pc: explicitly check maxmem limit when adding DIMM

Currently maxmem limit is not checked and depends on
hotplug region container not being able to fit more RAM
than maxmem. Do check explicitly so that it would
be possible to change hotplug container size later
to deal with fragmentation.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 021ec44768a7b53c733efc3755c4b8e6455c5cdc..3d732cf5a5a5e9b3689c60db1ca8c9982fa278c3 100644 (file)
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1545,6 +1545,37 @@ void qemu_register_pc_machine(QEMUMachine *m)
     g_free(name);
 }
 
+static int pc_dimm_count(Object *obj, void *opaque)
+{
+    int *count = opaque;
+
+    if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
+        (*count)++;
+    }
+
+    object_child_foreach(obj, pc_dimm_count, opaque);
+    return 0;
+}
+
+static int pc_existing_dimms_capacity(Object *obj, void *opaque)
+{
+    Error *local_err = NULL;
+    uint64_t *size = opaque;
+
+    if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
+        (*size) += object_property_get_int(obj, PC_DIMM_SIZE_PROP, &local_err);
+
+        if (local_err) {
+            qerror_report_err(local_err);
+            error_free(local_err);
+            return 1;
+        }
+    }
+
+    object_child_foreach(obj, pc_dimm_count, opaque);
+    return 0;
+}
+
 static void pc_dimm_plug(HotplugHandler *hotplug_dev,
                          DeviceState *dev, Error **errp)
 {
@@ -1556,6 +1587,7 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
     PCDIMMDevice *dimm = PC_DIMM(dev);
     PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
     MemoryRegion *mr = ddc->get_memory_region(dimm);
+    uint64_t existing_dimms_capacity = 0;
     uint64_t align = TARGET_PAGE_SIZE;
     uint64_t addr;
 
@@ -1576,6 +1608,19 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
         goto out;
     }
 
+    if (pc_existing_dimms_capacity(OBJECT(machine), &existing_dimms_capacity)) {
+        error_setg(&local_err, "failed to get total size of existing DIMMs");
+        goto out;
+    }
+
+    if (existing_dimms_capacity + memory_region_size(mr) >
+        machine->maxram_size - machine->ram_size) {
+        error_setg(&local_err, "not enough space, currently 0x%" PRIx64
+                   " in use of total 0x" RAM_ADDR_FMT,
+                   existing_dimms_capacity, machine->maxram_size);
+        goto out;
+    }
+
     object_property_set_int(OBJECT(dev), addr, PC_DIMM_ADDR_PROP, &local_err);
     if (local_err) {
         goto out;