Fix bugs in KVM's (mis)handling of secondary execution controls. KVM overrides the secondary execution control VMX MSR during KVM_SET_CPUID. Similar to the somewhat recent reverts 8805875aa473 ("Revert "KVM: nVMX: Do not expose MPX VMX controls when guest MPX disabled"") 9389d5774aca ("Revert "KVM: nVMX: Expose load IA32_PERF_GLOBAL_CTRL VM-{Entry,Exit} control"") undo misguided KVM behavior where KVM overrides allowed-1 settings in the secondary execution controls in response to changes to the guest's CPUID model. To avoid breaking userspace that doesn't take ownership of the VMX MSRs, go hands off if and only if userpace sets the MSR in question. Before fixing that, fix another bug it was hiding where the umwait/tpause control was being exposed to L1 for nVMX only after KVM_SET_CPUID, and harden KVM against similar bugs in the future. v2: Fix the ENABLE_USR_WAIT_PAUSE bug too. [Aaron] v1: https://lore.kernel.org/all/20221110005706.1064832-1-seanjc@xxxxxxxxxx Sean Christopherson (4): KVM: nVMX: Properly expose ENABLE_USR_WAIT_PAUSE control to L1 KVM: nVMX: Don't stuff secondary execution control if it's not supported KVM: nVMX: Don't muck with allowed sec exec controls on CPUID changes KVM: selftests: Test KVM's handling of VMX's sec exec MSR on KVM_SET_CPUID arch/x86/kvm/vmx/capabilities.h | 1 + arch/x86/kvm/vmx/nested.c | 6 +- arch/x86/kvm/vmx/vmx.c | 17 +++- .../selftests/kvm/include/x86_64/processor.h | 1 + .../selftests/kvm/include/x86_64/vmx.h | 4 +- .../selftests/kvm/x86_64/vmx_msrs_test.c | 92 +++++++++++++++++++ 6 files changed, 116 insertions(+), 5 deletions(-) base-commit: 02076de83f4de19a045227b9d44084a30e936c26 -- 2.39.0.rc1.256.g54fd8350bd-goog