@ofborg eval

It doesn't seem too important, but how's the i686 case for you? I'm getting stuck on

vm-test-run-installer-luksroot-format1> boot-after-install: starting vm

both before and after this PR (and even if I increase it to 1024 as well).

@vcunat If I make it so qemu’s stderr doesn’t disappear into the ether:

--- a/nixos/lib/test-driver/test-driver.py
+++ b/nixos/lib/test-driver/test-driver.py
@@ -748,7 +748,6 @@ class Machine:
             self.script,
             stdin=subprocess.DEVNULL,
             stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
             shell=True,
             cwd=self.state_dir,
             env=environment,

I see this error from the i686 test:

machine # [  450.464576] reboot: Power down
(4.72 seconds)
(5.25 seconds)
deleting VM state directory /tmp/vm-state-boot-after-install
if you want to keep the VM state, pass --keep-vm-state
boot-after-install: starting vm
qemu-system-i386: -enable-kvm: unsupported machine type
Use -machine help to list supported machines

The -enable-kvm actually comes from two places.

1. In the qemu-kvm wrapper:

   nixpkgs/nixos/lib/test-driver/test-driver.py

   Lines 253 to 255 in 5ff6700

   	start_command = (
   	"qemu-kvm -m 384 " + net_backend + " " + net_frontend + " $QEMU_OPTS "
   	)

   nixpkgs/pkgs/applications/virtualization/qemu/default.nix

   Lines 159 to 166 in 5ff6700

   	# Add a ‘qemu-kvm’ wrapper for compatibility/convenience.
   	postInstall = ''
   	if [ -x $out/bin/qemu-system-${stdenv.hostPlatform.qemuArch} ]; then
   	makeWrapper $out/bin/qemu-system-${stdenv.hostPlatform.qemuArch} \
   	$out/bin/qemu-kvm \
   	--add-flags "\$([ -e /dev/kvm ] && echo -enable-kvm)"
   	fi
   	'';

   (Note that i386 is indeed the “host platform” here since we’re overriding system.)

2. In the test:

   nixpkgs/nixos/tests/installer.nix

   Lines 76 to 82 in 5ff6700

   	def assemble_qemu_flags():
   	flags = "-cpu max"
   	${if system == "x86_64-linux"
   	then ''flags += " -m 768"''
   	else ''flags += " -m 512 -enable-kvm -machine virt,gic-version=host"''
   	}
   	return flags

   introduced by 059845b (it was previously only for aarch64-linux).

But the i686 test is not channel-blocking, so we should deal with it separately.

OK, let's not complicate this here. I wonder if there's even any use case for an i686 installer nowadays. I only know really about using i686 on a 64-bit OS.