[libvirt] [PATCHv6 1/3] libvirt/qemu - support persistent modification of devices.

[KAMEZAWA Hiroyuki]

Thank you for comments. This is a rebased/fixed one.

=
>From 5858b9d6b33a9d917576f6179be13a306272ff45 Mon Sep 17 00:00:00 2001
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
Date: Wed, 23 Mar 2011 17:45:12 +0900
Subject: [PATCHv6 1/3] libvirt/qemu - support persistent modification of devices.

Now, qemudDomainAttachDeviceFlags() and qemudDomainDetachDeviceFlags()
doesn't support VIR_DOMAIN_DEVICE_MODIFY_CONFIG. By this, virsh's
at(de)tatch-device --persistent cannot modify qemu config.
(Xen allows it.)

This patch is a base patch for adding support of devices in
step by step manner. Following patches will add some device
support.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>

Changelog v5->v6
 - fixed Indentation
 - clean up.

Changelog v4->v5:
 - fixed error codes at reporting Error.
 - fixed unlock code after calling qemuDomainObjBeginJobWithDriver()
 - fixed virDomainFindByUUID() to be virDomainFindByName()
 - fixed spelling, indent, etc..
 - removed unnecessary checks.

---
 src/qemu/qemu_driver.c |  137 +++++++++++++++++++++++++++++++++++++++++++-----
 1 files changed, 124 insertions(+), 13 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 6f296c9..468361b 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -4140,16 +4140,124 @@ cleanup:
     return ret;
 }
 
-static int qemudDomainAttachDeviceFlags(virDomainPtr dom,
-                                        const char *xml,
-                                        unsigned int flags) {
-    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
-        qemuReportError(VIR_ERR_OPERATION_INVALID,
-                        "%s", _("cannot modify the persistent configuration of a domain"));
+/*
+ * Attach a device given by XML, the change will be persistent
+ * and domain XML definition file is updated.
+ */
+static int qemuDomainAttachDevicePersistent(virDomainDefPtr vmdef,
+                                            virDomainDeviceDefPtr newdev)
+{
+
+    switch(newdev->type) {
+    default:
+        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                        _("Sorry, the device is not supported for now"));
+        return -1;
+    }
+
+    return 0;
+}
+
+static int qemuDomainDetachDevicePersistent(virDomainDefPtr vmdef,
+                                            virDomainDeviceDefPtr device)
+{
+    switch(device->type) {
+    default:
+        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                        _("Sorry, the device is not supported for now"));
         return -1;
     }
+    return 0;
+}
+
+static int qemuDomainModifyDevicePersistent(virDomainPtr dom,
+                                            const char *xml,
+                                            unsigned int attach, unsigned int flags)
+{
+    struct qemud_driver *driver;
+    virDomainDeviceDefPtr device;
+    virDomainDefPtr vmdef;
+    virDomainObjPtr vm;
+    int ret = -1;
+
+    /*
+     * When both of MODIFY_CONFIG and MODIFY_LIVE is specified at the same time,
+     * return error for now. We should support this later.
+     */
+    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE) {
+        qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                        _("Now, cannot modify alive domain and its definition "
+                          "at the same time."));
+        return -1;
+    }
+
+    driver = dom->conn->privateData;
+    qemuDriverLock(driver);
+    vm = virDomainFindByName(&driver->domains, dom->name);
+    if (!vm) {
+        qemuReportError(VIR_ERR_NO_DOMAIN, _("no domain with name : '%s'"),
+                        dom->name);
+        goto unlock_out;
+    }
+
+    if (qemuDomainObjBeginJobWithDriver(driver, vm) < 0)
+        goto unlock_out;
+
+    if (virDomainObjIsActive(vm)) {
+        /*
+         * For now, just allow updating inactive domains. Further development
+         * will allow updating both active domain and its config file at
+         * the same time.
+         */
+        qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                        _("unsupported to update active domain's definition."));
+        goto endjob;
+    }
+
+    vmdef = virDomainObjGetPersistentDef(driver->caps, vm);
 
-    return qemudDomainAttachDevice(dom, xml);
+    if (!vmdef)
+        goto endjob;
+
+    device = virDomainDeviceDefParse(driver->caps,
+                                     vmdef, xml, VIR_DOMAIN_XML_INACTIVE);
+    if (!device)
+        goto endjob;
+
+    if (attach)
+        ret = qemuDomainAttachDevicePersistent(vmdef, device);
+    else
+        ret = qemuDomainDetachDevicePersistent(vmdef, device);
+
+    if (!ret) /* save the result */
+        ret = virDomainSaveConfig(driver->configDir, vmdef);
+
+    virDomainDeviceDefFree(device);
+
+endjob:
+    if (qemuDomainObjEndJob(vm) == 0)
+        vm = NULL;
+unlock_out:
+    if (vm)
+        virDomainObjUnlock(vm);
+    qemuDriverUnlock(driver);
+    return ret;
+}
+
+static int qemudDomainAttachDeviceFlags(virDomainPtr dom,
+                                        const char *xml,
+                                        unsigned int flags)
+{
+    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG)
+        return qemuDomainModifyDevicePersistent(dom, xml, 1, flags);
+
+    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)
+        return qemudDomainAttachDevice(dom, xml);
+
+    qemuReportError(VIR_ERR_INVALID_ARG,
+                    _("bad flag: %x not supported"), flags);
+
+    return -1;
 }
 
 
@@ -4364,13 +4472,16 @@ cleanup:
 static int qemudDomainDetachDeviceFlags(virDomainPtr dom,
                                         const char *xml,
                                         unsigned int flags) {
-    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
-        qemuReportError(VIR_ERR_OPERATION_INVALID,
-                        "%s", _("cannot modify the persistent configuration of a domain"));
-        return -1;
-    }
 
-    return qemudDomainDetachDevice(dom, xml);
+    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG)
+        return qemuDomainModifyDevicePersistent(dom, xml, 0, flags);
+
+    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)
+        return qemudDomainDetachDevice(dom, xml);
+
+    qemuReportError(VIR_ERR_INVALID_ARG,
+                    _("bad flag: %x not supported now"), flags);
+    return -1;
 }
 
 static int qemudDomainGetAutostart(virDomainPtr dom,
-- 
1.7.4.1