Re: [PATCH v2 0/9] Convert x86 pgd_lists to ptdescs

[Vishal Moola <vishal.moola@gmail.com>]

On Mon, Jun 29, 2026 at 11:57:33AM -0700, Vishal Moola wrote:
> 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@gmail.com/
> 
> ----------------
> 
> v2:
>   - Collect Review tags
>   - Rebase on 7.2-rc1
> 
> 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 7.2-rc1. Dave, can you please take this through
> the x86 mm tree?

Hi Dave, will you take this through your tree? Let me know if there
are any changes you'd like to see, or if you'd rather this go through
some other tree.

> 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(-)
> 
> -- 
> 2.54.0
>