tree 68dbc457bf3f12e8273ab34811d4bbc6a05f98cb
parent f1b8325508327a302f1d5cd8a4bf51e2c9c72fa9
author Sean Christopherson <seanjc@google.com> 1623775532 -0700
committer Paolo Bonzini <pbonzini@redhat.com> 1624011889 -0400

KVM: VMX: Refuse to load kvm_intel if EPT and NX are disabled

Refuse to load KVM if NX support is not available and EPT is not enabled.
Shadow paging has assumed NX support since commit 9167ab799362 ("KVM:
vmx, svm: always run with EFER.NXE=1 when shadow paging is active"), so
for all intents and purposes this has been a de facto requirement for
over a year.

Do not require NX support if EPT is enabled purely because Intel CPUs let
firmware disable NX support via MSR_IA32_MISC_ENABLES.  If not for that,
VMX (and KVM as a whole) could require NX support with minimal risk to
breaking userspace.

Fixes: 9167ab799362 ("KVM: vmx, svm: always run with EFER.NXE=1 when shadow paging is active")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20210615164535.2146172-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>