[PATCH v1 5/6] migration/dirtyrate: check support of calculation for vcpu

[huangy81]

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

vcpu method only works when kvm dirty ring is enabled, use
kvm_dirty_ring_enabled to probe if dirty ring is enabled.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
---
 migration/dirtyrate.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index 7952eb6117..da6500c8ec 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -16,6 +16,7 @@
 #include "cpu.h"
 #include "exec/ramblock.h"
 #include "qemu/rcu_queue.h"
+#include "sysemu/kvm.h"
 #include "qapi/qapi-commands-migration.h"
 #include "ram.h"
 #include "trace.h"
@@ -415,6 +416,14 @@ void qmp_calc_dirty_rate(int64_t calc_time,
         return;
     }
 
+    /*
+     * Vcpu method only works when kvm dirty ring is enabled.
+     */
+    if (has_vcpu && vcpu && !kvm_dirty_ring_enabled()) {
+        error_setg(errp, "kvm dirty ring is disabled, use sample method.");
+        return;
+    }
+
     /*
      * Init calculation state as unstarted.
      */
@@ -427,6 +436,7 @@ void qmp_calc_dirty_rate(int64_t calc_time,
 
     config.sample_period_seconds = calc_time;
     config.sample_pages_per_gigabytes = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
+    config.vcpu = has_vcpu ? vcpu : false;
     qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
                        (void *)&config, QEMU_THREAD_DETACHED);
 }
-- 
2.24.3