[PATCH 00/22] Implement managing VMs with Nix

Alyssa Ross
2022-10-10T23:32:19Z

IMPORTANT NOTE: this series should be applied on top of v2 of my
previous series "Introduce a shared base for application VMs" [1].
I'm much happier with v2 of that series, but I only posted it
yesterday so I still want to leave a little more opportunity for
comment before applying it.

[1]: https://spectrum-os.org/lists/archives/spectrum-devel/20221009114036.463071-1-hi@alyssa.is/

This series contains the final big chunk of work I had left to do on
Spectrum's original NLnet grant. It adds support for managing
Spectrum VMs from the Spectrum system itself using Nix. Nix is
optional, and can co-exist with VMs provided in some other way. More
information is included in the new documentation. Most of this work
was done earlier this year, but I got stuck on some implementation
details that prevented me from getting over the last hurdle until I
came up with a solution. That's explained in more detail in patch 15.

Patches 1–10 add support for configuring VMs with read/write access to
host directories using virtiofs. Then, in patches 11–14, come various
changes that make the default user data partition more suitable as a
mutable filesystem, which we haven't actually used it for before. And
then the remaining patches actually implement support for a VM that
can run Nix and easily build VMs that are available on the host.

Alyssa Ross (22):
host/start-vm: use MAP_SHARED memory for VMs
host/start-vm: implement shared directories
host/rootfs: generate virtiofsd services
Documentation: explain VM shared directories
vm-lib/make-vm.nix: support shared directories
img/app: add support for testing virtiofs
img/app: don't block app startup on network online
img/app: auto-mount virtiofs0 filesystem
vm/app/mg.nix: init
vm/app/mg.nix: open virtio filesystem in dired
host/rootfs: move ext mounting to s6-rc service
host/rootfs: automatically grow user partition
host/rootfs: use a bigger test ext partition
host/initramfs/extfs.nix: tar2ext4 -> mkfs.ext4 -d
host/start-vm: resolve VM symlinks with /ext root
host/rootfs: resolve VM symlinks with /ext root
Documentation: explain /ext symlink resolution
host/start-vm: increase memory size to 512M
vm/app/nix: add
vm-lib/make-vms.nix: add
host/initramfs/extfs.nix: add example Nix-built VM
Documentation: add how-to guide for Nix-built VMs

.gitignore | 5 +-
Documentation/_sass/custom/custom.scss | 22 ++++++
Documentation/creating-vms.adoc | 12 ++-
Documentation/nix-vms.adoc | 22 ++++++
host/initramfs/extfs.nix | 29 +++++--
host/rootfs/Makefile | 13 +++-
host/rootfs/default.nix | 16 +++-
host/rootfs/etc/mdev/block/add | 1 -
host/rootfs/etc/s6-rc/ext-rc-init/up | 19 ++++-
host/rootfs/etc/s6-rc/ext/up | 5 +-
host/rootfs/etc/template/fs/notification-fd | 1 +
.../etc/template/fs/notification-fd.license | 2 +
host/rootfs/etc/template/fs/run | 11 +++
host/rootfs/etc/template/fs/type | 1 +
host/rootfs/etc/template/fs/type.license | 2 +
host/start-vm/fs.c | 17 +++++
host/start-vm/fs.rs | 68 +++++++++++++++++
host/start-vm/lib.rs | 54 ++++++++++---
host/start-vm/meson.build | 2 +-
host/start-vm/start-vm.rs | 15 ++--
host/start-vm/tests/meson.build | 4 +
host/start-vm/tests/vm_command-basic.rs | 6 +-
.../tests/vm_command-config-symlink.rs | 30 ++++++++
host/start-vm/tests/vm_command-shared-dir.rs | 43 +++++++++++
img/app/Makefile | 24 +++++-
img/app/etc/mdev.conf | 3 +-
img/app/etc/mdev/iface | 4 +-
img/app/etc/mdev/listen | 12 +++
img/app/etc/mdev/virtiofs | 10 +++
img/app/etc/mdev/wait | 15 ++++
img/app/etc/s6-rc/ok-all/contents | 1 +
img/app/shell.nix | 6 +-
tools/resolve_in_root/default.nix | 23 ++++++
tools/resolve_in_root/meson.build | 10 +++
tools/resolve_in_root/resolve_in_root.c | 76 +++++++++++++++++++
tools/resolve_in_root/test.sh | 11 +++
vm-lib/make-vm.nix | 20 ++++-
vm-lib/make-vms.nix | 19 +++++
vm/app/catgirl.nix | 1 +
vm/app/lynx.nix | 1 +
vm/app/{lynx.nix => mg.nix} | 10 ++-
vm/app/nix/bin/vm-rebuild | 25 ++++++
vm/app/nix/default.nix | 43 +++++++++++
vm/app/nix/example.nix | 13 ++++
44 files changed, 673 insertions(+), 54 deletions(-)
create mode 100644 Documentation/_sass/custom/custom.scss
create mode 100644 Documentation/nix-vms.adoc
create mode 100644 host/rootfs/etc/template/fs/notification-fd
create mode 100644 host/rootfs/etc/template/fs/notification-fd.license
create mode 100755 host/rootfs/etc/template/fs/run
create mode 100644 host/rootfs/etc/template/fs/type
create mode 100644 host/rootfs/etc/template/fs/type.license
create mode 100644 host/start-vm/fs.c
create mode 100644 host/start-vm/fs.rs
create mode 100644 host/start-vm/tests/vm_command-config-symlink.rs
create mode 100644 host/start-vm/tests/vm_command-shared-dir.rs
create mode 100755 img/app/etc/mdev/listen
create mode 100755 img/app/etc/mdev/virtiofs
create mode 100755 img/app/etc/mdev/wait
create mode 100644 tools/resolve_in_root/default.nix
create mode 100644 tools/resolve_in_root/meson.build
create mode 100644 tools/resolve_in_root/resolve_in_root.c
create mode 100755 tools/resolve_in_root/test.sh
create mode 100644 vm-lib/make-vms.nix
copy vm/app/{lynx.nix => mg.nix} (52%)
create mode 100755 vm/app/nix/bin/vm-rebuild
create mode 100644 vm/app/nix/default.nix
create mode 100644 vm/app/nix/example.nix

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2.37.1