All of lore.kernel.org
 help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: David Woodhouse <dwmw2@infradead.org>
Cc: arjan@linux.intel.com, karahmed@amazon.de, x86@kernel.org,
	linux-kernel@vger.kernel.org, tim.c.chen@linux.intel.com,
	bp@alien8.de, peterz@infradead.org, pbonzini@redhat.com,
	ak@linux.intel.com, torvalds@linux-foundation.org,
	gregkh@linux-foundation.org, dave.hansen@intel.com,
	gnomes@lxorguk.ukuu.org.uk, ashok.raj@intel.com,
	mingo@kernel.org
Subject: Re: [PATCH v4 6/7] x86/cpufeature: Blacklist SPEC_CTRL on early Spectre v2 microcodes
Date: Thu, 25 Jan 2018 15:58:35 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1801251557490.2020@nanos> (raw)
In-Reply-To: <1516887714.30244.121.camel@infradead.org>

On Thu, 25 Jan 2018, David Woodhouse wrote:
> On Thu, 2018-01-25 at 12:34 +0100, Thomas Gleixner wrote:
> > 
> > This stuff is really a master piece of trainwreck engineering.
> > 
> > So yeah, whatever we do we end up with a proper mess. Lets go for a
> > blacklist and hope that we'll have something which holds at some
> > foreseeable day in the future.
> > 
> > The other concern I have is IBRS vs. IBPB. Are we sufficiently sure that
> > IBPB is working on those IBRS blacklisted ucode revisions? Or should we
> > just play safe and not touch any of this at all when we detect a
> > blacklisted one?
> 
> That isn't sufficiently clear to me. I've changed it back to blacklist
> *everything* for now, to be safe. If at any point Intel want to get
> their act together and give us coherent information to the contrary, we
> can change to separate IBPB/IBRS blacklists.

Thanks for that. That's the only sensible approach as long as we have to
deal with the current Quality Assumptions...

Thanks,

	tglx

  reply	other threads:[~2018-01-25 14:58 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-25  9:23 [PATCH v4 0/7] Basic Speculation Control feature support David Woodhouse
2018-01-25  9:23 ` [PATCH v4 1/7] x86/cpufeatures: Add CPUID_7_EDX CPUID leaf David Woodhouse
2018-01-25  9:23 ` [PATCH v4 2/7] x86/cpufeatures: Add Intel feature bits for Speculation Control David Woodhouse
2018-01-25  9:23 ` [PATCH v4 3/7] x86/cpufeatures: Add AMD " David Woodhouse
2018-01-25  9:23 ` [PATCH v4 4/7] x86/msr: Add definitions for new speculation control MSRs David Woodhouse
2018-01-25  9:23 ` [PATCH v4 5/7] x86/pti: Do not enable PTI on processors which are not vulnerable to Meltdown David Woodhouse
2018-01-25  9:42   ` Peter Zijlstra
2018-01-25  9:56     ` David Woodhouse
2018-01-25 10:01       ` Thomas Gleixner
2018-01-25 15:12   ` Alan Cox
2018-01-25  9:23 ` [PATCH v4 6/7] x86/cpufeature: Blacklist SPEC_CTRL on early Spectre v2 microcodes David Woodhouse
2018-01-25 10:43   ` David Woodhouse
2018-01-25 10:54     ` Thomas Gleixner
2018-01-25 11:20       ` David Woodhouse
2018-01-25 11:34         ` Thomas Gleixner
2018-01-25 13:41           ` David Woodhouse
2018-01-25 14:58             ` Thomas Gleixner [this message]
2018-01-25 16:16             ` Alan Cox
2018-01-25 16:24               ` Thomas Gleixner
2018-01-25 16:35                 ` David Woodhouse
2018-01-26  9:40             ` Ingo Molnar
2018-01-25  9:23 ` [PATCH v4 7/7] x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support David Woodhouse
2018-01-25 11:41   ` Borislav Petkov
2018-01-25 11:47     ` David Woodhouse
2018-01-25 11:50       ` Borislav Petkov
2018-01-25 11:58         ` David Woodhouse
2018-01-25 12:03           ` Borislav Petkov
2018-01-25 12:11             ` David Woodhouse

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=alpine.DEB.2.20.1801251557490.2020@nanos \
    --to=tglx@linutronix.de \
    --cc=ak@linux.intel.com \
    --cc=arjan@linux.intel.com \
    --cc=ashok.raj@intel.com \
    --cc=bp@alien8.de \
    --cc=dave.hansen@intel.com \
    --cc=dwmw2@infradead.org \
    --cc=gnomes@lxorguk.ukuu.org.uk \
    --cc=gregkh@linux-foundation.org \
    --cc=karahmed@amazon.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    --cc=tim.c.chen@linux.intel.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.