GripNewsApr 11
🌘 Apple Silicon 與虛擬機：突破雙 VM 限制
➤ 深入 macOS 核心，手動解除虛擬化配額限制的技術實戰
✤ https://khronokernel.com/macos/2023/08/08/AS-VM.html
這篇文章揭示了 Apple Silicon 架構下 macOS 限制同時運行僅能開啟兩臺虛擬機（VM）的技術底層。作者透過深入分析 XNU 內核與 `Virtualization.framework`，發現此限制源於內核層級的 `hv_apple_isa_vm_quota` 變數。他詳細說明瞭如何透過安裝開發版內核（Development Kernel）、配置自定義核心集合（Kernel Collection），以及利用 `boot-args` 參數覆蓋內核限制，成功繞過 Apple 的虛擬機配額，為開發人員與研究人員提供了擴展 VM 數量的實作方案。
+ 這簡直是 macOS 開發者的福音！終於不需要為了測
#macOS Internals #Apple Silicon #Virtualization #Kernel Development #XNU
Apple Silicon and Virtual Machines: Beating the 2 VM Limit

macOS Internals Deep Dive Building a Development Kernel Collection Configuring our Mac to boot the Development Kernel Collection Putting our machine to work! When did Apple grace us with this feature? Undoing our work for OS updates Closing Thoughts

Mykola’s blog
looopToolsApr 11
Anyone whom have contributed to #darwin or #xnu whom is outside of #apple who can shed some light on the process?
JdeBPApr 9

Here are some things that one can add to the analysis of the MacOS TCP timeout clock freeze bug.

The code for calculate_tcp_clock() in XNU was changed in May 2025. Older versions of this function (e.g. in xnu-11417) worked quite differently and wouldn't have stopped ticking the clock at 32-bit unsigned integer wraparound.

None of #NetBSD, #FreeBSD, nor #OpenBSD share this exact way of doing TCP timeout processing with #XNU.

FreeBSD does not have a tcp_now and works off the global 32-bit ticks variable. OpenBSD effectively works off the kernel's system clock, too, but with a randomized offset, and does 64-bit unsigned modular arithmetic. NetBSD uses a distinct 32-bit unsigned tcp_now counter that it simply increments by 1 at regular intervals, and does modular arithmetic subtraction.

https://photon.codes/blog/we-found-a-ticking-time-bomb-in-macos-tcp-networking

#TCP #MacOS

We Found a Ticking Time Bomb in macOS TCP Networking - It Detonates After Exactly 49 Days - Photon Blog

Photon powers conversational AI agents on iMessage, WhatsApp, Telegram, and more. Open-source Spectrum framework + SDK for seamless agent interactions.

Jonas Kruckenberg Dec 23

This neighborhood belongs to us!! (the macos kernel)

#xnu #macos #osdev

NerdNextDoor Sep 29, 2025

Finally got x86_64 #XNU for #macOS 15.6 built into some kind of a binary on my M4 MBA.

Now I’m not quite sure how to boot the kernel in a VM… any ideas?

#Apple #Tech #Technology

Show threadFR4NÇ01S 🖍️🇫🇷🍉Sep 28, 2025

@nico @iorsh

#XNU 😉
Sorry.
I run macOS natively, on a mac 😁

Benjamin Carr, Ph.D. 👨🏻‍💻🧬Apr 17, 2025
We call this kernel saunters: How Apple rearranged its #XNU with exclaves
Based on the references to exclaves in XNU source for #Apple's M4 chips and the A18 used in iPhone 16, source argues exclaves form the basis of a significant redesign of XNU's security model.
"In iOS 18, exclaves refer to specific resources that are separated from the main iOS kernel (XNU) and cannot be accessed by it, even if the kernel is compromised," the researcher explained in a document.
https://www.theregister.com/2025/03/08/kernel_sanders_apple_rearranges_xnu/
We call this kernel saunters: How Apple rearranged its XNU core with exclaves

: iPhone giant compartmentalizes OS for the sake of security

The Register
Linux MagazineApr 11, 2025
Changes to Apple Silicon put the @AsahiLinux project at odds with adding support for the M4 chips
https://www.linux-magazine.com/Online/News/Asahi-Linux-Runs-into-Issues-with-M4-Support?utm_source=MLM
#Linux #Asahi #AppleSilicon #M4 #XNU #hypervisor
Asahi Linux Runs into Issues with M4 Support » Linux Magazine

Due to Apple Silicon changes, the Asahi Linux project is at odds with adding support for the M4 chips.

Linux Magazine
st1nger  🏴‍☠️  Apr 7, 2025
#Apple Darwin #OS and #XNU #Kernel Deep Dive - Tracing its evolution from Mach and #BSD roots to powering #macOS #iOS and Apple Silicon. This post explores the hybrid kernel’s design, its adaptation to new hardware and security paradigms, and why XNU remains a uniquely resilient and scalable foundation for Apple’s platforms https://tansanrao.com/blog/2025/04/xnu-kernel-and-darwin-evolution-and-architecture/
GripNewsApr 6, 2025
🌗 蘋果的 Darwin 作業系統與 XNU 核心深度解析
➤ 蘋果作業系統底層核心技術的演變與解析
✤ https://tansanrao.com/blog/2025/04/xnu-kernel-and-darwin-evolution-and-architecture/
本文深入探討了蘋果的 Darwin 作業系統及其核心 XNU 的架構演變，從 Mach 與 BSD 的起源，到如今驅動 macOS、iOS 和 Apple Silicon 的強大基礎。文章追溯了這款混合式核心的設計、對新硬體和安全模式的適應，以及 XNU 獨特的彈性和可擴展性。作者分享了個人深入研究 XNU 的心得，並詳細分析了其架構、排程、記憶體管理和虛擬化支援等關鍵技術。
+ 這篇文章真的寫得很深入，對於想了解 macOS 和 iOS 底層原理的人來說，非常有價值。
+ 以前只知道蘋果的系統很穩定，沒想到背後有這麼複雜的技術演進和架構設計，令人印象深刻。
#作業系統 #蘋果 #XNU #Darwin #核心技術