The AMD APM states that if VMMCALL instruction is not intercepted, the instruction raises a #UD exception. Create a vmmcall exit handler that generates a #UD if a VMMCALL exit from L2 is being handled by L0, which means that L1 did not intercept the VMMCALL instruction. Suggested-by: Sean Christopherson Signed-off-by: Kevin Cheng Reviewed-by: Yosry Ahmed Reviewed-by: Manali Shukla Tested-by: Manali Shukla --- arch/x86/kvm/svm/svm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 1888211e20988..9257976ded539 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3194,6 +3194,20 @@ static int bus_lock_exit(struct kvm_vcpu *vcpu) return 0; } +static int vmmcall_interception(struct kvm_vcpu *vcpu) +{ + /* + * VMMCALL #UDs if it's not intercepted, and KVM reaches this point if + * and only if the VMMCALL intercept is not set in vmcb12. + */ + if (is_guest_mode(vcpu)) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 1; + } + + return kvm_emulate_hypercall(vcpu); +} + static int (*const svm_exit_handlers[])(struct kvm_vcpu *vcpu) = { [SVM_EXIT_READ_CR0] = cr_interception, [SVM_EXIT_READ_CR3] = cr_interception, @@ -3244,7 +3258,7 @@ static int (*const svm_exit_handlers[])(struct kvm_vcpu *vcpu) = { [SVM_EXIT_TASK_SWITCH] = task_switch_interception, [SVM_EXIT_SHUTDOWN] = shutdown_interception, [SVM_EXIT_VMRUN] = vmrun_interception, - [SVM_EXIT_VMMCALL] = kvm_emulate_hypercall, + [SVM_EXIT_VMMCALL] = vmmcall_interception, [SVM_EXIT_VMLOAD] = vmload_interception, [SVM_EXIT_VMSAVE] = vmsave_interception, [SVM_EXIT_STGI] = stgi_interception, -- 2.52.0.457.g6b5491de43-goog