[RFC PATCH v4 0/8] This patch-set is to enable Guest CET support

[Yang Weijiang]

Control-flow Enforcement Technology (CET) provides protection against
return/jump-oriented programming (ROP) attacks. To make kvm Guest OS own
the capability, this patch-set is required. It enables CET related CPUID
report, xsaves/xrstors, vmx entry configuration etc. for Guest OS.

PATCH 1    : Define CET VMCS fields and bits.
PATCH 2/3  : Report CET feature support in CPUID.
PATCH 4    : Fix xsaves size calculation issue.
PATCH 5    : Pass through CET MSRs to Guest.
PATCH 6    : Set Guest CET state auto loading bit.
PATCH 7    : Load Guest fpu state when accessing CET XSAVES managed MSRs.
PATCH 8    : Add CET MSR user space access interface.

Changelog:

 v4:
 - Add Sean's patch for loading Guest fpu state before access XSAVES
   managed CET MSRs.
 - Melt down CET bits setting into CPUID configuration patch.
 - Add VMX interface to query Host XSS.
 - Check Host and Guest XSS support bits before set Guest XSS.
 - Make Guest SHSTK and IBT feature enabling independent.
 - Do not report CET support to Guest when Host CET feature is
   Disabled.

 v3:
 - Modified patches to make Guest CET independent to Host enabling.
 - Added patch 8 to add user space access for Guest CET MSR access.
 - Modified code comments and patch description to reflect changes.

 v2:
 - Re-ordered patch sequence, combined one patch.
 - Added more description for CET related VMCS fields.
 - Added Host CET capability check while enabling Guest CET loading bit.
 - Added Host CET capability check while reporting Guest CPUID(EAX=7,
   EXC=0).
 - Modified code in reporting Guest CPUID(EAX=D,ECX>=1), make it clearer.
 - Added Host and Guest XSS mask check while setting bits for Guest XSS.


Sean Christopherson (1):
  KVM:x86: load guest fpu state when accessing MSRs managed by XSAVES

Yang Weijiang (7):
  KVM:VMX: Define CET VMCS fields and bits
  KVM:CPUID: Add CET CPUID support for Guest
  KVM:CPUID: Fix xsaves area size calculation for CPUID.(EAX=0xD,ECX=1).
  KVM:VMX: Pass through host CET related MSRs to Guest.
  KVM:VMX: Load Guest CET via VMCS when CET is enabled in Guest
  KVM:x86: Allow Guest to set supported bits in XSS
  KVM:x86: Add user-space read/write interface for CET MSRs

 arch/x86/include/asm/kvm_host.h  |  5 +-
 arch/x86/include/asm/msr-index.h |  2 +
 arch/x86/include/asm/vmx.h       |  8 +++
 arch/x86/kvm/cpuid.c             | 53 ++++++++++++++------
 arch/x86/kvm/vmx.c               | 86 ++++++++++++++++++++++++++++++--
 arch/x86/kvm/x86.c               | 32 +++++++++++-
 arch/x86/kvm/x86.h               |  4 ++
 7 files changed, 167 insertions(+), 23 deletions(-)

-- 
2.17.1