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Date: Fri, 15 Jun 2018 23:55:36 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCHv3 07/17] x86/mm: Preserve KeyID on pte_modify() and
 pgprot_modify()
Message-ID: <20180615205535.32nhgqelbyjihzts@black.fi.intel.com>
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To: Dave Hansen <dave.hansen@intel.com>
Cc: 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>, Kai Huang <kai.huang@linux.intel.com>, Jacob Pan <jacob.jun.pan@linux.intel.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org

On Fri, Jun 15, 2018 at 08:45:21PM +0000, Dave Hansen wrote:
> On 06/15/2018 01:45 PM, Kirill A. Shutemov wrote:
> > On Fri, Jun 15, 2018 at 04:58:24PM +0000, Dave Hansen wrote:
> >> On 06/15/2018 09:06 AM, Kirill A. Shutemov wrote:
> >>> I have no idea what such concept should be called. I cannot come with
> >>> anything better than PTE_PFN_MASK_MAX. Do you?
> >> PTE_PRESERVE_MASK
> >>
> >> Or maybe:
> >>
> >> PTE_MODIFY_PRESERVE_MASK
> > It just replacing one confusion with another. Preserve what?
> 
> "Preserve this mask when modifying pte permission bits"

We preserve more than these bits. See _PAGE_CHG_MASK.

-- 
 Kirill A. Shutemov