[PATCH 0/2] riscv: ptdump: Refactor for KVM gstage ptdump support

[Dylan.Wu]

This series refactors the RISC-V ptdump implementation to support
dumping KVM gstage (stage-2) page tables via debugfs.

Patch 1 moves the pagetable walking state and level definitions to a
common header (arch/riscv/include/asm/ptdump.h), updates the attribute
parsing logic to use per-level bit definitions, and exports note_page()
so that it can be reused by the KVM ptdump implementation.

Patch 2 introduces KVM gstage ptdump support, registering a
'gstage_page_tables' file under the guest debugfs directory. This
allows userspace to inspect the gstage layout and permissions, which
is useful for architectural debugging and memory management audits.

Testing:
  - Booted on QEMU riscv64 with CONFIG_PTDUMP_DEBUGFS=y and
    CONFIG_PTDUMP_GSTAGE_DEBUGFS=y
  - Verified /sys/kernel/debug/kernel_page_tables output unchanged
  - Created a KVM guest and verified gstage_page_tables output: 
0x0000000080200000-0x0000000080209000    0x000000010c94e000        36K PTE   ..   D A U X W R V
0x000000008020a000-0x0000000080223000    0x000000010c9af000       100K PTE   ..   D A U X W R V
0x0000000080229000-0x000000008022b000    0x000000010c978000         8K PTE   ..   D A U X W R V
0x000000008022d000-0x000000008022e000    0x000000010c844000         4K PTE   ..   D A U X W R V
0x000000008022f000-0x0000000080232000    0x000000010c846000        12K PTE   ..   D A U X W R V
0x0000000080234000-0x0000000080238000    0x000000010ca13000        16K PTE   ..   D A U X W R V
0x000000008023a000-0x000000008023f000    0x00000001083bd000        20K PTE   ..   D A U X W R V
0x0000000080242000-0x000000008024b000    0x0000000106975000        36K PTE   ..   D A U X W R V
0x000000008024d000-0x0000000080252000    0x000000010cb54000        20K PTE   ..   D A U X W R V
0x0000000080255000-0x0000000080258000    0x000000010c164000        12K PTE   ..   D A U X W R V
0x000000008025a000-0x000000008025c000    0x00000001036a9000         8K PTE   ..   D A U X W R V
0x0000000080260000-0x0000000080275000    0x0000000107917000        84K PTE   ..   D A U X W R V
0x0000000080276000-0x000000008027e000    0x00000001078ed000        32K PTE   ..   D A U X W R V
0x000000008027f000-0x00000000802bb000    0x0000000108986000       240K PTE   ..   D A U X W R V
0x00000000802bc000-0x00000000802c0000    0x000000010762b000        16K PTE   ..   D A U X W R V
0x00000000802c2000-0x00000000802d2000    0x00000001083fd000        64K PTE   ..   D A U X W R V
0x00000000802d4000-0x00000000802e0000    0x000000010790b000        48K PTE   ..   D A U X W R V
0x00000000802e1000-0x00000000802e4000    0x0000000102f74000        12K PTE   ..   D A U X W R V
0x00000000802e5000-0x00000000802ef000    0x0000000104b9c000        40K PTE   ..   D A U X W R V
0x00000000802f1000-0x00000000802f2000    0x0000000103778000         4K PTE   ..   D A U X W R V
0x00000000802f3000-0x00000000802f9000    0x000000010377a000        24K PTE   ..   D A U X W R V


Dylan.Wu (2):
  riscv: ptdump: Move pagetable definitions to common header
  KVM: riscv: Register ptdump with debugfs on guest creation

 arch/riscv/include/asm/kvm_host.h |   6 +
 arch/riscv/include/asm/ptdump.h   |  42 +++++++
 arch/riscv/kvm/Kconfig            |  15 +++
 arch/riscv/kvm/Makefile           |   1 +
 arch/riscv/kvm/ptdump.c           | 178 ++++++++++++++++++++++++++++++
 arch/riscv/kvm/vm.c               |   5 +
 arch/riscv/mm/ptdump.c            | 102 ++++++-----------
 7 files changed, 282 insertions(+), 67 deletions(-)
 create mode 100644 arch/riscv/include/asm/ptdump.h
 create mode 100644 arch/riscv/kvm/ptdump.c

-- 
2.34.1