[Xen-devel] [PATCH] xl save but leave domain paused

[Ian Murray <murrayie@xxxxxxxxxxx>]

New feature to allow xl save to leave a domain paused after its
memory has been saved. This is to allow disk snapshots of domU
to be taken that exactly correspond to the memory state at save time.
Once the snapshot(s) have been taken or whatever, the domain can be
unpaused in the usual manner.

Usage:
  xl save -p <domid> <filespec>

Signed-off-by: Ian Murray <murrayie@xxxxxxxxxxx>
---
 tools/libxl/xl_cmdimpl.c  |   16 ++++++++++++----
 tools/libxl/xl_cmdtable.c |    4 +++-
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 8a478ba..670620b 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -3266,7 +3266,7 @@ static void save_domain_core_writeconfig(int fd, const 
char *source,
 }
 
 static int save_domain(uint32_t domid, const char *filename, int checkpoint,
-                const char *override_config_file)
+                int leavepaused, const char *override_config_file)
 {
     int fd;
     uint8_t *config_data;
@@ -3293,8 +3293,12 @@ static int save_domain(uint32_t domid, const char 
*filename, int checkpoint,
     if (rc < 0)
         fprintf(stderr, "Failed to save domain, resuming domain\n");
 
-    if (checkpoint || rc < 0)
+    if (leavepaused || checkpoint || rc < 0) {
+        if (leavepaused && !(rc < 0)) {
+            libxl_domain_pause(ctx, domid);
+        }
         libxl_domain_resume(ctx, domid, 1, 0);
+    }
     else
         libxl_domain_destroy(ctx, domid, 0);
 
@@ -3838,12 +3842,16 @@ int main_save(int argc, char **argv)
     const char *filename;
     const char *config_filename = NULL;
     int checkpoint = 0;
+    int leavepaused = 0;
     int opt;
 
-    SWITCH_FOREACH_OPT(opt, "c", NULL, "save", 2) {
+    SWITCH_FOREACH_OPT(opt, "cp", NULL, "save", 2) {
     case 'c':
         checkpoint = 1;
         break;
+    case 'p':
+        leavepaused = 1;
+        break;
     }
 
     if (argc-optind > 3) {
@@ -3856,7 +3864,7 @@ int main_save(int argc, char **argv)
     if ( argc - optind >= 3 )
         config_filename = argv[optind + 2];
 
-    save_domain(domid, filename, checkpoint, config_filename);
+    save_domain(domid, filename, checkpoint, leavepaused, config_filename);
     return 0;
 }
 
diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c
index 44b42b0..c429cea 100644
--- a/tools/libxl/xl_cmdtable.c
+++ b/tools/libxl/xl_cmdtable.c
@@ -142,7 +142,9 @@ struct cmd_spec cmd_table[] = {
       "Save a domain state to restore later",
       "[options] <Domain> <CheckpointFile> [<ConfigFile>]",
       "-h  Print this help.\n"
-      "-c  Leave domain running after creating the snapshot."
+      "-c  Leave domain running after creating the snapshot.\n"
+      "-p  Leave domain paused after creating the snapshot."
+
     },
     { "migrate",
       &main_migrate, 0, 1,
-- 
1.7.9.5


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