qemu: bulk stats: implement balloon group

This patch implements the VIR_DOMAIN_STATS_BALLOON group of statistics.
Signed-off-by: NFrancesco Romani <fromani@redhat.com>

include/libvirt/libvirt.h.in

@@ -2514,6 +2514,7 @@ struct _virDomainStatsRecord {
 typedef enum {
     VIR_DOMAIN_STATS_STATE = (1 << 0), /* return domain state */
     VIR_DOMAIN_STATS_CPU_TOTAL = (1 << 1), /* return domain CPU info */
+    VIR_DOMAIN_STATS_BALLOON = (1 << 2), /* return domain balloon info */
 } virDomainStatsTypes;
 
 typedef enum {

src/libvirt.c

@@ -21603,6 +21603,12 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
  * "cpu.user" - user cpu time spent in nanoseconds as unsigned long long.
  * "cpu.system" - system cpu time spent in nanoseconds as unsigned long long.
  *
+ * VIR_DOMAIN_STATS_BALLOON: Return memory balloon device information.
+ * The typed parameter keys are in this format:
+ * "balloon.current" - the memory in kiB currently used
+ *                     as unsigned long long.
+ * "balloon.maximum" - the maximum memory in kiB allowed
+ *                     as unsigned long long.
  *
  * Using 0 for @stats returns all stats groups supported by the given
  * hypervisor.

src/qemu/qemu_driver.c

@@ -17448,6 +17448,42 @@ qemuDomainGetStatsCpu(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
     return 0;
 }
 
+static int
+qemuDomainGetStatsBalloon(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
+                          virDomainObjPtr dom,
+                          virDomainStatsRecordPtr record,
+                          int *maxparams,
+                          unsigned int privflags ATTRIBUTE_UNUSED)
+{
+    qemuDomainObjPrivatePtr priv = dom->privateData;
+    unsigned long long cur_balloon = 0;
+    int err = 0;
+
+    if (dom->def->memballoon &&
+        dom->def->memballoon->model == VIR_DOMAIN_MEMBALLOON_MODEL_NONE) {
+        cur_balloon = dom->def->mem.max_balloon;
+    } else if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BALLOON_EVENT)) {
+        cur_balloon = dom->def->mem.cur_balloon;
+    } else {
+        err = -1;
+    }
+
+    if (!err && virTypedParamsAddULLong(&record->params,
+                                        &record->nparams,
+                                        maxparams,
+                                        "balloon.current",
+                                        cur_balloon) < 0)
+        return -1;
+
+    if (virTypedParamsAddULLong(&record->params,
+                                &record->nparams,
+                                maxparams,
+                                "balloon.maximum",
+                                dom->def->mem.max_balloon) < 0)
+        return -1;
+
+    return 0;
+}
 
 typedef int
 (*qemuDomainGetStatsFunc)(virQEMUDriverPtr driver,
@@ -17465,6 +17501,7 @@ struct qemuDomainGetStatsWorker {
 static struct qemuDomainGetStatsWorker qemuDomainGetStatsWorkers[] = {
     { qemuDomainGetStatsState, VIR_DOMAIN_STATS_STATE, false },
     { qemuDomainGetStatsCpu, VIR_DOMAIN_STATS_CPU_TOTAL, false },
+    { qemuDomainGetStatsBalloon, VIR_DOMAIN_STATS_BALLOON, true },
     { NULL, 0, false }
 };