API: add trivial qemu support for VIR_TYPED_PARAM_STRING

Qemu will be the first driver to make use of a typed string in the
next round of additions.  Separate out the trivial addition.

* src/qemu/qemu_driver.c (qemudSupportsFeature): Advertise feature.
(qemuDomainGetBlkioParameters, qemuDomainGetMemoryParameters)
(qemuGetSchedulerParametersFlags, qemudDomainBlockStatsFlags):
Allow typed strings flag where trivially supported.

src/qemu/qemu_driver.c

@@ -917,6 +917,7 @@ qemudSupportsFeature (virConnectPtr conn ATTRIBUTE_UNUSED, int feature)
     case VIR_DRV_FEATURE_MIGRATION_P2P:
     case VIR_DRV_FEATURE_MIGRATE_CHANGE_PROTECTION:
     case VIR_DRV_FEATURE_FD_PASSING:
+    case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
         return 1;
     default:
         return 0;
@@ -6038,9 +6039,13 @@ static int qemuDomainGetBlkioParameters(virDomainPtr dom,
     bool isActive;
 
     virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
-                  VIR_DOMAIN_AFFECT_CONFIG, -1);
+                  VIR_DOMAIN_AFFECT_CONFIG |
+                  VIR_TYPED_PARAM_STRING_OKAY, -1);
     qemuDriverLock(driver);
 
+    /* We don't return strings, and thus trivially support this flag.  */
+    flags &= ~VIR_TYPED_PARAM_STRING_OKAY;
+
     vm = virDomainFindByUUID(&driver->domains, dom->uuid);
 
     if (vm == NULL) {
@@ -6333,10 +6338,14 @@ static int qemuDomainGetMemoryParameters(virDomainPtr dom,
     bool isActive;
 
     virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
-                  VIR_DOMAIN_AFFECT_CONFIG, -1);
+                  VIR_DOMAIN_AFFECT_CONFIG |
+                  VIR_TYPED_PARAM_STRING_OKAY, -1);
 
     qemuDriverLock(driver);
 
+    /* We don't return strings, and thus trivially support this flag.  */
+    flags &= ~VIR_TYPED_PARAM_STRING_OKAY;
+
     vm = virDomainFindByUUID(&driver->domains, dom->uuid);
 
     if (vm == NULL) {
@@ -6880,10 +6889,14 @@ qemuGetSchedulerParametersFlags(virDomainPtr dom,
     int saved_nparams = 0;
 
     virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
-                  VIR_DOMAIN_AFFECT_CONFIG, -1);
+                  VIR_DOMAIN_AFFECT_CONFIG |
+                  VIR_TYPED_PARAM_STRING_OKAY, -1);
 
     qemuDriverLock(driver);
 
+    /* We don't return strings, and thus trivially support this flag.  */
+    flags &= ~VIR_TYPED_PARAM_STRING_OKAY;
+
     if ((flags & (VIR_DOMAIN_AFFECT_LIVE | VIR_DOMAIN_AFFECT_CONFIG)) ==
         (VIR_DOMAIN_AFFECT_LIVE | VIR_DOMAIN_AFFECT_CONFIG)) {
         qemuReportError(VIR_ERR_INVALID_ARG, "%s",
@@ -7139,7 +7152,10 @@ qemuDomainBlockStatsFlags(virDomainPtr dom,
     long long wr_total_times, flush_req, flush_total_times, errs;
     virTypedParameterPtr param;
 
-    virCheckFlags(0, -1);
+    virCheckFlags(VIR_TYPED_PARAM_STRING_OKAY, -1);
+
+    /* We don't return strings, and thus trivially support this flag.  */
+    flags &= ~VIR_TYPED_PARAM_STRING_OKAY;
 
     qemuDriverLock(driver);
     vm = virDomainFindByUUID(&driver->domains, dom->uuid);