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Date: Mon, 29 Jan 2018 18:39:45 +0300
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>, x86@kernel.org,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andy Lutomirski <luto@amacapital.net>,
        Cyrill Gorcunov <gorcunov@openvz.org>, Borislav Petkov <bp@suse.de>,
        Andi Kleen <ak@linux.intel.com>, Matthew Wilcox <willy@infradead.org>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv7 5/4] x86/boot/compressed/64: Support switching from 5-
 to 4-level paging
Message-ID: <20180129153945.sme6f2zx3fpj24qy@node.shutemov.name>
References: <20180129115351.85224-1-kirill.shutemov@linux.intel.com>
 <20180129150758.81016-1-kirill.shutemov@linux.intel.com>
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On Mon, Jan 29, 2018 at 06:07:58PM +0300, Kirill A. Shutemov wrote:
> +	/*
> +	 * We are in 5-level paging mode, but we want to switch to 4-level.
> +	 * Let's take the first entry in the top-level page table as our new CR3.
> +	 */
> +	movl	%cr3, %eax
> +	movl	(%eax), %eax
> +	movl	%eax, %cr3

Aghh.. Please ignore this.

It would fail if CR3 points above 4G.

-- 
 Kirill A. Shutemov