linux-kernel - Re: [PATCHv5 01/13] x86/mm: Fix CR3_ADDR

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Date:   Thu, 21 Jul 2022 15:10:18 +0200
From:   Alexander Potapenko <glider@...gle.com>
To:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Kostya Serebryany <kcc@...gle.com>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Taras Madan <tarasmadan@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        "H . J . Lu" <hjl.tools@...il.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        Linux Memory Management List <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv5 01/13] x86/mm: Fix CR3_ADDR_MASK

On Wed, Jul 13, 2022 at 1:13 AM Kirill A. Shutemov
<kirill.shutemov@...ux.intel.com> wrote:
>
> 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@...ux.intel.com>
> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
Reviewed-by: Alexander Potapenko <glider@...gle.com>
Tested-by: Alexander Potapenko <glider@...gle.com>

> ---
>  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 @@
>   */
>  #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
>


-- 
Alexander Potapenko
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