[PATCH v10 02/31] tools/libxl: introduce libxl__domain_common_switch_qemu_logdirty()

[Wen Congyang <wency@cn.fujitsu.com>]

Secondary vm is running in COLO mode, we need to send secondary
vm's dirty page information to primary host at checkpoint, so we
have to enable qemu logdirty on secondary.

libxl__domain_suspend_common_switch_qemu_logdirty() is to enable
qemu logdirty. But it uses libxl__domain_save_state, and calls
libxl__xc_domain_saverestore_async_callback_done() before exits.
This can not be used for secondary vm.

Update libxl__domain_suspend_common_switch_qemu_logdirty() to
introduce a new API libxl__domain_common_switch_qemu_logdirty().
This API only uses libxl__logdirty_switch, and calls
lds->callback before exits. This new API will be used by the patch:
  secondary vm suspend/resume/checkpoint code

Signed-off-by: Yang Hongyang <hongyang.yang@easystack.cn>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
---
 tools/libxl/libxl_dom_save.c | 95 ++++++++++++++++++++++++--------------------
 tools/libxl/libxl_internal.h |  8 ++++
 2 files changed, 60 insertions(+), 43 deletions(-)

diff --git a/tools/libxl/libxl_dom_save.c b/tools/libxl/libxl_dom_save.c
index 7d345f9..72b61c7 100644
--- a/tools/libxl/libxl_dom_save.c
+++ b/tools/libxl/libxl_dom_save.c
@@ -42,7 +42,7 @@ static void switch_logdirty_timeout(libxl__egc *egc, libxl__ev_time *ev,
 static void switch_logdirty_xswatch(libxl__egc *egc, libxl__ev_xswatch*,
                             const char *watch_path, const char *event_path);
 static void switch_logdirty_done(libxl__egc *egc,
-                                 libxl__domain_save_state *dss, int rc);
+                                 libxl__logdirty_switch *lds, int rc);
 
 void libxl__logdirty_init(libxl__logdirty_switch *lds)
 {
@@ -52,13 +52,10 @@ void libxl__logdirty_init(libxl__logdirty_switch *lds)
 }
 
 static void domain_suspend_switch_qemu_xen_traditional_logdirty
-                               (int domid, unsigned enable,
-                                libxl__save_helper_state *shs)
+                               (libxl__egc *egc, int domid, unsigned enable,
+                                libxl__logdirty_switch *lds)
 {
-    libxl__egc *egc = shs->egc;
-    libxl__domain_save_state *dss = shs->caller_state;
-    libxl__logdirty_switch *lds = &dss->logdirty;
-    STATE_AO_GC(dss->ao);
+    STATE_AO_GC(lds->ao);
     int rc;
     xs_transaction_t t = 0;
     const char *got;
@@ -120,26 +117,34 @@ static void domain_suspend_switch_qemu_xen_traditional_logdirty
  out:
     LOG(ERROR,"logdirty switch failed (rc=%d), abandoning suspend",rc);
     libxl__xs_transaction_abort(gc, &t);
-    switch_logdirty_done(egc,dss,rc);
+    switch_logdirty_done(egc,lds,rc);
 }
 
 static void domain_suspend_switch_qemu_xen_logdirty
-                               (int domid, unsigned enable,
-                                libxl__save_helper_state *shs)
+                               (libxl__egc *egc, int domid, unsigned enable,
+                                libxl__logdirty_switch *lds)
 {
-    libxl__egc *egc = shs->egc;
-    libxl__domain_save_state *dss = shs->caller_state;
-    STATE_AO_GC(dss->ao);
+    STATE_AO_GC(lds->ao);
     int rc;
 
     rc = libxl__qmp_set_global_dirty_log(gc, domid, enable);
-    if (!rc) {
-        libxl__xc_domain_saverestore_async_callback_done(egc, shs, 0);
-    } else {
+    if (rc)
         LOG(ERROR,"logdirty switch failed (rc=%d), abandoning suspend",rc);
+
+    lds->callback(egc, lds, rc);
+}
+
+static void domain_suspend_switch_qemu_logdirty_done
+                        (libxl__egc *egc, libxl__logdirty_switch *lds, int rc)
+{
+    libxl__domain_save_state *dss = CONTAINER_OF(lds, *dss, logdirty);
+
+    if (rc) {
         dss->rc = rc;
-        libxl__xc_domain_saverestore_async_callback_done(egc, shs, -1);
-    }
+        libxl__xc_domain_saverestore_async_callback_done(egc,
+                                                         &dss->sws.shs, -1);
+    } else
+        libxl__xc_domain_saverestore_async_callback_done(egc, &dss->sws.shs, 0);
 }
 
 void libxl__domain_suspend_common_switch_qemu_logdirty
@@ -148,42 +153,52 @@ void libxl__domain_suspend_common_switch_qemu_logdirty
     libxl__save_helper_state *shs = user;
     libxl__egc *egc = shs->egc;
     libxl__domain_save_state *dss = shs->caller_state;
-    STATE_AO_GC(dss->ao);
+
+    /* Convenience aliases. */
+    libxl__logdirty_switch *const lds = &dss->logdirty;
+
+    lds->callback = domain_suspend_switch_qemu_logdirty_done;
+    libxl__domain_common_switch_qemu_logdirty(egc, domid, enable, lds);
+}
+
+void libxl__domain_common_switch_qemu_logdirty(libxl__egc *egc,
+                                               int domid, unsigned enable,
+                                               libxl__logdirty_switch *lds)
+{
+    STATE_AO_GC(lds->ao);
 
