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!