[PATCH 3/4] qemu_driver: add check for qemu capabilities requirements

[Hiroki Narukawa <hnarukaw@xxxxxxxxxxxxx>]

query-dirty-rate command is used for virsh domstats by default, but this
is available only on qemu >=5.2.0.

By this commit, qemu domain stats will check capabilities requirements before issuing actual query.

Signed-off-by: Hiroki Narukawa <hnarukaw@xxxxxxxxxxxxx>
---
 src/qemu/qemu_driver.c | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index ac5eaf139e..9cfd0a6ca5 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -18714,13 +18714,28 @@ static struct qemuDomainGetStatsWorker qemuDomainGetStatsWorkers[] = {
 
 static int
 qemuDomainGetStatsCheckSupport(unsigned int *stats,
-                               bool enforce)
+                               bool enforce,
+                               virDomainObj *vm)
 {
+    qemuDomainObjPrivate *priv = vm->privateData;
     unsigned int supportedstats = 0;
     size_t i;
+    virQEMUCapsFlags* flagCursor;
 
-    for (i = 0; qemuDomainGetStatsWorkers[i].func; i++)
-        supportedstats |= qemuDomainGetStatsWorkers[i].stats;
+    for (i = 0; qemuDomainGetStatsWorkers[i].func; i++) {
+        bool supportedByQemu = true;
+
+        for (flagCursor = qemuDomainGetStatsWorkers[i].requiredCaps; *flagCursor != QEMU_CAPS_LAST;
+             ++flagCursor) {
+            if (!virQEMUCapsGet(priv->qemuCaps, *flagCursor)) {
+                supportedByQemu = false;
+                break;
+            }
+        }
+        if (supportedByQemu) {
+            supportedstats |= qemuDomainGetStatsWorkers[i].stats;
+        }
+    }
 
     if (*stats == 0) {
         *stats = supportedstats;
@@ -18791,7 +18806,7 @@ static int
 qemuConnectGetAllDomainStats(virConnectPtr conn,
                              virDomainPtr *doms,
                              unsigned int ndoms,
-                             unsigned int stats,
+                             unsigned int requestedStats,
                              virDomainStatsRecordPtr **retStats,
                              unsigned int flags)
 {
@@ -18805,11 +18820,12 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
     int nstats = 0;
     size_t i;
     int ret = -1;
-    unsigned int privflags = 0;
+    unsigned int privflags;
     unsigned int domflags = 0;
     unsigned int lflags = flags & (VIR_CONNECT_LIST_DOMAINS_FILTERS_ACTIVE |
                                    VIR_CONNECT_LIST_DOMAINS_FILTERS_PERSISTENT |
                                    VIR_CONNECT_LIST_DOMAINS_FILTERS_STATE);
+    unsigned int stats;
 
     virCheckFlags(VIR_CONNECT_LIST_DOMAINS_FILTERS_ACTIVE |
                   VIR_CONNECT_LIST_DOMAINS_FILTERS_PERSISTENT |
@@ -18821,9 +18837,6 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
     if (virConnectGetAllDomainStatsEnsureACL(conn) < 0)
         return -1;
 
-    if (qemuDomainGetStatsCheckSupport(&stats, enforce) < 0)
-        return -1;
-
     if (ndoms) {
         if (virDomainObjListConvert(driver->domains, conn, doms, ndoms, &vms,
                                     &nvms, virConnectGetAllDomainStatsCheckACL,
@@ -18838,14 +18851,19 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
 
     tmpstats = g_new0(virDomainStatsRecordPtr, nvms + 1);
 
-    if (qemuDomainGetStatsNeedMonitor(stats))
-        privflags |= QEMU_DOMAIN_STATS_HAVE_JOB;
-
     for (i = 0; i < nvms; i++) {
         virDomainStatsRecordPtr tmp = NULL;
         domflags = 0;
+        privflags = 0;
         vm = vms[i];
 
+        stats = requestedStats;
+        if (qemuDomainGetStatsCheckSupport(&stats, enforce, vm) < 0)
+            return -1;
+
+        if (qemuDomainGetStatsNeedMonitor(stats))
+            privflags |= QEMU_DOMAIN_STATS_HAVE_JOB;
+
         virObjectLock(vm);
 
         if (HAVE_JOB(privflags)) {
-- 
2.17.1