From: "H. Peter Anvin" <hpa@zytor.com>
To: Dave Hansen <dave.hansen@intel.com>,
"Ren, Qiaowei" <qiaowei.ren@intel.com>,
Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 07/10] x86, mpx: decode MPX instruction to get bound violation information
Date: Thu, 19 Jun 2014 10:32:45 -0700 [thread overview]
Message-ID: <53A31EBD.8060708@zytor.com> (raw)
In-Reply-To: <53A3181F.9070005@intel.com>
On 06/19/2014 10:04 AM, Dave Hansen wrote:
>
> Could you please support this position with some data? I'm a bit
> skeptical that instruction decoding is going to be a
> performance-critical path.
>
> I also don't see the extra field that you talked about in the previous
> thread? What's the extra field? I see a 'limit' vs. 'length', but you
> don't use 'length' at all, so I think you can use it instead, or at
> least union it.
>
> I've taken a quick stab at trying to consolidate things. I think I may
> have screwed up this:
>
> insn->limit = MAX_MPX_INSN_SIZE - bytes;
>
> Qiaowei, is there anything fundamentally broken with what I've got here?
>
So I encouraged Qiaowei to do a limited special-purpose decoder, simply
because the glue to use the generic decoder was almost as large. I am
overall not a huge fan of using the generic decoder in constrained
situation, because the generic decoder is very heavyweight not just in
terms of performance but in terms of interface -- because it has to.
-hpa
next prev parent reply other threads:[~2014-06-19 17:33 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-18 9:44 [PATCH v6 00/10] Intel MPX support Qiaowei Ren
2014-06-18 9:44 ` [PATCH v6 01/10] x86, mpx: introduce VM_MPX to indicate that a VMA is MPX specific Qiaowei Ren
2014-06-18 9:44 ` [PATCH v6 02/10] x86, mpx: add MPX specific mmap interface Qiaowei Ren
2014-06-23 19:49 ` Andy Lutomirski
2014-06-23 20:03 ` Dave Hansen
2014-06-23 20:06 ` Andy Lutomirski
2014-06-23 20:28 ` Dave Hansen
2014-06-23 21:04 ` Andy Lutomirski
2014-06-24 5:53 ` Ren, Qiaowei
2014-06-24 23:55 ` Andy Lutomirski
2014-06-25 1:40 ` Ren, Qiaowei
2014-06-25 21:04 ` Andy Lutomirski
2014-06-25 21:05 ` Andy Lutomirski
2014-06-25 21:45 ` Dave Hansen
2014-06-26 22:19 ` Andy Lutomirski
2014-06-26 22:58 ` Dave Hansen
2014-06-26 23:15 ` Andy Lutomirski
2014-06-27 0:19 ` Dave Hansen
2014-06-27 0:26 ` Andy Lutomirski
2014-06-27 17:34 ` Dave Hansen
2014-06-27 17:42 ` Dave Hansen
2014-06-27 18:57 ` Andy Lutomirski
2014-06-25 21:43 ` Dave Hansen
2014-06-24 2:53 ` Ren, Qiaowei
2014-06-18 9:44 ` [PATCH v6 03/10] x86, mpx: add macro cpu_has_mpx Qiaowei Ren
2014-06-18 9:57 ` Borislav Petkov
2014-06-18 14:35 ` Dave Hansen
2014-06-18 14:44 ` Borislav Petkov
2014-06-18 14:58 ` Dave Hansen
2014-06-18 15:25 ` Borislav Petkov
2014-06-18 16:17 ` Dave Hansen
2014-06-18 15:00 ` H. Peter Anvin
2014-06-18 15:27 ` Borislav Petkov
2014-06-18 14:59 ` H. Peter Anvin
2014-06-18 16:25 ` Dave Hansen
2014-06-18 17:21 ` Borislav Petkov
2014-06-19 18:02 ` H. Peter Anvin
2014-06-19 18:50 ` Dave Hansen
2014-06-20 3:28 ` H. Peter Anvin
2014-06-18 9:44 ` [PATCH v6 04/10] x86, mpx: hook #BR exception handler to allocate bound tables Qiaowei Ren
2014-06-23 19:54 ` Andy Lutomirski
2014-06-24 1:53 ` Ren, Qiaowei
2014-07-11 16:23 ` Dave Hansen
2014-06-18 9:44 ` [PATCH v6 05/10] x86, mpx: extend siginfo structure to include bound violation information Qiaowei Ren
2014-06-18 9:44 ` [PATCH v6 06/10] mips: sync struct siginfo with general version Qiaowei Ren
2014-06-18 9:44 ` [PATCH v6 07/10] x86, mpx: decode MPX instruction to get bound violation information Qiaowei Ren
2014-06-18 10:07 ` Borislav Petkov
2014-06-19 1:13 ` Ren, Qiaowei
2014-06-19 6:28 ` Borislav Petkov
2014-06-19 6:53 ` Ren, Qiaowei
2014-06-19 17:04 ` Dave Hansen
2014-06-19 17:32 ` H. Peter Anvin [this message]
2014-06-20 3:21 ` Ren, Qiaowei
2014-06-18 9:44 ` [PATCH v6 08/10] x86, mpx: add prctl commands PR_MPX_REGISTER, PR_MPX_UNREGISTER Qiaowei Ren
2014-06-19 20:58 ` Dave Hansen
2014-06-23 20:00 ` Andy Lutomirski
2014-06-23 20:09 ` Dave Hansen
2014-06-23 22:00 ` Andy Lutomirski
2014-06-23 23:42 ` Dave Hansen
2014-06-24 0:01 ` Andy Lutomirski
2014-06-24 0:10 ` Dave Hansen
2014-06-18 9:44 ` [PATCH v6 09/10] x86, mpx: cleanup unused bound tables Qiaowei Ren
2014-06-23 19:57 ` Andy Lutomirski
2014-06-18 9:44 ` [PATCH v6 10/10] x86, mpx: add documentation on Intel MPX Qiaowei Ren
2014-06-18 14:41 ` [PATCH v6 00/10] Intel MPX support Dave Hansen
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