Large Virtual Adress support in ARM64 kernel
summary
Linux 5.4 adds ARM64 support for 52‑bit LVA/LPA (ARMv8.2) and flips the kernel virtual map so the direct linear map moves to the top of the 52‑bit range, requiring 64KB pages and three‑level page tables; older CPUs fall back at early boot via va_bits_ variables. Debug tools like kexec-tools, makedumpfile, crash-utility break until patched. User space stays 48‑bit by default and can opt in with an mmap hint larger than 48‑bit. Test using QEMU and ARMv8 fast model* simulators.
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chapters (9)
- 0:00Start
- 8:44Address Spaces
- 9:52Translation Table Walk
- 11:41Virtual Addressing Ranges
- 12:23Virtual Addressing Range
- 13:38Kernel Page Tables
- 15:41Kernel Design Approach
- 16:57Kernel Variables
- 22:15Pain Points
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