[PATCH v8 0/4] KVM: Add virtualization support of split lock detection

[Xiaoyao Li <xiaoyao.li@intel.com>]

This series aims to add the virtualization of split lock detection in
KVM.

Due to the fact MSR TEST_CTRL is per-core scope, feature split lock
detection can be exposed to guest only when SMT is disabled/unsupported.

Changes in v8:
 - rebase to v5.7-rc1.
 - basic enabling of split lock detection already merged.
 - When host is sld_warn and nosmt, load guest's sld bit when in KVM
   context, i.e., between vmx_prepare_switch_to_guest() and before
   vmx_prepare_switch_to_host(), KVM uses guest sld setting.  

Changes in v7:
https://lkml.kernel.org/r/20200325030924.132881-1-xiaoyao.li@intel.com
 - only pick patch 1 and patch 2, and hold all the left.
 - Update SLD bit on each processor based on sld_state.

Changes in v6:
https://lkml.kernel.org/r/20200324151859.31068-1-xiaoyao.li@intel.com
 - Drop the sld_not_exist flag and use X86_FEATURE_SPLIT_LOCK_DETECT to
   check whether need to init split lock detection. [tglx]
 - Use tglx's method to verify the existence of split lock detectoin.
 - small optimization of sld_update_msr() that the default value of
   msr_test_ctrl_cache has split_lock_detect bit cleared.
 - Drop the patch3 in v5 that introducing kvm_only option. [tglx]
 - Rebase patch4-8 to kvm/queue.
 - use the new kvm-cpu-cap to expose X86_FEATURE_CORE_CAPABILITIES in
   Patch 6.

Changes in v5:
https://lkml.kernel.org/r/20200315050517.127446-1-xiaoyao.li@intel.com
 - Use X86_FEATURE_SPLIT_LOCK_DETECT flag in kvm to ensure split lock
   detection is really supported.
 - Add and export sld related helper functions in their related usecase 
   kvm patches.

Xiaoyao Li (4):
  kvm: x86: Emulate MSR IA32_CORE_CAPABILITIES
  kvm: vmx: Enable MSR TEST_CTRL for guest
  x86/split_lock: Export sld_update_msr() and sld_state
  kvm: vmx: virtualize split lock detection

 arch/x86/include/asm/cpu.h      | 12 +++++
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kernel/cpu/intel.c     | 13 ++----
 arch/x86/kvm/cpuid.c            |  3 +-
 arch/x86/kvm/vmx/vmx.c          | 83 ++++++++++++++++++++++++++++++---
 arch/x86/kvm/vmx/vmx.h          |  2 +
 arch/x86/kvm/x86.c              | 35 +++++++++++++-
 7 files changed, 132 insertions(+), 17 deletions(-)

-- 
2.20.1