How can I get a FlameGraph for a custom unikernel running in a same-arch QEMU VM?

Question

I would like to profile a unikernel I am developing. This is an x86_64 unikernel, written in Rust, which runs on an x86_64 host using QEMU to manage the KVM VM. I have enabled frame pointers.

I don't care what tool is used, anything resembling a FlameGraph would work.

I have tried:

• https://github.com/maestro-os/kern-profile: only works for cross-architecture emulated QEMU guests
• perf-kvm: I believe requires a Linux kernel in the VM and does not support custom kernels? I get no output when I run it, and the options like "Guest OS root file system mount directory" makes it seem like the wrong tool.
• https://github.com/tjfontaine/vm_profile_guest: requires DTrace which I struggled to install on Ubuntu 24.04; systemtap-sdt-dev does not support the CLI options used by vm_profile_guest, and dtrace4linux hasn't been updated in 6 years.

I have not yet tried using GDB's backtrace support to manually generate profiling data, but I wanted to check I hadn't missed something obvious before working on that.