kvm: nVMX: Enforce cpl=0 for VMX instructions

VMX instructions executed inside a L1 VM will always trigger a VM exit
even when executed with cpl 3. This means we must perform the
privilege check in software.

Fixes: 70f3aac964ae("kvm: nVMX: Remove superfluous VMX instruction fault checks")
Cc: stable@vger.kernel.org
Signed-off-by: Felix Wilhelm <fwilhelm@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
static int vmx_deliver_nested_posted_interrupt(struct kvm_vcpu *vcpu,
						int vector)
{
	struct vcpu_vmx *vmx = to_vmx(vcpu);

	if (is_guest_mode(vcpu) &&
	    vector == vmx->nested.posted_intr_nv) {
		/*
		 * If a posted intr is not recognized by hardware,
		 * we will accomplish it in the next vmentry.
		 */
		vmx->nested.pi_pending = true;
		kvm_make_request(KVM_REQ_EVENT, vcpu);
		/* the PIR and ON have been set by L1. */
		if (!kvm_vcpu_trigger_posted_interrupt(vcpu, true))
			kvm_vcpu_kick(vcpu);
		return 0;
	}
	return -1;
}

static int vmx_deliver_nested_posted_interrupt(struct kvm_vcpu *vcpu,
						int vector)
{
	struct vcpu_vmx *vmx = to_vmx(vcpu);

	if (is_guest_mode(vcpu) &&
	    vector == vmx->nested.posted_intr_nv) {
		/*
		 * If a posted intr is not recognized by hardware,
		 * we will accomplish it in the next vmentry.
		 */
		vmx->nested.pi_pending = true;
		kvm_make_request(KVM_REQ_EVENT, vcpu);
		/* the PIR and ON have been set by L1. */
		if (!kvm_vcpu_trigger_posted_interrupt(vcpu, true))
			kvm_vcpu_kick(vcpu);
		return 0;
	}
	return -1;
}
