vfio/{iommufd, container}: Invoke HostIOMMUDevice::realize() during attach_device()

Move the HostIOMMUDevice::realize() to be invoked during the attach of the device
before we allocate IOMMUFD hardware pagetable objects (HWPT). This allows the use
of the hw_caps obtained by IOMMU_GET_HW_INFO that essentially tell if the IOMMU
behind the device supports dirty tracking.

Note: The HostIOMMUDevice data from legacy backend is static and doesn't
need any information from the (type1-iommu) backend to be initialized.
In contrast however, the IOMMUFD HostIOMMUDevice data requires the
iommufd FD to be connected and having a devid to be able to successfully
GET_HW_INFO. This means vfio_device_hiod_realize() is called in
different places within the backend .attach_device() implementation.

Suggested-by: Cédric Le Goater <clg@redhat.cm>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
[ clg: Fixed error handling in iommufd_cdev_attach() ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

1 files changed, 6 insertions, 10 deletions

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index d7f02be595..26e74fa430 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1536,7 +1536,7 @@ bool vfio_attach_device(char *name, VFIODevice *vbasedev,
 {
     const VFIOIOMMUClass *ops =
         VFIO_IOMMU_CLASS(object_class_by_name(TYPE_VFIO_IOMMU_LEGACY));
-    HostIOMMUDevice *hiod;
+    HostIOMMUDevice *hiod = NULL;
 
     if (vbasedev->iommufd) {
         ops = VFIO_IOMMU_CLASS(object_class_by_name(TYPE_VFIO_IOMMU_IOMMUFD));
@@ -1544,21 +1544,17 @@ bool vfio_attach_device(char *name, VFIODevice *vbasedev,
 
     assert(ops);
 
-    if (!ops->attach_device(name, vbasedev, as, errp)) {
-        return false;
-    }
 
-    if (vbasedev->mdev) {
-        return true;
+    if (!vbasedev->mdev) {
+        hiod = HOST_IOMMU_DEVICE(object_new(ops->hiod_typename));
+        vbasedev->hiod = hiod;
     }
 
-    hiod = HOST_IOMMU_DEVICE(object_new(ops->hiod_typename));
-    if (!HOST_IOMMU_DEVICE_GET_CLASS(hiod)->realize(hiod, vbasedev, errp)) {
+    if (!ops->attach_device(name, vbasedev, as, errp)) {
         object_unref(hiod);
-        ops->detach_device(vbasedev);
+        vbasedev->hiod = NULL;
         return false;
     }
-    vbasedev->hiod = hiod;
 
     return true;
 }