numa: allow memory-less nodes when using memdev as backend

QEMU fails to start if memory-less node is present when memdev
is used
  qemu-system-x86_64 -object memory-backend-ram,id=ram0,size=128M \
                     -numa node -numa node,memdev=ram0
with error:
  "memdev option must be specified for either all or no nodes"

which works as expected if legacy 'mem' is used.

Fix check to make memory-less nodes valid when memdev option is used
but still disallow mix of mem and memdev options.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20190702140745.27767-2-imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 7 insertions, 12 deletions

diff --git a/hw/core/numa.c b/hw/core/numa.c
index 2d984b025b..a11431483c 100644
--- a/hw/core/numa.c
+++ b/hw/core/numa.c
@@ -45,7 +45,8 @@ QemuOptsList qemu_numa_opts = {
     .desc = { { 0 } } /* validated with OptsVisitor */
 };
 
-static int have_memdevs = -1;
+static int have_memdevs;
+static int have_mem;
 static int max_numa_nodeid; /* Highest specified NUMA node ID, plus one.
                              * For all nodes, nodeid < max_numa_nodeid
                              */
@@ -103,17 +104,11 @@ static void parse_numa_node(MachineState *ms, NumaNodeOptions *node,
         }
     }
 
-    if (node->has_mem && node->has_memdev) {
-        error_setg(errp, "cannot specify both mem= and memdev=");
-        return;
-    }
-
-    if (have_memdevs == -1) {
-        have_memdevs = node->has_memdev;
-    }
-    if (node->has_memdev != have_memdevs) {
-        error_setg(errp, "memdev option must be specified for either "
-                   "all or no nodes");
+    have_memdevs = have_memdevs ? : node->has_memdev;
+    have_mem = have_mem ? : node->has_mem;
+    if ((node->has_mem && have_memdevs) || (node->has_memdev && have_mem)) {
+        error_setg(errp, "numa configuration should use either mem= or memdev=,"
+                   "mixing both is not allowed");
         return;
     }