[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 | 48 ++++++++++++++++++++++++++++++++++++++----
 1 file changed, 44 insertions(+), 4 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 3b5c3db6..0a2be6d3 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -18057,10 +18057,50 @@ qemuDomainGetStatsCpuHaltPollTime(virDomainObj *dom,
 {
     unsigned long long haltPollSuccess = 0;
     unsigned long long haltPollFail = 0;
-    pid_t pid = dom->pid;
+    qemuDomainObjPrivate *priv = dom->privateData;
+    bool canQueryStats = virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_QUERY_STATS);
 
-    if (virHostCPUGetHaltPollTime(pid, &haltPollSuccess, &haltPollFail) < 0)
-        return 0;
+    if (!canQueryStats) {
+        pid_t pid = dom->pid;
+
+        if (virHostCPUGetHaltPollTime(pid, &haltPollSuccess, &haltPollFail) < 0)
+            return 0;
+    } else {
+        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;
+        const char *success_str = "halt_poll_success_ns";
+        const char *fail_str = "halt_poll_fail_ns";
+
+        provider = qemuMonitorQueryStatsProviderNew(QEMU_MONITOR_QUERY_STATS_PROVIDER_KVM);
+        provider->names = g_new0(char *, 3);
+        provider->names[0] = g_strdup(success_str), provider->names[1] = g_strdup(fail_str);
+
+        providers = g_ptr_array_new_full(1, (GDestroyNotify) qemuMonitorQueryStatsProviderFree);
+        g_ptr_array_add(providers, provider);
+
+        queried_stats = qemuMonitorQueryStats(priv->mon, target, NULL, providers);
+
+        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, *fail;
+
+            success = g_hash_table_lookup(cur_table, success_str);
+            fail = g_hash_table_lookup(cur_table, fail_str);
+
+            ignore_value(virJSONValueGetNumberUlong(success, &curHaltPollSuccess));
+            ignore_value(virJSONValueGetNumberUlong(fail, &curHaltPollFail));
+
+            haltPollSuccess += curHaltPollSuccess;
+            haltPollFail += curHaltPollFail;
+        }
+    }
 
     if (virTypedParamListAddULLong(params, haltPollSuccess, "cpu.haltpoll.success.time") < 0 ||
         virTypedParamListAddULLong(params, haltPollFail, "cpu.haltpoll.fail.time") < 0)
@@ -18915,7 +18955,7 @@ 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