github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-31 02:24:24 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

RISC-V: KVM: Fix lost write protection on huge pages during dirty logging

Browse Source 
When enabling dirty log in small chunks (e.g., QEMU default chunk
size of 256K), the chunk size is always smaller than the page size
of huge pages (1G or 2M) used in the gstage page tables. This caused
the write protection to be incorrectly skipped for huge PTEs because
the condition `(end - addr) >= page_size` was not satisfied.

Remove the size check in `kvm_riscv_gstage_wp_range()` to ensure huge
PTEs are always write-protected regardless of the chunk size. Additionally,
explicitly align the address down to the page size before invoking
`kvm_riscv_gstage_op_pte()` to guarantee that the address passed to the
operation function is page-aligned.

This fixes the issue where dirty pages might not be tracked correctly
when using huge pages.

Fixes: 9d05c1fee8 ("RISC-V: KVM: Implement stage2 page table programming")
Signed-off-by: Wang Yechao <wang.yechao255@zte.com.cn>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/202603301610527120YZ-pAJY6x9SBpSRo1Wg4@zte.com.cn
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Wang Yechao 2026-03-30 16:10:52 +08:00 committed by Anup Patel
parent 1762ac42ee
commit a216e24fc9
1 changed files with 3 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/riscv/kvm/gstage.c
View File

@ -304,10 +304,9 @@ void kvm_riscv_gstage_wp_range(struct kvm_gstage *gstage, gpa_t start, gpa_t end
if (!found_leaf)
goto next;
if (!(addr & (page_size - 1)) && ((end - addr) >= page_size))
kvm_riscv_gstage_op_pte(gstage, addr, ptep,
ptep_level, GSTAGE_OP_WP);
addr = ALIGN_DOWN(addr, page_size);
kvm_riscv_gstage_op_pte(gstage, addr, ptep,
ptep_level, GSTAGE_OP_WP);
next:
addr += page_size;
}