Re: [PATCH v2] x86/kfence: Fix booting on 32bit non-PAE systems

[Andrew Morton]

On Mon, 26 Jan 2026 21:10:46 +0000 Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:

> The original patch inverted the PTE unconditionally to avoid
> L1TF-vulnerable PTEs, but Linux doesn't make this adjustment in 2-level
> paging.
> 
> Adjust the logic to use the flip_protnone_guard() helper, which is a nop on
> 2-level paging but inverts the address bits in all other paging modes.
> 
> This doesn't matter for the Xen aspect of the original change.  Linux no
> longer supports running 32bit PV under Xen, and Xen doesn't support running
> any 32bit PV guests without using PAE paging.

Great thanks.  I'll add

	Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>

and, importantly,

	Cc: <stable@xxxxxxxxxxxxxxx>

to help everything get threaded together correctly.


I'll queue this as a 6.19-rcX hotfix.