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From: Eduardo Habkost <ehabkost@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: "Borislav Petkov" <bp@suse.de>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Christophe de Dinechin" <christophe.de.dinechin@gmail.com>,
	"Alan Cox" <gnomes@lxorguk.ukuu.org.uk>,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"David Woodhouse" <dwmw2@infradead.org>,
	"Arjan van de Ven" <arjan@linux.intel.com>,
	"KarimAllah Ahmed" <karahmed@amazon.de>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Andi Kleen" <ak@linux.intel.com>,
	"Andrea Arcangeli" <aarcange@redhat.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Ashok Raj" <ashok.raj@intel.com>,
	"Asit Mallick" <asit.k.mallick@intel.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Dave Hansen" <dave.hansen@intel.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"H . Peter Anvin" <hpa@zytor.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Janakarajan Natarajan" <Janakarajan.Natarajan@amd.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Jun Nakajima" <jun.nakajima@intel.com>,
	"Laura Abbott" <labbott@redhat.com>,
	"Masami Hiramatsu" <mhiramat@kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Tim Chen" <tim.c.chen@linux.intel.com>,
	"Tom Lendacky" <thomas.lendacky@amd.com>,
	"KVM list" <kvm@vger.kernel.org>,
	"the arch/x86 maintainers" <x86@kernel.org>
Subject: Re: [RFC,05/10] x86/speculation: Add basic IBRS support infrastructure
Date: Wed, 31 Jan 2018 12:44:41 -0200	[thread overview]
Message-ID: <20180131144441.GK26425@localhost.localdomain> (raw)
In-Reply-To: <20180131140449.GF2521@work-vm>

On Wed, Jan 31, 2018 at 02:04:49PM +0000, Dr. David Alan Gilbert wrote:
> * Borislav Petkov (bp@suse.de) wrote:
> > On Wed, Jan 31, 2018 at 12:30:36PM +0000, Dr. David Alan Gilbert wrote:
> > > Indeed, it's only for this weird case where you suddenly need to change
> > > it.
> > 
> > No, there's more:
> > 
> > 	.name = "Broadwell-noTSX",
> > 	.name = "Haswell-noTSX",
> 
> Haswell came out and we made the CPU definition, and then got a
> microcode update that removed the feature.
> 
> So the common feature of noTSX and IBRS is that they're the only two
> cases where a CPU has released and then the flags have changed later.

Also, if anybody don't like it, users can already specify, e.g.,
"Broadwell,-hle,-rtm" or "Skylake,+spec_ctrl".

QEMU only adds have the -noTSX and -IBRS CPU for convenience of
management systems that don't know how to check/configure
individual CPU features.  We're working with libvirt and
OpenStack folks to make this kind of trick unnecessary.

-- 
Eduardo

  reply	other threads:[~2018-01-31 14:44 UTC|newest]

