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Date:   Fri, 5 Feb 2021 19:01:27 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>, x86@kernel.org,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        "H . J . Lu" <hjl.tools@gmail.com>,
        Andi Kleen <ak@linux.intel.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC 0/9] Linear Address Masking enabling
Message-ID: <20210205160127.ylcdd6bbve6q2bbk@black.fi.intel.com>
References: <20210205151631.43511-1-kirill.shutemov@linux.intel.com>
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On Fri, Feb 05, 2021 at 04:49:05PM +0100, Peter Zijlstra wrote:
> On Fri, Feb 05, 2021 at 06:16:20PM +0300, Kirill A. Shutemov wrote:
> > The feature competes for bits with 5-level paging: LAM_U48 makes it
> > impossible to map anything about 47-bits. The patchset made these
> > capability mutually exclusive: whatever used first wins. LAM_U57 can be
> > combined with mappings above 47-bits.
> 
> And I suppose we still can't switch between 4 and 5 level at runtime,
> using a CR3 bit?

No. And I can't imagine how would it work with 5-level on kernel side.

-- 
 Kirill A. Shutemov