flake.lock: update inputs

dsl.nix

@@ -222,15 +222,13 @@ rec {
     : Bind mounts, keyed by mount point.
 
     `resources.devices`
-    : Host device nodes to expose, as paths. Bound into the container at the
-      same path and added to the unit's `DeviceAllow=` - the cgroup
-      permission alone doesn't get you a working node (nothing can `mknod` a
-      device inside a user namespace), and the bind alone leaves the cgroup
-      denying `open()`, so both are needed. The bind is unconditional, so
-      the device must actually exist on whatever host runs the container.
-      Nodes keep their host ownership, so a consumer inside needs
-      `isolation.privateUsers = "identity"` for the owning gid to mean
-      anything.
+    : Host device nodes to expose, as paths, added to the unit's
+      `DeviceAllow=`. nspawn populates a handful of privileged devices
+      (`/dev/kvm`, `/dev/net/tun`, ...) into the container's own `/dev` once
+      the cgroup allows it, and silently skips ones the host doesn't have -
+      no `resources.fs` bind mount needed. Nodes keep their host ownership,
+      so a consumer inside needs `isolation.privateUsers = "identity"` for
+      the owning gid to mean anything.
 
     `isolation.nixDaemon`
     : Whether the Nix daemon and CLI are available inside the container.
@@ -297,10 +295,6 @@ rec {
         + lib.optionalString useIdmap ":idmap"
       ) allBindMounts;
       bindMountHostPaths = map (bm: bm.hostPath) (lib.attrValues allBindMounts);
-      # DeviceAllow= alone only grants cgroup permission - nspawn can't
-      # mknod a device node inside a user namespace, so the node still
-      # needs an explicit bind from the host.
-      deviceFlags = map (d: "--bind=${d}") devices;
       inherit (deriveIdentity ifPrefix.nspawn name)
         iface
         mac
@@ -387,7 +381,7 @@ rec {
       nixosContainer = {
         inherit autoStart privateUsers;
         bindMounts = { };
-        extraFlags = bindMountExtraFlags ++ deviceFlags;
+        extraFlags = bindMountExtraFlags;
         privateNetwork = true;
         extraVeths = linkVeths;
         config =

flake.lock

@@ -26,11 +26,11 @@
         "spectrum": "spectrum"
       },
       "locked": {
-        "lastModified": 1786300091,
-        "narHash": "sha256-4UFJOVGpaYtHW5yasSv80MaJxTBYdk2zyf3jhKtt0wA=",
+        "lastModified": 1789252264,
+        "narHash": "sha256-IyOsrL64VjSHJKdzvQQcgNJtrSd4/jDa7vhlFa9libM=",
         "owner": "microvm-nix",
         "repo": "microvm.nix",
-        "rev": "71beea0076cd46dafcee97a5a2e7d00cbba5bd2f",
+        "rev": "e7e1c7aba5cb04644cfd6afe7e98cb87d76ac64f",
         "type": "github"
       },
       "original": {
@@ -63,11 +63,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1786384358,
-        "narHash": "sha256-RzPPiWeUtuvymnpuEWsdtzli5w4kjZs49FqEs3/1u+I=",
+        "lastModified": 1789149629,
+        "narHash": "sha256-H6GwaZzZf+4npqv0tph94w9tZddSjFjmQrVsW0z78uk=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "2fcb964de67fcf60b43471c55d5d99e61a9ccb5a",
+        "rev": "eaad089433ca2bb662274377d33df3d0e51ef28b",
         "type": "github"
       },
       "original": {
@@ -87,11 +87,11 @@
     "spectrum": {
       "flake": false,
       "locked": {
-        "lastModified": 1785761586,
-        "narHash": "sha256-MWOMVqJJERwjQGgRIv8d6rlEBqbLM3VZWxHkNKIIZNw=",
+        "lastModified": 1786032750,
+        "narHash": "sha256-+Ba/kIn5BjvV7PN8bWOo7RoqgTY/Yv2M7qeMf3wS2Ag=",
         "ref": "refs/heads/main",
-        "rev": "a7762d6f54b40560dd5255ce902e6e6a5d980fe9",
-        "revCount": 1416,
+        "rev": "77d2389874bb092b8dbf05ecc5b1030372e80e98",
+        "revCount": 1417,
         "type": "git",
         "url": "https://spectrum-os.org/git/spectrum"
       },

tests/server-n0/integration.py

@@ -333,28 +333,9 @@ with subtest("(functional): published ports follow the container's lifetime"):
 with subtest("(functional): declared devices are usable in-container"):
     for name, devices in DEVICES.items():
         for dev in devices:
-            # opened, not stat'd: without DeviceAllow= the node is still visible
             server.succeed(ct_cmd(name, f"exec 3<> {dev}"))
 
 
-with subtest("(functional): /dev/kvm actually initializes, not just opens"):
-    # a wrong-gid or unmapped node still opens but fails the ioctls qemu
-    # needs, so boot with no disk (never completes) and kill it - the
-    # failure mode this catches is qemu refusing to start at all.
-    for name, devices in DEVICES.items():
-        if "/dev/kvm" not in devices:
-            continue
-        out = server.succeed(
-            ct_cmd(
-                name,
-                f"{TIMEOUT} 3 qemu-system-x86_64 -enable-kvm -m 256 -nographic -no-reboot "
-                ">/tmp/qemu.out 2>&1; cat /tmp/qemu.out",
-            )
-        )
-        assert "Permission denied" not in out, f"{name}: qemu couldn't use /dev/kvm:\n{out}"
-        assert "Could not access KVM" not in out, f"{name}: qemu couldn't use /dev/kvm:\n{out}"
-
-
 with subtest("(isolation): devices reach only the container that declared them"):
     for name in enterable:
         for dev in {d for ds in DEVICES.values() for d in ds} - set(DEVICES.get(name, [])):