RE: [PATCHv5 01/13] x86/mm: Fix CR3_ADDR_MASK

[Hu, Robert]

> -----Original Message-----
> From: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Sent: Wednesday, July 13, 2022 07:13
> To: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>; Lutomirski, Andy
> <luto@xxxxxxxxxx>; Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: x86@xxxxxxxxxx; Kostya Serebryany <kcc@xxxxxxxxxx>; Andrey Ryabinin
> <ryabinin.a.a@xxxxxxxxx>; Andrey Konovalov <andreyknvl@xxxxxxxxx>;
> Alexander Potapenko <glider@xxxxxxxxxx>; Taras Madan
> <tarasmadan@xxxxxxxxxx>; Dmitry Vyukov <dvyukov@xxxxxxxxxx>; H . J . Lu
> <hjl.tools@xxxxxxxxx>; Andi Kleen <ak@xxxxxxxxxxxxxxx>; Edgecombe, Rick P
> <rick.p.edgecombe@xxxxxxxxx>; linux-mm@xxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Subject: [PATCHv5 01/13] x86/mm: Fix CR3_ADDR_MASK
> 
> The mask must not include bits above physical address mask. These bits are
> reserved and can be used for other things. Bits 61 and 62 are used for Linear
> Address Masking.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
> ---
>  arch/x86/include/asm/processor-flags.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/processor-flags.h
> b/arch/x86/include/asm/processor-flags.h
> index 02c2cbda4a74..a7f3d9100adb 100644
> --- a/arch/x86/include/asm/processor-flags.h
> +++ b/arch/x86/include/asm/processor-flags.h
> @@ -35,7 +35,7 @@
>   */
[Hu, Robert] 
The comments above these #define's, explaining CR3 layout, can be updated on
the new CR3 bits as well?

>  #ifdef CONFIG_X86_64
>  /* Mask off the address space ID and SME encryption bits. */
> -#define CR3_ADDR_MASK	__sme_clr(0x7FFFFFFFFFFFF000ull)
> +#define CR3_ADDR_MASK	__sme_clr(PHYSICAL_PAGE_MASK)
>  #define CR3_PCID_MASK	0xFFFull
>  #define CR3_NOFLUSH	BIT_ULL(63)
> 
> --
> 2.35.1