qemu: Implement chardev hotplug on config level

There are two levels on which a device may be hotplugged: config
and live. The config level requires just an insert or remove from
internal domain definition structure, which is exactly what this
patch does. There is currently no implementation for a chardev
update action, as there's not much to be updated. But more
importantly, the only thing that can be updated is path or socket
address by which chardevs are distinguished. So the update action
is currently not supported.

src/conf/domain_conf.c

@@ -10099,7 +10099,7 @@ virDomainLeaseRemove(virDomainDefPtr def,
     return virDomainLeaseRemoveAt(def, idx);
 }
 
-static bool
+bool
 virDomainChrEquals(virDomainChrDefPtr src,
                    virDomainChrDefPtr tgt)
 {
@@ -18036,9 +18036,11 @@ virDomainDeviceDefCopy(virDomainDeviceDefPtr src,
     case VIR_DOMAIN_DEVICE_RNG:
         rc = virDomainRNGDefFormat(&buf, src->data.rng, flags);
         break;
+    case VIR_DOMAIN_DEVICE_CHR:
+        rc = virDomainChrDefFormat(&buf, src->data.chr, flags);
+        break;
     case VIR_DOMAIN_DEVICE_NONE:
     case VIR_DOMAIN_DEVICE_SMARTCARD:
-    case VIR_DOMAIN_DEVICE_CHR:
     case VIR_DOMAIN_DEVICE_MEMBALLOON:
     case VIR_DOMAIN_DEVICE_NVRAM:
     case VIR_DOMAIN_DEVICE_LAST:

src/conf/domain_conf.h

@@ -2399,6 +2399,9 @@ virDomainChrGetDomainPtrs(virDomainDefPtr vmdef,
 virDomainChrDefPtr
 virDomainChrFind(virDomainDefPtr def,
                  virDomainChrDefPtr target);
+bool
+virDomainChrEquals(virDomainChrDefPtr src,
+                   virDomainChrDefPtr tgt);
 int
 virDomainChrInsert(virDomainDefPtr vmdef,
                    virDomainChrDefPtr chr);

src/libvirt_private.syms

@@ -115,6 +115,7 @@ virDomainChrConsoleTargetTypeToString;
 virDomainChrDefForeach;
 virDomainChrDefFree;
 virDomainChrDefNew;
+virDomainChrEquals;
 virDomainChrFind;
 virDomainChrGetDomainPtrs;
 virDomainChrInsert;

src/qemu/qemu_driver.c

@@ -6686,6 +6686,12 @@ qemuDomainAttachDeviceConfig(virQEMUCapsPtr qemuCaps,
             return -1;
         break;
 
+    case VIR_DOMAIN_DEVICE_CHR:
+        if (qemuDomainChrInsert(vmdef, dev->data.chr) < 0)
+            return -1;
+        dev->data.chr = NULL;
+        break;
+
     default:
          virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
                         _("persistent attach of device '%s' is not supported"),
@@ -6705,6 +6711,7 @@ qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef,
     virDomainHostdevDefPtr hostdev, det_hostdev;
     virDomainLeaseDefPtr lease, det_lease;
     virDomainControllerDefPtr cont, det_cont;
+    virDomainChrDefPtr chr;
     int idx;
     char mac[VIR_MAC_STRING_BUFLEN];
 
@@ -6772,6 +6779,15 @@ qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef,
 
         break;
 
+    case VIR_DOMAIN_DEVICE_CHR:
+        if (!(chr = qemuDomainChrRemove(vmdef, dev->data.chr)))
+            return -1;
+
+        virDomainChrDefFree(chr);
+        virDomainChrDefFree(dev->data.chr);
+        dev->data.chr = NULL;
+        break;
+
     default:
         virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
                        _("persistent detach of device '%s' is not supported"),

src/qemu/qemu_hotplug.c

@@ -1172,6 +1172,78 @@ error:
 
 }
 
+int
+qemuDomainChrInsert(virDomainDefPtr vmdef,
+                    virDomainChrDefPtr chr)
+{
+    if (chr->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE &&
+        chr->targetType == VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+                       _("attaching serial console is not supported"));
+        return -1;
+    }
+
+    if (virDomainChrFind(vmdef, chr)) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("chardev already exists"));
+        return -1;
+    }
+
+    if (virDomainChrInsert(vmdef, chr) < 0)
+        return -1;
+
+    /* Due to some crazy backcompat stuff, the first serial device is an alias
+     * to the first console too. If this is the case, the definition must be
+     * duplicated as first console device. */
+    if (vmdef->nserials == 1 && vmdef->nconsoles == 0) {
+        if ((!vmdef->consoles && VIR_ALLOC(vmdef->consoles) < 0) ||
+            VIR_ALLOC(vmdef->consoles[0]) < 0) {
+            virDomainChrRemove(vmdef, chr);
+            return -1;
+        }
+        vmdef->nconsoles = 1;
+
+        /* Create an console alias for the serial port */
+        vmdef->consoles[0]->deviceType = VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE;
+        vmdef->consoles[0]->targetType = VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL;
+    }
+
+    return 0;
+}
+
+virDomainChrDefPtr
+qemuDomainChrRemove(virDomainDefPtr vmdef,
+                    virDomainChrDefPtr chr)
+{
+    virDomainChrDefPtr ret;
+    bool removeCompat;
+
+    if (chr->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE &&
+        chr->targetType == VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("detaching serial console is not supported"));
+        return NULL;
+    }
+
+    /* Due to some crazy backcompat stuff, the first serial device is an alias
+     * to the first console too. If this is the case, the definition must be
+     * duplicated as first console device. */
+    removeCompat = vmdef->nserials && vmdef->nconsoles &&
+        vmdef->consoles[0]->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE &&
+        vmdef->consoles[0]->targetType == VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL &&
+        virDomainChrEquals(vmdef->serials[0], chr);
+
+    if (!(ret = virDomainChrRemove(vmdef, chr))) {
+        virReportError(VIR_ERR_INVALID_ARG, "%s",
+                       _("device not present in domain configuration"));
+            return NULL;
+    }
+
+    if (removeCompat)
+        VIR_DELETE_ELEMENT(vmdef->consoles, 0, vmdef->nconsoles);
+
+    return ret;
+}
 int qemuDomainAttachHostUsbDevice(virQEMUDriverPtr driver,
                                   virDomainObjPtr vm,
                                   virDomainHostdevDefPtr hostdev)

src/qemu/qemu_hotplug.h

@@ -106,4 +106,11 @@ int qemuDomainDetachLease(virQEMUDriverPtr driver,
                           virDomainLeaseDefPtr lease);
 
 
+int
+qemuDomainChrInsert(virDomainDefPtr vmdef,
+                    virDomainChrDefPtr chr);
+virDomainChrDefPtr
+qemuDomainChrRemove(virDomainDefPtr vmdef,
+                    virDomainChrDefPtr chr);
+
 #endif /* __QEMU_HOTPLUG_H__ */