Re: [Qemu-devel] [PATCH 0/7] CPU model updates for CVE-2017-5715 (Spectre variant #2)

[Eduardo Habkost <ehabkost@redhat.com>]

I'm queueing patches 1-5 on x86-next.

On Tue, Jan 09, 2018 at 01:45:12PM -0200, Eduardo Habkost wrote:
> This series adds support for the new IA32_SPEC_CTRL MSR on Intel
> CPU models.  The new MSR and the spec-ctrl CPUID bit
> (CPUID[EAX=7,ECX=0].EDX[bit 26]) were introduced by a recent
> Intel microcode updated and can be used by OSes to mitigate
> CVE-2017-5715.
> 
> It also adds a new EPYC-IBPB CPU model that includes
> CPUID[0x80000008].EBX[bit 12] (IBPB).  That patch is a RFC
> because I couldn't find any detailed info on the new CPUID bit
> and the IA32_PRED_CMD MSR.
> 
> Additionally, the last patch on this series changes the new
> Westmere-IBRS, SandyBridge-IBRS and IvyBridge-IBRS to include the
> PCID feature, because PCID helps to reduce the performance impact
> of KPTI on the guest.  The patch is also a RFC because we need to
> confirm if all Westmere (and newer) CPUs out there have PCID
> available.
> 
> References:
> * https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5715
> * Google Security Blog on Meltdown/Spectre mitigations:
>   https://security.googleblog.com/2018/01/more-details-about-mitigations-for-cpu_4.html
> * Kernel patches to make use of the new MSRs:
>   https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1578798.html
> * KVM kernel patches for the new CPUID bits and MSRs:
>   https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1580363.html
> * Patches adding PCID to the existing CPU models:
>   https://patchew.org/QEMU/20180108205052.24385-1-vincent@bernat.im
>   https://patchew.org/QEMU/20180109070112.30806-1-vincent@bernat.im
> 
> Eduardo Habkost (6):
>   i386: Change X86CPUDefinition::model_id to const char*
>   i386: Add spec-ctrl CPUID bit
>   i386: Add FEAT_8000_0008_EBX CPUID feature word
>   i386: Add new -IBRS versions of Intel CPU models
>   [RFC] i386: Add EPYC-IBPB CPU model
>   [RFC] i386: Add PCID to {Westmere,SandyBridge,IvyBridge}-IBRS
> 
> Paolo Bonzini (1):
>   i386: Add support for SPEC_CTRL MSR
> 
>  target/i386/cpu.h     |   7 +
>  target/i386/cpu.c     | 454 +++++++++++++++++++++++++++++++++++++++++++++++++-
>  target/i386/kvm.c     |  14 ++
>  target/i386/machine.c |  20 +++
>  4 files changed, 491 insertions(+), 4 deletions(-)
> 
> -- 
> 2.14.3
> 
> 

-- 
Eduardo