On Fri, 2012-06-08 at 19:39 +0200, Andreas Hartmann wrote: > Andreas Hartmann wrote: > > Hello Alex, > > > > You can probably say, what this message on host side means: > > > > kernel: [ 3902.124109] vfio_dma_do_map: RLIMIT_MEMLOCK (65536) exceeded > > > > The WLAN card in the VM doesn't work any more. It came up after a few > > times of restarting the VM (with unbinding / rebinding - procedures). > > > > I'll see if it is reproducible. I had to reboot to get it working again. > > It is reproducible. And id seems not to be a problem of binding / > unbinding, but the fact of not starting it as root user seems to be the > problem. > > I never saw these problems with a root VM (and root does have the same > value for ulimit -l). Yes, this is expected when running as non-root. VFIO needs to lock pages on behalf of the user, so the user needs limits granted to be able to do that. Otherwise a VFIO user could lock down all the memory in the system. > - Is it possible to run the VM / VFIO in user context? Yes, this is one of the key design requirements of VFIO. Pre-requirements are that a privileged entity has sequestered all the devices as being owned by vfio-pci or pci-stub, the user has permissions to /dev/vfio/<group#> and /dev/vfio/vfio (the latter is expected to be safe to leave as 0666), and the user has limits set to lock pages sufficient for what they need (note that the default of 64k might be enough for some userspace driver applications). > - What size should be used for ulimit -l? It should be about the size of memory assigned to the guest. Once we have libvirt support, all of this should be relatively transparent as that will take care of the limits setting. For now, it's a bit of a pain running it as a normal user. If you come up with an easy way of doing it, please share. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
