All of lore.kernel.org
 help / color / mirror / Atom feed
From: Konrad Rzeszutek Wilk <konrad@darnok.org>
To: "Hansen, Dave" <dave.hansen@intel.com>
Cc: "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Andi Kleen" <ak@linux.intel.com>,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"David Woodhouse" <dwmw2@infradead.org>,
	"Liran Alon" <liran.alon@oracle.com>,
	"Laura Abbott" <labbott@redhat.com>,
	"Andrew Lutomirski" <luto@kernel.org>,
	"Janakarajan Natarajan" <Janakarajan.Natarajan@amd.com>,
	"Borislav Petkov" <bp@suse.de>,
	"Mallick, Asit K" <asit.k.mallick@intel.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"KarimAllah Ahmed" <karahmed@amazon.de>,
	"Peter Anvin" <hpa@zytor.com>,
	"Nakajima, Jun" <jun.nakajima@intel.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"Van De Ven, Arjan" <arjan.van.de.ven@intel.com>
Subject: Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation
Date: Sat, 27 Jan 2018 08:42:43 -0500	[thread overview]
Message-ID: <20180127134239.GA25029@localhost.localdomain> (raw)
In-Reply-To: <0089A7AA75120F4087B2E7CB6BF3E53442A9AA0A@CRSMSX104.amr.corp.intel.com>

On Fri, Jan 26, 2018 at 07:11:47PM +0000, Hansen, Dave wrote:
> The need for RSB stuffing in all the various scenarios and what the heck it actually mitigates is freakishly complicated.  I've tried to write it all down in one place: https://goo.gl/pXbvBE

Thank you for sharing that.

One question on the third from the top (' RSB Stuff (16) After
irq/nmi/#PF/...').

It says that :"Return from interrupt path (more than 16 deep) can empty
RSB".

Just to clarify - you mean all the returns ('ret') that are happening after
we call do_IRQ and the stack unwinds - but before we do an 'iret' correct?

I am 99% sure that is what you mean, but just confirming as one could read
this as: 'Need to do RSB after an iret' (say you are in the kernel
and then get an interrupt and iret back to kernel).

WARNING: multiple messages have this Message-ID (diff)
From: Konrad Rzeszutek Wilk <konrad@darnok.org>
To: "Hansen, Dave" <dave.hansen@intel.com>
Cc: "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Andi Kleen" <ak@linux.intel.com>,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"David Woodhouse" <dwmw2@infradead.org>,
	"Liran Alon" <liran.alon@oracle.com>,
	"Laura Abbott" <labbott@redhat.com>,
	"Andrew Lutomirski" <luto@kernel.org>,
	"Janakarajan Natarajan" <Janakarajan.Natarajan@amd.com>,
	"Borislav Petkov" <bp@suse.de>,
	"Mallick, Asit K" <asit.k.mallick@intel.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"KarimAllah Ahmed" <karahmed@amazon.de>,
	"Peter Anvin" <hpa@zytor.com>,
	"Nakajima, Jun" <jun.nakajima@intel.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"Van De Ven, Arjan" <arjan.van.de.ven@intel.com>,
	"Tim Chen" <tim.c.chen@linux.intel.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Masami Hiramatsu" <mhiramat@kernel.org>,
	"Arjan van de Ven" <arjan@linux.intel.com>,
	"Tom Lendacky" <thomas.lendacky@amd.com>,
	"Williams, Dan J" <dan.j.williams@intel.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Andrea Arcangeli" <aarcange@redhat.com>,
	"KVM list" <kvm@vger.kernel.org>,
	"Boris Ostrovsky" <boris.ostrovsky@oracle.com>
Subject: Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation
Date: Sat, 27 Jan 2018 08:42:43 -0500	[thread overview]
Message-ID: <20180127134239.GA25029@localhost.localdomain> (raw)
In-Reply-To: <0089A7AA75120F4087B2E7CB6BF3E53442A9AA0A@CRSMSX104.amr.corp.intel.com>

On Fri, Jan 26, 2018 at 07:11:47PM +0000, Hansen, Dave wrote:
> The need for RSB stuffing in all the various scenarios and what the heck it actually mitigates is freakishly complicated.  I've tried to write it all down in one place: https://goo.gl/pXbvBE

Thank you for sharing that.

