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From: Matthew Wilcox <willy@infradead.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org,
	peterz@infradead.org, x86@kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] x86/mm: Move LDT remap out of KASLR region on 5-level paging
Date: Wed, 24 Oct 2018 04:54:47 -0700	[thread overview]
Message-ID: <20181024115447.GE25444@bombadil.infradead.org> (raw)
In-Reply-To: <20181023163157.41441-2-kirill.shutemov@linux.intel.com>

On Tue, Oct 23, 2018 at 07:31:56PM +0300, Kirill A. Shutemov wrote:
> -ffff880000000000 - ffffc7ffffffffff (=64 TB) direct mapping of all phys. memory
> +ffff888000000000 - ffff887fffffffff (=39 bits) LDT remap for PTI

I'm a little bit cross-eyed at this point, but I think the above '888'
should be '880'.

> @@ -14,7 +15,6 @@ ffffec0000000000 - fffffbffffffffff (=44 bits) kasan shadow memory (16TB)
>  ... unused hole ...
>  				    vaddr_end for KASLR
>  fffffe0000000000 - fffffe7fffffffff (=39 bits) cpu_entry_area mapping
> -fffffe8000000000 - fffffeffffffffff (=39 bits) LDT remap for PTI

... and the line above this one should be adjusted to finish at
fffffeffffffffff (also it's now 40 bits).  Or should there be something
else here?

>  ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
>  ... unused hole ...
>  ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space
> @@ -30,8 +30,8 @@ Virtual memory map with 5 level page tables:
>  0000000000000000 - 00ffffffffffffff (=56 bits) user space, different per mm
>  hole caused by [56:63] sign extension
>  ff00000000000000 - ff0fffffffffffff (=52 bits) guard hole, reserved for hypervisor
> -ff10000000000000 - ff8fffffffffffff (=55 bits) direct mapping of all phys. memory
> -ff90000000000000 - ff9fffffffffffff (=52 bits) LDT remap for PTI
> +ff10000000000000 - ff10ffffffffffff (=48 bits) LDT remap for PTI
> +ff11000000000000 - ff90ffffffffffff (=55 bits) direct mapping of all phys. memory

What's at ff910..0 to ff9f..f ?

Is there any way we can generate this part of this file to prevent human
error from creeping in over time?  ;-)


  reply	other threads:[~2018-10-24 11:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-23 16:31 [PATCH 0/2] Fix couple of issues with LDT remap for PTI Kirill A. Shutemov
2018-10-23 16:31 ` [PATCH 1/2] x86/mm: Move LDT remap out of KASLR region on 5-level paging Kirill A. Shutemov
2018-10-24 11:54   ` Matthew Wilcox [this message]
2018-10-24 12:44     ` Kirill A. Shutemov
2018-10-23 16:31 ` [PATCH 2/2] x86/ldt: Unmap PTEs for the slow before freeing LDT Kirill A. Shutemov
2018-10-24 11:12   ` Christoph Hellwig
2018-10-24 18:49   ` Andy Lutomirski
2018-10-25  7:26     ` Kirill A. Shutemov
2018-10-24 19:39   ` H. Peter Anvin

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