Re: [PATCH v4 08/39] x86/mm: Remove _PAGE_DIRTY from kernel RO pages

Borislav Petkov
2022-12-20T19:12:09Z

Just typos and spelling fixes:

On Fri, Dec 02, 2022 at 04:35:35PM -0800, Rick Edgecombe wrote:
> From: Yu-cheng Yu <yu-cheng.yu@intel.com>
>
> New processors that support Shadow Stack regard Write=0,Dirty=1 PTEs as
> shadow stack pages.
>
> In normal cases, it can be helpful to create Write=1 PTEs as also Dirty=1
> if HW dirty tracking is not needed, because if the Dirty bit is not already
> set the CPU has to set Dirty=1 when it the memory gets written to. This

s/it //

> creates addiontal work for the CPU.

"additional"

> So tradional wisdom was to simply set

Unknown word [tradional] in commit message.
Suggestions: ['traditional', ...

> the Dirty bit whenever you didn't care about it. However, it was never
> really very helpful for read only kernel memory.

read-only

> When CR4.CET=1 and IA32_S_CET.SH_STK_EN=1, some instructions can write to
> such supervisor memory. The kernel does not set IA32_S_CET.SH_STK_EN, so
> avoiding kernel Write=0,Dirty=1 memory is not strictly needed for any
> functional reason. But having Write=0,Dirty=1 kernel memory doesn't have
> any functional benefit either, so to reduce ambiguity between shadow stack
> and regular Write=0 pages, removed Dirty=1 from any kernel Write=0 PTEs.

s/removed/remove/

--
Regards/Gruss,
Boris.