[PATCH 2/2] tools/libxl: Introduce LIBXL_CPUPOOL_POOLID_ANY

[George Dunlap <george.dunlap@citrix.com>]

Callers to libxl_cpupool_create() can either request a specific pool
id, or request that Xen do it for them.  But at the moment, the
"automatic" selection is indicated by using a magic value, 0.  This is
undesirable both because it doesn't obviously have meaning, but also
because '0' is a valid cpupool (albeit one which at the moment can't
be changed).

Introduce a constant, LIBXL_CPUPOOL_POOLID_ANY, to indicate this
instead.  Still accept '0' as meaning "ANY" for backwards
compatibility.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
---
CC: Ian Jackson <ian.jackson@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Juergen Gross <jgross@suse.com>
CC: Dario Faggioli <dario.faggioli@citrix.com>
CC: Ronald Rojas <ronladred@gmail.com>
---
 tools/libxl/libxl.c      | 8 ++++++--
 tools/libxl/libxl.h      | 6 ++++++
 tools/libxl/xl_cmdimpl.c | 2 +-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 51325d9..32e537a 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -6287,8 +6287,12 @@ int libxl_cpupool_create(libxl_ctx *ctx, const char *name,
     char *uuid_string;
     uint32_t xcpoolid;
 
-    /* Zero means "choose a poolid for me" */
-    xcpoolid = (*poolid) ? (*poolid) : XC_CPUPOOL_POOLID_ANY;
+    /* Accept '0' as 'any poolid' for backwards compatibility */
+    if ( *poolid == LIBXL_CPUPOOL_POOLID_ANY
+         || *poolid == 0 ) 
+        xcpoolid = XC_CPUPOOL_POOLID_ANY;
+    else
+        xcpoolid = *poolid;
 
     uuid_string = libxl__uuid2string(gc, *uuid);
     if (!uuid_string) {
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 3924464..d5559c0 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -2086,6 +2086,12 @@ int libxl_tmem_shared_auth(libxl_ctx *ctx, uint32_t domid, char* uuid,
 int libxl_tmem_freeable(libxl_ctx *ctx);
 
 int libxl_get_freecpus(libxl_ctx *ctx, libxl_bitmap *cpumap);
+
+/* 
+ * Set poolid to LIBXL_CPUOOL_POOLID_ANY to have Xen choose a
+ * free poolid for you.
+ */
+#define LIBXL_CPUPOOL_POOLID_ANY 0xFFFFFFFF
 int libxl_cpupool_create(libxl_ctx *ctx, const char *name,
                          libxl_scheduler sched,
                          libxl_bitmap cpumap, libxl_uuid *uuid,
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 358757f..80ddeac 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -8366,7 +8366,7 @@ int main_cpupoolcreate(int argc, char **argv)
     printf("number of cpus: %d\n", n_cpus);
 
     if (!dryrun_only) {
-        poolid = 0;
+        poolid = LIBXL_CPUPOOL_POOLID_ANY;
         if (libxl_cpupool_create(ctx, name, sched, cpumap, &uuid, &poolid)) {
             fprintf(stderr, "error on creating cpupool\n");
             goto out_cfg;
-- 
2.1.4


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