[RFC PATCH 0/3] KVM: x86: Disallow writes to feature MSRs post-KVM_RUN

From: Sean Christopherson
Date: Fri Aug 05 2022 - 13:29:56 EST


Give feature MSRs that same treatment as CPUID and disallow changing said
MSRs after KVM_RUN.

RFC as this is lightly tested and should come with a selftests update to
verify it actually works. Posting early to get feedback on the overall
idea, and on the VMX MSRs trickery (though I think patches 1-2 are a good
idea irrespective of trying to reduce the overhead of the new check).

Sean Christopherson (3):
KVM: x86: Add macros to track first...last VMX feature MSRs
KVM: x86: Generate set of VMX feature MSRs using first/last
definitions
KVM: x86: Disallow writes to immutable feature MSRs after KVM_RUN

arch/x86/kvm/svm/svm.c | 2 +-
arch/x86/kvm/vmx/vmx.c | 8 ++--
arch/x86/kvm/x86.c | 90 +++++++++++++++++++++++++++---------------
arch/x86/kvm/x86.h | 8 ++++
4 files changed, 72 insertions(+), 36 deletions(-)


base-commit: 93472b79715378a2386598d6632c654a2223267b
--
2.37.1.559.g78731f0fdb-goog