     switch (libxl__device_model_version_running(gc, domid)) {
     case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
-        domain_suspend_switch_qemu_xen_traditional_logdirty(domid, enable, shs);
+        domain_suspend_switch_qemu_xen_traditional_logdirty(egc, domid, enable,
+                                                            lds);
         break;
     case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
-        domain_suspend_switch_qemu_xen_logdirty(domid, enable, shs);
+        domain_suspend_switch_qemu_xen_logdirty(egc, domid, enable, lds);
         break;
     case LIBXL_DEVICE_MODEL_VERSION_NONE:
-        libxl__xc_domain_saverestore_async_callback_done(egc, shs, 0);
+        lds->callback(egc, lds, 0);
         break;
     default:
         LOG(ERROR,"logdirty switch failed"
             ", no valid device model version found, abandoning suspend");
-        dss->rc = ERROR_FAIL;
-        libxl__xc_domain_saverestore_async_callback_done(egc, shs, -1);
+        lds->callback(egc, lds, ERROR_FAIL);
     }
 }
 static void switch_logdirty_timeout(libxl__egc *egc, libxl__ev_time *ev,
                                     const struct timeval *requested_abs,
                                     int rc)
 {
-    libxl__domain_save_state *dss = CONTAINER_OF(ev, *dss, logdirty.timeout);
-    STATE_AO_GC(dss->ao);
+    libxl__logdirty_switch *lds = CONTAINER_OF(ev, *lds, timeout);
+    STATE_AO_GC(lds->ao);
     LOG(ERROR,"logdirty switch: wait for device model timed out");
-    switch_logdirty_done(egc,dss,ERROR_FAIL);
+    switch_logdirty_done(egc,lds,ERROR_FAIL);
 }
 
 static void switch_logdirty_xswatch(libxl__egc *egc, libxl__ev_xswatch *watch,
                             const char *watch_path, const char *event_path)
 {
-    libxl__domain_save_state *dss =
-        CONTAINER_OF(watch, *dss, logdirty.watch);
-    libxl__logdirty_switch *lds = &dss->logdirty;
-    STATE_AO_GC(dss->ao);
+    libxl__logdirty_switch *lds = CONTAINER_OF(watch, *lds, watch);
+    STATE_AO_GC(lds->ao);
     const char *got;
     xs_transaction_t t = 0;
     int rc;
@@ -229,28 +244,20 @@ static void switch_logdirty_xswatch(libxl__egc *egc, libxl__ev_xswatch *watch,
     if (rc <= 0) {
         if (rc < 0)
             LOG(ERROR,"logdirty switch: failed (rc=%d)",rc);
-        switch_logdirty_done(egc,dss,rc);
+        switch_logdirty_done(egc,lds,rc);
     }
 }
 
 static void switch_logdirty_done(libxl__egc *egc,
-                                 libxl__domain_save_state *dss,
+                                 libxl__logdirty_switch *lds,
                                  int rc)
 {
-    STATE_AO_GC(dss->ao);
-    libxl__logdirty_switch *lds = &dss->logdirty;
+    STATE_AO_GC(lds->ao);
 
     libxl__ev_xswatch_deregister(gc, &lds->watch);
     libxl__ev_time_deregister(gc, &lds->timeout);
 
-    int broke;
-    if (rc) {
-        broke = -1;
-        dss->rc = rc;
-    } else {
-        broke = 0;
-    }
-    libxl__xc_domain_saverestore_async_callback_done(egc, &dss->sws.shs, broke);
+    lds->callback(egc, lds, rc);
 }
 
 /*----- callbacks, called by xc_domain_save -----*/
@@ -346,6 +353,8 @@ void libxl__domain_save(libxl__egc *egc, libxl__domain_save_state *dss)
 
     dss->rc = 0;
     libxl__logdirty_init(&dss->logdirty);
+    dss->logdirty.ao = ao;
+
     dsps->ao = ao;
     dsps->domid = domid;
     rc = libxl__domain_suspend_init(egc, dsps, type);
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 5320e5e..53a6388 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -3088,6 +3088,11 @@ libxl__stream_write_inuse(const libxl__stream_write_state *stream)
 }
 
 typedef struct libxl__logdirty_switch {
+    /* Set by caller of libxl__domain_common_switch_qemu_logdirty */
+    libxl__ao *ao;
+    void (*callback)(libxl__egc *egc, struct libxl__logdirty_switch *lds,
+                     int rc);
+
     const char *cmd;
     const char *cmd_path;
     const char *ret_path;
@@ -3506,6 +3511,9 @@ void libxl__xc_domain_saverestore_async_callback_done(libxl__egc *egc,
 
 _hidden void libxl__domain_suspend_common_switch_qemu_logdirty
                                (int domid, unsigned int enable, void *data);
+_hidden void libxl__domain_common_switch_qemu_logdirty(libxl__egc *egc,
+                                               int domid, unsigned enable,
+                                               libxl__logdirty_switch *lds);
 _hidden int libxl__save_emulator_xenstore_data(libxl__domain_save_state *dss,
                                                char **buf, uint32_t *len);
 _hidden int libxl__restore_emulator_xenstore_data
-- 
2.5.0