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From: Thomas Gleixner <tglx@linutronix.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>,
	linux-kernel@vger.kernel.org,
	the arch/x86 maintainers <x86@kernel.org>,
	Borislav Petkov <bp@alien8.de>,
	dave.hansen@intel.com, tony.luck@intel.com, ak@linux.intel.com,
	ravi.v.shankar@intel.com
Subject: Re: [PATCH v8 00/17] Enable FSGSBASE instructions
Date: Mon, 16 Sep 2019 11:21:50 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.21.1909161119340.10731@nanos.tec.linutronix.de> (raw)
In-Reply-To: <034aaf3a-a93d-ec03-0bbd-068e1905b774@kernel.org>

On Thu, 12 Sep 2019, Andy Lutomirski wrote:

Thanks, for adding me and the others on Cc. I had to dig out the cover
letter from my LKML archive ....

> On 9/12/19 1:06 PM, Chang S. Bae wrote:
> 
> > Updates from v7 [7]:
> > (1) Consider FSGSBASE when determining which Spectre SWAPGS mitigations are
> >      required.
> > (2) Fixed save_fsgs() to be aware of interrupt conditions
> > (3) Made selftest changes based on Andy's previous fixes and cleanups
> > (4) Included Andy's paranoid exit cleanup
> > (5) Included documentation rewritten by Thomas
> > (6) Carried on Thomas' edits on multiple changelogs and comments
> > (7) Used '[FS|GS] base' consistently, except for selftest where GSBASE has
> >      been already used in its test messages
> > (8) Dropped the READ_MSR_GSBASE macro
> > 
> 
> This looks unpleasant to review.  I wonder if it would be better to unrevert
> the reversion, merge up to Linus' tree or -tip, and then base the changes on
> top of that.

I don't think that's a good idea. The old code is broken in several ways
and not bisectable. So we really better start from scratch.

Thanks,

	tglx

  reply	other threads:[~2019-09-16  9:21 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-12 20:06 [PATCH v8 00/17] Enable FSGSBASE instructions Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 01/17] x86/ptrace: Prevent ptrace from clearing the FS/GS selector Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 02/17] selftests/x86/fsgsbase: Test GS selector on ptracer-induced GS base write Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 03/17] x86/cpu: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 04/17] x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 05/17] x86/fsgsbase/64: Enable FSGSBASE instructions in helper functions Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 06/17] x86/fsgsbase/64: Use FSGSBASE in switch_to() if available Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 07/17] x86/fsgsbase/64: Use FSGSBASE instructions on thread copy and ptrace Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 08/17] x86/entry/64: Clean up paranoid exit Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 09/17] x86/entry/64: Switch CR3 before SWAPGS in paranoid entry Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 10/17] x86/entry/64: Introduce the FIND_PERCPU_BASE macro Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 11/17] x86/entry/64: Handle FSGSBASE enabled paranoid entry/exit Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 12/17] x86/entry/64: Document GSBASE handling in the paranoid path Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 13/17] x86/speculation/swapgs: Check FSGSBASE in enabling SWAPGS mitigation Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 14/17] selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 15/17] x86/fsgsbase/64: Enable FSGSBASE on 64bit by default and add a chicken bit Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 16/17] x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 Chang S. Bae
2019-09-12 20:06 ` [PATCH v8 17/17] Documentation/x86/64: Add documentation for GS/FS addressing mode Chang S. Bae
2019-09-27 21:25   ` Randy Dunlap
2019-09-27 21:50     ` Bae, Chang Seok
2019-09-13  4:10 ` [PATCH v8 00/17] Enable FSGSBASE instructions Andy Lutomirski
2019-09-16  9:21   ` Thomas Gleixner [this message]
2019-09-18 21:02   ` Bae, Chang Seok

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