[libvirt] [PATCH 3/3] qemu: Auto-generate controller for hotplugged hostdev

[Eric Farman]

If a SCSI hostdev is included in an initial domain XML, without a
corresponding controller statement, one is created silently when the
guest is booted.

When hotplugging a SCSI hostdev, a presumption is that the controller
is already present in the domain either from the original XML, or via
an earlier hotplug.

  [root at xxxxxxxx ~]# cat disk.xml
  <hostdev mode='subsystem' type='scsi'>
    <source>
      <adapter name='scsi_host0'/>
      <address bus='0' target='3' unit='1088438288'/>
    </source>
  </hostdev>
  [root at xxxxxxxx ~]# virsh attach-device guest01 disk.xml
  error: Failed to attach device from disk.xml
  error: internal error: unable to execute QEMU command 'device_add': Bus 'scsi0.0' not found

Since the infrastructure is in place, we can also create a controller
silently for use by the hotplugged hostdev device.

Signed-off-by: Eric Farman <farman at linux.vnet.ibm.com>
---
 src/qemu/qemu_hotplug.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 99496e5..5f54c44 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1508,6 +1508,7 @@ qemuDomainAttachHostScsiDevice(virQEMUDriverPtr driver,
 {
     int ret = -1;
     qemuDomainObjPrivatePtr priv = vm->privateData;
+    virDomainControllerDefPtr cont = NULL;
     char *devstr = NULL;
     char *drvstr = NULL;
     bool teardowncgroup = false;
@@ -1520,6 +1521,10 @@ qemuDomainAttachHostScsiDevice(virQEMUDriverPtr driver,
         return -1;
     }
 
+    cont = qemuDomainFindOrCreateSCSIDiskController(driver, vm, hostdev->info->addr.drive.controller);
+    if (!cont)
+        return -1;
+
     if (qemuPrepareHostdevSCSIDevices(driver, vm->def->name,
                                       &hostdev, 1)) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
-- 
1.7.9.5