[cstrahan]

> the device itself calls back into a BPF function in the NVMe driver

This statement contradicts itself. A driver (a “kernel module” in Linux lingo) runs in the kernel, and sure, that driver can call out to BPF or whatever else it desires, but then that isn’t the device doing so, that’s your computer (running your Linux kernel, in turn executing the aforementioned kernel module / driver) doing so.

Restated from another perspective, drivers don’t run on devices. Something may run on devices too, but that’s different, and we’d call that something like “firmware”.

Edit: the intended takeaway being that device manufacturers/designers should have little to gain from BPF being standardized (unless that BPF is being executed on the device, as this now implies an API contract between device and host) — a driver can always declare that the semantics is whatever the Linux kernel does and call it a day.