[PATCH v5 3/9] qemu_driver: Probe capability before calculating dirty page rate

[huangy81 at chinatelecom.cn]

From: Hyman Huang(黄勇) <huangy81 at chinatelecom.cn>

Probing QEMU_CAPS_CALC_DIRTY_RATE capability in advance
in case of failure when calculating dirty page rate.

Signed-off-by: Hyman Huang(黄勇) <huangy81 at chinatelecom.cn>
---
 src/qemu/qemu_driver.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index a22646c..18775e7 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -20691,6 +20691,13 @@ qemuDomainStartDirtyRateCalc(virDomainPtr dom,
     if (virDomainStartDirtyRateCalcEnsureACL(dom->conn, vm->def) < 0)
         goto cleanup;
 
+    priv = vm->privateData;
+    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_CALC_DIRTY_RATE)) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+                       _("QEMU does not support calculating dirty page rate"));
+        goto cleanup;
+    }
+
     if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
         goto cleanup;
 
@@ -20702,7 +20709,6 @@ qemuDomainStartDirtyRateCalc(virDomainPtr dom,
 
     VIR_DEBUG("Calculate dirty rate in next %d seconds", seconds);
 
-    priv = vm->privateData;
     qemuDomainObjEnterMonitor(driver, vm);
     ret = qemuMonitorStartDirtyRateCalc(priv->mon, seconds);
 
-- 
1.8.3.1