libxl: Clarify that 'xenlight' should only be used internally

The libxl driver has suffered an identity crisis since its introduction.
It took on the name 'libxl' since at the time libvirt already contained
a 'xen' driver for the old Xen toolstack implementation. 'libxl' is short
for libxenlight, which is often called xenlight. Unfortunately all forms
of the name are used in the libxl driver.

The only remaining use of the 'xenlight' form is when interacting with
the host device manager, which is difficult to change since it would
cause problems when upgrading the driver.

Rename the #define to make it clear the 'xenlight' form is internal and
add a comment describing why the name exists and that its use should be
discouraged.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

src/libxl/libxl_conf.h

@@ -39,7 +39,12 @@
 #include "libxl_logger.h"
 
 #define LIBXL_DRIVER_EXTERNAL_NAME "Xen"
-#define LIBXL_DRIVER_NAME "xenlight"
+/*
+ * We are stuck with the 'xenlight' name since it is used by the hostdev
+ * manager. Changing it would break management of any host devices previously
+ * managed under the name 'xenlight'.
+ */
+#define LIBXL_DRIVER_INTERNAL_NAME "xenlight"
 #define LIBXL_VNC_PORT_MIN  5900
 #define LIBXL_VNC_PORT_MAX  65535
 

src/libxl/libxl_domain.c

@@ -873,7 +873,7 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver,
         VIR_FREE(xml);
     }
 
-    virHostdevReAttachDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    virHostdevReAttachDomainDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                     vm->def, hostdev_flags, NULL);
 
     VIR_FREE(priv->lockState);
@@ -1370,7 +1370,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
     if (cfg->autoballoon && libxlDomainFreeMem(cfg->ctx, &d_config) < 0)
         goto cleanup_dom;
 
-    if (virHostdevPrepareDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    if (virHostdevPrepareDomainDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                        vm->def, hostdev_flags) < 0)
         goto cleanup_dom;
 

src/libxl/libxl_driver.c

@@ -431,7 +431,7 @@ libxlReconnectDomain(virDomainObjPtr vm,
     libxlLoggerOpenFile(cfg->logger, vm->def->id, vm->def->name, NULL);
 
     /* Update hostdev state */
-    if (virHostdevUpdateActiveDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    if (virHostdevUpdateActiveDomainDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                             vm->def, hostdev_flags) < 0)
         goto error;
 
@@ -3127,7 +3127,7 @@ libxlDomainAttachHostPCIDevice(libxlDriverPrivatePtr driver,
     if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs + 1) < 0)
         goto cleanup;
 
-    if (virHostdevPreparePCIDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    if (virHostdevPreparePCIDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                     vm->def->name, vm->def->uuid,
                                     &hostdev, 1, 0) < 0)
         goto cleanup;
@@ -3149,7 +3149,7 @@ libxlDomainAttachHostPCIDevice(libxlDriverPrivatePtr driver,
     goto cleanup;
 
  error:
-    virHostdevReAttachPCIDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    virHostdevReAttachPCIDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                  vm->def->name, &hostdev, 1, NULL);
 
  cleanup:
@@ -3264,7 +3264,7 @@ libxlDomainAttachHostUSBDevice(libxlDriverPrivatePtr driver,
     if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs + 1) < 0)
         goto cleanup;
 
-    if (virHostdevPrepareUSBDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    if (virHostdevPrepareUSBDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                     vm->def->name, &hostdev, 1, 0) < 0)
         goto cleanup;
 
@@ -3284,7 +3284,7 @@ libxlDomainAttachHostUSBDevice(libxlDriverPrivatePtr driver,
     goto cleanup;
 
  reattach:
-    virHostdevReAttachUSBDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    virHostdevReAttachUSBDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                  vm->def->name, &hostdev, 1);
 
  cleanup:
@@ -3689,7 +3689,7 @@ libxlDomainDetachHostPCIDevice(libxlDriverPrivatePtr driver,
 
     virDomainHostdevRemove(vm->def, idx);
 
-    virHostdevReAttachPCIDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    virHostdevReAttachPCIDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                  vm->def->name, &hostdev, 1, NULL);
 
     ret = 0;
@@ -3811,7 +3811,7 @@ libxlDomainDetachHostUSBDevice(libxlDriverPrivatePtr driver,
 
     virDomainHostdevRemove(vm->def, idx);
 
-    virHostdevReAttachUSBDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
+    virHostdevReAttachUSBDevices(hostdev_mgr, LIBXL_DRIVER_INTERNAL_NAME,
                                  vm->def->name, &hostdev, 1);
 
     ret = 0;