Provides userspace with per-VM capability(KVM_CAP_X86_DISABLE_EXITS) to 
not intercept MWAIT/HLT/PAUSE in order that to improve latency in some 
workloads.

The patchset implements the original proposal from Radim.
https://www.spinics.net/lists/kvm/msg146879.html

In addition, thanks to Jan H. Schönherr's attempt last year.

v1 -> v2:
 * remove blinding setting KVM_ENABLE_CAP statement in doc
 * move PV_UNHALT associated statement to 2/3
 * rename kvm_mwait_can_in_guest to kvm_can_mwait_in_guest
 * remove unconditionally set INTERCEPT HLT in svm 
 * call vmx_clear_hlt() from pre_enter_smm()
 * add a check to kvm_update_cpuid() that forbits KVM_FEATURE_PV_UNHALT
   when halt exits are disabld

Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Radim Krčmář <rkrc...@redhat.com>
Cc: Jan H. Schönherr <jscho...@amazon.de>

Wanpeng Li (3):
  KVM: X86: Provides userspace with a capability to not intercept MWAIT
  KVM: X86: Provides userspace with a capability to not intercept HLT
  KVM: X86: Provides userspace with a capability to not intercept PAUSE

 Documentation/virtual/kvm/api.txt | 24 ++++++++++++-------
 arch/x86/include/asm/kvm_host.h   |  4 ++++
 arch/x86/kvm/cpuid.c              |  5 ++++
 arch/x86/kvm/svm.c                |  9 ++++---
 arch/x86/kvm/vmx.c                | 50 ++++++++++++++++++++++++++++++++-------
 arch/x86/kvm/x86.c                | 29 +++++++++++++++++++----
 arch/x86/kvm/x86.h                | 24 +++++++++++++++----
 include/uapi/linux/kvm.h          |  2 +-
 tools/include/uapi/linux/kvm.h    |  2 +-
 9 files changed, 118 insertions(+), 31 deletions(-)

-- 
2.7.4

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