From: David Woodhouse <dwmw2@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: jmattson@google.com, aliguori@amazon.com,
thomas.lendacky@amd.com, bp@alien8.de
Subject: Re: [PATCH 3/7] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest
Date: Mon, 08 Jan 2018 19:41:07 +0000 [thread overview]
Message-ID: <1515440467.7317.43.camel@infradead.org> (raw)
In-Reply-To: <1515434925-10250-4-git-send-email-pbonzini@redhat.com>
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On Mon, 2018-01-08 at 19:08 +0100, Paolo Bonzini wrote:
>
> + if (have_spec_ctrl && vmx->spec_ctrl != 0)
> + wrmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
> +
I think this one probably *is* safe even without an 'else lfence',
which means that the CPU can speculate around it, but it wants a
comment explaining that someone has properly analysed it and saying
precisely why.
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next prev parent reply other threads:[~2018-01-08 19:41 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-08 18:08 [PATCH 0/7] KVM: x86: expose CVE-2017-5715 ("Spectre variant 2") mitigations to guest Paolo Bonzini
2018-01-08 18:08 ` [PATCH 1/7] KVM: x86: add SPEC_CTRL and IBPB_SUPPORT accessors Paolo Bonzini
2018-01-08 18:33 ` Konrad Rzeszutek Wilk
2018-01-08 19:09 ` Liran Alon
2018-01-09 10:32 ` Paolo Bonzini
2018-01-09 11:14 ` David Hildenbrand
2018-01-09 11:18 ` Paolo Bonzini
2018-01-08 18:08 ` [PATCH 2/7] x86/msr: add definitions for indirect branch predictor MSRs Paolo Bonzini
2018-01-08 18:35 ` Konrad Rzeszutek Wilk
2018-01-08 18:52 ` Jim Mattson
2018-01-08 19:10 ` Liran Alon
2018-01-08 18:08 ` [PATCH 3/7] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest Paolo Bonzini
2018-01-08 18:43 ` Konrad Rzeszutek Wilk
2018-01-08 19:18 ` Jim Mattson
2018-01-08 20:23 ` Liran Alon
2018-01-08 22:32 ` Paolo Bonzini
2018-01-08 23:19 ` Jim Mattson
2018-01-09 10:11 ` Paolo Bonzini
2018-01-08 19:22 ` Liran Alon
2018-01-08 19:41 ` David Woodhouse [this message]
2018-01-08 22:33 ` Paolo Bonzini
2018-01-08 22:09 ` Ashok Raj
2018-01-08 22:25 ` Paolo Bonzini
2018-01-11 2:47 ` Tim Chen
2018-01-11 10:41 ` Paolo Bonzini
2018-01-08 18:08 ` [PATCH 4/7] kvm: vmx: Set IBPB when running a different VCPU Paolo Bonzini
2018-01-08 19:23 ` Liran Alon
2018-01-08 19:36 ` Jim Mattson
2018-01-09 8:33 ` Paolo Bonzini
2018-01-09 11:01 ` David Hildenbrand
2018-01-08 18:08 ` [PATCH 5/7] kvm: svm: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to guest Paolo Bonzini
2018-01-08 19:41 ` Liran Alon
2018-01-08 18:08 ` [PATCH 6/7] x86/svm: Set IBPB when running a different VCPU Paolo Bonzini
2018-01-08 20:00 ` Liran Alon
2018-01-09 11:07 ` Paolo Bonzini
2018-01-08 18:08 ` [PATCH 7/7] KVM: x86: add SPEC_CTRL and IBPB_SUPPORT to MSR and CPUID lists Paolo Bonzini
2018-01-08 20:07 ` Liran Alon
2018-01-08 20:15 ` Jim Mattson
2018-01-09 10:15 ` [PATCH 0/7] KVM: x86: expose CVE-2017-5715 ("Spectre variant 2") mitigations to guest Thomas Gleixner
2018-01-09 11:12 ` Paolo Bonzini
2018-01-09 12:03 ` Thomas Gleixner
2018-01-09 14:06 ` Paolo Bonzini
2018-01-08 23:58 [PATCH 3/7] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest Liran Alon
2018-01-09 8:35 ` Paolo Bonzini
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