[PATCH V2 0/3] riscv: mm: Add soft-dirty and uffd-wp support

Chunyan Zhang
2024-07-31T04:06:14Z

This patchset adds soft dirty and userfaultfd write protect tracking support
for RISC-V.

As described in the patches, we are trying to utilize only one free PTE bit to
support three kernel features (devmap, soft-dirty,uffd-wp). Users cannot have
them supported at the same time (have to select one when building the kernel).

This patchset has been tested with:
1) The kselftest mm suite in which soft-dirty, madv_populate, test_unmerge_uffd_wp,
and uffd-unit-tests run and pass, and no regressions are observed in any of the
other tests.

2) CRIU:
- 'criu check --feature mem_dirty_track' returns supported
- incremental_dumps works fine
- zdtm test suite can run under host mode

V1 -> V2:
- Add uffd-wp supported;
- Make soft-dirty uffd-wp and devmap mutually exclusive which all use the same PTE bit;
- Add test results of CRIU in the cover-letter.

Chunyan Zhang (3):
riscv: mm: Prepare for reuse PTE RSW bit(9)
riscv: mm: Add soft-dirty page tracking support
riscv: mm: Add uffd write-protect support

arch/riscv/Kconfig | 34 ++++++-
arch/riscv/include/asm/pgtable-64.h | 2 +-
arch/riscv/include/asm/pgtable-bits.h | 31 ++++++
arch/riscv/include/asm/pgtable.h | 132 +++++++++++++++++++++++++-
4 files changed, 196 insertions(+), 3 deletions(-)

--
2.34.1