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Diffstat (limited to 'nixos/modules/testing/test-instrumentation.nix')
-rw-r--r-- | nixos/modules/testing/test-instrumentation.nix | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/nixos/modules/testing/test-instrumentation.nix b/nixos/modules/testing/test-instrumentation.nix new file mode 100644 index 000000000000..28494e1c7b2a --- /dev/null +++ b/nixos/modules/testing/test-instrumentation.nix @@ -0,0 +1,91 @@ +# This module allows the test driver to connect to the virtual machine +# via a root shell attached to port 514. + +{ config, pkgs, ... }: + +with pkgs.lib; + +let kernel = config.boot.kernelPackages.kernel; in + +{ + + config = { + + systemd.services.backdoor = + { wantedBy = [ "multi-user.target" ]; + requires = [ "dev-hvc0.device" "dev-ttyS0.device" ]; + after = [ "dev-hvc0.device" "dev-ttyS0.device" ]; + script = + '' + export USER=root + export HOME=/root + export DISPLAY=:0.0 + source /etc/profile + cd /tmp + exec < /dev/hvc0 > /dev/hvc0 + while ! exec 2> /dev/ttyS0; do sleep 0.1; done + echo "connecting to host..." >&2 + stty -F /dev/hvc0 raw -echo # prevent nl -> cr/nl conversion + echo + PS1= exec /bin/sh + ''; + serviceConfig.KillSignal = "SIGHUP"; + }; + + # Prevent agetty from being instantiated on ttyS0, since it + # interferes with the backdoor (writes to ttyS0 will randomly fail + # with EIO). Likewise for hvc0. + systemd.services."serial-getty@ttyS0".enable = false; + systemd.services."serial-getty@hvc0".enable = false; + + boot.initrd.postDeviceCommands = + '' + # Using acpi_pm as a clock source causes the guest clock to + # slow down under high host load. This is usually a bad + # thing, but for VM tests it should provide a bit more + # determinism (e.g. if the VM runs at lower speed, then + # timeouts in the VM should also be delayed). + echo acpi_pm > /sys/devices/system/clocksource/clocksource0/current_clocksource + ''; + + boot.postBootCommands = + '' + # Panic on out-of-memory conditions rather than letting the + # OOM killer randomly get rid of processes, since this leads + # to failures that are hard to diagnose. + echo 2 > /proc/sys/vm/panic_on_oom + + # Coverage data is written into /tmp/coverage-data. + mkdir -p /tmp/xchg/coverage-data + ''; + + # If the kernel has been built with coverage instrumentation, make + # it available under /proc/gcov. + boot.kernelModules = [ "gcov-proc" ]; + + # Panic if an error occurs in stage 1 (rather than waiting for + # user intervention). + boot.kernelParams = + [ "console=tty1" "console=ttyS0" "panic=1" "boot.panic_on_fail" ]; + + # `xwininfo' is used by the test driver to query open windows. + environment.systemPackages = [ pkgs.xorg.xwininfo ]; + + # Log everything to the serial console. + services.journald.console = "/dev/console"; + + # Prevent tests from accessing the Internet. + networking.defaultGateway = mkOverride 150 ""; + networking.nameservers = mkOverride 150 [ ]; + + systemd.globalEnvironment.GCOV_PREFIX = "/tmp/xchg/coverage-data"; + + system.requiredKernelConfig = with config.lib.kernelConfig; [ + (isYes "SERIAL_8250_CONSOLE") + (isYes "SERIAL_8250") + (isEnabled "VIRTIO_CONSOLE") + ]; + + }; + +} |