[PATCH] CI: Stop building QEMU in general

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

We spend an awful lot of CI time building QEMU, even though most changes don't
touch the subset of tools/libs/ used by QEMU.  Some numbers taken at a time
when CI was otherwise quiet:

                       With     Without
  Alpine:              13m38s   6m04s
  Debian 12:           10m05s   8m10s
  OpenSUSE Tumbleweed: 11m40s   7m54s
  Ubuntu 24.04:        14m56s   8m06s

which is a >50% improvement in wallclock time in some cases.

The only build we have that needs QEMU is alpine-3.18-gcc-debug.  This is the
build deployed and used by the QubesOS ADL-* and Zen3p-* jobs.

Xilinx-x86_64 deploys it too, but is PVH-only and doesn't use QEMU.

QEMU is also built by CirrusCI for FreeBSD (fully Clang/LLVM toolchain).

This should help quite a lot with Gitlab CI capacity.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Michal Orzel <michal.orzel@xxxxxxx>
CC: Doug Goldstein <cardoe@xxxxxxxxxx>
CC: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>

I did consider putting in a build of QEMU on arm64 for good measure, but I
can't find any build job which currently does; none of the arm64 containers
have ninja by the looks of things.

Run with this patch in place:
  https://gitlab.com/xen-project/people/sstabellini/xen/-/pipelines/1486822209
---
 automation/gitlab-ci/build.yaml       |  1 +
 automation/scripts/build              |  7 ++-----
 automation/scripts/qemu-deps-check.py | 19 -------------------
 3 files changed, 3 insertions(+), 24 deletions(-)
 delete mode 100755 automation/scripts/qemu-deps-check.py

diff --git a/automation/gitlab-ci/build.yaml b/automation/gitlab-ci/build.yaml
index c668736bdc2f..c83e0bdbe119 100644
--- a/automation/gitlab-ci/build.yaml
+++ b/automation/gitlab-ci/build.yaml
@@ -339,6 +339,7 @@ alpine-3.18-gcc-debug:
   extends: .gcc-x86-64-build-debug
   variables:
     CONTAINER: alpine:3.18
+    QEMU: y
 
 debian-bookworm-gcc-debug:
   extends: .gcc-x86-64-build-debug
diff --git a/automation/scripts/build b/automation/scripts/build
index 34416297a4b7..926cf5b46d17 100755
--- a/automation/scripts/build
+++ b/automation/scripts/build
@@ -91,11 +91,8 @@ else
         cfgargs+=("--with-extra-qemuu-configure-args=\"--disable-werror\"")
     fi
 
-    # Qemu requires Python 3.8 or later, and ninja
-    # and Clang 10 or later
-    if ! type python3 || ! python3 automation/scripts/qemu-deps-check.py \
-            || [[ "$cc_is_clang" == y && "$cc_ver" -lt 0x0a0000 ]] \
-            || ! type ninja; then
+    # QEMU is only for those who ask
+    if [[ "$QEMU" != "y" ]]; then
         cfgargs+=("--with-system-qemu=/bin/false")
     fi
 
diff --git a/automation/scripts/qemu-deps-check.py 
b/automation/scripts/qemu-deps-check.py
deleted file mode 100755
index f6188afb3e2a..000000000000
--- a/automation/scripts/qemu-deps-check.py
+++ /dev/null
@@ -1,19 +0,0 @@
-#!/usr/bin/env python3
-# -*- coding: utf-8 -*-
-import sys
-
-if sys.version_info < (3, 8):
-    print("Python %d.%d.%d too old" %
-          (sys.version_info.major,
-           sys.version_info.minor,
-           sys.version_info.micro))
-    exit(1)
-
-try:
-    import tomllib
-except ImportError:
-    try:
-        import tomli
-    except ImportError:
-        print("No tomli")
-        exit(1)
-- 
2.39.5