Re: [PATCH v23 07/28] x86/mm: Remove _PAGE_DIRTY from kernel RO pages

Yu, Yu-cheng
2021-03-22T14:54:38Z

On 3/22/2021 2:13 AM, Kirill A. Shutemov wrote:
> On Tue, Mar 16, 2021 at 08:10:33AM -0700, Yu-cheng Yu wrote:
>> The x86 family of processors do not directly create read-only and Dirty
>> PTEs. These PTEs are created by software. One such case is that kernel
>> read-only pages are historically setup as Dirty.
>>
>> New processors that support Shadow Stack regard read-only and Dirty PTEs as
>> shadow stack pages. This results in ambiguity between shadow stack and
>> kernel read-only pages. To resolve this, removed Dirty from kernel read-
>> only pages.
>>
>> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
>> Cc: "H. Peter Anvin" <hpa@zytor.com>
>> Cc: Kees Cook <keescook@chromium.org>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Dave Hansen <dave.hansen@linux.intel.com>
>> Cc: Christoph Hellwig <hch@lst.de>
>> Cc: Andy Lutomirski <luto@kernel.org>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Borislav Petkov <bp@alien8.de>
>> Cc: Peter Zijlstra <peterz@infradead.org>
>
> Looks good to me.
>
> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
>

Thanks for reviewing.

Yu-cheng