nodedev: fix xml output for mdev parents in test suite

Commit 51fbbfdce8 attempted to get the proper nodedev name for the
parent of an defined mdev by traversing the filesystem and looking for a
device that had the appropriate sysfs path.  This works, but it would be
cleaner to to avoid mucking around in the filesystem and instead just
just examine the list of devices we have in memory.

We already had a function nodeDeviceFindAddressByName() which constructs
an address for parent device in a format that can be used with mdevctl.
So if we refactor this function into a a function that simply formats an
address for an arbitrary virNodeDeviceObj*, then we can use this
function as a predicate for our new virNodeDeviceObjListFind() function
from the previous commit. This will search our list of devices for one
whose address matches the address we get from mdevctl.

One nice benefit of this approach is that our test cases will now
display xml output with the proper parent name for mdevs (assuming that
we've added the appropriate mock parent devices to the test driver).
Previously they just displayed 'computer' for the parent because the
alternative would have required specially constructing a mock filesystem
environment with a sysfs that mapped to the appropriate parent.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/node_device/node_device_driver.c

@@ -648,17 +648,11 @@ nodeDeviceDefToMdevctlConfig(virNodeDeviceDef *def, char **buf)
 
 
 static char *
-nodeDeviceFindAddressByName(const char *name)
+nodeDeviceObjFormatAddress(virNodeDeviceObj *obj)
 {
-    virNodeDeviceDef *def = NULL;
     virNodeDevCapsDef *caps = NULL;
     char *addr = NULL;
-    virNodeDeviceObj *dev = virNodeDeviceObjListFindByName(driver->devs, name);
-
-    if (!dev)
-        return NULL;
-
-    def = virNodeDeviceObjGetDef(dev);
+    virNodeDeviceDef *def = virNodeDeviceObjGetDef(obj);
     for (caps = def->caps; caps != NULL; caps = caps->next) {
         switch (caps->data.type) {
         case VIR_NODE_DEV_CAP_PCI_DEV: {
@@ -714,8 +708,6 @@ nodeDeviceFindAddressByName(const char *name)
             break;
     }
 
-    virNodeDeviceObjEndAPI(&dev);
-
     return addr;
 }
 
@@ -730,6 +722,7 @@ nodeDeviceGetMdevctlCommand(virNodeDeviceDef *def,
     g_autoptr(virCommand) cmd = NULL;
     const char *subcommand = virMdevctlCommandTypeToString(cmd_type);
     g_autofree char *inbuf = NULL;
+    virNodeDeviceObj *parent_obj = NULL;
 
     switch (cmd_type) {
     case MDEVCTL_CMD_CREATE:
@@ -754,7 +747,10 @@ nodeDeviceGetMdevctlCommand(virNodeDeviceDef *def,
     switch (cmd_type) {
     case MDEVCTL_CMD_CREATE:
     case MDEVCTL_CMD_DEFINE:
-        parent_addr = nodeDeviceFindAddressByName(def->parent);
+        if ((parent_obj = nodeDeviceObjFindByName(def->parent))) {
+            parent_addr = nodeDeviceObjFormatAddress(parent_obj);
+            virNodeDeviceObjEndAPI(&parent_obj);
+        }
 
         if (!parent_addr) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -1042,6 +1038,21 @@ static void mdevGenerateDeviceName(virNodeDeviceDef *dev)
 }
 
 
+static bool
+matchDeviceAddress(virNodeDeviceObj *obj,
+                   const void *opaque)
+{
+    g_autofree char *addr = NULL;
+    bool want = false;
+
+    virObjectLock(obj);
+    addr = nodeDeviceObjFormatAddress(obj);
+    want = STREQ_NULLABLE(addr, opaque);
+    virObjectUnlock(obj);
+    return want;
+}
+
+
 static virNodeDeviceDef*
 nodeDeviceParseMdevctlChildDevice(const char *parent,
                                   virJSONValue *json)
@@ -1051,7 +1062,7 @@ nodeDeviceParseMdevctlChildDevice(const char *parent,
     virJSONValue *props;
     virJSONValue *attrs;
     g_autoptr(virNodeDeviceDef) child = g_new0(virNodeDeviceDef, 1);
-    g_autofree char *parent_sysfs_path = NULL;
+    virNodeDeviceObj *parent_obj;
 
