3 Jul
2022
3 Jul
'22
10:55 p.m.
On Sun, Jul 3, 2022 at 9:27 AM Clem Cole <clemc(a)ccc.com> wrote:
On Sun, Jul 3, 2022 at 11:30 AM Bakul Shah <bakul(a)iitbombay.org> wrote:
IPMI is an entirely different subsystem from the ME.
ME runs on one of at least two superfluous x86 cores within the CPU die of
intel CPUs for a while that can run Intel and vendor supervisors. When
this blew up in Intel’s face several years ago Minix 3 was the latest
incarnation.
https://github.com/hardenedlinux/firmware-anatomy/blob/master/hack_ME/me_in…
IPMI is a sideband and could be anything including embedded Linux on a
dedicated ARM SoC which is common in large scale installations.
is MINIX 3, ... with NetBSD userland.
You may be thinking of MINIX 1. It was a
from-scratch implementation that
was syscall compatible with V7 but IIRC it didn't have any sort of memory
protection as it was designed to run on 8088.
Minux and specifically M1 was and always has been, a uK. And yes, M1 does
not need an MMU - since it was designed to run on an 8088. IIRC this was
Linus' original objection when he wanted to run on his 386-based PC (Wyse
32:16 box, IIRC). The key was Andy wanted to teach his students about V7
without running afoul of the AT&T license as Lions had with V6.
What runs on the Intel Management Engine
It's called the Intelligent Platform Management Interface
<https://streaklinks.com/BHBsBCyMjMy7xGTaiw4nohuO/https%3A%2F%2Fwww.intel.com%2Fcontent%2Fwww%2Fus%2Fen%2Fproducts%2Fdocs%2Fservers%2Fipmi%2Fipmi-second-gen-interface-spec-v2-rev1-1.html>
- *a.k.a.* IPMI
Actually, if you want to pick nits, neither statement is correct (remember
for whom I work).
Maybe you are talking about something else. Minix 3 (Andy’s last OS) does
indeed match this description, uK with NetBSD user.
MINIX 1 and MINIX 3 are related
That's because M3 added the MMU support that M1
lacked. But there is
nothing in M3 that IPMI is using other than it is the current version from
Andy's team. What IPMI has as an underlying uK is heavily hacked and is a
'derivative work' - the local uk is basically providing V7 interfaces to
some special programs.
It made little sense to recreate something for the platform engine, and
Minux was picked because it was smaller than any of the *BSDs and was not
GPL'ed so Intel IP was still protected.
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