libxl: Make libxl_domain_unpause async

libxl_domain_unpause needs to make QMP calls, which are asynchronous,
change the API to reflect that.

Do the same with libxl_domain_pause async, even if it will keep
completing synchronously.

Also fix some coding style issue in those functions.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/libxl/libxl.h

@@ -638,7 +638,8 @@ typedef struct libxl__ctx libxl_ctx;
 /* API compatibility. */
 #ifdef LIBXL_API_VERSION
 #if LIBXL_API_VERSION != 0x040200 && LIBXL_API_VERSION != 0x040300 && \
-    LIBXL_API_VERSION != 0x040400 && LIBXL_API_VERSION != 0x040500
+    LIBXL_API_VERSION != 0x040400 && LIBXL_API_VERSION != 0x040500 && \
+    LIBXL_API_VERSION != 0x041300
 #error Unknown LIBXL_API_VERSION
 #endif
 #endif
@@ -1210,6 +1211,17 @@ void libxl_mac_copy(libxl_ctx *ctx, libxl_mac *dst, const libxl_mac *src);
  */
 #define LIBXL_HAVE_PVCALLS 1
 
+/*
+ * LIBXL_HAVE_FN_USING_QMP_ASYNC
+ *
+ * This define indicates that some function's API has changed and have an
+ * extra parameter "ao_how" which means that the function can be executed
+ * asynchronously. Those functions are:
+ *   libxl_domain_pause()
+ *   libxl_domain_unpause()
+ */
+#define LIBXL_HAVE_FN_USING_QMP_ASYNC 1
+
 typedef char **libxl_string_list;
 void libxl_string_list_dispose(libxl_string_list *sl);
 int libxl_string_list_length(const libxl_string_list *sl);
@@ -1614,8 +1626,27 @@ int libxl_domain_rename(libxl_ctx *ctx, uint32_t domid,
    * transactionally that the domain has the old old name; if
    * trans is not 0 we use caller's transaction and caller must do retries */
 
-int libxl_domain_pause(libxl_ctx *ctx, uint32_t domid);
-int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid);
+int libxl_domain_pause(libxl_ctx *ctx, uint32_t domid,
+                       const libxl_asyncop_how *ao_how)
+                       LIBXL_EXTERNAL_CALLERS_ONLY;
+int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid,
+                         const libxl_asyncop_how *ao_how)
+                         LIBXL_EXTERNAL_CALLERS_ONLY;
+#if defined(LIBXL_API_VERSION) && LIBXL_API_VERSION < 0x041300
+static inline int libxl_domain_pause_0x041200(
+    libxl_ctx *ctx, uint32_t domid)
+{
+    return libxl_domain_pause(ctx, domid, NULL);
+}
+static inline int libxl_domain_unpause_0x041200(
+    libxl_ctx *ctx, uint32_t domid)
+{
+    return libxl_domain_unpause(ctx, domid, NULL);
+}
+#define libxl_domain_pause libxl_domain_pause_0x041200
+#define libxl_domain_unpause libxl_domain_unpause_0x041200
+#endif
+
 
 int libxl_domain_core_dump(libxl_ctx *ctx, uint32_t domid,
                            const char *filename,

tools/libxl/libxl_colo_restore.c

@@ -853,7 +853,7 @@ static void colo_unpause_svm(libxl__egc *egc,
     EGC_GC;
 
     /* We have enabled secondary vm's logdirty, so we can unpause it now */
-    rc = libxl_domain_unpause(CTX, domid);
+    rc = libxl__domain_unpause(gc, domid);
     if (rc) {
         LOGD(ERROR, domid, "cannot unpause secondary vm");
         goto out;

tools/libxl/libxl_colo_save.c

@@ -480,7 +480,7 @@ static void colo_preresume_cb(libxl__egc *egc,
      * no disk migration.
      */
     if (css->paused) {
-        rc = libxl_domain_unpause(CTX, dss->domid);
+        rc = libxl__domain_unpause(gc, dss->domid);
         if (rc) {
             LOGD(ERROR, dss->domid, "cannot unpause primary vm");
             goto out;

tools/libxl/libxl_dm.c

@@ -2402,7 +2402,7 @@ static void stubdom_pvqemu_cb(libxl__egc *egc,
         goto out;
     }
 
-    rc = libxl_domain_unpause(CTX, dm_domid);
+    rc = libxl__domain_unpause(gc, dm_domid);
     if (rc) goto out;
 
     sdss->xswait.ao = ao;

tools/libxl/libxl_domain.c

@@ -557,18 +557,18 @@ int libxl_domain_suspend_only(libxl_ctx *ctx, uint32_t domid,
     return AO_CREATE_FAIL(rc);
 }
 
