
2019-11-11  3:04   ` David Stevens [this message]
2019-11-11 15:36     ` [virtio-dev] " Liam Girdwood
2019-11-12  0:54       ` Gurchetan Singh
2019-11-12 13:56         ` Liam Girdwood
2019-11-12 22:55           ` Gurchetan Singh

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