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From: Tom Lendacky <thomas.lendacky@amd.com>
To: David Woodhouse <dwmw2@infradead.org>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg KH <gregkh@linuxfoundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andi Kleen <ak@linux.intel.com>,
	Arjan Van De Ven <arjan.van.de.ven@intel.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/7] x86/feature: Detect the x86 feature to control Speculation
Date: Fri, 5 Jan 2018 09:14:40 -0600	[thread overview]
Message-ID: <197c55e4-4341-8151-6463-d2a91f0cc95b@amd.com> (raw)
In-Reply-To: <1515150882.29312.114.camel@infradead.org>

On 1/5/2018 5:14 AM, David Woodhouse wrote:
> On Thu, 2018-01-04 at 09:56 -0800, Tim Chen wrote:
>> cpuid ax=0x7, return rdx bit 26 to indicate presence of this feature
>> IA32_SPEC_CTRL (0x48) and IA32_PRED_CMD (0x49)
>> IA32_SPEC_CTRL, bit0 – Indirect Branch Restricted Speculation (IBRS)
>> IA32_PRED_CMD,  bit0 – Indirect Branch Prediction Barrier (IBPB)
> 
> In a previous iteration of these patches, hadn't you already merged
> support for the AMD variant? Where'd that go?

It looks like this series is strictly IBRS related.  Even though some of
the IBPB definitions are in here, there isn't support later for indicating
IBPB is in use or any places where IBPB would be used. I was assuming that
there would be another series for IBPB support.  Is that the plan?

AMD is covered by the IBRS support as is, but we also have support for
the IBPB feature alone, identified by a different CPUID bit.  I was
waiting for the IBPB series to see if I needed to submit anything or
whether the patches were included.

Thanks,
Tom

> 

  reply	other threads:[~2018-01-05 15:14 UTC|newest]

