[libvirt] [PATCH 2/3] qemu: SCSI hostdev hot-plug: Fix automatic creation of SCSI controllers

[Marc Hartmayer]

Ensure that the given controller and all controllers with a smaller
index exist; there must not be any missing index in between.

Reviewed-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk at linux.vnet.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay at linux.vnet.ibm.com>
---
 src/qemu/qemu_hotplug.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 5e6a8cb..037e601 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1873,6 +1873,7 @@ qemuDomainAttachHostSCSIDevice(virConnectPtr conn,
                                virDomainObjPtr vm,
                                virDomainHostdevDefPtr hostdev)
 {
+    size_t i;
     int ret = -1;
     qemuDomainObjPrivatePtr priv = vm->privateData;
     virErrorPtr orig_err;
@@ -1888,9 +1889,23 @@ qemuDomainAttachHostSCSIDevice(virConnectPtr conn,
         return -1;
     }
 
-    cont = qemuDomainFindOrCreateSCSIDiskController(driver, vm, hostdev->info->addr.drive.controller);
-    if (!cont)
-        return -1;
+    /* Let's make sure the disk has a controller defined and loaded before
+     * trying to add it. The controller used by the disk must exist before a
+     * qemu command line string is generated.
+     *
+     * Ensure that the given controller and all controllers with a smaller index
+     * exist; there must not be any missing index in between.
+     */
+    for (i = 0; i <= hostdev->info->addr.drive.controller; i++) {
+        cont = qemuDomainFindOrCreateSCSIDiskController(driver, vm, i);
+        if (!cont)
+            return -1;
+    }
+
+    /* Tell clang that "cont" is non-NULL.
+       This is because disk->info.addr.driver.controller is unsigned,
+       and hence the above loop must iterate at least once. */
+    sa_assert(cont);
 
     if (qemuHostdevPrepareSCSIDevices(driver, vm->def->name,
                                       &hostdev, 1)) {
-- 
2.5.5