vfio/pci: Remove vfio_detach_device from vfio_realize error path

In vfio_realize, on the error path, we currently call
vfio_detach_device() after a successful vfio_attach_device.
While this looks natural, vfio_instance_finalize also induces
a vfio_detach_device(), and it seems to be the right place
instead as other resources are released there which happen
to be a prerequisite to a successful UNSET_CONTAINER.

So let's rely on the finalize vfio_detach_device call to free
all the relevant resources.

Fixes: a28e066 ("vfio/pci: Introduce vfio_[attach/detach]_device")
Reported-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/vfio/pci.c

@@ -3115,7 +3115,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     vfio_populate_device(vdev, &err);
     if (err) {
         error_propagate(errp, err);
-        goto out_detach;
+        goto error;
     }
 
     /* Get a copy of config space */
@@ -3125,7 +3125,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     if (ret < (int)MIN(pci_config_size(&vdev->pdev), vdev->config_size)) {
         ret = ret < 0 ? -errno : -EFAULT;
         error_setg_errno(errp, -ret, "failed to read device config space");
-        goto out_detach;
+        goto error;
     }
 
     /* vfio emulates a lot for us, but some bits need extra love */
@@ -3144,7 +3144,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     if (vdev->vendor_id != PCI_ANY_ID) {
         if (vdev->vendor_id >= 0xffff) {
             error_setg(errp, "invalid PCI vendor ID provided");
-            goto out_detach;
+            goto error;
         }
         vfio_add_emulated_word(vdev, PCI_VENDOR_ID, vdev->vendor_id, ~0);
         trace_vfio_pci_emulated_vendor_id(vbasedev->name, vdev->vendor_id);
@@ -3155,7 +3155,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     if (vdev->device_id != PCI_ANY_ID) {
         if (vdev->device_id > 0xffff) {
             error_setg(errp, "invalid PCI device ID provided");
-            goto out_detach;
+            goto error;
         }
         vfio_add_emulated_word(vdev, PCI_DEVICE_ID, vdev->device_id, ~0);
         trace_vfio_pci_emulated_device_id(vbasedev->name, vdev->device_id);
@@ -3166,7 +3166,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     if (vdev->sub_vendor_id != PCI_ANY_ID) {
         if (vdev->sub_vendor_id > 0xffff) {
             error_setg(errp, "invalid PCI subsystem vendor ID provided");
-            goto out_detach;
+            goto error;
         }
         vfio_add_emulated_word(vdev, PCI_SUBSYSTEM_VENDOR_ID,
                                vdev->sub_vendor_id, ~0);
@@ -3177,7 +3177,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     if (vdev->sub_device_id != PCI_ANY_ID) {
         if (vdev->sub_device_id > 0xffff) {
             error_setg(errp, "invalid PCI subsystem device ID provided");
-            goto out_detach;
+            goto error;
         }
         vfio_add_emulated_word(vdev, PCI_SUBSYSTEM_ID, vdev->sub_device_id, ~0);
         trace_vfio_pci_emulated_sub_device_id(vbasedev->name,
@@ -3210,7 +3210,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
     vfio_msix_early_setup(vdev, &err);
     if (err) {
         error_propagate(errp, err);
-        goto out_detach;
+        goto error;
     }
 
     vfio_bars_register(vdev);
@@ -3326,8 +3326,6 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
 out_teardown:
     vfio_teardown_msi(vdev);
     vfio_bars_exit(vdev);
-out_detach:
-    vfio_detach_device(vbasedev);
 error:
     error_prepend(errp, VFIO_MSG_PREFIX, vbasedev->name);
 }