[libvirt] running Libvirt from source code, IPC_LOCK and VFIO

Hi, I'm facing a strange behavior when running Libvirt from source code, latest upstream, on an Ubuntu 18.04.1 LTS Power 9 server. My QEMU guest - which is using VFIO and GPU passthrough - breaks on boot when trying to allocate a DMA window inside KVM. Debugging the code, I've found out that the problem is related to the process not having CAP_IPC_LOCK - at least from the host kernel perspective. This is strange because: - the same VM running directly from QEMU command line works - the same VM running in the system Libvirt (v4.0.0, Ubuntu version) also works What am I missing? My understanding on Linux process is that a process running as root should inherit the same capabilities of the user, which includes CAP_IPC_LOCK. Running Libvirt from source code should grant ipc_lock to it ... right? Any help is appreciated. I can provide more details (VM XML for example) if necessary. Thanks!