DR6_BD
dr6 |= DR6_BD | DR6_ACTIVE_LOW;
return ex->payload & ~DR6_BD;
vcpu->run->debug.arch.dr6 = DR6_BD | DR6_ACTIVE_LOW;
kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BD);
target_dr6 = 0xffff0ff0 | DR6_BD;