Thread overview: 143+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-20 19:22 [RFC 00/10] Speculation Control feature support KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 01/10] x86/speculation: Add basic support for IBPB KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 02/10] x86/kvm: Add IBPB support KarimAllah Ahmed
2018-01-20 20:18   ` Woodhouse, David
2018-01-22 18:56   ` Jim Mattson
2018-01-22 19:31     ` Jim Mattson
2018-01-20 19:22 ` [RFC 03/10] x86/speculation: Use Indirect Branch Prediction Barrier in context switch KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 04/10] x86/mm: Only flush indirect branches when switching into non dumpable process KarimAllah Ahmed
2018-01-20 21:06   ` Woodhouse, David
2018-01-22 18:29     ` Tim Chen
2018-01-21 11:22   ` Peter Zijlstra
2018-01-21 12:04     ` David Woodhouse
2018-01-21 14:07       ` H.J. Lu
2018-01-22 10:19       ` Peter Zijlstra
2018-01-22 10:23         ` David Woodhouse
2018-01-21 16:21     ` Ingo Molnar
2018-01-21 16:25       ` Arjan van de Ven
2018-01-21 22:20       ` Woodhouse, David
2018-01-29  6:35     ` Jon Masters
2018-01-29 14:07       ` Peter Zijlstra
2018-01-20 19:22 ` [RFC 05/10] x86/speculation: Add basic IBRS support infrastructure KarimAllah Ahmed
2018-01-21 14:31   ` Thomas Gleixner
2018-01-21 14:56     ` Borislav Petkov
2018-01-22  9:51       ` Peter Zijlstra
2018-01-22 12:06         ` Borislav Petkov
2018-01-22 13:30           ` Greg Kroah-Hartman
2018-01-22 13:37             ` Woodhouse, David
2018-01-21 15:25     ` David Woodhouse
2018-01-23 20:58     ` David Woodhouse
2018-01-23 22:43       ` Johannes Erdfelt
2018-01-24  8:47       ` Peter Zijlstra
2018-01-24  9:02         ` David Woodhouse
2018-01-24  9:10           ` Greg Kroah-Hartman
2018-01-24 15:09             ` Arjan van de Ven
2018-01-24 15:18               ` David Woodhouse
2018-01-24  9:34           ` Peter Zijlstra
2018-01-24 10:49           ` Henrique de Moraes Holschuh
2018-01-24 12:30             ` David Woodhouse
2018-01-24 12:14         ` David Woodhouse
2018-01-24 12:29           ` Peter Zijlstra
2018-01-24 12:58             ` David Woodhouse
2018-01-29 20:14   ` [RFC,05/10] " Eduardo Habkost
2018-01-29 20:17     ` David Woodhouse
2018-01-29 20:42       ` Eduardo Habkost
2018-01-29 20:44         ` Arjan van de Ven
2018-01-29 21:02           ` David Woodhouse
2018-01-29 21:37             ` Jim Mattson
2018-01-29 21:50               ` Eduardo Habkost
2018-01-29 22:12                 ` Jim Mattson
2018-01-30  1:22                   ` Eduardo Habkost
2018-01-29 22:25                 ` Andi Kleen
2018-01-30  1:37                   ` Eduardo Habkost
2018-01-29 21:37             ` Andi Kleen
2018-01-29 21:44             ` Eduardo Habkost
2018-01-29 22:10               ` Konrad Rzeszutek Wilk
2018-01-30  1:12                 ` Eduardo Habkost
2018-01-30  0:23             ` Linus Torvalds
2018-01-30  1:03               ` Jim Mattson
2018-01-30  3:13                 ` Andi Kleen
2018-01-31 15:03                   ` Paolo Bonzini
2018-01-31 15:07                     ` Dr. David Alan Gilbert
2018-01-30  1:32               ` Arjan van de Ven
2018-01-30  3:32                 ` Linus Torvalds
2018-01-30 12:04                   ` Eduardo Habkost
2018-01-30 13:54                   ` Arjan van de Ven
2018-01-30  8:22               ` David Woodhouse
2018-01-30 11:35               ` David Woodhouse
2018-01-30 11:56               ` Dr. David Alan Gilbert
2018-01-30 12:11               ` Christian Borntraeger
2018-01-30 14:46                 ` Christophe de Dinechin
2018-01-30 14:52                   ` Christian Borntraeger
2018-01-30 14:56                     ` Christophe de Dinechin
2018-01-30 15:33                       ` Christian Borntraeger
2018-01-30 20:46               ` Alan Cox
