On 14 Oct 2024, at 6:59, Ryan Roberts wrote: > Introduce a new Kconfig, ARM64_BOOT_TIME_PAGE_SIZE, which can be > selected instead of a page size. When selected, the resulting kernel's > page size can be configured at boot via the command line. > > For now, boot-time page size kernels are limited to 48-bit VA, since > more work is required to support LPA2. Additionally MMAP_RND_BITS and > SECTION_SIZE_BITS are configured for the worst case (64K pages). Future > work could be implemented to be able to configure these at boot time for > optimial page size-specific values. > > Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx> > --- <snip> > > @@ -1588,9 +1601,10 @@ config XEN > # 4K | 27 | 12 | 15 | 10 | > # 16K | 27 | 14 | 13 | 11 | > # 64K | 29 | 16 | 13 | 13 | > +# BOOT| 29 | 16 (max) | 13 | 13 | > config ARCH_FORCE_MAX_ORDER > int > - default "13" if ARM64_64K_PAGES > + default "13" if ARM64_64K_PAGES || ARM64_BOOT_TIME_PAGE_SIZE > default "11" if ARM64_16K_PAGES > default "10" > help So boot-time page size kernel always has the highest MAX_PAGE_ORDER, which means the section size increases for 4KB and 16KB page sizes. Any downside for this? Is there any plan (not in this patchset) to support boot-time MAX_PAGE_ORDER to keep section size the same? Best Regards, Yan, Zi
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