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Subject: Re: [RFC, PATCH 16/22] x86/mm: Preserve KeyID on pte_modify() and
 pgprot_modify()
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Ingo Molnar <mingo@redhat.com>, x86@kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Tom Lendacky <thomas.lendacky@amd.com>
References: <20180305162610.37510-1-kirill.shutemov@linux.intel.com>
 <20180305162610.37510-17-kirill.shutemov@linux.intel.com>
Cc:     Kai Huang <kai.huang@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
From:   Dave Hansen <dave.hansen@intel.com>
Message-ID: <774c1251-46d9-534e-24c2-ca04f1e0a8bb@intel.com>
Date:   Mon, 5 Mar 2018 11:09:23 -0800
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On 03/05/2018 08:26 AM, Kirill A. Shutemov wrote:
> + * It includes full range of PFN bits regardless if they were claimed for KeyID
> + * or not: we want to preserve KeyID on pte_modify() and pgprot_modify().
>   */
> -#define _PAGE_CHG_MASK	(PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |		\
> +#define PTE_PFN_MASK_MAX \
> +	(((signed long)PAGE_MASK) & ((1UL << __PHYSICAL_MASK_SHIFT) - 1))
> +#define _PAGE_CHG_MASK	(PTE_PFN_MASK_MAX | _PAGE_PCD | _PAGE_PWT |		\
>  			 _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY |	\
>  			 _PAGE_SOFT_DIRTY)

Is there a way to make this:

#define _PAGE_CHG_MASK	(PTE_PFN_MASK | PTE_KEY_MASK...? | _PAGE_PCD |

That would be a lot more understandable.