From: Wei Liu <wei.liu2@citrix.com>
Date: Wed, 8 Jun 2016 14:01:02 +0000 (+0100)
Subject: libxl: only issue cpu-add call to QEMU for not present CPU
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~804
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=56bac262e097684b20f7753ceb6debe594e9725c;p=xen.git

libxl: only issue cpu-add call to QEMU for not present CPU

Calculate the final bitmap for CPUs to add to avoid having annoying
error messages complaining those CPUs are already present. Example
message is like (wrapped):

libxl: error: libxl_qmp.c:287:qmp_handle_error_response: received an
error message from QMP server: Unable to add CPU: 0, it already exists

We can also properly handle error from QMP now.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
---

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index d059251010..e49741d34e 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -5756,19 +5756,38 @@ static int libxl__set_vcpuonline_qmp(libxl__gc *gc, uint32_t domid,
                                      libxl_bitmap *cpumap,
                                      const libxl_dominfo *info)
 {
-    int i;
+    int i, rc;
+    libxl_bitmap current_map, final_map;
+
+    libxl_bitmap_init(&current_map);
+    libxl_bitmap_init(&final_map);
+
+    libxl_bitmap_alloc(CTX, &current_map, info->vcpu_max_id + 1);
+    libxl_bitmap_set_none(&current_map);
+    rc = libxl__qmp_query_cpus(gc, domid, &current_map);
+    if (rc) {
+        LOG(ERROR, "failed to query cpus for domain %d", domid);
+        goto out;
+    }
+
+    libxl_bitmap_copy_alloc(CTX, &final_map, cpumap);
 
-    for (i = 0; i <= info->vcpu_max_id; i++) {
-        if (libxl_bitmap_test(cpumap, i)) {
-            /* Return value is ignore because it does not tell anything useful
-             * on the completion of the command.
-             * (For instance, "CPU already plugged-in" give the same return
-             * value as "command not supported".)
-             */
-            libxl__qmp_cpu_add(gc, domid, i);
+    libxl_for_each_set_bit(i, current_map)
+        libxl_bitmap_reset(&final_map, i);
+
+    libxl_for_each_set_bit(i, final_map) {
+        rc = libxl__qmp_cpu_add(gc, domid, i);
+        if (rc) {
+            LOG(ERROR, "failed to add cpu %d to domain %d", i, domid);
+            goto out;
         }
     }
-    return 0;
+
+    rc = 0;
+out:
+    libxl_bitmap_dispose(&current_map);
+    libxl_bitmap_dispose(&final_map);
+    return rc;
 }
 
 int libxl_set_vcpuonline(libxl_ctx *ctx, uint32_t domid, libxl_bitmap *cpumap)