Hmm, with strace showing almost a hang on a single of those ioctl calls you'D think that is easy to spot :-/
But this isn't as clear as expected: sudo trace-cmd record -p function_graph -l vfio_pci_ioctl -O graph-time Disable all but 1 CPUs to have less concurrency in the trace. => Not much better But it is the handler: 1276 »···.ioctl»·»···= vfio_pci_ioctl, There seem to be a lot of calls to vfio_pci_ioctl and not just a few slow ones. Whatever strace thought, that is not how it looks like. Starting again with wider traces to check what the entry might be. sys_splice is high on the radar atm. As a bonus now the test env broke and can't passthrough anymore. The emulex firmware breaks and fails. Maybe abort for now and focus on other things and resetup the testbed another day. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1838575 Title: passthrough devices cause >17min boot delay Status in linux package in Ubuntu: Confirmed Status in qemu package in Ubuntu: Incomplete Bug description: Adding passthrough devices to a guest introduces a boot delay of > 17 minutes. During this time libvirt reports the guest to be "paused". The delay does not seem to scale with the # of hostdevs - that is, 1 hostdev causes about a 17min delay, while 16 only bumps that up to ~18min. Removing all hostdevs avoids the delay. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1838575/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp