From: Pavel Hrdina <[email protected]>
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 <[email protected]>
---
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
