From: Pavel Hrdina <phrdina@redhat.com> On systems with selinux enabled starting a VM with managed host device using IOMMUFD backend can run into race-condition where both libvirt and udev are setting selinux label on /dev/vfio/devices/vfioX device. If udev is the last one to set selinux label starting VM fails with: error: internal error: QEMU unexpectedly closed the monitor (vm='test'): 2026-03-26T15:47:36.620422Z qemu-kvm: -device {"driver":"vfio-pci","id":"hostdev0","iommufd":"iommufd0","fd":"20","bus":"pci.7","addr":"0x0"}: vfio hostdev0: Failed to add fd 20 to KVM VFIO device: Invalid argument We need to wait for udev to finish processing all events. Signed-off-by: Pavel Hrdina <phrdina@redhat.com> --- src/hypervisor/virhostdev.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/hypervisor/virhostdev.c b/src/hypervisor/virhostdev.c index f4d2176204..b063a44f62 100644 --- a/src/hypervisor/virhostdev.c +++ b/src/hypervisor/virhostdev.c @@ -782,6 +782,9 @@ virHostdevPreparePCIDevicesImpl(virHostdevManager *mgr, } } + /* Step 2.5: Wait for udev to handle all events for devices. */ + virWaitForDevices(); + /* At this point, all devices are attached to the stub driver and have * been marked as inactive */ -- 2.53.0