From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>,
Nadav Amit <nadav.amit@gmail.com>,
Liran Alon <liran.alon@oracle.com>,
jmattson@google.com, x86@kernel.org, dwmw@amazon.co.uk,
bp@alien8.de, aliguori@amazon.com, thomas.lendacky@amd.com,
rkrcmar@redhat.com, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Subject: Re: [PATCH 3/8] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest
Date: Wed, 10 Jan 2018 10:41:38 -0500 [thread overview]
Message-ID: <20180110154138.GE29272@char.us.oracle.com> (raw)
In-Reply-To: <91d41f66-d744-e8b0-89f0-a167d3a3918c@redhat.com>
On Wed, Jan 10, 2018 at 03:28:43PM +0100, Paolo Bonzini wrote:
> On 10/01/2018 15:06, Arjan van de Ven wrote:
> > On 1/10/2018 5:20 AM, Paolo Bonzini wrote:
> >> * a simple specification that does "IBRS=1 blocks indirect branch
> >> prediction altogether" would actually satisfy the specification just as
> >> well, and it would be nice to know if that's what the processor actually
> >> does.
> >
> > it doesn't exactly, not for all.
> >
> > so you really do need to write ibrs again.
>
> Okay, so "always set IBRS=1" does *not* protect against variant 2. Thanks,
And what is the point of this "always set IBRS=1" then? Are there some other
things lurking in the shadows?
>
> Paolo
next prev parent reply other threads:[~2018-01-10 15:41 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-09 16:48 [PATCH 3/8] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest Liran Alon
2018-01-09 16:57 ` Paolo Bonzini
2018-01-10 5:03 ` Nadav Amit
2018-01-10 13:20 ` Paolo Bonzini
2018-01-10 14:06 ` Arjan van de Ven
2018-01-10 14:28 ` Paolo Bonzini
2018-01-10 15:41 ` Konrad Rzeszutek Wilk [this message]
2018-01-10 15:45 ` Paolo Bonzini
2018-01-10 15:48 ` Woodhouse, David
2018-01-10 15:56 ` Paolo Bonzini
2018-01-10 16:05 ` David Woodhouse
2018-01-12 23:17 ` Jim Mattson
2018-01-12 23:19 ` Nadav Amit
-- strict thread matches above, loose matches on Subject: below --
2018-01-10 16:51 Liran Alon
2018-01-10 17:07 ` David Woodhouse
2018-01-10 16:19 Liran Alon
2018-01-10 16:27 ` Paolo Bonzini
2018-01-10 17:14 ` Jim Mattson
2018-01-10 17:16 ` Paolo Bonzini
2018-01-10 17:23 ` Nadav Amit
2018-01-10 17:32 ` Jim Mattson
2018-01-10 16:47 ` David Woodhouse
2018-01-10 0:33 Liran Alon
2018-01-09 16:06 Liran Alon
2018-01-09 12:03 [PATCH v2 0/8] KVM: x86: expose CVE-2017-5715 ("Spectre variant 2") mitigations to guest Paolo Bonzini
2018-01-09 12:03 ` [PATCH 3/8] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest Paolo Bonzini
2018-01-13 10:16 ` Longpeng (Mike)
2018-01-15 9:23 ` Paolo Bonzini
2018-01-15 9:34 ` Thomas Gleixner
[not found] ` <1515839272.22302.520.camel@amazon.co.uk>
2018-01-15 9:23 ` Paolo Bonzini
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