[RFC PATCH 08/10] host: add support for Wayland in VMs

Alyssa Ross
2022-09-30T12:50:32Z

When a VM is configured with Wayland support, the ext-rc-init service
will create an additional service to supervise the crosvm GPU backend,
and start-vm will pass the required arguments to cloud-hypervisor to
tell it how to connect to crosvm.

Signed-off-by: Alyssa Ross <alyssa.ross@unikie.com>
---

We're using the Glibc version of crosvm here, rather than getting it
from pkgsGui like we should be. That's blocked on making
pkgsMusl.cargo work in Nixpkgs:

https://github.com/NixOS/nixpkgs/pull/190796

Documentation/creating-vms.adoc | 5 +++++
host/rootfs/Makefile | 4 ++++
host/rootfs/default.nix | 4 ++--
host/rootfs/etc/s6-rc/ext-rc-init/up | 8 ++++++++
host/rootfs/etc/template/gpu/data/check | 5 +++++
host/rootfs/etc/template/gpu/notification-fd | 1 +
host/rootfs/etc/template/gpu/notification-fd.license | 2 ++
host/rootfs/etc/template/gpu/run | 9 +++++++++
host/rootfs/etc/template/gpu/type | 1 +
host/rootfs/etc/template/gpu/type.license | 2 ++
host/start-vm/start-vm.rs | 9 +++++++++
vm-lib/make-vm.nix | 9 ++++++++-
12 files changed, 56 insertions(+), 3 deletions(-)
create mode 100755 host/rootfs/etc/template/gpu/data/check
create mode 100644 host/rootfs/etc/template/gpu/notification-fd
create mode 100644 host/rootfs/etc/template/gpu/notification-fd.license
create mode 100755 host/rootfs/etc/template/gpu/run
create mode 100644 host/rootfs/etc/template/gpu/type
create mode 100644 host/rootfs/etc/template/gpu/type.license

diff --git a/Documentation/creating-vms.adoc b/Documentation/creating-vms.adoc
index 6d4fde0..a4d5acf 100644
--- a/Documentation/creating-vms.adoc
+++ b/Documentation/creating-vms.adoc
@@ -2,6 +2,7 @@
:page-parent: Reference

// SPDX-FileCopyrightText: 2022 Alyssa Ross <hi@alyssa.is>
+// SPDX-FileCopyrightText: 2022 Unikie
// SPDX-License-Identifier: GFDL-1.3-no-invariants-or-later OR CC-BY-SA-4.0

== Configuration
@@ -23,6 +24,10 @@ providers/net:: A directory containing a file named for each VM that
should provide networking to this VM. The contents of these files are
ignored.

+wayland:: An empty file, whose presence indicates that the host should
+set up a virtio-gpu device supporting the cross-domain context type,
+for the VM to send Wayland messages over.
+
=== Example

A configuration directory for a VM called "appvm-lynx" dedicated to
diff --git a/host/rootfs/Makefile b/host/rootfs/Makefile
index 31f76d2..f0f6a4b 100644
--- a/host/rootfs/Makefile
+++ b/host/rootfs/Makefile
@@ -28,6 +28,10 @@ FILES = \
etc/mdev/wait \
etc/parse-devname \
etc/passwd \
+ etc/template/gpu/data/check \
+ etc/template/gpu/notification-fd \
+ etc/template/gpu/run \
+ etc/template/gpu/type \
etc/s6-linux-init/run-image/service/getty-tty1/run \
etc/s6-linux-init/run-image/service/getty-tty2/run \
etc/s6-linux-init/run-image/service/getty-tty3/run \
diff --git a/host/rootfs/default.nix b/host/rootfs/default.nix
index 4788628..ad6ea1f 100644
--- a/host/rootfs/default.nix
+++ b/host/rootfs/default.nix
@@ -44,8 +44,8 @@ let
foot = pkgsGui.foot.override { allowPgo = false; };

packages = [
- cloud-hypervisor execline jq kmod mdevd s6 s6-linux-init s6-rc socat
- start-vm
+ cloud-hypervisor pkgs.crosvm execline jq kmod mdevd s6 s6-linux-init s6-rc
+ socat start-vm

(cryptsetup.override {
programs = {
diff --git a/host/rootfs/etc/s6-rc/ext-rc-init/up b/host/rootfs/etc/s6-rc/ext-rc-init/up
index 1aec7fb..2ab3f03 100644
--- a/host/rootfs/etc/s6-rc/ext-rc-init/up
+++ b/host/rootfs/etc/s6-rc/ext-rc-init/up
@@ -1,5 +1,6 @@
# SPDX-License-Identifier: EUPL-1.2+
# SPDX-FileCopyrightText: 2021-2022 Alyssa Ross <hi@alyssa.is>
+# SPDX-FileCopyrightText: 2022 Unikie

if { mkdir -p /run/s6-rc.ext.src }

@@ -15,6 +16,13 @@ if {
if { redirfd -w 1 ${name}/notification-fd echo 3 }
if { ln -s -- /bin/start-vm ${name}/run }

