xl: move away from the use of cpumap for hard affinity

and start using the vcpu_hard_affinity array instead. This is done
as when, in a subsequent patch ("libxl/xl: make it possible to
specify soft-affinity in domain config file") we will become able
to deal with soft affinity, code can be shared.

This change also enables more advanced VCPU to PCPU (hard, for now)
affinity specification, in case a list is used, like:

      cpus = ["3-4", "2-6,^4"]

What it means is that VCPU 0 must be pinned to PCPU 3,4 and VCPU 1
to PCPUs 2,3,5,6 (before this change, cpus=[xx, yy] only supported
single values). Of course, the old (e.g., cpus=[2, 3]) syntax
continues to work.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

docs/man/xl.cfg.pod.5

@@ -143,11 +143,15 @@ Combining this with "all" is also possible, meaning "all,^nodes:1"
 results in all the vcpus of the guest running on all the cpus on the
 host, except for the cpus belonging to the host NUMA node 1.
 
-=item ["2", "3"] (or [2, 3])
+=item ["2", "3-8,^5"]
 
-To ask for specific vcpu mapping. That means (in this example), vcpu #0
-of the guest will run on cpu #2 of the host and vcpu #1 of the guest will
-run on cpu #3 of the host.
+To ask for specific vcpu mapping. That means (in this example), vcpu 0
+of the guest will run on cpu 2 of the host and vcpu 1 of the guest will
+run on cpus 3,4,6,7,8 of the host.
+
+More complex notation can be also used, exactly as described above. So
+"all,^5-8", or just "all", or "node:0,node:2,^9-11,18-20" are all legal,
+for each element of the list.
 
 =back
 

tools/libxl/xl_cmdimpl.c

@@ -808,16 +808,15 @@ static void parse_config_data(const char *config_source,
         b_info->vcpu_hard_affinity = xmalloc(num_cpus * sizeof(libxl_bitmap));
 
         while ((buf = xlu_cfg_get_listitem(cpus, j)) != NULL && j < num_cpus) {
-            i = atoi(buf);
-
             libxl_bitmap_init(&b_info->vcpu_hard_affinity[j]);
             if (libxl_cpu_bitmap_alloc(ctx,
                                        &b_info->vcpu_hard_affinity[j], 0)) {
                 fprintf(stderr, "Unable to allocate cpumap for vcpu %d\n", j);
                 exit(1);
             }
-            libxl_bitmap_set_none(&b_info->vcpu_hard_affinity[j]);
-            libxl_bitmap_set(&b_info->vcpu_hard_affinity[j], i);
+
+            if (vcpupin_parse(buf, &b_info->vcpu_hard_affinity[j]))
+                exit(1);
 
             j++;
         }
@@ -827,15 +826,31 @@ static void parse_config_data(const char *config_source,
         libxl_defbool_set(&b_info->numa_placement, false);
     }
     else if (!xlu_cfg_get_string (config, "cpus", &buf, 0)) {
-        if (libxl_cpu_bitmap_alloc(ctx, &b_info->cpumap, 0)) {
-            fprintf(stderr, "Unable to allocate cpumap\n");
+        b_info->vcpu_hard_affinity =
+            xmalloc(b_info->max_vcpus * sizeof(libxl_bitmap));
+
+        libxl_bitmap_init(&b_info->vcpu_hard_affinity[0]);
+        if (libxl_cpu_bitmap_alloc(ctx,
+                                   &b_info->vcpu_hard_affinity[0], 0)) {
+            fprintf(stderr, "Unable to allocate cpumap for vcpu 0\n");
             exit(1);
         }
 
-        libxl_bitmap_set_none(&b_info->cpumap);
-        if (vcpupin_parse(buf, &b_info->cpumap))
+        if (vcpupin_parse(buf, &b_info->vcpu_hard_affinity[0]))
             exit(1);
 
+        for (i = 1; i < b_info->max_vcpus; i++) {
+            libxl_bitmap_init(&b_info->vcpu_hard_affinity[i]);
+            if (libxl_cpu_bitmap_alloc(ctx,
+                                       &b_info->vcpu_hard_affinity[i], 0)) {
+                fprintf(stderr, "Unable to allocate cpumap for vcpu %d\n", i);
+                exit(1);
+            }
+            libxl_bitmap_copy(ctx, &b_info->vcpu_hard_affinity[i],
+                              &b_info->vcpu_hard_affinity[0]);
+        }
+        b_info->num_vcpu_hard_affinity = b_info->max_vcpus;
+
         libxl_defbool_set(&b_info->numa_placement, false);
     }