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Migrate VM shares from 9p to virtiofs; update QEMU and doctor

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This commit is contained in:
Joshua Bell 2026-01-29 13:58:49 -06:00
parent 221d0ca596
commit 2555a47d62
3 changed files with 34 additions and 68 deletions
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92
flake/default-vm/flake.nix
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@ -130,71 +130,42 @@
# Josh's timezone
time.timeZone = "America/Chicago";
# Git safe.directory for 9p ownership issues
# Git safe.directory for virtiofs ownership issues
environment.etc."gitconfig".text = ''
[safe]
directory = *
'';
# 9p mount points for caches (must match qvm-start mount tags)
# virtiofs mount points for caches (must match qvm virtiofsd mount tags)
# Using virtiofs instead of 9p for better performance and hot-mount support
fileSystems."/cache/cargo" = {
device = "cargo_home";
fsType = "9p";
options = [
"trans=virtio"
"version=9p2000.L"
"msize=104857600"
"_netdev"
"nofail"
];
fsType = "virtiofs";
options = [ "nofail" ];
};
fileSystems."/cache/target" = {
device = "cargo_target";
fsType = "9p";
options = [
"trans=virtio"
"version=9p2000.L"
"msize=104857600"
"_netdev"
"nofail"
];
fsType = "virtiofs";
options = [ "nofail" ];
};
fileSystems."/cache/pnpm" = {
device = "pnpm_store";
fsType = "9p";
options = [
"trans=virtio"
"version=9p2000.L"
"msize=104857600"
"_netdev"
"nofail"
];
fsType = "virtiofs";
options = [ "nofail" ];
};
fileSystems."/cache/sccache" = {
device = "sccache";
fsType = "9p";
options = [
"trans=virtio"
"version=9p2000.L"
"msize=104857600"
"_netdev"
"nofail"
];
fsType = "virtiofs";
options = [ "nofail" ];
};
fileSystems."/root/.config/opencode" = {
device = "opencode_config";
fsType = "9p";
options = [
"trans=virtio"
"version=9p2000.L"
"msize=104857600"
"_netdev"
"nofail"
];
fsType = "virtiofs";
options = [ "nofail" ];
};
# Environment variables for cache directories
@ -215,47 +186,46 @@
"d /cache/sccache 0755 root root -"
];
# Systemd mount units for cache directories
# The NixOS VM runner doesn't include custom fileSystems entries in the generated fstab,
# so we use systemd mount units to automount the 9p virtfs shares at boot.
# Systemd mount units for cache directories using virtiofs
# virtiofs provides better performance than 9p and supports hot-mounting
systemd.mounts = [
{
what = "cargo_home";
where = "/cache/cargo";
type = "9p";
options = "trans=virtio,version=9p2000.L,msize=104857600,nofail";
type = "virtiofs";
options = "nofail";
wantedBy = [ "multi-user.target" ];
after = [ "systemd-modules-load.service" ];
}
{
what = "cargo_target";
where = "/cache/target";
type = "9p";
options = "trans=virtio,version=9p2000.L,msize=104857600,nofail";
type = "virtiofs";
options = "nofail";
wantedBy = [ "multi-user.target" ];
after = [ "systemd-modules-load.service" ];
}
{
what = "pnpm_store";
where = "/cache/pnpm";
type = "9p";
options = "trans=virtio,version=9p2000.L,msize=104857600,nofail";
type = "virtiofs";
options = "nofail";
wantedBy = [ "multi-user.target" ];
after = [ "systemd-modules-load.service" ];
}
{
what = "sccache";
where = "/cache/sccache";
type = "9p";
options = "trans=virtio,version=9p2000.L,msize=104857600,nofail";
type = "virtiofs";
options = "nofail";
wantedBy = [ "multi-user.target" ];
after = [ "systemd-modules-load.service" ];
}
{
what = "opencode_config";
where = "/root/.config/opencode";
type = "9p";
options = "trans=virtio,version=9p2000.L,msize=104857600,nofail";
type = "virtiofs";
options = "nofail";
wantedBy = [ "multi-user.target" ];
after = [ "systemd-modules-load.service" ];
}
@ -298,15 +268,9 @@
# GB disk size
virtualisation.diskSize = 40 * 1024;
# NOTE: Using 9p virtfs for filesystem sharing
# The NixOS VM runner doesn't support virtio-fs out of the box.
# We use 9p (-virtfs) which is the standard method for QEMU VMs.
#
# See: https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/virtualisation/qemu-vm.nix#L530
# The sharedDirectories option hardcodes: -virtfs local,path=...,security_model=...
#
# 9p mounts are configured via QEMU_OPTS environment variable:
# -virtfs local,path=$HOST_PATH,mount_tag=$TAG,security_model=mapped-xattr,msize=104857600
# NOTE: Using virtiofs for filesystem sharing (via virtiofsd + vhost-user-fs-pci)
# This provides better performance than 9p and supports hot-mounting workspaces
# without VM restart. The qvm CLI manages virtiofsd daemons for each mount.
system.stateVersion = stateVersion;
};