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

Kirill A. Shutemov
2021-03-22T09:14:37Z

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>

--
Kirill A. Shutemov