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