     /* the child object should have a single key equal to its uuid.
      * The value is an object describing the properties of the mdev */
@@ -1064,20 +1075,12 @@ nodeDeviceParseMdevctlChildDevice(const char *parent,
     /* Look up id of parent device. mdevctl supports defining mdevs for parent
      * devices that are not present on the system (to support starting mdevs on
      * hotplug, etc) so the parent may not actually exist. */
-    parent_sysfs_path = g_strdup_printf("/sys/class/mdev_bus/%s", parent);
-    if (virFileExists(parent_sysfs_path)) {
-        g_autofree char *canon_syspath = virFileCanonicalizePath(parent_sysfs_path);
-        virNodeDeviceObj *parentobj = NULL;
-
-        if ((parentobj = virNodeDeviceObjListFindBySysfsPath(driver->devs,
-                                                             canon_syspath))) {
-            virNodeDeviceDef *parentdef = virNodeDeviceObjGetDef(parentobj);
-            child->parent = g_strdup(parentdef->name);
-            virNodeDeviceObjEndAPI(&parentobj);
-
-            child->parent_sysfs_path = g_steal_pointer(&canon_syspath);
-        }
-    }
+    if ((parent_obj = virNodeDeviceObjListFind(driver->devs, matchDeviceAddress,
+                                               (void *)parent))) {
+        virNodeDeviceDef *parentdef = virNodeDeviceObjGetDef(parent_obj);
+        child->parent = g_strdup(parentdef->name);
+        virNodeDeviceObjEndAPI(&parent_obj);
+    };
     if (!child->parent)
         child->parent = g_strdup("computer");
     child->caps = g_new0(virNodeDevCapsDef, 1);

tests/nodedevmdevctldata/mdevctl-list-multiple.out.xml

@@ -1,6 +1,6 @@
 <device>
   <name>mdev_200f228a_c80a_4d50_bfb7_f5a0e4e34045</name>
-  <parent>computer</parent>
+  <parent>pci_0000_00_02_0</parent>
   <capability type='mdev'>
     <type id='i915-GVTg_V5_4'/>
     <uuid>200f228a-c80a-4d50-bfb7-f5a0e4e34045</uuid>
@@ -9,7 +9,7 @@
 </device>
 <device>
   <name>mdev_de807ffc_1923_4d5f_b6c9_b20ecebc6d4b</name>
-  <parent>computer</parent>
+  <parent>pci_0000_00_02_0</parent>
   <capability type='mdev'>
     <type id='i915-GVTg_V5_4'/>
     <uuid>de807ffc-1923-4d5f-b6c9-b20ecebc6d4b</uuid>
@@ -18,7 +18,7 @@
 </device>
 <device>
   <name>mdev_435722ea_5f43_468a_874f_da34f1217f13</name>
-  <parent>computer</parent>
+  <parent>pci_0000_00_02_0</parent>
   <capability type='mdev'>
     <type id='i915-GVTg_V5_8'/>
     <uuid>435722ea-5f43-468a-874f-da34f1217f13</uuid>
@@ -28,7 +28,7 @@
 </device>
 <device>
   <name>mdev_783e6dbb_ea0e_411f_94e2_717eaad438bf</name>
-  <parent>computer</parent>
+  <parent>ap_matrix</parent>
   <capability type='mdev'>
     <type id='vfio_ap-passthrough'/>
     <uuid>783e6dbb-ea0e-411f-94e2-717eaad438bf</uuid>

tests/nodedevmdevctltest.c

@@ -231,7 +231,7 @@ fakeRootDevice(void)
  * parent of the mdev, and it needs a PCI address
  */
 static virNodeDeviceDef *
-fakeParentDevice(void)
+fakePCIDevice(void)
 {
     virNodeDeviceDef *def = NULL;
     virNodeDevCapPCIDev *pci_dev;
@@ -252,6 +252,29 @@ fakeParentDevice(void)
     return def;
 }
 
+
+/* Add a fake matrix device that can be used as a parent device for mediated
+ * devices. For our purposes, it only needs to have a name that matches the
+ * parent of the mdev, and it needs the proper name
+ */
+static virNodeDeviceDef *
+fakeMatrixDevice(void)
+{
+    virNodeDeviceDef *def = NULL;
+    virNodeDevCapAPMatrix *cap;
+
+    def = g_new0(virNodeDeviceDef, 1);
+    def->caps = g_new0(virNodeDevCapsDef, 1);
+
+    def->name = g_strdup("ap_matrix");
+    def->parent = g_strdup("computer");
+
+    def->caps->data.type = VIR_NODE_DEV_CAP_AP_MATRIX;
+    cap = &def->caps->data.ap_matrix;
+    cap->addr = g_strdup("matrix");
+
+    return def;
+}
 static int
 addDevice(virNodeDeviceDef *def)
 {
@@ -274,7 +297,8 @@ static int
 nodedevTestDriverAddTestDevices(void)
 {
     if (addDevice(fakeRootDevice()) < 0 ||
-        addDevice(fakeParentDevice()) < 0)
+        addDevice(fakePCIDevice()) < 0 ||
+        addDevice(fakeMatrixDevice()) < 0)
         return -1;
 
     return 0;