From: Baoquan He <bhe@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-doc@vger.kernel.org, tglx@linutronix.de,
thgarnie@google.com, corbet@lwn.net,
Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 4/3] x86/mm/doc: Enhance the x86-64 virtual memory layout descriptions
Date: Sat, 6 Oct 2018 22:41:53 +0800 [thread overview]
Message-ID: <20181006144153.GE5140@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20181006123322.GA60572@gmail.com>
On 10/06/18 at 02:33pm, Ingo Molnar wrote:
>
> * Ingo Molnar <mingo@kernel.org> wrote:
>
> > +========================================================
> > +| Complete virtual memory map with 4-level page tables |
> > +========================================================
>
> > +--------------------------------------------------------------------------------
> > +start addr | offset | end addr | size | VM area description
> > +-----------------|------------|------------------|---------|--------------------
>
> > +
> > +# Identical layout to the 56-bit one from here on:
> > +
> > +ffffff8000000000 | -512 GB | fffffffeefffffff | ~507 GB | ... unused hole
> > +ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region mapping space
>
> > +========================================================
> > +| Complete virtual memory map with 5-level page tables |
> > +========================================================
>
> > +ffffff8000000000 | -0.5 TB | ffffffeeffffffff | 444 GB | ... unused hole
> > +
> > +# Identical layout to the 47-bit one from here on:
> > +
> > +ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region mapping space
>
> So patch #2 appears to have introduced an error/typo in the 47-bit table. Note the weird size
> and discontinuity of the 'unused hole' in the 47-bit table, and compare it with 56-bit table:
>
> fffffffeefffffff
> ffffffeeffffffff
>
> (Note how the incorrect end address was cargo-cult-copied into the 'size' field of ~507 GB...)
>
> The correct number is the 56-bit one, and both tables should show the following identical
> layout:
>
> ffffff8000000000 | -512 GB | fffffffeefffffff | 444 GB | ... unused hole
> ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region mapping space
>
> Agreed?
Yes, you are right. I wondered why the size is a weird unaligned value.
Sorry about that.
Thanks
Baoquan
next prev parent reply other threads:[~2018-10-06 14:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-06 8:43 [PATCH 0/3] x86/mm/doc: Clean up mm.txt Baoquan He
2018-10-06 8:43 ` [PATCH 1/3] x86/KASLR: Update KERNEL_IMAGE_SIZE description Baoquan He
2018-10-06 8:43 ` [PATCH 2/3] x86/mm/doc: Clean up the memory region layout descriptions Baoquan He
2018-10-06 8:43 ` [PATCH 3/3] x86/doc/kaslr.txt: Create a separate part of document abourt KASLR at the end of file Baoquan He
2018-10-06 11:28 ` [PATCH 0/3] x86/mm/doc: Clean up mm.txt Baoquan He
2018-10-06 12:21 ` Ingo Molnar
2018-10-06 12:22 ` [PATCH 4/3] x86/mm/doc: Enhance the x86-64 virtual memory layout descriptions Ingo Molnar
2018-10-06 12:33 ` Ingo Molnar
2018-10-06 14:41 ` Baoquan He [this message]
2018-10-06 14:38 ` [PATCH 4/3 v2] " Ingo Molnar
2018-10-06 15:02 ` Baoquan He
2018-10-06 17:03 ` Ingo Molnar
2018-10-06 22:17 ` Andy Lutomirski
2018-10-09 0:35 ` Baoquan He
2018-10-09 4:48 ` Baoquan He
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