+ if {
+ if -t { test -e ${dir}/wayland }
+ if { cp -R /etc/template/gpu /run/s6-rc.ext.src/${name}-gpu }
+ if { mkdir /run/s6-rc.ext.src/${name}-gpu/env }
+ touch /run/s6-rc.ext.src/${name}/dependencies.d/${name}-gpu
+ }
+
elglob -0 paths /ext/svc/data/${name}/providers/net/*
forx -pE path { $paths }
backtick -E dep { basename -- $path }
diff --git a/host/rootfs/etc/template/gpu/data/check b/host/rootfs/etc/template/gpu/data/check
new file mode 100755
index 0000000..868346b
--- /dev/null
+++ b/host/rootfs/etc/template/gpu/data/check
@@ -0,0 +1,5 @@
+#!/bin/execlineb -P
+# SPDX-License-Identifier: EUPL-1.2+
+# SPDX-FileCopyrightText: Unikie
+
+test -S env/crosvm.sock
diff --git a/host/rootfs/etc/template/gpu/notification-fd b/host/rootfs/etc/template/gpu/notification-fd
new file mode 100644
index 0000000..00750ed
--- /dev/null
+++ b/host/rootfs/etc/template/gpu/notification-fd
@@ -0,0 +1 @@
+3
diff --git a/host/rootfs/etc/template/gpu/notification-fd.license b/host/rootfs/etc/template/gpu/notification-fd.license
new file mode 100644
index 0000000..2241beb
--- /dev/null
+++ b/host/rootfs/etc/template/gpu/notification-fd.license
@@ -0,0 +1,2 @@
+SPDX-License-Identifier: CC0-1.0
+SPDX-FileCopyrightText: 2022 Unikie
diff --git a/host/rootfs/etc/template/gpu/run b/host/rootfs/etc/template/gpu/run
new file mode 100755
index 0000000..d1913dd
--- /dev/null
+++ b/host/rootfs/etc/template/gpu/run
@@ -0,0 +1,9 @@
+#!/bin/execlineb -P
+# SPDX-License-Identifier: EUPL-1.2+
+# SPDX-FileCopyrightText: Unikie
+
+s6-notifyoncheck -d
+crosvm --no-syslog device gpu
+ --socket env/crosvm.sock
+ --wayland-sock /run/user/0/wayland-1
+ --params "{\"context-types\": \"cross-domain\"}"
diff --git a/host/rootfs/etc/template/gpu/type b/host/rootfs/etc/template/gpu/type
new file mode 100644
index 0000000..5883cff
--- /dev/null
+++ b/host/rootfs/etc/template/gpu/type
@@ -0,0 +1 @@
+longrun
diff --git a/host/rootfs/etc/template/gpu/type.license b/host/rootfs/etc/template/gpu/type.license
new file mode 100644
index 0000000..2241beb
--- /dev/null
+++ b/host/rootfs/etc/template/gpu/type.license
@@ -0,0 +1,2 @@
+SPDX-License-Identifier: CC0-1.0
+SPDX-FileCopyrightText: 2022 Unikie
diff --git a/host/start-vm/start-vm.rs b/host/start-vm/start-vm.rs
index 41a4fbc..b954ebd 100644
--- a/host/start-vm/start-vm.rs
+++ b/host/start-vm/start-vm.rs
@@ -104,6 +104,15 @@ fn vm_command(dir: PathBuf) -> Result<Command, String> {
Err(e) => return Err(format!("reading directory {:?}: {}", blk_dir, e)),
}

+ if definition_path.join("wayland").exists() {
+ command.arg("--gpu").arg({
+ let mut gpu = OsString::from("socket=../");
+ gpu.push(vm_name);
+ gpu.push("-gpu/env/crosvm.sock");
+ gpu
+ });
+ }
+
if command.get_args().last() == Some(OsStr::new("--disk")) {
return Err("no block devices specified".to_string());
}
diff --git a/vm-lib/make-vm.nix b/vm-lib/make-vm.nix
index 20cdba4..f595481 100644
--- a/vm-lib/make-vm.nix
+++ b/vm-lib/make-vm.nix
@@ -1,12 +1,13 @@
# SPDX-License-Identifier: MIT
# SPDX-FileCopyrightText: 2022 Alyssa Ross <hi@alyssa.is>
+# SPDX-FileCopyrightText: 2022 Unikie

{ config ? import ../nix/eval-config.nix {} }:
config.pkgs.pkgsStatic.callPackage (

{ lib, runCommand, writeReferencesToFile, e2fsprogs, tar2ext4 }:

-{ name, run, providers ? {} }:
+{ name, run, providers ? {}, wayland ? false }:

let
inherit (lib)
@@ -20,6 +21,8 @@ assert !(any (hasInfix "\n") (concatLists (attrValues providers)));
runCommand "spectrum-vm-${name}" {
nativeBuildInputs = [ e2fsprogs tar2ext4 ];

+ inherit wayland;
+
providerDirs = concatStrings (concatLists
(mapAttrsToList (kind: map (vm: "${kind}/${vm}\n")) providers));
passAsFile = [ "providerDirs" ];
@@ -41,6 +44,10 @@ runCommand "spectrum-vm-${name}" {
xargs -rd '\n' touch -- < "$providerDirsPath"
popd

+ if [ -n "$wayland" ]; then
+ touch "$out/data/${name}/wayland"
+ fi
+
ln -s /usr/img/appvm/blk/root.img "$out/data/${name}/blk"
ln -s /usr/img/appvm/vmlinux "$out/data/${name}"
''
--
2.37.1