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

[Eduardo Habkost]

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/address@hidden/msg1578798.html
* KVM kernel patches for the new CPUID bits and MSRs:
  https://www.mail-archive.com/address@hidden/msg1580363.html
* Patches adding PCID to the existing CPU models:
  https://patchew.org/QEMU/address@hidden
  https://patchew.org/QEMU/address@hidden

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