[PATCH] GPU acceleration

[Demi Marie Obenour <demiobenour@gmail.com>]

This exposes GPU acceleration to VMs via virtio-GPU native contexts on
AMD and Qualcomm GPUs.  Apple GPU support also exists but might require
patches to virglrenderer that are not upstream yet.

On a system with an AMD GPU, this has been tested by running vkcube in
the VM.  It reports that the AMD GPU is being used for rendering.

Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
---
I used an empty string for the hashes in 'gitfetch' and
'buildRustPackage'.  This is, of course, incorrect.  The correct value
according to my own testing is
"sha256-EOMkQ0aPRjsowdGuZjy5K1yKyKEzd5AVYxaECTz7n6k=" (git hash) and
"sha256-k3dmxIuCQoOrn/VwauTdzuRw/XKQB6LPLgO5ql0rE7E=" (cargoHash).
However, these should be validated before applying them, which is why I
didn't include them in the patch themselves.  This is a security
precaution: anyone who wants to inject malicious content must serve it
to multiple people, not just one.
---
 .../template/data/service/vhost-user-gpu/run            |  2 +-
 img/app/Makefile                                        |  2 +-
 img/app/default.nix                                     | 14 ++++++++++++--
 img/app/image/etc/mdev.conf                             |  1 +
 .../notification-fd                                     |  0
 .../notification-fd.license                             |  0
 .../{wayland-proxy-virtwl => wl-cross-domain-proxy}/run | 17 +++++------------
 .../type                                                |  0
 .../type.license                                        |  0
 9 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-gpu/run b/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-gpu/run
index fb9ac9971aef82dabe0b54c1299ac8c66d133eb5..87d72f55e293ea81b6f4aa12786a993bafc623e2 100755
--- a/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-gpu/run
+++ b/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-gpu/run
@@ -42,4 +42,4 @@ bwrap
 crosvm --no-syslog device gpu
   --fd 0
   --wayland-sock $WAYLAND_DISPLAY
-  --params "{\"context-types\":\"cross-domain\"}"
+  --params "{\"context-types\":\"cross-domain:drm\"}"
diff --git a/img/app/Makefile b/img/app/Makefile
index 2e720a91b4cc98a780aae90435f018ba2dd2d965..d34bcf2604d43eaa55d9100711374eba689bfdce 100644
--- a/img/app/Makefile
+++ b/img/app/Makefile
@@ -77,7 +77,7 @@ start-vhost-user-gpu:
 	$(CROSVM_DEVICE_GPU) \
 	    --socket build/vhost-user-gpu.sock \
 	    --wayland-sock "$$XDG_RUNTIME_DIR/$$WAYLAND_DISPLAY" \
-	    --params '{"context-types":"cross-domain"}' &
+	    --params '{"context-types":"cross-domain:drm"}' &
 	while ! [ -S build/vhost-user-gpu.sock ] && sleep .1; do :; done
 .PHONY: start-vhost-user-gpu
 
diff --git a/img/app/default.nix b/img/app/default.nix
index 71e6fa02e78553d027d59f5b2ff728830276d480..1ce32258edf3f0ae535e050745e60d1d193a838e 100644
--- a/img/app/default.nix
+++ b/img/app/default.nix
@@ -5,10 +5,20 @@ import ../../lib/call-package.nix (
 { spectrum-app-tools, spectrum-build-tools, src, terminfo
 , lib, appimageTools, buildFHSEnv, runCommand, stdenvNoCC, writeClosure
 , erofs-utils, jq, s6-rc, util-linux, xorg
-, cacert, linux_latest
+, cacert, linux_latest, rustPlatform, fetchgit
 }:
 
 let
+  wl-cross-domain-proxy = rustPlatform.buildRustPackage rec {
+    pname = "wl-cross-domain-proxy";
+    version = "0.0.0";
+    src = fetchgit {
+      url = "https://codeberg.org/drakulix/wl-cross-domain-proxy";
+      rev = "167b5ade788d297cd19929c2f367484a09a87316";
+      hash = "";
+    };
+    cargoHash = "";
+  };
   kernelTarget =
     if stdenvNoCC.hostPlatform.isx86 then
       # vmlinux.bin is the stripped version of vmlinux.
@@ -75,7 +85,6 @@ let
       pkgs.s6-rc
       pkgs.socat
       pkgs.systemd
-      pkgs.wayland-proxy-virtwl
       pkgs.wireplumber
       pkgs.xdg-desktop-portal
       pkgs.xdg-desktop-portal-gtk
@@ -84,6 +93,7 @@ let
       kernel.modules
       spectrum-app-tools
       terminfo
+      wl-cross-domain-proxy
     ];
   })).fhsenv;
 
diff --git a/img/app/image/etc/mdev.conf b/img/app/image/etc/mdev.conf
index 33a07d6b1001bd883a3d54e706bc2eb30ca32d0b..bdfdf4b1688dff612c8a5a219c6530c7434668e7 100644
--- a/img/app/image/etc/mdev.conf
+++ b/img/app/image/etc/mdev.conf
@@ -5,6 +5,7 @@
 $INTERFACE=.* 0:0 0 ! +/etc/mdev/iface
 $MODALIAS=virtio:d0000001Av.* 0:0 0 ! +/etc/mdev/virtiofs
 dri/card0 user:user 660 +background { /etc/mdev/listen card0 }
+dri/renderD128 user:user 660 +background { /etc/mdev/listen renderD128 }
 
