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From: Juergen Gross <jgross@suse.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	David Woodhouse <dwmw@amazon.co.uk>
Cc: ak@linux.intel.com, Paul Turner <pjt@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linux-foundation.org>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Kees Cook <keescook@google.com>, Rik van Riel <riel@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Jiri Kosina <jikos@kernel.org>,
	gnomes@lxorguk.ukuu.org.uk
Subject: Re: [PATCH v3 01/13] x86/retpoline: Add initial retpoline support
Date: Fri, 5 Jan 2018 14:01:00 +0100	[thread overview]
Message-ID: <253b8320-e122-d5f7-b305-387db2f86818@suse.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1801051345490.1724@nanos>

On 05/01/18 13:54, Thomas Gleixner wrote:
> On Thu, 4 Jan 2018, David Woodhouse wrote:
>> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
>> index 07cdd1715705..900fa7016d3f 100644
>> --- a/arch/x86/include/asm/cpufeatures.h
>> +++ b/arch/x86/include/asm/cpufeatures.h
>> @@ -342,5 +342,6 @@
>>  #define X86_BUG_MONITOR			X86_BUG(12) /* IPI required to wake up remote CPU */
>>  #define X86_BUG_AMD_E400		X86_BUG(13) /* CPU is among the affected by Erratum 400 */
>>  #define X86_BUG_CPU_INSECURE		X86_BUG(14) /* CPU is insecure and needs kernel page table isolation */
>> +#define X86_BUG_NO_RETPOLINE		X86_BUG(15) /* Placeholder: disable retpoline branch thunks */
> 
> I think this is the wrong approach. We have X86_BUG_CPU_INSECURE, which now
> should be renamed to X86_BUG_CPU_MELTDOWN_V3 or something like that. It
> tells the kernel, that the CPU is affected by variant 3.

MELTDOWN is variant 3.

> 
> If the kernel detects that and has PTI support then it sets the 'pti'
> feature bit which tells that the mitigation is in place.
> 
> So what we really want is
> 
>    X86_BUG_MELTDOWN_V1/2/3

