Add persistence of PCI addresses to QEMU

Current PCI addresses are allocated at time of VM startup.
To make them truely persistent, it is neccessary to do this
at time of virDomainDefine/virDomainCreate. The code in
qemuStartVMDaemon still remains in order to cope with upgrades
from older libvirt releases

* src/qemu/qemu_driver.c: Rename existing qemuAssignPCIAddresses
  to qemuDetectPCIAddresses. Add new qemuAssignPCIAddresses which
  does auto-allocation upfront. Call qemuAssignPCIAddresses from
  qemuDomainDefine and qemuDomainCreate to assign PCI addresses that
  can then be persisted. Don't clear PCI addresses at shutdown if
  they are intended to be persistent

src/qemu/qemu_driver.c

@@ -95,6 +95,7 @@ struct _qemuDomainObjPrivate {
     int *vcpupids;
 
     qemuDomainPCIAddressSetPtr pciaddrs;
+    int persistentAddrs;
 };
 
 static int qemudShutdown(void);
@@ -857,6 +858,7 @@ qemuReconnectDomain(void *payload, const char *name ATTRIBUTE_UNUSED, void *opaq
     virDomainObjPtr obj = payload;
     struct qemud_driver *driver = opaque;
     qemuDomainObjPrivatePtr priv;
+    unsigned long long qemuCmdFlags;
 
     virDomainObjLock(obj);
 
@@ -872,6 +874,15 @@ qemuReconnectDomain(void *payload, const char *name ATTRIBUTE_UNUSED, void *opaq
         goto error;
     }
 
+    /* XXX we should be persisting the original flags in the XML
+     * not re-detecting them, since the binary may have changed
+     * since launch time */
+    if (qemudExtractVersionInfo(obj->def->emulator,
+                                NULL,
+                                &qemuCmdFlags) >= 0 &&
+        (qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE))
+        priv->persistentAddrs = 1;
+
     if (!(priv->pciaddrs = qemuDomainPCIAddressSetCreate(obj->def)))
         goto error;
 
@@ -1976,7 +1987,7 @@ qemuGetPCIWatchdogVendorProduct(virDomainWatchdogDefPtr def,
  * some static addrs on CLI. Have to check that...
  */
 static int
-qemuAssignPCIAddresses(virDomainObjPtr vm,
+qemuDetectPCIAddresses(virDomainObjPtr vm,
                        qemuMonitorPCIAddress *addrs,
                        int naddrs)
 {
@@ -2098,7 +2109,7 @@ qemuInitPCIAddresses(struct qemud_driver *driver,
                                            &addrs);
     qemuDomainObjExitMonitorWithDriver(driver, vm);
 
-    ret = qemuAssignPCIAddresses(vm, addrs, naddrs);
+    ret = qemuDetectPCIAddresses(vm, addrs, naddrs);
 
     VIR_FREE(addrs);
 
@@ -2141,6 +2152,44 @@ static int qemudNextFreeVNCPort(struct qemud_driver *driver ATTRIBUTE_UNUSED) {
     return -1;
 }
 
+
+static int
+qemuAssignPCIAddresses(virDomainDefPtr def)
+{
+    int ret = -1;
+    unsigned long long qemuCmdFlags = 0;
+    qemuDomainPCIAddressSetPtr addrs = NULL;
+    struct stat sb;
+
+    if (stat(def->emulator, &sb) < 0) {
+        virReportSystemError(errno,
+                             _("Cannot find QEMU binary %s"),
+                             def->emulator);
+        goto cleanup;
+    }
+
+    if (qemudExtractVersionInfo(def->emulator,
+                                NULL,
+                                &qemuCmdFlags) < 0)
+        goto cleanup;
+
+    if (qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE) {
+        if (!(addrs = qemuDomainPCIAddressSetCreate(def)))
+            goto cleanup;
+
+        if (qemuAssignDevicePCISlots(def, addrs) < 0)
+            goto cleanup;
+    }
+
+    ret = 0;
+
+cleanup:
+    qemuDomainPCIAddressSetFree(addrs);
+
+    return ret;
+}
+
+
 static pciDeviceList *
 qemuGetPciHostDeviceList(virDomainDefPtr def)
 {
@@ -2662,7 +2711,15 @@ static int qemudStartVMDaemon(virConnectPtr conn,
         goto cleanup;
     }
 
+    /*
+     * Normally PCI addresses are assigned inhe virDomainCreate
+     * or virDomainDefine methods. We might still need to assign
+     * some here to cope with the question of upgrades. Regardless
+     * we also need to populate the PCi address set cache for later
+     * use in hotplug
+     */
     if (qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE) {
+        /* Populate cache with current addresses */
         if (priv->pciaddrs) {
             qemuDomainPCIAddressSetFree(priv->pciaddrs);
             priv->pciaddrs = NULL;
@@ -2670,8 +2727,14 @@ static int qemudStartVMDaemon(virConnectPtr conn,
         if (!(priv->pciaddrs = qemuDomainPCIAddressSetCreate(vm->def)))
             goto cleanup;
 
+
+        /* Assign any remaining addresses */
         if (qemuAssignDevicePCISlots(vm->def, priv->pciaddrs) < 0)
             goto cleanup;
+
+        priv->persistentAddrs = 1;
+    } else {
+        priv->persistentAddrs = 0;
     }
 
     vm->def->id = driver->nextvmid++;
@@ -2903,10 +2966,12 @@ static void qemudShutdownVMDaemon(struct qemud_driver *driver,
         VIR_FREE(vm->def->seclabel.imagelabel);
     }
 
-    virDomainDefClearPCIAddresses(vm->def);
     virDomainDefClearDeviceAliases(vm->def);
-    qemuDomainPCIAddressSetFree(priv->pciaddrs);
-    priv->pciaddrs = NULL;
+    if (!priv->persistentAddrs) {
+        virDomainDefClearPCIAddresses(vm->def);
+        qemuDomainPCIAddressSetFree(priv->pciaddrs);
+        priv->pciaddrs = NULL;
+    }
 
     qemuDomainReAttachHostDevices(driver, vm->def);
 
@@ -3352,6 +3417,12 @@ static virDomainPtr qemudDomainCreate(virConnectPtr conn, const char *xml,
     if (virDomainObjIsDuplicate(&driver->domains, def, 1) < 0)
         goto cleanup;
 
+    if (qemudCanonicalizeMachine(driver, def) < 0)
+        goto cleanup;
+
+    if (qemuAssignPCIAddresses(def) < 0)
+        goto cleanup;
+
     if (!(vm = virDomainAssignDef(driver->caps,
                                   &driver->domains,
                                   def)))
@@ -5049,6 +5120,9 @@ static virDomainPtr qemudDomainDefine(virConnectPtr conn, const char *xml) {
     if (qemudCanonicalizeMachine(driver, def) < 0)
         goto cleanup;
 
+    if (qemuAssignPCIAddresses(def) < 0)
+        goto cleanup;
+
     if (!(vm = virDomainAssignDef(driver->caps,
                                   &driver->domains,
                                   def))) {