[PATCH 0/9] Convert x86 pgd_lists to ptdescs

From: Vishal Moola

Date: Wed May 27 2026 - 10:09:19 EST


This continues the ptdesc conversions for x86[1]. This is a necessary step
in preparation for the separate allocation of ptdescs from struct page.
Once ptdescs are not wrappers, the pgd_list should be used to find our
ptdesc, not page.

In fact, after patch 4 we can successfully boot a 32-bit x86 kernel
that separately allocates ptdescs.

All of the patches are rather straightforward, I just kept them split up
for ease of review. There are no intended functional changes as ptdescs
are currently still wrappers around struct page.

[1] https://lore.kernel.org/linux-mm/20260211195233.368497-1-vishal.moola@xxxxxxxxx/

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I've compiled and booted both 64 and 32 bit on a kernel with separately
allocated ptdescs. I ensured the codepaths were hit for all the changes
except Xen.

This applies cleanly to the tip bot. I'm thinking this can go through
Dave's mm.

Vishal Moola (9):
x86/mm/pat: Use IS_ENABLED() instead of ifdef
x86/mm/pat: Convert __set_pmd_pte() to ptdescs
x86/mm/pat: Convert collapse_pmd_page() to ptdescs
x86/mm: Convert arch_sync_kernel_mappings() to ptdescs
x86/mm: Convert sync_global_pgds_l5() to ptdescs
x86/mm: Convert sync_global_pgds_l4() to ptdescs
x86/mm: Convert pgd_page_get_mm() to ptdescs
x86/xen: Convert xen_mm_pin_all() to ptdescs
x86/xen: Convert xen_mm_unpin_all() to ptdescs

arch/x86/include/asm/pgtable.h | 2 +-
arch/x86/include/asm/pgtable_types.h | 2 +-
arch/x86/mm/fault.c | 8 ++++----
arch/x86/mm/init_64.c | 16 ++++++++--------
arch/x86/mm/pat/set_memory.c | 17 ++++++++---------
arch/x86/mm/pgtable.c | 4 ++--
arch/x86/xen/mmu_pv.c | 22 +++++++++++-----------
7 files changed, 35 insertions(+), 36 deletions(-)

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2.54.0