vz: add support for nested virtualization

[abiosoft]

This PR adds support for nested virtualization for the VZ driver via the nestedVirtualization yaml config.

It is dependent on upstream PR Code-Hex/vz#159 getting merged. VZ has been forked lima-vm/vz#1.

Nested virtualization is currently limited to m3 devices running macOS 15 or newer.

[abiosoft]

Testing Instructions

⚠️ This only works on macOS 15 (currently beta) with VZ driver and on M3 devices.

For those willing to try this out, these are the steps.

1. Clone the source

Clone my fork of Lima and checkout vz-nested-virtualization branch.

git clone -b vz-nested-virtualization github.com/abiosoft/lima

2. Build Lima

From the root directory of Lima, perform a build.

PS: You might need to unlink Brew version if previously installed with Brew. brew unlink lima

make && sudo make install

3. Start Lima with nested virtualization enabled

Use VZ driver and enabled nested virtualization.

The lima.yaml config file should contain the following.

vmType: vz
nestedVirtualization: true

4. Validate nested virtualization in Lima VM

Enter the Lima VM with lima (or similar command) and validate the existence of /dev/kvm.

$ ls -lh /dev/kvm
crw-rw---- 1 user kvm 10, 232 Aug 29 09:06 /dev/kvm

If the VM is running Ubuntu, you can install cpu-checker package and run kvm-ok to further ascertain.

$ kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used

[nirs]

It will be little nicer to add a helper like isNestedVirtualiztionAvailable() with these checks. This can also be implemented for linux, so it can be a common interface for all platforms.

[asauber]

I was able to create a Lima VM with KVM support with your testing instructions.

$ limactl shell ubuntunested
WARN[0000] treating lima version "bc39aed.m" from "/Users/asauber/.lima/ubuntunested/lima-version" as very latest release
asauber@lima-ubuntunested:/Users/asauber$ kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used

Very cool. Thank you for working on this.

[AkihiroSuda]

CI is failing https://github.com/lima-vm/lima/actions/runs/10903645853/job/30258186834?pr=2530

# github.com/lima-vm/lima/pkg/vz
Error: pkg/vz/vm_darwin.go:256:18: platformConfig.SetNestedVirtualizationEnabled undefined (type *"github.com/Code-Hex/vz/v3".GenericPlatformConfiguration has no field or method SetNestedVirtualizationEnabled)
make[1]: *** [_output/bin/limactl] Error 1

[abiosoft]

CI is failing https://github.com/lima-vm/lima/actions/runs/10903645853/job/30258186834?pr=2530

Yes, that is because the upstream PR is not yet merged and that is why I made it a draft PR.

[AkihiroSuda]

Code-Hex/vz#159 remains still unreviewed, maybe the repo should be forked?

[abiosoft]

Code-Hex/vz#159 remains still unreviewed, maybe the repo should be forked?

lima-vm/vz#1

[AkihiroSuda]

Thanks

[abiosoft]

The failing test does not appear related to the code change and it appears to run Lima successfully https://github.com/lima-vm/lima/actions/runs/11231643603/job/31221517661?pr=2530#step:10:1133. 😕

[jandubois]

The failing test does not appear related to the code change and it appears to run Lima successfully

This unfortunately happens all the time, and we are retriggering failed test many times each day. 😞

[AkihiroSuda]

CI is green on the master, but this PR seems failing 4 times.

Maybe the failure is caused by another recent change in vz?

[AkihiroSuda]

CI is now green, let's merge it