On Wed, Jun 25, 2025 at 3:19 PM Leon Romanovsky [off-list ref] wrote:

From: Leon Romanovsky <leonro@nvidia.com>

Hi Leon,

Convert the KMSAN DMA handling function from page-based to physical
address-based interface.

The refactoring renames kmsan_handle_dma() parameters from accepting
(struct page *page, size_t offset, size_t size) to (phys_addr_t phys,
size_t size).

Could you please elaborate a bit why this is needed? Are you fixing
some particular issue?

A PFN_VALID check is added to prevent KMSAN operations
on non-page memory, preventing from non struct page backed address,

As part of this change, support for highmem addresses is implemented
using kmap_local_page() to handle both lowmem and highmem regions
properly. All callers throughout the codebase are updated to use the
new phys_addr_t based interface.

KMSAN only works on 64-bit systems, do we actually have highmem on any of these?