From: Paolo Bonzini <pbonzini@redhat.com>
To: David Woodhouse <dwmw2@infradead.org>,
tglx@linutronix.de, x86@kernel.org, kvm@vger.kernel.org,
torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
arjan.van.de.ven@intel.com, dave.hansen@intel.com
Subject: Re: [PATCH 2/2] x86/speculation: Support "Enhanced IBRS" on future CPUs
Date: Tue, 13 Feb 2018 11:55:52 +0100 [thread overview]
Message-ID: <b55a1e8a-a70f-b007-e4d7-6864d7bdd683@redhat.com> (raw)
In-Reply-To: <1518519234.12890.58.camel@infradead.org>
On 13/02/2018 11:53, David Woodhouse wrote:
>> You have my vote. :) Really, IBRS_ALL makes no sense and it would be
>> nice to know _why_ Intel is pushing something that makes no sense.
> No, IBRS_ALL *does* make sense. It's not a complete fix, but it's as
> much of a fix as they should shoe-horn into the generation of CPUs
> which are currently going to the fabs.
>
> With IBRS_ALL they presumably add tags to the predictions with the VMX
> mode and ring, to give complete protection against predictions being
> used in a more privileged mode.
Yeah, but I still don't get why they need an MSR to turn those tags on.
Is it basically a chicken bit in the wrong direction?
Paolo
next prev parent reply other threads:[~2018-02-13 10:55 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-12 15:27 [PATCH 1/2] x86/speculation: Correct Speculation Control microcode blacklist again David Woodhouse
2018-02-12 15:27 ` [PATCH 2/2] x86/speculation: Support "Enhanced IBRS" on future CPUs David Woodhouse
2018-02-13 7:47 ` Ingo Molnar
2018-02-13 8:12 ` David Woodhouse
2018-02-13 8:02 ` Paolo Bonzini
2018-02-13 8:15 ` David Woodhouse
2018-02-13 9:58 ` Paolo Bonzini
2018-02-13 10:21 ` David Woodhouse
2018-02-13 10:36 ` David Woodhouse
2018-02-13 10:41 ` Paolo Bonzini
2018-02-13 10:53 ` David Woodhouse
2018-02-13 10:55 ` Paolo Bonzini [this message]
2018-02-16 9:58 ` David Woodhouse
2018-02-16 10:08 ` Paolo Bonzini
2018-02-16 10:21 ` David Woodhouse
2018-02-16 11:04 ` Paolo Bonzini
2018-02-16 12:10 ` David Woodhouse
2018-02-19 23:37 ` Jon Masters
2018-02-19 23:42 ` Van De Ven, Arjan
2018-02-19 23:53 ` valdis.kletnieks
2018-02-20 0:00 ` Van De Ven, Arjan
2018-02-20 0:13 ` Alan Cox
2018-02-20 0:43 ` Linus Torvalds
2018-02-20 1:03 ` Alan Cox
2018-02-20 1:08 ` Van De Ven, Arjan
2018-02-20 8:52 ` Thomas Gleixner
2018-02-20 11:43 ` Paolo Bonzini
2018-02-20 14:08 ` Van De Ven, Arjan
2018-02-20 14:46 ` Paolo Bonzini
2018-02-20 14:59 ` Van De Ven, Arjan
2018-02-20 15:09 ` Paolo Bonzini
2018-02-23 18:12 ` Is: RSB Alternative bit in IA32_ARCH_CAPABILITIES Was:Re: " Konrad Rzeszutek Wilk
2018-02-23 18:18 ` Van De Ven, Arjan
2018-02-15 15:21 ` Pavel Machek
2018-02-13 8:57 ` [tip:x86/pti] x86/speculation: Correct Speculation Control microcode blacklist again tip-bot for David Woodhouse
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