[Qemu-devel] [RFC PATCH v3 11/19] Implement qmp and hmp commands for notification lists

[Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>]

Guest can respond to ACPI hotplug events e.g. with _EJ or _OST method.
This patch implements a tail queue to store guest notifications for memory
hot-add and hot-remove requests.

Guest responses for memory hotplug command on a per-dimm basis can be detected
with the new hmp command "info memhp" or the new qmp command "query-memhp"
Examples:

(qemu) device_add dimm,id=ram0
(qemu) info memory-hotplug
dimm: ram0 hot-add success
or
dimm: ram0 hot-add failure

(qemu) device_del ram3
(qemu) info memory-hotplug
dimm: ram3 hot-remove success
or
dimm: ram3 hot-remove failure

Results are removed from the queue once read.

This patch only queues _EJ events that signal hot-remove success.
For  _OST event queuing, which cover the hot-remove failure and
hot-add success/failure cases, the _OST patches in this series are  are also
needed.

These notification items should probably be part of migration state (not yet
implemented).

Signed-off-by: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
---
 hmp-commands.hx  |    2 +
 hmp.c            |   17 ++++++++++++++
 hmp.h            |    1 +
 hw/dimm.c        |   62 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 hw/dimm.h        |    2 +-
 monitor.c        |    7 ++++++
 qapi-schema.json |   26 ++++++++++++++++++++++
 qmp-commands.hx  |   37 ++++++++++++++++++++++++++++++++
 8 files changed, 152 insertions(+), 2 deletions(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index ed67e99..cfb1b67 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1462,6 +1462,8 @@ show device tree
 show qdev device model list
 @item info roms
 show roms
+@item info memory-hotplug
+show memory-hotplug
 @end table
 ETEXI
 
diff --git a/hmp.c b/hmp.c
index ba6fbd3..4b3d63d 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1168,3 +1168,20 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict)
     qmp_screendump(filename, &err);
     hmp_handle_error(mon, &err);
 }
+
+void hmp_info_memory_hotplug(Monitor *mon)
+{
+    MemHpInfoList *info;
+    MemHpInfoList *item;
+    MemHpInfo *dimm;
+
+    info = qmp_query_memory_hotplug(NULL);
+    for (item = info; item; item = item->next) {
+        dimm = item->value;
+        monitor_printf(mon, "dimm: %s %s %s\n", dimm->dimm,
+                dimm->request, dimm->result);
+        dimm->dimm = NULL;
+    }
+
+    qapi_free_MemHpInfoList(info);
+}
diff --git a/hmp.h b/hmp.h
index 48b9c59..986705a 100644
--- a/hmp.h
+++ b/hmp.h
@@ -73,5 +73,6 @@ void hmp_getfd(Monitor *mon, const QDict *qdict);
 void hmp_closefd(Monitor *mon, const QDict *qdict);
 void hmp_send_key(Monitor *mon, const QDict *qdict);
 void hmp_screen_dump(Monitor *mon, const QDict *qdict);
+void hmp_info_memory_hotplug(Monitor *mon);
 
 #endif
diff --git a/hw/dimm.c b/hw/dimm.c
index 288b997..fbd93a8 100644
--- a/hw/dimm.c
+++ b/hw/dimm.c
@@ -65,6 +65,7 @@ static void dimm_bus_initfn(Object *obj)
     DimmBus *bus = DIMM_BUS(obj);
     QTAILQ_INIT(&bus->dimmconfig_list);
     QTAILQ_INIT(&bus->dimmlist);
+    QTAILQ_INIT(&bus->dimm_hp_result_queue);
 
     QTAILQ_FOREACH_SAFE(dimm_cfg, &dimmconfig_list, nextdimmcfg, next_dimm_cfg) {
         QTAILQ_REMOVE(&dimmconfig_list, dimm_cfg, nextdimmcfg);
@@ -236,20 +237,78 @@ void dimm_notify(uint32_t idx, uint32_t event)
 {
     DimmBus *bus = main_memory_bus;
     DimmDevice *s;
+    DimmConfig *slotcfg;
+    struct dimm_hp_result *result;
+
     s = dimm_find_from_idx(idx);
     assert(s != NULL);
+    result = g_malloc0(sizeof(*result));
+    slotcfg = dimmcfg_find_from_name(DEVICE(s)->id);
+    result->dimmname = slotcfg->name;
 
     switch(event) {
         case DIMM_REMOVE_SUCCESS:
             dimm_depopulate(s);
-            qdev_simple_unplug_cb((DeviceState*)s);
             QTAILQ_REMOVE(&bus->dimmlist, s, nextdimm);
+            qdev_simple_unplug_cb((DeviceState*)s);
+            QTAILQ_INSERT_TAIL(&bus->dimm_hp_result_queue, result, next);
             break;
         default:
+            g_free(result);
             break;
     }
 }
 