One question on the third from the top (' RSB Stuff (16) After
irq/nmi/#PF/...').

It says that :"Return from interrupt path (more than 16 deep) can empty
RSB".

Just to clarify - you mean all the returns ('ret') that are happening after
we call do_IRQ and the stack unwinds - but before we do an 'iret' correct?

I am 99% sure that is what you mean, but just confirming as one could read
this as: 'Need to do RSB after an iret' (say you are in the kernel
and then get an interrupt and iret back to kernel).

  reply	other threads:[~2018-01-27 13:42 UTC|newest]

Thread overview: 118+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-26  2:11 [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation 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 17:19       ` Linus Torvalds
2018-01-26 17:27       ` Borislav Petkov
2018-01-26 17:27         ` Borislav Petkov
2018-01-26 17:29       ` David Woodhouse
2018-01-26 17:29         ` David Woodhouse
2018-01-26 17:31         ` David Woodhouse
2018-01-26 17:31           ` David Woodhouse
2018-01-26 17:59       ` Andi Kleen
2018-01-26 17:59         ` Andi Kleen
2018-01-26 18:11         ` David Woodhouse
2018-01-26 18:11           ` David Woodhouse
2018-01-26 18:12           ` Arjan van de Ven
2018-01-26 18:12             ` Arjan van de Ven
2018-01-26 18:26             ` David Woodhouse
2018-01-26 18:26               ` David Woodhouse
2018-01-26 18:28               ` Van De Ven, Arjan
2018-01-26 18:28                 ` Van De Ven, Arjan
2018-01-26 18:43                 ` David Woodhouse
2018-01-26 18:43                   ` David Woodhouse
2018-01-26 18:44                   ` Van De Ven, Arjan
2018-01-26 18:44                     ` Van De Ven, Arjan
2018-01-26 18:53                     ` David Woodhouse
2018-01-26 18:53                       ` David Woodhouse
2018-01-26 19:02         ` Konrad Rzeszutek Wilk
2018-01-26 19:02           ` Konrad Rzeszutek Wilk
2018-01-26 19:11           ` Hansen, Dave
2018-01-26 19:11             ` Hansen, Dave
2018-01-27 13:42             ` Konrad Rzeszutek Wilk [this message]
2018-01-27 13:42               ` Konrad Rzeszutek Wilk
2018-01-27 15:55               ` Dave Hansen
2018-01-27 15:55                 ` Dave Hansen
2018-01-26 19:11           ` David Woodhouse
2018-01-26 19:11             ` David Woodhouse
2018-01-26  8:46 ` David Woodhouse
  -- strict thread matches above, loose matches on Subject: below --
2018-01-26  2:50 Liran Alon
2018-01-26  2:55 ` Van De Ven, Arjan
2018-01-26  2:55   ` Van De Ven, Arjan
2018-01-23 11:13 Liran Alon
2018-01-25 22:20 ` Dave Hansen
2018-01-22 22:15 Luke Kenneth Casson Leighton
2018-01-20 19:22 [RFC 00/10] Speculation Control feature support KarimAllah Ahmed
2018-01-20 19:23 ` [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation KarimAllah Ahmed
2018-01-20 19:23   ` KarimAllah Ahmed
2018-01-21 19:14   ` Andy Lutomirski
2018-01-21 19:14     ` Andy Lutomirski
2018-01-23 16:12     ` Tom Lendacky
2018-01-23 16:12       ` Tom Lendacky
2018-01-23 16:20       ` Woodhouse, David
2018-01-23 16:20         ` Woodhouse, David
2018-01-23 22:37         ` Tom Lendacky
2018-01-23 22:37           ` Tom Lendacky
2018-01-23 22:49           ` Andi Kleen
2018-01-23 22:49             ` Andi Kleen
2018-01-23 23:14             ` Woodhouse, David
2018-01-23 23:14               ` Woodhouse, David
2018-01-23 23:22               ` Andi Kleen
2018-01-23 23:22                 ` Andi Kleen
2018-01-24  0:47               ` Tim Chen
2018-01-24  0:47                 ` Tim Chen
2018-01-24  1:00                 ` Andy Lutomirski
