From: Dave Hansen <dave.hansen@intel.com>
To: Ingo Molnar <mingo@kernel.org>, David Woodhouse <dwmw2@infradead.org>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>,
"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>,
"Arjan van de Ven" <arjan@linux.intel.com>,
"Ashok Raj" <ashok.raj@intel.com>,
"Asit Mallick" <asit.k.mallick@intel.com>,
"Borislav Petkov" <bp@suse.de>,
"Dan Williams" <dan.j.williams@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>,
"Thomas Gleixner" <tglx@linutronix.de>,
"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>,
"Arjan Van De Ven" <arjan.van.de.ven@intel.com>
Subject: Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation
Date: Tue, 23 Jan 2018 07:01:31 -0800 [thread overview]
Message-ID: <e0b3aa79-f3f2-8b50-6f07-da891a0812a1@intel.com> (raw)
In-Reply-To: <20180123092756.iznzepwnolsviof7@gmail.com>
On 01/23/2018 01:27 AM, Ingo Molnar wrote:
>
> - All asynchronous contexts (IRQs, NMIs, etc.) stuff the RSB before IRET. (The
> tracking could probably made IRQ and maybe even NMI safe, but the worst-case
> nesting scenarios make my head ache.)
This all sounds totally workable to me. We talked about using ftrace
itself to track call depth, but it would be unusable in production, of
course. This seems workable, though. You're also totally right about
the zero overhead on most kernels with it turned off when we don't need
RSB underflow protection (basically pre-Skylake).
I also agree that the safe thing to do is to just stuff before iret. I
bet we can get a ftrace-driven RSB tracker working precisely enough even
with NMIs, but it's way simpler to just stuff and be done with it for now.
next prev parent reply other threads:[~2018-01-23 15:01 UTC|newest]
Thread overview: 161+ 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
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 [this message]
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
2018-01-22 22:15 [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation Luke Kenneth Casson Leighton
2018-01-23 11:13 Liran Alon
2018-01-25 22:20 ` Dave Hansen
2018-01-26 2:11 Liran Alon
2018-01-26 2:23 ` Dave Hansen
2018-01-26 9:11 ` David Woodhouse
2018-01-26 17:19 ` Linus Torvalds
2018-01-26 17:27 ` Borislav Petkov
2018-01-26 17:29 ` David Woodhouse
2018-01-26 17:31 ` David Woodhouse
2018-01-26 17:59 ` Andi Kleen
2018-01-26 18:11 ` David Woodhouse
2018-01-26 18:12 ` Arjan van de Ven
2018-01-26 18:26 ` David Woodhouse
2018-01-26 18:28 ` Van De Ven, Arjan
2018-01-26 18:43 ` David Woodhouse
2018-01-26 18:44 ` Van De Ven, Arjan
2018-01-26 18:53 ` David Woodhouse
2018-01-26 19:02 ` Konrad Rzeszutek Wilk
2018-01-26 19:11 ` Hansen, Dave
2018-01-27 13:42 ` Konrad Rzeszutek Wilk
2018-01-27 15:55 ` Dave Hansen
2018-01-26 19:11 ` David Woodhouse
2018-01-26 8:46 ` David Woodhouse
2018-01-26 2:50 Liran Alon
2018-01-26 2:55 ` Van De Ven, Arjan
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