Move QEMU to vcpkg by xmkg · Pull Request #4799 · canonical/multipass

xmkg · 2026-04-07T23:12:53Z

Description

What does this PR do?

Move QEMU dependency to vcpkg:

Move multipass-specific patches to the multipass-patches/ folder
Ensure static linkage of QEMU and QEMU tools by listing them as vcpkg dependencies
Prune unneeded QEMU features to reduce both build time and the amount of runtime dependencies:
- "--disable-xkbcommon"
- "--disable-gtk"
- "--disable-opengl"
- "--disable-libudev"
- "--disable-af-xdp"
- "--disable-rust"
- "--disable-slirp"
Remove system package reliance at all levels
Force Multipass to use vendored QEMU instead of the system one
Reduce build disparity between snap and non-snap builds
Remove redundant firmware files
- keymaps (VNC/GTK keyboard layouts)
- bios-256k.bin -> We're using UEFI boot
Better snap & macOS build times since QEMU is now vcpkg-cached
Enable MSYS/MinGW build in Windows to build qemu-img
One QEMU recipe for all platforms!

Why is this change needed?

Streamlining dependencies, consistency across platforms, and simplifying QEMU provisioning.

MULTI-2339

codecov · 2026-04-09T16:12:15Z

Codecov Report

❌ Patch coverage is 92.85714% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 87.47%. Comparing base (03a6685) to head (a8464d4).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
.../platform/backends/qemu/qemu_base_process_spec.cpp	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4799      +/-   ##
==========================================
+ Coverage   87.45%   87.47%   +0.02%     
==========================================
  Files         258      258              
  Lines       14094    14100       +6     
==========================================
+ Hits        12324    12332       +8     
+ Misses       1770     1768       -2

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xmkg · 2026-04-10T20:56:58Z

      run: |
        python3 -m pip install --user --upgrade distlib

-    - name: Install specific QEMU from Choco


No longer needed since we're bundling our own qemu-img

xmkg · 2026-04-10T20:58:19Z

@@ -0,0 +1,14 @@
+#!/bin/sh
+args=""
+for arg in "$@"; do


QEMU's configure is not like a traditional configure and it fails when some of the conventional configure flags are passed by vcpkg_configure_make(). This wrapper is here to strip those (we don't need them anyway).

xmkg · 2026-04-10T20:59:07Z

+
+vcpkg_from_github(
+    OUT_SOURCE_PATH SOURCE_PATH
+    REPO qemu/QEMU


Pulling upstream and applying our patches. Ditched the test option patch since we're now able to null out the test's meson file directly, achieving the same outcome.

xmkg · 2026-04-10T20:59:39Z

+
+file(WRITE "${SOURCE_PATH}/tests/meson.build" "")
+
+if("system" IN_LIST FEATURES)


system builds the emulator too. Non-system build is tool-only.

xmkg · 2026-04-10T21:00:22Z

+endif()
+
+set(QEMU_COMMON_OPTIONS
+    "--disable-bochs"


Derived from the old QEMU CMake + snapcraft.yaml. Has a couple of extra ones at the end, listed in PR description.

xmkg · 2026-04-10T21:16:36Z


  # binary and its libs
-  %4/usr/bin/%5 ixr,
+  %5 ixr,


Now, the program() is the full path to the executable. We no longer need to prefix it with anything.

xmkg · 2026-04-10T21:16:53Z

 QString mp::QemuImgProcessSpec::program() const
 {
-    return "qemu-img";
+    return QDir(QCoreApplication::applicationDirPath()).filePath("qemu-img");


Same as qemu-system.

xmkg · 2026-04-10T21:17:19Z

 )

-add_executable(qemu-img
+add_executable(mock-qemu-img


Name collision with qemu-img target declared before. This one is the mock, so the real one gets the "real" name.

xmkg · 2026-04-10T21:17:57Z

 ```
 sudo apt update
 sudo apt install libgl1 libpng16-16 libxml2 dnsmasq-base \
-    dnsmasq-utils qemu-utils libslang2 iproute2 iptables \


We no longer need to install anything-QEMU now.

xmkg · 2026-04-10T21:18:15Z


 option(MULTIPASS_VCPKG_BUILD_DEFAULT "Enable or disable building the dependencies in the default configuration, which includes both debug and release variants." OFF)
 option(MULTIPASS_ENABLE_TESTS "Build tests" ON)
+cmake_dependent_option(FORCE_ENABLE_VIRTUALBOX "Enable VirtualBox" ON UNIX OFF)


Moved this closer to the other options.

xmkg · 2026-04-13T15:23:11Z

Unassigned @ricab to better distribute review load.