[libvirt] [PATCH 4/4] qemu: add plumbing for persistent device changes

[Eric Blake]

There's still work to add persistent callback functions, and to
make sure this all works, but this demonstrates how having a
single function makes it easy to support flags for all three
types of device modifications.

* src/qemu/qemu_driver.c (qemuDomainModifyDeviceFlags): Add
parameter, and support VIR_DOMAIN_DEVICE_MODIFY_CURRENT.
(qemuDomainAttachDeviceFlags, qemuDomainUpdateDeviceFlags)
(qemuDomainDetachDeviceFlags): Update callers.
---

After this point, we can use Kame's patch 1/4 to add in the
persistent function callbacks (with slight tweaks to their
signatures), and 2/4 to make it easier to to temporary
modifications to a config:

if (flags & CONFIG) {
   create temporary def
   call persistent callback
}
if (flags & LIVE) {
   call live callback
}
if (no errors)
   commit temporary def and live state changes, as needed

But with the benefit that CURRENT support is now provided.

 src/qemu/qemu_driver.c |   47 +++++++++++++++++++++++++++++++++++------------
 1 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 4f0a057..8c978be 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -4031,7 +4031,8 @@ cleanup:
 static int
 qemuDomainModifyDeviceFlags(virDomainPtr dom, const char *xml,
                             unsigned int flags,
-                            qemuDomainModifyDeviceCallback cb)
+                            qemuDomainModifyDeviceCallback live,
+                            qemuDomainModifyDeviceCallback persistent)
 {
     struct qemud_driver *driver = dom->conn->privateData;
     virDomainObjPtr vm;
@@ -4039,12 +4040,7 @@ qemuDomainModifyDeviceFlags(virDomainPtr dom, const char *xml,
     virBitmapPtr qemuCaps = NULL;
     int ret = -1;
     bool force = (flags & VIR_DOMAIN_DEVICE_MODIFY_FORCE) != 0;
-
-    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
-        qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
-                        _("cannot modify domain persistent configuration"));
-        return -1;
-    }
+    bool active;

     qemuDriverLock(driver);
     vm = virDomainFindByUUID(&driver->domains, dom->uuid);
@@ -4059,12 +4055,32 @@ qemuDomainModifyDeviceFlags(virDomainPtr dom, const char *xml,
     if (qemuDomainObjBeginJobWithDriver(driver, vm) < 0)
         goto cleanup;

-    if (!virDomainObjIsActive(vm)) {
+    active = virDomainObjIsActive(vm);
+
+    if ((flags & (VIR_DOMAIN_DEVICE_MODIFY_LIVE
+                  | VIR_DOMAIN_DEVICE_MODIFY_CONFIG)) == 0)
+        flags |= (active ? VIR_DOMAIN_DEVICE_MODIFY_LIVE
+                  : VIR_DOMAIN_DEVICE_MODIFY_CONFIG);
+
+    if ((flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE) && !active) {
         qemuReportError(VIR_ERR_OPERATION_INVALID,
                         "%s", _("cannot modify device on inactive domain"));
         goto endjob;
     }

+    if ((flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) && !vm->persistent) {
+        qemuReportError(VIR_ERR_OPERATION_INVALID,
+                        "%s", _("cannot modify device on transient domain"));
+        goto endjob;
+    }
+
+    /* XXX add persistent support */
+    if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
+        qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                        _("cannot modify domain persistent configuration"));
+        return -1;
+    }
+
     dev = virDomainDeviceDefParse(driver->caps, vm->def, xml,
                                   VIR_DOMAIN_XML_INACTIVE);
     if (dev == NULL)
@@ -4075,7 +4091,11 @@ qemuDomainModifyDeviceFlags(virDomainPtr dom, const char *xml,
                                    &qemuCaps) < 0)
         goto endjob;

-    ret = (cb)(dom, driver, vm, dev, qemuCaps, force);
+    ret = 0;
+    if (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)
+        ret = (live)(dom, driver, vm, dev, qemuCaps, force);
+    if (ret == 0 && (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG))
+        ret = (persistent)(dom, driver, vm, dev, qemuCaps, force);

     /* update domain status forcibly because the domain status may be changed
      * even if we attach the device failed. For example, a new controller may
@@ -4105,7 +4125,8 @@ qemuDomainAttachDeviceFlags(virDomainPtr dom, const char *xml,
     virCheckFlags(VIR_DOMAIN_DEVICE_MODIFY_LIVE |
                   VIR_DOMAIN_DEVICE_MODIFY_CONFIG, -1);
     return qemuDomainModifyDeviceFlags(dom, xml, flags,
-                                       qemuDomainAttachDeviceLive);
+                                       qemuDomainAttachDeviceLive,
+                                       NULL);
 }

 static int
@@ -4124,7 +4145,8 @@ qemuDomainUpdateDeviceFlags(virDomainPtr dom, const char *xml,
                   VIR_DOMAIN_DEVICE_MODIFY_CONFIG |
                   VIR_DOMAIN_DEVICE_MODIFY_FORCE, -1);
     return qemuDomainModifyDeviceFlags(dom, xml, flags,
-                                       qemuDomainUpdateDeviceLive);
+                                       qemuDomainUpdateDeviceLive,
+                                       NULL);
 }


@@ -4135,7 +4157,8 @@ qemuDomainDetachDeviceFlags(virDomainPtr dom, const char *xml,
     virCheckFlags(VIR_DOMAIN_DEVICE_MODIFY_LIVE |
                   VIR_DOMAIN_DEVICE_MODIFY_CONFIG, -1);
     return qemuDomainModifyDeviceFlags(dom, xml, flags,
-                                       qemuDomainDetachDeviceLive);
+                                       qemuDomainDetachDeviceLive,
+                                       NULL);
 }

 static int
-- 
1.7.4.2