Re: [Xen-devel] [PATCH v3 COLOPre 12/26] tools/libxl: Update libxl_domain_unpause() to support qemu-xen

[Yang Hongyang]

On 07/01/2015 06:38 PM, Ian Campbell wrote:

On Wed, 2015-07-01 at 10:10 +0800, Yang Hongyang wrote:

On 06/30/2015 06:00 PM, Ian Campbell wrote:

On Thu, 2015-06-25 at 14:25 +0800, Yang Hongyang wrote:

Currently, libxl__domain_unpause() only supports
qemu-xen-traditional. Update it to support qemu-xen.
We use libxl__domain_resume_device_model to unpause guest dm.

There appears to be at least two significant semantic changes to the
libxl__domain_resume_device_model function (namely it now deals
internally with stubdom and checks the current status before doing
anything). What is the impact on the existing callers of those changes?

This change was suggested by Wei on last round(v2), he thought it is an
enhancement to the existing callers.

I don't think that contradicts what I've said. If multiple improvements
are needed to make libxl__domain_resume_device_model suitable for your
uses then there should be several patches. This will also give you an
opportunity to explain in each commit message why there is no impact (or
a positive impact) on the existing callers.

Yes, for this part, I agree with you, will separate it in the next version!
thank you!

I think those changes should be two separate preparatory patches.

Signed-off-by: Yang Hongyang <yan...@cn.fujitsu.com>
---
   tools/libxl/libxl.c             | 15 +++++----------
   tools/libxl/libxl_dom_suspend.c | 15 ++++++++++++---
   tools/libxl/libxl_internal.h    |  1 +
   3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 2ca59ea..59e2dfe 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -938,8 +938,6 @@ out:
   int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid)
   {
       GC_INIT(ctx);
-    char *path;
-    char *state;
       int ret, rc = 0;

       libxl_domain_type type = libxl__domain_type(gc, domid);
@@ -949,14 +947,11 @@ int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid)
       }

       if (type == LIBXL_DOMAIN_TYPE_HVM) {
-        uint32_t dm_domid = libxl_get_stubdom_id(ctx, domid);
-
-        path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
-        state = libxl__xs_read(gc, XBT_NULL, path);
-        if (state != NULL && !strcmp(state, "paused")) {
-            libxl__qemu_traditional_cmd(gc, domid, "continue");
-            libxl__wait_for_device_model_deprecated(gc, domid, "running",
-                                         NULL, NULL, NULL);
+        rc = libxl__domain_resume_device_model(gc, domid);
+        if (rc < 0) {
+            LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "failed to unpause device model "
+                       "for domain %u:%d", domid, rc);
+            goto out;
           }
       }
       ret = xc_domain_unpause(ctx->xch, domid);
diff --git a/tools/libxl/libxl_dom_suspend.c b/tools/libxl/libxl_dom_suspend.c
index 1c486c4..3edbd2e 100644
--- a/tools/libxl/libxl_dom_suspend.c
+++ b/tools/libxl/libxl_dom_suspend.c
@@ -376,13 +376,22 @@ static void 
domain_suspend_callback_common_done(libxl__egc *egc,

   /*======================= Domain resume ========================*/

-static int libxl__domain_resume_device_model(libxl__gc *gc, uint32_t domid)
+int libxl__domain_resume_device_model(libxl__gc *gc, uint32_t domid)
   {
+    char *path;
+    char *state;

       switch (libxl__device_model_version_running(gc, domid)) {
       case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL: {
-        libxl__qemu_traditional_cmd(gc, domid, "continue");
-        libxl__wait_for_device_model_deprecated(gc, domid, "running", NULL, 
NULL, NULL);
+        uint32_t dm_domid = libxl_get_stubdom_id(CTX, domid);
+
+        path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
+        state = libxl__xs_read(gc, XBT_NULL, path);
+        if (state != NULL && !strcmp(state, "paused")) {
+            libxl__qemu_traditional_cmd(gc, domid, "continue");
+            libxl__wait_for_device_model_deprecated(gc, domid, "running",
+                                                    NULL, NULL, NULL);
+        }
           break;
       }
       case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 0adc9b4..6960280 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -3326,6 +3326,7 @@ static inline bool libxl__save_helper_inuse(const 
libxl__save_helper_state *shs)
   /* Each time the dm needs to be saved, we must call suspend and then save */
   _hidden int libxl__domain_suspend_device_model(libxl__gc *gc,
                                              libxl__domain_suspend_state 
*dsps);
+_hidden int libxl__domain_resume_device_model(libxl__gc *gc, uint32_t domid);
   _hidden void libxl__domain_save_device_model(libxl__egc *egc,
                                        libxl__domain_save_state *dss,
                                        libxl__save_device_model_cb *callback);

.

.

--
Thanks,
Yang.

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