2018-01-31 10:05                 ` Christophe de Dinechin
2018-01-31 10:15                   ` Thomas Gleixner
2018-01-31 11:04                     ` Dr. David Alan Gilbert
2018-01-31 11:52                       ` Borislav Petkov
2018-01-31 12:30                         ` Dr. David Alan Gilbert
2018-01-31 13:18                           ` Borislav Petkov
2018-01-31 14:04                             ` Dr. David Alan Gilbert
2018-01-31 14:44                               ` Eduardo Habkost [this message]
2018-01-31 16:28                                 ` Borislav Petkov
2018-01-31 11:07                     ` Christophe de Dinechin
2018-01-31 15:00                     ` Eduardo Habkost
2018-01-31 15:11                     ` Arjan van de Ven
2018-01-31 10:03   ` [RFC 05/10] " Christophe de Dinechin
2018-01-20 19:22 ` [RFC 06/10] x86/speculation: Add inlines to control Indirect Branch Speculation KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 07/10] x86: Simplify spectre_v2 command line parsing KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 08/10] x86/idle: Control Indirect Branch Speculation in idle KarimAllah Ahmed
2018-01-20 19:23 ` [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation KarimAllah Ahmed
2018-01-21 19:14   ` Andy Lutomirski
2018-01-23 16:12     ` Tom Lendacky
2018-01-23 16:20       ` Woodhouse, David
2018-01-23 22:37         ` Tom Lendacky
2018-01-23 22:49           ` Andi Kleen
2018-01-23 23:14             ` Woodhouse, David
2018-01-23 23:22               ` Andi Kleen
2018-01-24  0:47               ` Tim Chen
2018-01-24  1:00                 ` Andy Lutomirski
2018-01-24  1:22                   ` David Woodhouse
2018-01-24  1:59                   ` Van De Ven, Arjan
2018-01-24  3:25                     ` Andy Lutomirski
2018-01-21 19:34   ` Linus Torvalds
2018-01-21 20:28     ` David Woodhouse
2018-01-21 21:35       ` Linus Torvalds
2018-01-21 22:00         ` David Woodhouse
2018-01-21 22:27           ` Linus Torvalds
2018-01-22 16:27             ` David Woodhouse
2018-01-23  7:29               ` Ingo Molnar
2018-01-23  7:53                 ` Ingo Molnar
2018-01-23  9:27                   ` Ingo Molnar
2018-01-23  9:37                     ` David Woodhouse
2018-01-23 15:01                     ` Dave Hansen
2018-01-23  9:30                   ` David Woodhouse
2018-01-23 10:15                     ` Ingo Molnar
2018-01-23 10:27                       ` David Woodhouse
2018-01-23 10:44                         ` Ingo Molnar
2018-01-23 10:57                           ` David Woodhouse
2018-01-23 10:23                     ` Ingo Molnar
2018-01-23 10:35                       ` David Woodhouse
2018-02-04 18:43                       ` Thomas Gleixner
2018-02-04 20:22                         ` David Woodhouse
2018-02-06  9:14                         ` David Woodhouse
2018-01-25 16:19                     ` Mason
2018-01-25 17:16                       ` Greg Kroah-Hartman
2018-01-29 11:59                         ` Mason
2018-01-24  0:05                 ` Andi Kleen
2018-01-23 20:16       ` Pavel Machek
2018-01-20 19:23 ` [RFC 10/10] x86/enter: Use IBRS on syscall and interrupts KarimAllah Ahmed
2018-01-21 13:50   ` Konrad Rzeszutek Wilk
2018-01-21 14:40     ` KarimAllah Ahmed
2018-01-21 17:22     ` Dave Hansen
2018-01-21 14:02 ` [RFC 00/10] Speculation Control feature support Konrad Rzeszutek Wilk
2018-01-22 21:27   ` David Woodhouse
2018-01-29 22:29 [RFC,05/10] x86/speculation: Add basic IBRS support infrastructure David Dunn
2018-01-29 22:41 ` Andi Kleen
2018-01-29 22:49   ` Jim Mattson
2018-01-30  1:10     ` Eduardo Habkost
2018-01-30  1:20       ` David Dunn
2018-01-30  1:30         ` Eduardo Habkost
2018-01-29 23:51 ` Fred Jacobs
2018-01-30  1:08 ` Eduardo Habkost

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