QMP, Introduce xen-set-global-dirty-log command.

This command is used during a migration of a guest under Xen. It calls
memory_global_dirty_log_start or memory_global_dirty_log_stop according to the
argument pass to the command.
Signed-off-by: NAnthony PERARD <anthony.perard@citrix.com>
Reviewed-by: NLuiz Capitulino <lcapitulino@redhat.com>

qapi-schema.json

@@ -1955,6 +1955,19 @@
 ##
 { 'command': 'xen-save-devices-state', 'data': {'filename': 'str'} }
 
+##
+# @xen-set-global-dirty-log
+#
+# Enable or disable the global dirty log mode.
+#
+# @enable: true to enable, false to disable.
+#
+# Returns: nothing
+#
+# Since: 1.3
+##
+{ 'command': 'xen-set-global-dirty-log', 'data': { 'enable': 'bool' } }
+
 ##
 # @device_del:
 #

qmp-commands.hx

@@ -490,6 +490,30 @@ Example:
      "arguments": { "filename": "/tmp/save" } }
 <- { "return": {} }
 
+EQMP
+
+    {
+        .name       = "xen-set-global-dirty-log",
+        .args_type  = "enable:b",
+        .mhandler.cmd_new = qmp_marshal_input_xen_set_global_dirty_log,
+    },
+
+SQMP
+xen-set-global-dirty-log
+-------
+
+Enable or disable the global dirty log mode.
+
+Arguments:
+
+- "enable": Enable it or disable it.
+
+Example:
+
+-> { "execute": "xen-set-global-dirty-log",
+     "arguments": { "enable": true } }
+<- { "return": {} }
+
 EQMP
 
     {

xen-all.c

@@ -14,6 +14,7 @@
 #include "hw/pc.h"
 #include "hw/xen_common.h"
 #include "hw/xen_backend.h"
+#include "qmp-commands.h"
 
 #include "range.h"
 #include "xen-mapcache.h"
@@ -36,6 +37,7 @@
 
 static MemoryRegion ram_memory, ram_640k, ram_lo, ram_hi;
 static MemoryRegion *framebuffer;
+static bool xen_in_migration;
 
 /* Compatibility with older version */
 #if __XEN_LATEST_INTERFACE_VERSION__ < 0x0003020a
@@ -552,10 +554,14 @@ static void xen_log_sync(MemoryListener *listener, MemoryRegionSection *section)
 
 static void xen_log_global_start(MemoryListener *listener)
 {
+    if (xen_enabled()) {
+        xen_in_migration = true;
+    }
 }
 
 static void xen_log_global_stop(MemoryListener *listener)
 {
+    xen_in_migration = false;
 }
 
 static void xen_eventfd_add(MemoryListener *listener,
@@ -588,6 +594,15 @@ static MemoryListener xen_memory_listener = {
     .priority = 10,
 };
 
+void qmp_xen_set_global_dirty_log(bool enable, Error **errp)
+{
+    if (enable) {
+        memory_global_dirty_log_start();
+    } else {
+        memory_global_dirty_log_stop();
+    }
+}
+
 /* VCPU Operations, MMIO, IO ring ... */
 
 static void xen_reset_vcpu(void *opaque)

xen-stub.c

@@ -11,6 +11,7 @@
 #include "qemu-common.h"
 #include "hw/xen.h"
 #include "memory.h"
+#include "qmp-commands.h"
 
 void xenstore_store_pv_console_info(int i, CharDriverState *chr)
 {
@@ -54,3 +55,7 @@ int xen_init(void)
 void xen_register_framebuffer(MemoryRegion *mr)
 {
 }
+
+void qmp_xen_set_global_dirty_log(bool enable, Error **errp)
+{
+}