+MemHpInfoList *qmp_query_memory_hotplug(Error **errp)
+{
+    DimmBus *bus = main_memory_bus;
+    MemHpInfoList *head = NULL, *cur_item = NULL, *info;
+    struct dimm_hp_result *item, *nextitem;
+
+    QTAILQ_FOREACH_SAFE(item, &bus->dimm_hp_result_queue, next, nextitem) {
+
+        info = g_malloc0(sizeof(*info));
+        info->value = g_malloc0(sizeof(*info->value));
+        info->value->dimm = g_malloc0(sizeof(char) * 32);
+        info->value->request = g_malloc0(sizeof(char) * 16);
+        info->value->result = g_malloc0(sizeof(char) * 16);
+        switch (item->ret) {
+            case DIMM_REMOVE_SUCCESS:
+                strcpy(info->value->request, "hot-remove");
+                strcpy(info->value->result, "success");
+                break;
+            case DIMM_REMOVE_FAIL:
+                strcpy(info->value->request, "hot-remove");
+                strcpy(info->value->result, "failure");
+                break;
+            case DIMM_ADD_SUCCESS:
+                strcpy(info->value->request, "hot-add");
+                strcpy(info->value->result, "success");
+                break;
+            case DIMM_ADD_FAIL:
+                strcpy(info->value->request, "hot-add");
+                strcpy(info->value->result, "failure");
+                break;
+            default:
+                break;    
+        }
+        strcpy(info->value->dimm, item->dimmname);
+        /* XXX: waiting for the qapi to support GSList */
+        if (!cur_item) {
+            head = cur_item = info;
+        } else {
+            cur_item->next = info;
+            cur_item = info;
+        }
+
+        /* hotplug notification copied to qmp list, delete original item */
+        QTAILQ_REMOVE(&bus->dimm_hp_result_queue, item, next);
+        g_free(item);
+    }
+
+    return head;
+}
+
 static int dimm_init(DeviceState *s)
 {
     DimmBus *bus = main_memory_bus;
@@ -286,6 +345,7 @@ static void dimm_class_init(ObjectClass *klass, void *data)
 
     dc->props = dimm_properties;
     dc->unplug = dimm_unplug_device;
+    dc->bus_type = TYPE_DIMM_BUS;
     dc->init = dimm_init;
 }
 
diff --git a/hw/dimm.h b/hw/dimm.h
index 5e991a6..95251ba 100644
--- a/hw/dimm.h
+++ b/hw/dimm.h
@@ -69,6 +69,7 @@ typedef struct DimmBus {
     dimm_calcoffset_fn dimm_calcoffset;
     DimmConfiglist dimmconfig_list;
     QTAILQ_HEAD(Dimmlist, DimmDevice) dimmlist;
+    QTAILQ_HEAD(dimm_hp_result_head, dimm_hp_result)  dimm_hp_result_queue;
 } DimmBus;
 
 struct dimm_hp_result {
@@ -86,5 +87,4 @@ void main_memory_bus_create(Object *parent);
 void dimm_config_create(char *id, uint64_t size, uint64_t node,
         uint32_t dimm_idx, uint32_t populated);
 
-
 #endif
diff --git a/monitor.c b/monitor.c
index 67064e2..be9a1d9 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2740,6 +2740,13 @@ static mon_cmd_t info_cmds[] = {
         .mhandler.info = do_trace_print_events,
     },
     {
+        .name       = "memory-hotplug",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show memory hotplug status",
+        .mhandler.info = hmp_info_memory_hotplug,
+    },
+    {
         .name       = NULL,
     },
 };
diff --git a/qapi-schema.json b/qapi-schema.json
index a9f465a..3706a2a 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2555,3 +2555,29 @@
 # Since: 0.14.0
 ##
 { 'command': 'screendump', 'data': {'filename': 'str'} }
+
+##
+# @MemHpInfo:
+#
+# Information about status of a memory hotplug command
+#
+# @dimm: the Dimm associated with the result
+#
+# @result: the result of the hotplug command
+#
+# Since: 1.3
+#
+##
+{ 'type': 'MemHpInfo',
+  'data': {'dimm': 'str', 'request': 'str', 'result': 'str'} }
+
+##
+# @query-memory-hotplug:
+#
+# Returns a list of information about pending hotplug commands
+#
+# Returns: a list of @MemhpInfo
+#
+# Since: 1.3
+##
+{ 'command': 'query-memory-hotplug', 'returns': ['MemHpInfo'] }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 6e21ddb..e50dcc2 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -2539,3 +2539,40 @@ EQMP
         .args_type  = "",
         .mhandler.cmd_new = qmp_marshal_input_query_target,
     },
+    {
+        .name       = "query-memory-hotplug",
+        .args_type  = "",
+        .mhandler.cmd_new = qmp_marshal_input_query_memory_hotplug
+    },
+SQMP
+query-memory-hotplug
+----------
+
+Show memory hotplug command notifications.
+
+Return a json-array. Each DIMM that has a pending notification is represented
+by a json-object, which contains:
+
+- "dimm": Dimm name (json-str)
+- "request": type of hot request: hot-add or hot-remove  (json-str)
+- "result": result of the hotplug request for this Dimm success or failure (json-str)
+
+Example:
+
+-> { "execute": "query-memory-hotplug" }
+<- {
+      "return":[
+         {
+            "result": "failure",
+            "request": "hot-remove",
+            "dimm": "dimm10"
+         },
+         {
+            "result": "success",
+            "request": "hot-add",
+            "dimm": "dimm3"
+         }
+      ]
+   }
+
+EQMP
-- 
1.7.9