LKML Archive on
 help / color / Atom feed
From: Dave Airlie <>
To: Sasha Levin <>
Cc: "Deucher, Alexander" <>,
	"Chris Wilson" <>,
	"Ville Syrjälä" <>,
	"Hawking Zhang" <>,
	"Ursulin, Tvrtko" <>,,,
	"Greg Kroah-Hartman" <>,, LKML <>,
	dri-devel <>,,,
	"Linux Fbdev development list" <>,,
Subject: Re: [RFC PATCH 0/4] DirectX on Linux
Date: Wed, 20 May 2020 08:42:43 +1000
Message-ID: <> (raw)
In-Reply-To: <>

On Wed, 20 May 2020 at 02:33, Sasha Levin <> wrote:
> There is a blog post that goes into more detail about the bigger
> picture, and walks through all the required pieces to make this work. It
> is available here:
> . The rest of
> this cover letter will focus on the Linux Kernel bits.
> Overview
> ========
> This is the first draft of the Microsoft Virtual GPU (vGPU) driver. The
> driver exposes a paravirtualized GPU to user mode applications running
> in a virtual machine on a Windows host. This enables hardware
> acceleration in environment such as WSL (Windows Subsystem for Linux)
> where the Linux virtual machine is able to share the GPU with the
> Windows host.
> The projection is accomplished by exposing the WDDM (Windows Display
> Driver Model) interface as a set of IOCTL. This allows APIs and user
> mode driver written against the WDDM GPU abstraction on Windows to be
> ported to run within a Linux environment. This enables the port of the
> D3D12 and DirectML APIs as well as their associated user mode driver to
> Linux. This also enables third party APIs, such as the popular NVIDIA
> Cuda compute API, to be hardware accelerated within a WSL environment.
> Only the rendering/compute aspect of the GPU are projected to the
> virtual machine, no display functionality is exposed. Further, at this
> time there are no presentation integration. So although the D3D12 API
> can be use to render graphics offscreen, there is no path (yet) for
> pixel to flow from the Linux environment back onto the Windows host
> desktop. This GPU stack is effectively side-by-side with the native
> Linux graphics stack.

Okay I've had some caffiene and absorbed some more of this.

This is a driver that connects a binary blob interface in the Windows
kernel drivers to a binary blob that you run inside a Linux guest.
It's a binary transport between two binary pieces. Personally this
holds little of interest to me, I can see why it might be nice to have
this upstream, but I don't forsee any other Linux distributor ever
enabling it or having to ship it, it's purely a WSL2 pipe. I'm not
saying I'd be happy to see this in the tree, since I don't see the
value of maintaining it upstream, but it probably should just exists
in a drivers/hyperv type area.

Having said that, I hit one stumbling block:
"Further, at this time there are no presentation integration. "

If we upstream this driver as-is into some hyperv specific place, and
you decide to add presentation integration this is more than likely
going to mean you will want to interact with dma-bufs and dma-fences.
If the driver is hidden away in a hyperv place it's likely we won't
even notice that feature landing until it's too late.

I would like to see a coherent plan for presentation support (not
code, just an architectural diagram), because I think when you
contemplate how that works it will change the picture of how this
driver looks and intergrates into the rest of the Linux graphics

As-is I'd rather this didn't land under my purview, since I don't see
the value this adds to the Linux ecosystem at all, and I think it's
important when putting a burden on upstream that you provide some


  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-19 16:32 Sasha Levin
2020-05-19 16:32 ` [RFC PATCH 1/4] gpu: dxgkrnl: core code Sasha Levin
2020-05-19 17:19   ` Greg KH
2020-05-19 17:21   ` Greg KH
2020-05-19 17:45     ` Sasha Levin
2020-05-20  6:13       ` Greg KH
2020-05-19 17:27   ` Greg KH
2020-05-19 16:32 ` [RFC PATCH 2/4] gpu: dxgkrnl: hook up dxgkrnl Sasha Levin
2020-05-19 16:32 ` [RFC PATCH 3/4] Drivers: hv: vmbus: " Sasha Levin
2020-05-19 16:32 ` [RFC PATCH 4/4] gpu: dxgkrnl: create a MAINTAINERS entry Sasha Levin
2020-05-19 19:21 ` [RFC PATCH 0/4] DirectX on Linux Daniel Vetter
2020-05-19 20:36   ` Sasha Levin
2020-05-20 10:37     ` Jan Engelhardt
2020-06-28 23:39     ` James Hilliard
2020-05-19 22:42 ` Dave Airlie [this message]
2020-05-19 23:01   ` Daniel Vetter
2020-05-20  3:47     ` [EXTERNAL] " Steve Pronovost
     [not found]       ` <>
     [not found]         ` <>
2020-05-20 15:34           ` Steve Pronovost
2020-06-16 10:51       ` Pavel Machek
2020-05-19 23:12   ` Dave Airlie
2020-06-16 10:51     ` Pavel Machek
2020-06-16 13:21       ` Sasha Levin
2020-05-20  7:10 ` Thomas Zimmermann
2020-05-20  7:42   ` [EXTERNAL] " Steve Pronovost
2020-05-20 11:06     ` Thomas Zimmermann
2020-06-16 10:51   ` Pavel Machek
2020-06-16 13:28     ` Sasha Levin
2020-06-16 14:41       ` Pavel Machek
2020-06-16 16:00         ` Sasha Levin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='' \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on

Archives are clonable:
	git clone --mirror lkml/git/0.git
	git clone --mirror lkml/git/1.git
	git clone --mirror lkml/git/2.git
	git clone --mirror lkml/git/3.git
	git clone --mirror lkml/git/4.git
	git clone --mirror lkml/git/5.git
	git clone --mirror lkml/git/6.git
	git clone --mirror lkml/git/7.git
	git clone --mirror lkml/git/8.git
	git clone --mirror lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ \
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:

AGPL code for this site: git clone