[PATCH-for-6.2 v2] hw/mem/pc-dimm: Restrict NUMA-specific code to NUMA machines

[PATCH-for-6.2 v2] hw/mem/pc-dimm: Restrict NUMA-specific code to NUMA machines

[Philippe Mathieu-Daudé]

When trying to use the pc-dimm device on a non-NUMA machine, we get:

  $ qemu-system-arm -M none -cpu max -S \
      -object memory-backend-file,id=mem1,size=1M,mem-path=/tmp/1m \
      -device pc-dimm,id=dimm1,memdev=mem1
  Segmentation fault (core dumped)

  (gdb) bt
  #0  pc_dimm_realize (dev=0x555556da3e90, errp=0x7fffffffcd10) at hw/mem/pc-dimm.c:184
  #1  0x0000555555fe1f8f in device_set_realized (obj=0x555556da3e90, value=true, errp=0x7fffffffce18) at hw/core/qdev.c:531
  #2  0x0000555555feb4a9 in property_set_bool (obj=0x555556da3e90, v=0x555556e54420, name=0x5555563c3c41 "realized", opaque=0x555556a704f0, errp=0x7fffffffce18) at qom/object.c:2257

To avoid that crash, restrict the pc-dimm NUMA check to machines
supporting NUMA, and do not allow the use of 'node' property on
non-NUMA machines.

Suggested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
v2: Follow Igor suggestion

Supersedes: <20210524171352.3796151-1-f4bug@amsat.org>
---
 hw/mem/pc-dimm.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
index a3a2560301c..48b913aba67 100644
--- a/hw/mem/pc-dimm.c
+++ b/hw/mem/pc-dimm.c
@@ -181,7 +181,21 @@ static void pc_dimm_realize(DeviceState *dev, Error **errp)
     PCDIMMDevice *dimm = PC_DIMM(dev);
     PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
     MachineState *ms = MACHINE(qdev_get_machine());
-    int nb_numa_nodes = ms->numa_state->num_nodes;
+
+    if (ms->numa_state) {
+        int nb_numa_nodes = ms->numa_state->num_nodes;
+
+        if (((nb_numa_nodes > 0) && (dimm->node >= nb_numa_nodes)) ||
+            (!nb_numa_nodes && dimm->node)) {
+            error_setg(errp, "'DIMM property " PC_DIMM_NODE_PROP " has value %"
+                       PRIu32 "' which exceeds the number of numa nodes: %d",
+                       dimm->node, nb_numa_nodes ? nb_numa_nodes : 1);
+            return;
+        }
+    } else if (dimm->node > 0) {
+        error_setg(errp, "machine doesn't support NUMA");
+        return;
+    }
 
     if (!dimm->hostmem) {
         error_setg(errp, "'" PC_DIMM_MEMDEV_PROP "' property is not set");
@@ -191,13 +205,6 @@ static void pc_dimm_realize(DeviceState *dev, Error **errp)
                    object_get_canonical_path_component(OBJECT(dimm->hostmem)));
         return;
     }
-    if (((nb_numa_nodes > 0) && (dimm->node >= nb_numa_nodes)) ||
-        (!nb_numa_nodes && dimm->node)) {
-        error_setg(errp, "'DIMM property " PC_DIMM_NODE_PROP " has value %"
-                   PRIu32 "' which exceeds the number of numa nodes: %d",
-                   dimm->node, nb_numa_nodes ? nb_numa_nodes : 1);
-        return;
-    }
 
     if (ddc->realize) {
         ddc->realize(dimm, errp);
-- 
2.31.1