vfio/iommufd: Add comment emphasizing no movement of hiod->realize() call
The nested IOMMU support needs device and hwpt id which are generated
only after attachment. Hiod encapsulates these information in realize()
and passes to vIOMMU.
Suggested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250521110301.3313877-1-zhenzhong.duan@intel.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index af1c7ab..6b26967 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -592,6 +592,10 @@
goto err_listener_register;
}
+ /*
+ * Do not move this code before attachment! The nested IOMMU support
+ * needs device and hwpt id which are generated only after attachment.
+ */
if (!vfio_device_hiod_create_and_realize(vbasedev,
TYPE_HOST_IOMMU_DEVICE_IOMMUFD_VFIO, errp)) {
goto err_listener_register;