 -SUBSYSTEM=sound;.* pipewire:pipewire 660
 snd/controlC0 pipewire:pipewire 660 +background { /etc/mdev/listen controlC0 }
diff --git a/img/app/image/etc/s6-rc/wayland-proxy-virtwl/notification-fd b/img/app/image/etc/s6-rc/wl-cross-domain-proxy/notification-fd
similarity index 100%
rename from img/app/image/etc/s6-rc/wayland-proxy-virtwl/notification-fd
rename to img/app/image/etc/s6-rc/wl-cross-domain-proxy/notification-fd
diff --git a/img/app/image/etc/s6-rc/wayland-proxy-virtwl/notification-fd.license b/img/app/image/etc/s6-rc/wl-cross-domain-proxy/notification-fd.license
similarity index 100%
rename from img/app/image/etc/s6-rc/wayland-proxy-virtwl/notification-fd.license
rename to img/app/image/etc/s6-rc/wl-cross-domain-proxy/notification-fd.license
diff --git a/img/app/image/etc/s6-rc/wayland-proxy-virtwl/run b/img/app/image/etc/s6-rc/wl-cross-domain-proxy/run
similarity index 50%
rename from img/app/image/etc/s6-rc/wayland-proxy-virtwl/run
rename to img/app/image/etc/s6-rc/wl-cross-domain-proxy/run
index 5d06b7aea93d790a0aff4c3aed0e821caddadfee..5ae3b96aa639053ff2f70e6b7ddc420fae3c53f1 100755
--- a/img/app/image/etc/s6-rc/wayland-proxy-virtwl/run
+++ b/img/app/image/etc/s6-rc/wl-cross-domain-proxy/run
@@ -1,19 +1,11 @@
 #!/bin/execlineb -P
 # SPDX-License-Identifier: EUPL-1.2+
 # SPDX-FileCopyrightText: 2023-2024 Alyssa Ross <hi@alyssa.is>
-#
-# Directory creation (if it's copyrightable):
-# SPDX-License-Identifier: MIT
-# SPDX-FileCopyrightText: 2022 Unikie
-
-foreground { mkdir /tmp/.X11-unix }
+# SPDX-FileCopyrightText: 2026 Demi Marie Obenour <demiobenour@gmail.com>
 
 s6-ipcserver-socketbinder -B /run/wayland
 fdmove -c 3 0
 
-s6-ipcserver-socketbinder -B /tmp/.X11-unix/X0
-fdmove -c 4 0
-
 redirfd -r 0 /dev/null
 
 # Notify readiness.
@@ -21,11 +13,12 @@ if { fdmove 1 5 echo }
 fdclose 5
 
 if { /etc/mdev/wait card0 }
+if { /etc/mdev/wait renderD128 }
 
-export LISTEN_FDS 2
-export LISTEN_FDNAMES wayland:x11
+export LISTEN_FDS 1
+export LISTEN_FDNAMES wayland
 getpid LISTEN_PID
 
 s6-setuidgid user
 
-wayland-proxy-virtwl --virtio-gpu --x-display=0
+wl-cross-domain-proxy --listen-fd
diff --git a/img/app/image/etc/s6-rc/wayland-proxy-virtwl/type b/img/app/image/etc/s6-rc/wl-cross-domain-proxy/type
similarity index 100%
rename from img/app/image/etc/s6-rc/wayland-proxy-virtwl/type
rename to img/app/image/etc/s6-rc/wl-cross-domain-proxy/type
diff --git a/img/app/image/etc/s6-rc/wayland-proxy-virtwl/type.license b/img/app/image/etc/s6-rc/wl-cross-domain-proxy/type.license
similarity index 100%
rename from img/app/image/etc/s6-rc/wayland-proxy-virtwl/type.license
rename to img/app/image/etc/s6-rc/wl-cross-domain-proxy/type.license

---
base-commit: 8a6e4f03951d80382e5dcf1a159d37dec8376a0b
change-id: 20260120-gpu-accel-2-7eec0ac9b071

-- 
Sincerely,
Demi Marie Obenour (she/her/hers)