linux-kernel - Re: [PATCHv3 1/3] x86/mm: Move LDT remap out of KASLR region on 5-level paging

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Message-ID: <20181203092601.h7fuhvbmgdbfgqcd@kshutemo-mobl1>
Date:   Mon, 3 Dec 2018 12:26:01 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Baoquan He <bhe@...hat.com>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
        boris.ostrovsky@...cle.com, jgross@...e.com, willy@...radead.org,
        x86@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv3 1/3] x86/mm: Move LDT remap out of KASLR region on
 5-level paging

On Mon, Dec 03, 2018 at 11:01:00AM +0800, Baoquan He wrote:
> It looks do-able, not sure if the test case is complicated or not, if
> not hard, I can have a try. And I have some internal bugs, can focus on
> this later. I saw you posted another patchset to fix xen issue, it may
> not be needed any more if we take this way?

Well, it depends on what is the first in the KALSR group. The fix will not
be needed if direct mapping comes the first.

But I would rather go with the patch anyway. The hypervisor hole is part
of ABI and we should not calculate it based on other movable entity
(direct mapping, LDT remap, whatever). It's too fragile.

-- 
 Kirill A. Shutemov