From: Chao Fan <fanc.fnst@cn.fujitsu.com>
To: <tglx@linutronix.de>, <mingo@redhat.com>, <hpa@zytor.com>,
<x86@kernel.org>, <linux-kernel@vger.kernel.org>,
<keescook@chromium.org>, <bhe@redhat.com>,
<n-horiguchi@ah.jp.nec.com>
Cc: <indou.takao@jp.fujitsu.com>, <caoj.fnst@cn.fujitsu.com>,
<douly.fnst@cn.fujitsu.com>
Subject: Re: [PATCH v5 0/4] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory.
Date: Thu, 23 Aug 2018 09:37:52 +0800 [thread overview]
Message-ID: <20180823013752.GA6769@localhost.localdomain> (raw)
In-Reply-To: <20180807065000.30958-1-fanc.fnst@cn.fujitsu.com>
Hi all,
No reply for 2 weeks, any comments?
Thanks,
Chao Fan
On Tue, Aug 07, 2018 at 02:49:56PM +0800, Chao Fan wrote:
>***Background:
>People reported that kaslr may randomly chooses some positions
>which are located in movable memory regions. This will break memory
>hotplug feature and make the memory can't be removed.
>
>***Solutions:
>There should be a method to limit kaslr to choosing immovable memory
>regions, so there are 2 solutions:
>1) Add a kernel parameter to specify the memory regions.
>2) Get the information of memory hotremove, then kaslr will know the
> right regions.
>In method 2, information about memory hot remove is in ACPI
>tables, which will be parsed after 'start_kernel', kaslr can't get
>the information.
>In method 1, users should know the regions address and specify in
>kernel parameter.
>
>In the earliest time, I tried to dig ACPI tabls to solve this problem.
>But I didn't splite the code in 'compressed/' and ACPI code, so the patch
>is hard to follow so refused by community.
>Somebody suggest to add a kernel parameter to specify the
>immovable memory so that limit kaslr in these regions. Then I make
>a patchset. After several versions, Ingo gave a suggestion:
>https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1634024.html
>Follow Ingo's suggestion, imitate the ACPI code to parse the acpi
>tables, so that the kaslr can get necessary memory information in
>ACPI tables.
>Since I think ACPI code is independent part, so copy the codes
>and functions to 'compressed/' directory, so that kaslr won't
>influence the initialization of ACPI.
>
>PATCH 1/4 Reuse the head file of linux/acpi.h, and copy a fcuntion from
> ACPI code.
>PATCH 2/4 Functions to parse ACPI code.
>PATCH 3/4 If 'CONFIG_MEMORY_HOTREMOVE' specified, walk all nodes and
> store the information of immovable memory regions.
>PATCH 4/4 According to the immovable memory regions, filter the
> immovable regions which KASLR can choose.
>
>***Test results:
> - I did a very simple test, and it can get the memory information in
> bios and efi KVM guest machine, and put it by early printk. But no
> more tests, so it's with RFC tag.
>
>v1->v2:
> - Simplify some code.
>Follow Baoquan He's suggestion:
> - Reuse the head file of acpi code.
>
>v2->v3:
> - Test in more conditions, so remove the 'RFC' tag.
> - Change some comments.
>
>v3->v4:
>Follow Thomas Gleixner's suggetsion:
> - Put the whole efi related function into #define CONFIG_EFI and return
> false in the other stub.
> - Simplify two functions in head file.
>
>v4->v5:
>Follow Dou Liyang's suggestion:
> - Add more comments about some functions based on kernel code.
> - Change some typo in comments.
> - Clean useless variable.
> - Add check for the boundary of array.
> - Add check for 'movable_node' parameter
>
>Any comments will be welcome.
>
>
>Chao Fan (4):
> x86/boot: Add acpitb.h to help parse acpi tables
> x86/boot: Add acpitb.c to parse acpi tables
> x86/boot/KASLR: Walk srat tables to filter immovable memory
> x86/boot/KASLR: Limit kaslr to choosing the immovable memory
>
> arch/x86/boot/compressed/Makefile | 4 +
> arch/x86/boot/compressed/acpitb.c | 272 ++++++++++++++++++++++++++++++
> arch/x86/boot/compressed/acpitb.h | 7 +
> arch/x86/boot/compressed/kaslr.c | 125 ++++++++++++--
> 4 files changed, 397 insertions(+), 11 deletions(-)
> create mode 100644 arch/x86/boot/compressed/acpitb.c
> create mode 100644 arch/x86/boot/compressed/acpitb.h
>
>--
>2.17.1
>
prev parent reply other threads:[~2018-08-23 1:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-07 6:49 [PATCH v5 0/4] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory Chao Fan
2018-08-07 6:49 ` [PATCH v5 1/4] x86/boot: Add acpitb.h to help parse acpi tables Chao Fan
2018-08-07 6:49 ` [PATCH v5 2/4] x86/boot: Add acpitb.c to " Chao Fan
2018-08-27 9:32 ` Baoquan He
2018-08-07 6:49 ` [PATCH v5 3/4] x86/boot/KASLR: Walk srat tables to filter immovable memory Chao Fan
2018-08-23 7:25 ` Baoquan He
2018-08-23 7:30 ` Chao Fan
2018-08-27 2:13 ` Baoquan He
2018-08-27 2:56 ` Chao Fan
2018-08-27 3:07 ` Baoquan He
2018-08-07 6:50 ` [PATCH v5 4/4] x86/boot/KASLR: Limit kaslr to choosing the " Chao Fan
2018-08-27 5:35 ` Baoquan He
2018-08-27 6:04 ` Baoquan He
2018-08-27 5:56 ` Baoquan He
2018-08-27 6:28 ` Chao Fan
2018-08-27 6:31 ` Chao Fan
2018-08-27 7:01 ` Baoquan He
2018-08-27 7:10 ` Baoquan He
2018-08-23 1:37 ` Chao Fan [this message]
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