[PATCH 0/3] KVM: x86: CET vs. nVMX fix and hardening

Sean Christopherson posted 3 patches 2 weeks ago
There is a newer version of this series
arch/x86/kvm/cpuid.c   | 29 +++++++++++++++++++++++++++--
arch/x86/kvm/cpuid.h   |  7 ++++++-
arch/x86/kvm/svm/svm.c |  4 +++-
arch/x86/kvm/vmx/vmx.c | 20 ++++++++++++++++++--
arch/x86/kvm/x86.c     | 14 --------------
arch/x86/kvm/x86.h     |  2 ++
6 files changed, 56 insertions(+), 20 deletions(-)
[PATCH 0/3] KVM: x86: CET vs. nVMX fix and hardening
Posted by Sean Christopherson 2 weeks ago
Fix a bug where KVM will clear IBT and SHSTK bits after nested VMX MSRs
have been configured, e.g. if the kernel is built with CONFIG_X86_CET=y
but CONFIG_X86_KERNEL_IBT=n.  The late clearing results in kvm-intel.ko
refusing to load as the CPU compatible checks generate their VMCS configs
with IBT=n and SHSTK=n, ultimately causing a mismatch on the CET entry
and exit controls.

Patch 2 hardens against similar bugs in the future by added a flag and
WARNs to yell if KVM sets or clear feature flags outside of the dedicated
flow.

Patch 3 adds (very, very) long overdue printing of the mistmatching offsets
in the VMCS configs.

Sean Christopherson (3):
  KVM: x86: Finalize kvm_cpu_caps setup from {svm,vmx}_set_cpu_caps()
  KVM: x86: Harden against unexpected adjustments to kvm_cpu_caps
  KVM: VMX: Print out "bad" offsets+value on VMCS config mismatch

 arch/x86/kvm/cpuid.c   | 29 +++++++++++++++++++++++++++--
 arch/x86/kvm/cpuid.h   |  7 ++++++-
 arch/x86/kvm/svm/svm.c |  4 +++-
 arch/x86/kvm/vmx/vmx.c | 20 ++++++++++++++++++--
 arch/x86/kvm/x86.c     | 14 --------------
 arch/x86/kvm/x86.h     |  2 ++
 6 files changed, 56 insertions(+), 20 deletions(-)


base-commit: e81f7c908e1664233974b9f20beead78cde6343a
-- 
2.52.0.457.g6b5491de43-goog