hubris VS miri

> The CPUs in Oxide racks are AMD, so, presumably AMD-based compute rather than ARM.

These don’t run Hubris though; based on the chips directory in the repo [0], they’re targeting a mix of NXP and ST parts, which are Arm, and the user isn’t likely to see them or care what firmware they’re running: they’re really pretty “boring”.

[0] : https://github.com/oxidecomputer/hubris/tree/020d014880382d8...

I wouldn't put this comment here. It's not just some detail of this function; it's an invariant of the field that all writers have to respect (maybe this is the only one now but still) and all readers can take advantage of. So I'd add it to the `TaskDesc::regions` docstring. [1]

[1] https://github.com/oxidecomputer/hubris/commit/b44e677fb39cd...

With respect to Hubris, the build badge was, in turns out, pointing to a stale workflow. (That is, the build was succeeding, but the build badge was busted.) This comment has been immortalized in the fix.[0]

With respect to Humility, I am going to resist the temptation of pointing out why one of those directories has a different nomenclature with respect to its delimiter -- and just leave it at this: if you really want to find some filthy code in Humility, you can do much, much better than that!

[0] https://github.com/oxidecomputer/hubris/commit/651a9546b20ce...

A lot of questions in there! Taking these in order:

1. We aren't making standalone servers: the Oxide compute sled comes in the Oxide rack. So are not (and do not intend to be) a drop in replacement for extant rack mounted servers.

2. We have taken a fundamentally different approach to firmware, with a true root of trust that can attest to the service processor -- which can turn attest to the system software. This prompts a lot of questions (e.g., who attests to the root of trust?), and there is a LOT to say about this; look for us to talk a lot more about this

3. In stark contrast (sadly) to nearly everyone else in the server space, the firmware we are developing is entirely open source. More details on that can be found in Cliff Biffle's 2021 OSFC talk and the Hubris and Humility repos.[0][1][2]

4. Definitely not vaporware! We are in the process of shipping to our first customers; you can follow our progress in our Oxide and Friends podcast.[3]

[0] https://www.osfc.io/2021/talks/on-hubris-and-humility-develo...

[1] https://github.com/oxidecomputer/hubris

[2] https://github.com/oxidecomputer/humility

[3] https://oxide-and-friends.transistor.fm/

everywhere, for example in https://github.com/oxidecomputer/hubris/search?q=dyn

Is Box really allocating here? Is the "Rust By Example" text incomplete?

Then I had to stop learning Rust for other reasons, but this doubt really hit me at the time.

I work on an embedded OS in Rust (Hubris) that has a very bespoke build system. As part of the build system, it has to set environmental variables based on (1) the target device and (2) the specific "task"; this is an OS with task-level isolation, so tasks are compiled as individual Rust crates.

Oxide Computer told some storied about the difficulty of bring up of a new motherboard, and mentioned a lot of gotcha details and hack solutions for managing their AMD chip.

They talked about their bring up sequence, boot chain verification on their motherboard, and designing / creating / verifying their hardware root of trust.

I heard mention of this on a podcast recently, trying to find the reference.

I'm pretty sure it was [S3]

- "Tales from the Bringup Lab" https://lnns.co/FBf5oLpyHK3

- or "More Tales from the Bringup Lab" https://lnns.co/LQur_ToJX9m

But I found again these interesting things worth sharing on that search. https://oxide.computer/blog/hubris-and-humility, https://github.com/oxidecomputer/hubris

Search 1 [S1], Trammell Hudson ep mentioning firmware (chromebook related iirc) https://lnns.co/pystdPm0QvG.

Search 2 [S2], Security, Cryptography, Whatever podcast episode mentioning Oxide and roots of trust or similar. https://lnns.co/VnyTvdhBiGC

Search links:

[S1]: https://www.listennotes.com/search/?q=oxide+tpm

[S2]: https://www.listennotes.com/search/?q=oxide%20and%20friends%...

[S3]: https://www.listennotes.com/search/?q=oxide%20and%20friends%...

When we started the company, we knew it would be a three year build -- and indeed, our first product is in the final stages of development (i.e. EMC/safety certification). We have been very transparent about our progress along the way[0][1][2][3][4][5][6][7] -- and our software is essentially all open source, so you can follow along there as well.[8][9][10]

If you are asking "does anyone want a rack-scale computer?" the (short) answer is: yes, they do. The on-prem market has been woefully underserved -- and there are plenty of folks who are sick of Dell/HPE/VMware/Cisco, to say nothing of those who are public cloud borne and wondering if they should perhaps own some of their own compute rather than rent it all.

[0] https://oxide-and-friends.transistor.fm/episodes/holistic-bo...

[1] https://oxide-and-friends.transistor.fm/episodes/the-oxide-s...

[2] https://oxide-and-friends.transistor.fm/episodes/bringup-lab...

[3] https://oxide-and-friends.transistor.fm/episodes/more-tales-...

[4] https://oxide-and-friends.transistor.fm/episodes/another-lpc...

[5] https://oxide-and-friends.transistor.fm/episodes/the-pragmat...

[6] https://oxide-and-friends.transistor.fm/episodes/tales-from-...

[7] https://oxide-and-friends.transistor.fm/episodes/the-sidecar...

[8] https://github.com/oxidecomputer/omicron

[9] https://github.com/oxidecomputer/propolis

[10] https://github.com/oxidecomputer/hubris

>While we are many missing language features away from this being the case, the noalias case is also magic descended upon box itself, with no user code ever having access to it.

I'm not sure why the author thinks there's magic behind Box. Box is not a special case of `noalias`. Run this snippet with miri and you'll see the same issue: https://play.rust-lang.org/?version=stable&mode=debug&editio...

`Box` _does_ have an expectation that its inner pointer is not aliased to another Box (even if used for readonly operations). See: https://github.com/rust-lang/miri/issues/1800#issuecomment-8...)

Miri [0] is an interpreter for the mid-level intermediate representation (MIR) generated by the Rust compiler. MIR is input for more processing steps of the compiler. However miri also runs MIR directly. This means miri is a VM. Of course it's not a bytecode VM, because MIR is not a bytecode AFAIK. I still think that miri is a interesting example.

And why does miri exist?

It is a lot slower. However it can check for some undefined behavior.

[0]: https://github.com/rust-lang/miri

Provenance is a dynamic property of pointer values. The actual underlying rules that a program must follow, even when using raw pointers and `unsafe`, are written in terms of provenance. Miri (https://github.com/rust-lang/miri) represents provenance as an actual value stored alongside each pointer's address, so it can check for violations of these rules.

Lifetimes are a static approximation of provenance. They are erased after being validated by the borrow checker, and do not exist in Miri or have any impact on what transformations the optimizer may perform. In other words, the provenance rules allow a superset of what the borrow checker allows.

There has been discussion of doing this with MIRI, which would be easier than all of rustc.

This issue has been fixed: https://github.com/rust-lang/miri/issues/2964

Actually, I've done more advanced tests with MIRI (see https://github.com/rust-lang/miri/issues/2920 for example) which allowed me to fix some issues. I've also made the code compatible with loom, but I didn't found the time yet to write and execute loom tests. That's on the TODO-list, and I need to track it with an issue too.

He is one of the big brains behind Miri, which is a interpreter that runs on the MIR (compiler representation between human code and asm/machine code) and detects undefined behavior. Super useful tool for language safety, pretty interesting on its own.

I would also run your tests in Miri (https://github.com/rust-lang/miri) to try to cover more bases.