LWN: Comments on "Standardizing the BPF ISA"

Standardizing the BPF ISA

foom — Wed, 05 Jun 2024 12:14:20 +0000

You should use the BPF VM if you are writing code inside the Linux kernel (you're not going to be able to get a WASM VM accepted there). You might also want to use a BPF VM if you would benefit from the ability to run programs originally written in BPF for the Linux kernel's BPF VM.

In all other contexts, use a WASM VM.

Standardizing the BPF ISA

joib — Tue, 04 Jun 2024 11:09:51 +0000

So from someone who has heard of both but used neither, if my project needs some small virtual machine for whatever reason, when and why should I choose BPF instead of WASM and vice versa?

PREVAIL verifier question

anselm — Mon, 03 Jun 2024 10:44:20 +0000

Isn't "Docker on Windows or MacOS" simply a Linux VM under the hood?

On Linux, Docker containers are glorified chroot environments. On a non-Linux machine, you need to somehow bring in the underlying Linux bits that support the glorified chroot environment, and a VM is one reasonable way of doing this.

PREVAIL verifier question

alison — Mon, 03 Jun 2024 00:02:15 +0000

> Isn't "Docker on Windows or MacOS" simply a Linux VM under the hood?

On Linux, Docker is a container, so it's running the host's Linux kernel (with all the security implications thereof). Presumably therefore a Linux Docker container won't run on other hosts, but my ignorance of Windows and MacOs is total.

-- Alison, about to hit new LWN comment limit

PREVAIL verifier question

intelfx — Sun, 02 Jun 2024 22:55:36 +0000

> Certainly if those docker invocations referred to in the document will run on Windows or MacOs, they must not need the Linux kernel.

Isn't "Docker on Windows or MacOS" simply a Linux VM under the hood?

(That is not to say that PREVAIL needs Linux kernel. At a glance, it looks like a purely userspace solution.)

PREVAIL verifier question

alison — Sun, 02 Jun 2024 17:35:13 +0000

Thanks. Certainly if those docker invocations referred to in the document will run on Windows or MacOs, they must not need the Linux kernel.

PREVAIL verifier question

willy — Sun, 02 Jun 2024 17:19:58 +0000

Seems to me that PREVAIL can run entirely in userspace:

https://github.com/vbpf/ebpf-verifier

It does talk about using sudo, but I'm pretty sure that's just to run the Linux verifier as a contrast to PREVAIL.

PREVAIL verifier question

alison — Sat, 01 Jun 2024 04:34:03 +0000

Is it possible to run the PREVAIL verifier (or the Linux one for that matter) without trying to load the BPF program into the kernel? In other words, can these verifiers be run as standalone binaries, or via libraries that non-kernel applications can address? It would be great to be able to invoke a verifier from a build rule or a test script as part of CI. Doing so would greatly speed up code development.