[libvirt] [PATCH 2/2] qemu: alias: Fix calculation of memory device aliases

[Peter Krempa]

For device hotplug, the new alias ID needs to be checked in the list
rather than using the count of devices. Unplugging a device that is not
last in the array will make further hotplug impossible due to alias
collision.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1324551
---
 src/qemu/qemu_alias.c   | 27 +++++++++++++++++++++++++++
 src/qemu/qemu_alias.h   |  4 ++++
 src/qemu/qemu_hotplug.c |  2 +-
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_alias.c b/src/qemu/qemu_alias.c
index 052a829..c56e5e4 100644
--- a/src/qemu/qemu_alias.c
+++ b/src/qemu/qemu_alias.c
@@ -409,6 +409,33 @@ qemuAssignDeviceRNGAlias(virDomainDefPtr def,


 int
+qemuAssignDeviceMemoryAlias(virDomainDefPtr def,
+                            virDomainMemoryDefPtr mem,
+                            size_t idx)
+{
+    if (idx == -1) {
+        size_t i;
+        idx = 0;
+        for (i = 0; i < def->nmems; i++) {
+            int thisidx;
+            if ((thisidx = qemuDomainDeviceAliasIndex(&def->mems[i]->info, "dimm")) < 0) {
+                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                               _("Unable to determine device index for memory device"));
+                return -1;
+            }
+            if (thisidx >= idx)
+                idx = thisidx + 1;
+        }
+    }
+
+    if (virAsprintf(&mem->info.alias, "dimm%zu", idx) < 0)
+        return -1;
+
+    return 0;
+}
+
+
+int
 qemuAssignDeviceAliases(virDomainDefPtr def, virQEMUCapsPtr qemuCaps)
 {
     size_t i;
diff --git a/src/qemu/qemu_alias.h b/src/qemu/qemu_alias.h
index f311583..ba91d32 100644
--- a/src/qemu/qemu_alias.h
+++ b/src/qemu/qemu_alias.h
@@ -58,6 +58,10 @@ int qemuAssignDeviceRNGAlias(virDomainDefPtr def,
                              virDomainRNGDefPtr rng,
                              size_t idx);

+int qemuAssignDeviceMemoryAlias(virDomainDefPtr def,
+                                virDomainMemoryDefPtr mems,
+                                size_t idx);
+
 int qemuAssignDeviceAliases(virDomainDefPtr def, virQEMUCapsPtr qemuCaps);

 int qemuDomainDeviceAliasIndex(const virDomainDeviceInfo *info,
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 93cc8e2..010eccd 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -1751,7 +1751,7 @@ qemuDomainAttachMemory(virQEMUDriverPtr driver,
     if (qemuDomainDefValidateMemoryHotplug(vm->def, priv->qemuCaps, mem) < 0)
         goto cleanup;

-    if (virAsprintf(&mem->info.alias, "dimm%zu", vm->def->nmems) < 0)
+    if (qemuAssignDeviceMemoryAlias(vm->def, mem, -1) < 0)
         goto cleanup;

     if (virAsprintf(&objalias, "mem%s", mem->info.alias) < 0)
-- 
2.8.0