Thread overview: 114+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-04 17:56 [PATCH 0/7] IBRS patch series Tim Chen
2018-01-04 17:56 ` [PATCH 1/7] x86/feature: Detect the x86 feature to control Speculation Tim Chen
2018-01-04 19:58   ` Greg KH
2018-01-04 20:47     ` Tim Chen
2018-01-05 11:14   ` David Woodhouse
2018-01-05 15:14     ` Tom Lendacky [this message]
2018-01-05 17:07       ` Tim Chen
2018-01-05 13:09   ` Thomas Gleixner
2018-01-05 13:44     ` Andrea Arcangeli
2018-01-05 13:51       ` Thomas Gleixner
2018-01-04 17:56 ` [PATCH 2/7] x86/enter: MACROS to set/clear IBRS Tim Chen
2018-01-04 22:16   ` Peter Zijlstra
2018-01-04 22:21     ` Tim Chen
2018-01-04 22:23       ` Dave Hansen
2018-01-05  4:54         ` Andy Lutomirski
2018-01-05  5:05           ` Dave Hansen
2018-01-05 13:19       ` Thomas Gleixner
2018-01-04 17:56 ` [PATCH 3/7] x86/enter: Use IBRS on syscall and interrupts Tim Chen
2018-01-04 20:00   ` Greg KH
2018-01-04 20:26     ` Tim Chen
2018-01-04 20:45   ` Dave Hansen
2018-01-04 22:33   ` Peter Zijlstra
2018-01-04 23:12     ` Andrea Arcangeli
2018-01-05  0:08     ` Dave Hansen
2018-01-05  4:51       ` Andy Lutomirski
2018-01-05  5:11         ` Dave Hansen
2018-01-05 12:01           ` Alan Cox
2018-01-05 13:35   ` Thomas Gleixner
2018-01-04 17:56 ` [PATCH 4/7] x86/idle: Disable IBRS entering idle and enable it on wakeup Tim Chen
2018-01-04 22:47   ` Peter Zijlstra
2018-01-04 23:00     ` Andrea Arcangeli
2018-01-04 23:22     ` Tim Chen
2018-01-04 23:42       ` Andrea Arcangeli
2018-01-04 23:45         ` Thomas Gleixner
2018-01-05  0:03           ` Andrea Arcangeli
2018-01-08  8:24       ` Peter Zijlstra
2018-01-04 17:56 ` [PATCH 5/7] x86: Use IBRS for firmware update path Tim Chen
2018-01-04 18:48   ` Alan Cox
2018-01-04 20:05   ` Greg KH
2018-01-04 20:08     ` Woodhouse, David
2018-01-05 16:08       ` gregkh
2018-01-05 16:37         ` Andrea Arcangeli
2018-01-04 20:21     ` Andrew Cooper
2018-01-04 20:48     ` Andrea Arcangeli
2018-01-04 20:51   ` Yves-Alexis Perez
2018-01-04 21:13     ` Tim Chen
2018-01-04 22:51   ` Peter Zijlstra
2018-01-05 13:40   ` Thomas Gleixner
2018-01-04 17:56 ` [PATCH 6/7] x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature Tim Chen
2018-01-04 18:33   ` Borislav Petkov
2018-01-04 18:36     ` Dave Hansen
2018-01-04 18:52       ` Borislav Petkov
2018-01-04 18:57         ` Andrea Arcangeli
2018-01-04 18:59         ` Dave Hansen
2018-01-04 19:06           ` Borislav Petkov
2018-01-05 13:48       ` Thomas Gleixner
2018-01-04 18:38     ` Andrea Arcangeli
2018-01-04 18:54       ` Dave Hansen
2018-01-04 18:56         ` Borislav Petkov
2018-01-04 18:55       ` Borislav Petkov
2018-01-04 18:34   ` Andrea Arcangeli
2018-01-04 19:02     ` Tim Chen
2018-01-04 18:50   ` Alan Cox
2018-01-04 20:16   ` Greg KH
2018-01-04 20:58     ` Tim Chen
2018-01-04 22:54   ` Peter Zijlstra
2018-01-04 23:26     ` Tim Chen
2018-01-04 23:51       ` Andrea Arcangeli
2018-01-04 23:59         ` Borislav Petkov
2018-01-05  0:07           ` Thomas Gleixner
2018-01-05 11:16   ` David Woodhouse
2018-01-06  1:29     ` Tim Chen
2018-01-04 17:56 ` [PATCH 7/7] x86/microcode: Recheck IBRS features on microcode reload Tim Chen
2018-01-04 18:28   ` Borislav Petkov
2018-01-04 18:34     ` Andrea Arcangeli
2018-01-04 18:50       ` Borislav Petkov
2018-01-04 19:10         ` Tim Chen
2018-01-05 13:32         ` Greg KH
2018-01-05 13:37           ` Borislav Petkov
2018-01-05 13:47             ` Greg KH
2018-01-05 15:28           ` Andrea Arcangeli
2018-01-04 19:00 ` [PATCH 0/7] IBRS patch series Linus Torvalds
2018-01-04 19:19   ` David Woodhouse
2018-01-04 19:33     ` Linus Torvalds
2018-01-04 19:39       ` David Woodhouse
2018-01-04 19:40       ` Andrew Cooper
2018-01-04 19:46         ` David Woodhouse
2018-01-04 21:22       ` Van De Ven, Arjan
2018-01-05 11:32         ` Paolo Bonzini
2018-01-05 12:09           ` Paul Turner
2018-01-05 14:45           ` Van De Ven, Arjan
2018-01-05 14:43         ` Andrea Arcangeli
2018-01-05 14:52           ` Van De Ven, Arjan
2018-01-05 15:03             ` Andrea Arcangeli
2018-01-05 14:54           ` Thomas Gleixner
2018-01-05 11:52       ` Paul Turner
2018-01-05 14:28         ` David Woodhouse
2018-01-05 14:42           ` Van De Ven, Arjan
2018-01-05 15:38             ` David Woodhouse
2018-01-05 16:05               ` Andrea Arcangeli
2018-01-05 16:37                 ` David Woodhouse
2018-01-05 16:42                   ` Andrea Arcangeli
2018-01-05 16:44                     ` Van De Ven, Arjan
2018-01-05 16:46                     ` David Woodhouse
2018-01-05  5:25   ` Florian Weimer
2018-01-05 11:05     ` David Woodhouse
2018-01-04 19:05 ` Justin Forbes
2018-01-04 19:10   ` Tim Chen
2018-01-04 21:01     ` Yves-Alexis Perez
2018-01-05 13:28       ` Greg KH
2018-01-05 13:47         ` Yves-Alexis Perez
2018-01-05 14:01           ` Greg KH
2018-01-05 14:26             ` Paolo Bonzini
2018-01-05 14:54               ` Yves-Alexis Perez

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