-int libxl_domain_pause(libxl_ctx *ctx, uint32_t domid)
+int libxl_domain_pause(libxl_ctx *ctx, uint32_t domid,
+                       const libxl_asyncop_how *ao_how)
 {
-    int ret;
-    GC_INIT(ctx);
-    ret = xc_domain_pause(ctx->xch, domid);
-    if (ret<0) {
+    AO_CREATE(ctx, domid, ao_how);
+    int r;
+    r = xc_domain_pause(ctx->xch, domid);
+    if (r < 0) {
         LOGED(ERROR, domid, "Pausing domain");
-        GC_FREE;
-        return ERROR_FAIL;
+        return AO_CREATE_FAIL(ERROR_FAIL);
     }
-    GC_FREE;
-    return 0;
+    libxl__ao_complete(egc, ao, 0);
+    return AO_INPROGRESS;
 }
 
 int libxl_domain_core_dump(libxl_ctx *ctx, uint32_t domid,
@@ -593,10 +593,9 @@ out:
     return AO_INPROGRESS;
 }
 
-int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid)
+int libxl__domain_unpause(libxl__gc *gc, libxl_domid domid)
 {
-    GC_INIT(ctx);
-    int ret, rc = 0;
+    int r, rc;
 
     libxl_domain_type type = libxl__domain_type(gc, domid);
     if (type == LIBXL_DOMAIN_TYPE_INVALID) {
@@ -612,16 +611,33 @@ int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid)
             goto out;
         }
     }
-    ret = xc_domain_unpause(ctx->xch, domid);
-    if (ret<0) {
+    r = xc_domain_unpause(CTX->xch, domid);
+    if (r < 0) {
         LOGED(ERROR, domid, "Unpausing domain");
         rc = ERROR_FAIL;
+        goto out;
     }
- out:
-    GC_FREE;
+    rc = 0;
+out:
     return rc;
 }
 
+int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid,
+                         const libxl_asyncop_how *ao_how)
+{
+    AO_CREATE(ctx, domid, ao_how);
+    int rc = 0;
+
+    rc = libxl__domain_unpause(gc, domid);
+    if (rc) goto out;
+
+    libxl__ao_complete(egc, ao, rc);
+    return AO_INPROGRESS;
+
+ out:
+    return AO_CREATE_FAIL(rc);
+}
+
 int libxl__domain_pvcontrol_available(libxl__gc *gc, uint32_t domid)
 {
     libxl_ctx *ctx = libxl__gc_owner(gc);

tools/libxl/libxl_internal.h

@@ -4109,6 +4109,7 @@ _hidden void libxl__remus_teardown(libxl__egc *egc,
                                    int rc);
 _hidden void libxl__remus_restore_setup(libxl__egc *egc,
                                         libxl__domain_create_state *dcs);
+_hidden int libxl__domain_unpause(libxl__gc *, libxl_domid domid);
 
 
 /*

tools/xl/xl_migrate.c

@@ -394,7 +394,7 @@ static void migrate_receive(int debug, int daemonize, int monitor,
             /* The guest is running after failover in COLO mode */
             exit(rc ? -ERROR_FAIL: 0);
 
-        rc = libxl_domain_unpause(ctx, domid);
+        rc = libxl_domain_unpause(ctx, domid, NULL);
         if (rc)
             fprintf(stderr, "migration target (%s): "
                     "Failed to unpause domain %s (id: %u):%d\n",
@@ -429,7 +429,7 @@ static void migrate_receive(int debug, int daemonize, int monitor,
     }
 
     if (!pause_after_migration) {
-        rc = libxl_domain_unpause(ctx, domid);
+        rc = libxl_domain_unpause(ctx, domid, NULL);
         if (rc) goto perhaps_destroy_notify_rc;
     }
 

tools/xl/xl_saverestore.c

@@ -150,7 +150,7 @@ static int save_domain(uint32_t domid, const char *filename, int checkpoint,
     }
     else if (leavepaused || checkpoint) {
         if (leavepaused)
-            libxl_domain_pause(ctx, domid);
+            libxl_domain_pause(ctx, domid, NULL);
         libxl_domain_resume(ctx, domid, 1, 0);
     }
     else

tools/xl/xl_vmcontrol.c

@@ -34,12 +34,12 @@ static int fd_lock = -1;
 
 static void pause_domain(uint32_t domid)
 {
-    libxl_domain_pause(ctx, domid);
+    libxl_domain_pause(ctx, domid, NULL);
 }
 
 static void unpause_domain(uint32_t domid)
 {
-    libxl_domain_unpause(ctx, domid);
+    libxl_domain_unpause(ctx, domid, NULL);
 }
 
 static void destroy_domain(uint32_t domid, int force)
@@ -972,7 +972,7 @@ start:
     }
 
     if (!paused)
-        libxl_domain_unpause(ctx, domid);
+        libxl_domain_unpause(ctx, domid, NULL);
 
     ret = domid; /* caller gets success in parent */
     if (!daemonize && !monitor)