[PATCH v5 COLOPre 09/18] tools/libxl: introduce libxl__domain_common_switch_qemu_logdirty()

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

From: Yang Hongyang <hongyang.yang@easystack.cn>

Secondary vm is running in colo mode, we need to send
secondary vm's dirty page information to master 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 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.

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>
---
 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 88cb1b3..3ffcfd9 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);
 
 static void logdirty_init(libxl__logdirty_switch *lds)
 {
@@ -52,13 +52,10 @@ static void 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;
     logdirty_init(&dss->logdirty);
+    dss->logdirty.ao = ao;
+
     dsps->ao = ao;
     dsps->domid = domid;
     rc = libxl__domain_suspend_init(egc, dsps);
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 27a4590..0abfefa 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -3071,6 +3071,11 @@ 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;
@@ -3490,6 +3495,9 @@ 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