2018-01-24  1:00                   ` Andy Lutomirski
2018-01-24  1:22                   ` David Woodhouse
2018-01-24  1:22                     ` David Woodhouse
2018-01-24  1:59                   ` Van De Ven, Arjan
2018-01-24  1:59                     ` Van De Ven, Arjan
2018-01-24  3:25                     ` Andy Lutomirski
2018-01-24  3:25                       ` Andy Lutomirski
2018-01-21 19:34   ` Linus Torvalds
2018-01-21 20:28     ` David Woodhouse
2018-01-21 20:28       ` David Woodhouse
2018-01-21 21:35       ` Linus Torvalds
2018-01-21 21:35         ` Linus Torvalds
2018-01-21 22:00         ` David Woodhouse
2018-01-21 22:00           ` David Woodhouse
2018-01-21 22:27           ` Linus Torvalds
2018-01-21 22:27             ` Linus Torvalds
2018-01-22 16:27             ` David Woodhouse
2018-01-22 16:27               ` David Woodhouse
2018-01-23  7:29               ` Ingo Molnar
2018-01-23  7:29                 ` Ingo Molnar
2018-01-23  7:53                 ` Ingo Molnar
2018-01-23  7:53                   ` Ingo Molnar
2018-01-23  9:27                   ` Ingo Molnar
2018-01-23  9:27                     ` Ingo Molnar
2018-01-23  9:37                     ` David Woodhouse
2018-01-23  9:37                       ` David Woodhouse
2018-01-23 15:01                     ` Dave Hansen
2018-01-23 15:01                       ` Dave Hansen
2018-01-23  9:30                   ` David Woodhouse
2018-01-23  9:30                     ` David Woodhouse
2018-01-23 10:15                     ` Ingo Molnar
2018-01-23 10:15                       ` Ingo Molnar
2018-01-23 10:27                       ` David Woodhouse
2018-01-23 10:27                         ` David Woodhouse
2018-01-23 10:44                         ` Ingo Molnar
2018-01-23 10:44                           ` Ingo Molnar
2018-01-23 10:57                           ` David Woodhouse
2018-01-23 10:23                     ` Ingo Molnar
2018-01-23 10:23                       ` Ingo Molnar
2018-01-23 10:35                       ` David Woodhouse
2018-02-04 18:43                       ` Thomas Gleixner
2018-02-04 18:43                         ` Thomas Gleixner
2018-02-04 20:22                         ` David Woodhouse
2018-02-04 20:22                           ` David Woodhouse
2018-02-06  9:14                         ` David Woodhouse
2018-02-06  9:14                           ` David Woodhouse
2018-01-25 16:19                     ` Mason
2018-01-25 16:19                       ` Mason
2018-01-25 17:16                       ` Greg Kroah-Hartman
2018-01-25 17:16                         ` Greg Kroah-Hartman
2018-01-29 11:59                         ` Mason
2018-01-29 11:59                           ` Mason
2018-01-24  0:05                 ` Andi Kleen
2018-01-23 20:16       ` Pavel Machek
2018-01-23 20:16         ` Pavel Machek

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180127134239.GA25029@localhost.localdomain \
    --to=konrad@darnok.org \
    --cc=Janakarajan.Natarajan@amd.com \
    --cc=ak@linux.intel.com \
    --cc=arjan.van.de.ven@intel.com \
    --cc=ashok.raj@intel.com \
    --cc=asit.k.mallick@intel.com \
    --cc=bp@suse.de \
    --cc=dave.hansen@intel.com \
    --cc=dwmw2@infradead.org \
    --cc=hpa@zytor.com \
    --cc=jun.nakajima@intel.com \
    --cc=karahmed@amazon.de \
    --cc=konrad.wilk@oracle.com \
    --cc=labbott@redhat.com \
    --cc=liran.alon@oracle.com \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=rkrcmar@redhat.com \
    --cc=torvalds@linux-foundation.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.