Re: [PATCH v3 RESEND] x86/mm: Fix PAT bit missing from page protection modify mask

[Janusz Krzysztofik]

Hi Borislav,

On Monday, 10 July 2023 10:05:19 CEST Borislav Petkov wrote:
> On Mon, Jul 10, 2023 at 09:36:14AM +0200, Janusz Krzysztofik wrote:
> > Assume that adding _PAGE_PAT to _PAGE_CHG_MASK doesn't break pte_modify()
> > and its users, and go for it.  Also, add _PAGE_PAT_LARGE to
> 
> That's my only worry.

Let me remind you that v1 was free of concerns on potential breakage of 
pte_modify().  I can update its commit description as Dave requested and 
resubmit if you confirm that it will be reconsidered as a potential solution.

Thanks,
Janusz

> 
> I'd suggest we queue this but not send it to Linus now. Instead, let it
> cook in linux-next for the whole 6.5 release cycle so that it can get at
> least *some* testing.
> 
> Because if we send it now and something else obscure breaks in a weird
> way in his tree, then we'll have to scramble to fix that too and it'll
> be one helluva mess.
> 
> Dave?
> 
>