arm64: ptdump: Make note_page_flush() range aware

Browse source

note_page_flush() calls note_page() with addr == 0 and level == -1 to
dump the last row of a ptdump. addr == 0 (1 << 64 wrapped around)
renders a huge region with enormous size for address spaces with
IA bits < 64. For example the stage-2 page tables and the EFI runtime
page table.

More importantly, the last region of the address space and everything
after the address space up to 1 << 64 are merged into one row of
output. If the last region within the address space is valid, it will
appear to remain valid up to 1 << 64 with the same attributes.

Currently only the EFI runtime ptdump is affected by this, but KVM will
soon fix its stage-2 ptdump by using note_page_flush(). Here is an
example of an EFI runtime ptdump (last row):

0x0000008000000000-0x0000000000000000   17179868672G PGD

With this patch:

0x0000008000000000-0x0001000000000000      261632G PGD

To fix this, cache the end address of a ptdump in ptdump_pg_state so
note_page_flush() can call the final note_page() with the correct end
address.

Fixes: 9d80448ac9 ("efi/arm64: Add debugfs node to dump UEFI runtime page tables")
Signed-off-by: Wei-Lin Chang <weilin.chang@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

...

This commit is contained in:

Wei-Lin Chang 2026-08-14 23:24:57 +01:00 • committed by Will Deacon

parent 26b77009ee

commit 902caade3c

2 changed files with 15 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

arch/arm64/include/asm/ptdump.h

View file

14

arch/arm64/mm/ptdump.c

View file