X86_BUG_MELTDOWN, X86_BUG_SPECTRE_V1, X86_BUG_SPECTRE_V2


Juergen

  reply	other threads:[~2018-01-05 13:01 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-04  9:10 [RFC] Retpoline: Binary mitigation for branch-target-injection (aka "Spectre") Paul Turner
2018-01-04  9:12 ` Paul Turner
2018-01-04  9:24 ` Paul Turner
2018-01-04  9:48   ` Greg Kroah-Hartman
2018-01-04  9:56     ` Woodhouse, David
2018-01-04  9:30 ` Woodhouse, David
2018-01-04 14:36   ` [PATCH v3 01/13] x86/retpoline: Add initial retpoline support David Woodhouse
2018-01-04 18:03     ` Linus Torvalds
2018-01-04 19:32       ` Woodhouse, David
2018-01-04 18:17     ` Alexei Starovoitov
2018-01-04 18:25       ` Linus Torvalds
2018-01-04 18:36         ` Alexei Starovoitov
2018-01-04 19:27           ` David Woodhouse
2018-01-05 10:28             ` Paul Turner
2018-01-05 10:55               ` David Woodhouse
2018-01-05 11:19                 ` Paul Turner
2018-01-05 11:25                 ` Paul Turner
2018-01-05 11:26               ` Paolo Bonzini
2018-01-05 12:20                 ` Paul Turner
2018-01-05 10:40         ` Paul Turner
2018-01-04 18:40       ` Andi Kleen
2018-01-05 10:32         ` Paul Turner
2018-01-05 12:54     ` Thomas Gleixner
2018-01-05 13:01       ` Juergen Gross [this message]
2018-01-05 13:03         ` Thomas Gleixner
2018-01-05 13:56       ` Woodhouse, David
2018-01-05 16:41         ` Woodhouse, David
2018-01-05 16:45           ` Borislav Petkov
2018-01-05 17:08             ` Josh Poimboeuf
2018-01-06  0:30               ` Borislav Petkov
2018-01-06  8:23                 ` David Woodhouse
2018-01-06 17:02                   ` Borislav Petkov
2018-01-07  9:40                     ` David Woodhouse
2018-01-07 11:46                       ` Borislav Petkov
2018-01-07 12:21                         ` David Woodhouse
2018-01-07 14:03                           ` Borislav Petkov
2018-01-08 21:50                             ` David Woodhouse
2018-01-08  5:06                 ` Josh Poimboeuf
2018-01-08  7:55                   ` Woodhouse, David
2018-01-05 17:12             ` Woodhouse, David
2018-01-05 17:28               ` Linus Torvalds
2018-01-05 17:48                 ` David Woodhouse
2018-01-05 18:05                 ` Andi Kleen
2018-01-05 20:32                 ` Woodhouse, David
2018-01-05 21:11                   ` Brian Gerst
2018-01-05 22:16                     ` Woodhouse, David
2018-01-05 22:43                       ` Borislav Petkov
2018-01-05 22:00                 ` Woodhouse, David
2018-01-05 22:06                   ` Borislav Petkov
2018-01-05 23:50                   ` Linus Torvalds
2018-01-06 10:53                     ` Woodhouse, David
2018-01-04 14:36   ` [PATCH v3 02/13] x86/retpoline/crypto: Convert crypto assembler indirect jumps David Woodhouse
2018-01-04 14:37   ` [PATCH v3 03/13] x86/retpoline/entry: Convert entry " David Woodhouse
2018-01-04 14:46     ` Dave Hansen
2018-01-04 14:49       ` Woodhouse, David
2018-01-04 14:37   ` [PATCH v3 04/13] x86/retpoline/ftrace: Convert ftrace " David Woodhouse
2018-01-04 14:37   ` [PATCH v3 05/13] x86/retpoline/hyperv: Convert " David Woodhouse
2018-01-04 14:37   ` [PATCH v3 06/13] x86/retpoline/xen: Convert Xen hypercall " David Woodhouse
2018-01-04 15:10     ` Juergen Gross
2018-01-04 15:18       ` David Woodhouse
2018-01-04 15:54     ` Juergen Gross
2018-01-04 14:37   ` [PATCH v3 07/13] x86/retpoline/checksum32: Convert assembler " David Woodhouse
2018-01-04 14:37   ` [PATCH v3 08/13] x86/alternatives: Add missing \n at end of ALTERNATIVE inline asm David Woodhouse
2018-01-05 13:04     ` [tip:x86/pti] x86/alternatives: Add missing '\n' " tip-bot for David Woodhouse
2018-01-04 14:37   ` [PATCH v3 09/13] x86/retpoline/irq32: Convert assembler indirect jumps David Woodhouse
2018-01-04 14:37   ` [PATCH v3 10/13] x86/retpoline/pvops: " David Woodhouse
2018-01-04 15:02     ` Juergen Gross
2018-01-04 15:12       ` Woodhouse, David
2018-01-04 15:18       ` Andrew Cooper
2018-01-04 16:04         ` Juergen Gross
2018-01-04 16:37       ` Andi Kleen
2018-01-04 14:37   ` [PATCH v3 11/13] retpoline/taint: Taint kernel for missing retpoline in compiler David Woodhouse
2018-01-04 22:06     ` Justin Forbes
2018-01-04 14:37   ` [PATCH v3 12/13] retpoline/objtool: Disable some objtool warnings David Woodhouse
2018-01-04 14:37   ` [PATCH v3 13/13] retpoline: Attempt to quiten objtool warning for unreachable code David Woodhouse
2018-01-04 16:18   ` [RFC] Retpoline: Binary mitigation for branch-target-injection (aka "Spectre") Andy Lutomirski
2018-01-04 16:24     ` David Woodhouse
2018-01-05 10:49     ` Paul Turner
2018-01-05 11:43       ` Woodhouse, David

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