From: Baoquan He <bhe@redhat.com>
To: tglx@linutronix.de, stable@vger.kernel.org, mingo@kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
peterz@infradead.org, keescook@chromium.org, bp@suse.de,
luto@kernel.org, hpa@zytor.com, kirill@linux.intel.com,
dave.hansen@linux.intel.com
Cc: linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/urgent] x86/mm/KASLR: Compute the size of the vmemmap section properly
Date: Sat, 8 Jun 2019 10:14:04 +0800 [thread overview]
Message-ID: <20190608021404.GA26148@MiWiFi-R3L-srv> (raw)
In-Reply-To: <tip-00e5a2bbcc31d5fea853f8daeba0f06c1c88c3ff@git.kernel.org>
On 06/07/19 at 02:16pm, tip-bot for Baoquan He wrote:
> Commit-ID: 00e5a2bbcc31d5fea853f8daeba0f06c1c88c3ff
> Gitweb: https://git.kernel.org/tip/00e5a2bbcc31d5fea853f8daeba0f06c1c88c3ff
> Author: Baoquan He <bhe@redhat.com>
> AuthorDate: Thu, 23 May 2019 10:57:44 +0800
> Committer: Borislav Petkov <bp@suse.de>
> CommitDate: Fri, 7 Jun 2019 23:12:13 +0200
>
> x86/mm/KASLR: Compute the size of the vmemmap section properly
>
> The size of the vmemmap section is hardcoded to 1 TB to support the
> maximum amount of system RAM in 4-level paging mode - 64 TB.
>
> However, 1 TB is not enough for vmemmap in 5-level paging mode. Assuming
> the size of struct page is 64 Bytes, to support 4 PB system RAM in 5-level,
> 64 TB of vmemmap area is needed:
>
> 4 * 1000^5 PB / 4096 bytes page size * 64 bytes per page struct / 1000^4 TB = 62.5 TB.
Thanks for picking this, Boris.
Here, 4PB = 4*2^50 = 4*1024^5, the vmemmap should be 64 TB, am I right?
>
> This hardcoding may cause vmemmap to corrupt the following
> cpu_entry_area section, if KASLR puts vmemmap very close to it and the
> actual vmemmap size is bigger than 1 TB.
next prev parent reply other threads:[~2019-06-08 2:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 2:57 [PATCH v5] x86/mm/KASLR: Fix the size of vmemmap section Baoquan He
[not found] ` <20190529131454.9818321019@mail.kernel.org>
2019-05-30 0:46 ` Baoquan He
2019-06-07 21:16 ` [tip:x86/urgent] x86/mm/KASLR: Compute the size of the vmemmap section properly tip-bot for Baoquan He
2019-06-08 2:14 ` Baoquan He [this message]
2019-06-08 7:49 ` Borislav Petkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190608021404.GA26148@MiWiFi-R3L-srv \
--to=bhe@redhat.com \
--cc=bp@suse.de \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=keescook@chromium.org \
--cc=kirill@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.