[PATCH 3/3] qemu_driver: use qemuMonitorQueryStats to extract halt poll time

[Amneesh Singh]

Related: https://gitlab.com/libvirt/libvirt/-/issues/276

This patch uses qemuMonitorQueryStats to query "halt_poll_success_ns"
and "halt_poll_fail_ns" for every vCPU. The respective values for each
vCPU are then added together.

Signed-off-by: Amneesh Singh <natto at weirdnatto.in>
---
 src/qemu/qemu_driver.c | 69 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 61 insertions(+), 8 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index da95f947..e1c595e5 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -18066,15 +18066,68 @@ qemuDomainGetStatsCpuCgroup(virDomainObj *dom,
 }
 
 static int
-qemuDomainGetStatsCpuHaltPollTime(virDomainObj *dom,
-                                  virTypedParamList *params)
+qemuDomainGetStatsCpuHaltPollTime(virQEMUDriver *driver,
+                                  virDomainObj *dom,
+                                  virTypedParamList *params,
+                                  unsigned int privflags)
 {
     unsigned long long haltPollSuccess = 0;
     unsigned long long haltPollFail = 0;
-    pid_t pid = dom->pid;
+    qemuDomainObjPrivate *priv = dom->privateData;
+    bool queryStatsCap = virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_QUERY_STATS);
 
-    if (virHostCPUGetHaltPollTime(pid, &haltPollSuccess, &haltPollFail) < 0)
-        return 0;
+    if (queryStatsCap && HAVE_JOB(privflags) && virDomainObjIsActive(dom)) {
+        size_t i;
+        qemuMonitorQueryStatsTargetType target = QEMU_MONITOR_QUERY_STATS_TARGET_VCPU;
+        qemuMonitorQueryStatsProvider *provider = NULL;
+        g_autoptr(GPtrArray) providers = NULL;
+        g_autoptr(GPtrArray) queried_stats = NULL;
+        provider = qemuMonitorQueryStatsProviderNew(
+            QEMU_MONITOR_QUERY_STATS_PROVIDER_KVM,
+            QEMU_MONITOR_QUERY_STATS_NAME_HALT_POLL_SUCCESS_NS,
+            QEMU_MONITOR_QUERY_STATS_NAME_HALT_POLL_FAIL_NS,
+            QEMU_MONITOR_QUERY_STATS_NAME_LAST);
+
+        providers = g_ptr_array_new_full(1, (GDestroyNotify) qemuMonitorQueryStatsProviderFree);
+        g_ptr_array_add(providers, provider);
+
+        qemuDomainObjEnterMonitor(driver, dom);
+        queried_stats = qemuMonitorQueryStats(priv->mon, target, NULL, providers);
+        qemuDomainObjExitMonitor(dom);
+
+        if (!queried_stats)
+            return 0;
+
+        for (i = 0; i < queried_stats->len; i++) {
+            unsigned long long curHaltPollSuccess, curHaltPollFail;
+            GHashTable *cur_table = queried_stats->pdata[i];
+            virJSONValue *success_obj, *fail_obj;
+            const char *success_str = qemuMonitorQueryStatsNameTypeToString(
+                QEMU_MONITOR_QUERY_STATS_NAME_HALT_POLL_SUCCESS_NS);
+            const char *fail_str = qemuMonitorQueryStatsNameTypeToString(
+                QEMU_MONITOR_QUERY_STATS_NAME_HALT_POLL_FAIL_NS);
+
+            success_obj = g_hash_table_lookup(cur_table, success_str);
+            fail_obj = g_hash_table_lookup(cur_table, fail_str);
+
+            if (!success_obj || !fail_obj)
+                return 0;
+
+            if (virJSONValueGetNumberUlong(success_obj, &curHaltPollSuccess) < 0)
+                return 0;
+
+            if (virJSONValueGetNumberUlong(fail_obj, &curHaltPollFail) < 0)
+                return 0;
+
+            haltPollSuccess += curHaltPollSuccess;
+            haltPollFail += curHaltPollFail;
+        }
+    } else {
+        pid_t pid = dom->pid;
+
+        if (virHostCPUGetHaltPollTime(pid, &haltPollSuccess, &haltPollFail) < 0)
+            return 0;
+    }
 
     if (virTypedParamListAddULLong(params, haltPollSuccess, "cpu.haltpoll.success.time") < 0 ||
         virTypedParamListAddULLong(params, haltPollFail, "cpu.haltpoll.fail.time") < 0)
@@ -18087,7 +18140,7 @@ static int
 qemuDomainGetStatsCpu(virQEMUDriver *driver,
                       virDomainObj *dom,
                       virTypedParamList *params,
-                      unsigned int privflags G_GNUC_UNUSED)
+                      unsigned int privflags)
 {
     if (qemuDomainGetStatsCpuCgroup(dom, params) < 0)
         return -1;
@@ -18095,7 +18148,7 @@ qemuDomainGetStatsCpu(virQEMUDriver *driver,
     if (qemuDomainGetStatsCpuCache(driver, dom, params) < 0)
         return -1;
 
-    if (qemuDomainGetStatsCpuHaltPollTime(dom, params) < 0)
+    if (qemuDomainGetStatsCpuHaltPollTime(driver, dom, params, privflags) < 0)
         return -1;
 
     return 0;
@@ -18929,7 +18982,7 @@ static virQEMUCapsFlags queryDirtyRateRequired[] = {
 
 static struct qemuDomainGetStatsWorker qemuDomainGetStatsWorkers[] = {
     { qemuDomainGetStatsState, VIR_DOMAIN_STATS_STATE, false, NULL },
-    { qemuDomainGetStatsCpu, VIR_DOMAIN_STATS_CPU_TOTAL, false, NULL },
+    { qemuDomainGetStatsCpu, VIR_DOMAIN_STATS_CPU_TOTAL, true, NULL },
     { qemuDomainGetStatsBalloon, VIR_DOMAIN_STATS_BALLOON, true, NULL },
     { qemuDomainGetStatsVcpu, VIR_DOMAIN_STATS_VCPU, true, NULL },
     { qemuDomainGetStatsInterface, VIR_DOMAIN_STATS_INTERFACE, false, NULL },
-- 
2.36.1