Julian Stecklina

This talk gives an overview about the state of Lanzaboote, a set of tools that enable Secure Boot for NixOS.

UEFI Secure Boot is a firmware security feature that prevents untrusted code from booting on a system. Users can utilize this technology to prevent certain kinds of attacks that involve booting malicious code on their computers. Unfortunately, NixOS has no support for Secure Boot yet.

The talk will give a short background of Secure Boot, go through NixOS-specific challenges, and explain the strategy we took for enabling Secure Boot in NixOS. We will highlight the newly developed components, such as a custom UEFI boot stub and companion Linux userspace tool, which are both written in Rust. Finally, we will explain the current state of upstreaming Secure Boot support in NixOS.

Concurrent code is hard to get right, but at the same time also hard to test. It gets worse when hardware interaction is required. This leads to a comparatively poor culture of unit testing in kernel code, where both come together.

In this talk, I’m going to highlight one particular method of unit testing the page table manipulation code in Hedron, a microkernel written in C++ specially geared towards virtualization workloads. This code safely modifies page tables that are concurrently used by the CPU. Usually, unit tests only check whether the state after an operation meets the expectation of the programmer. In contrast, Hedron employs completely deterministic unit tests that show that the CPU will always see a valid virtual memory mappings while a page table manipulation is in progress (for the tested cases).

The goal of this task is to show that unit tests can be a powerful tool even for properties of code that are usually not deemed unit testable.

Panel discussion and an extended Q&A session on the state of microkernel-based operating systems in 2021 and related topics. The panelists (in order of acceptance):

• Martin Decky (HelenOS, Huawei)
• Jakub Jermar (Kernkonzept, HelenOS)
• Norman Feske (Genode Labs)
• Julian Stecklina (Cyberus)
• Udo Steinberg (BedRock Systems)
• Matthias Lange (Kernkonzept)
• Gernot Heiser (seL4)

The discussion will smoothly evolve into the traditional and less formal "microkernel dinner". Please bring your own food and beverages.

Other people: Jakub Jermář Martin Děcký Norman Feske Udo Steinberg Matthias Lange Gernot Heiser

A short introduction of the hosts of the devroom and some warm words.

Panel discussion on various topics with authors of several microkernel / multiserver operating systems.

Other people: Ben Gras Christian Helmuth Jakub Jermář

The NOVA virtualization architecture is comprised of a microhypervisor and a capability-based multiserver userland with a specific focus on enabling secure and efficient virtualization using x86 hardware virtualization extensions (VT-x, VT-d, SR-IOV). It does so by moving almost all of the actual "virtualization" into a per-VM userspace component that is not in the Trusted Computing Base of other virtual machines. This talk will give an overview of NOVA's unique execution model and API with a strong focus on how this enables efficient execution of a VMM. Specifically, this talk will cover how tasks and threads are realized in NOVA, how communication between threads works, how VM exits are handled in NOVA and how this extends to SMP machines.