Large Virtual Address support (52-bit) in ARM64 kernel
summary
Linux mainline (since 5.4) gains 52-bit VA/PA (ARMv8.2 LVA/LPA) support enabling up to 4 PB addresses but only with 64K page size, 3-level page tables; the kernel flips the direct-linear map vs text layout to accommodate the larger range. Debugging tools that perform VA→PA walks (kexec-tools, makedumpfile, crash) break unless updated; fixes are upstream or proposed. Old CPUs stay on 48-bit by early-boot detection; userland opts in to 52-bit pointers by supplying an mmap hint >48-bit. Use ARMv8 fast model for testing.
AI-written summary · about
chapters (15)
- 0:00Introduction
- 3:48Overview
- 8:10Translation Table Walk
- 19:00User Space Issues
- 20:29Pain Points
- 24:34Slide deck
- 24:54Wrap up
- 26:54Hardware debugger vendors
- 27:56Use cases
- 29:37Different use cases
- 31:23Containerization of applications
- 33:35How to get involved
- 38:27Where to keep an eye
- 39:30Major changes or competitors
- 42:33Wrapup
related talks
25mLarge Virtual Adress support in ARM64 kernel
26mArm64 Linux Kernel Architecture update
47mLinux's Leap Beyond Fixed Pages
30mFlexible Paging in Linux: Per-process Page Size
36mShared Virtual Addressing for High Performance Arm Infrastructure Platforms
43mAddress Space Isolation for Enhanced Safety of the Linux Kernel
37m32-bit Linux Support Now and in the Future
46mKernel Hardening for 32-bit Arm Processors