xl: implement and enable dryrun mode for `xl vcpu-pin'

As it can be useful to see if the outcome of some complex vCPU
pinning bitmap specification looks as expected.

This also allow for the introduction of some automatic testing
and verification for the bitmap parsing code, as it happens
already in check-xl-disk-parse and check-xl-vif-parse.

In particular, to make the above possible, this commit also
changes the implementation of the vcpu-pin command so that,
instead of always returning 0, it returns an error if the
parsing fails.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index fa5916e1faba83ddbf01e12736420dd5afb691ae..bd26bccd7540d761c64aa34d9909a880f19122f3 100644 (file)
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -4586,40 +4586,62 @@ int main_vcpulist(int argc, char **argv)
     return 0;
 }
 
-static void vcpupin(uint32_t domid, const char *vcpu, char *cpu)
+static int vcpupin(uint32_t domid, const char *vcpu, char *cpu)
 {
     libxl_vcpuinfo *vcpuinfo;
     libxl_bitmap cpumap;
 
     uint32_t vcpuid;
     char *endptr;
-    int i, nb_vcpu;
+    int i, nb_cpu, nb_vcpu, rc = -1;
+
+    libxl_bitmap_init(&cpumap);
 
     vcpuid = strtoul(vcpu, &endptr, 10);
     if (vcpu == endptr) {
         if (strcmp(vcpu, "all")) {
             fprintf(stderr, "Error: Invalid argument.\n");
-            return;
+            goto out;
         }
         vcpuid = -1;
     }
 
-    if (libxl_cpu_bitmap_alloc(ctx, &cpumap, 0)) {
-        goto vcpupin_out;
-    }
+    if (libxl_cpu_bitmap_alloc(ctx, &cpumap, 0))
+        goto out;
 
     if (vcpupin_parse(cpu, &cpumap))
-        goto vcpupin_out1;
+        goto out;
+
+    if (dryrun_only) {
+        nb_cpu = libxl_get_online_cpus(ctx);
+        if (nb_cpu < 0) {
+            fprintf(stderr, "libxl_get_online_cpus failed.\n");
+            goto out;
+        }
+
+        fprintf(stdout, "cpumap: ");
+        print_bitmap(cpumap.map, nb_cpu, stdout);
+        fprintf(stdout, "\n");
+
+        if (ferror(stdout) || fflush(stdout)) {
+            perror("stdout");
+            exit(-1);
+        }
+
+        rc = 0;
+        goto out;
+    }
 
     if (vcpuid != -1) {
         if (libxl_set_vcpuaffinity(ctx, domid, vcpuid, &cpumap) == -1) {
             fprintf(stderr, "Could not set affinity for vcpu `%u'.\n", vcpuid);
+            goto out;
         }
     }
     else {
         if (!(vcpuinfo = libxl_list_vcpu(ctx, domid, &nb_vcpu, &i))) {
             fprintf(stderr, "libxl_list_vcpu failed.\n");
-            goto vcpupin_out1;
+            goto out;
         }
         for (i = 0; i < nb_vcpu; i++) {
             if (libxl_set_vcpuaffinity(ctx, domid, vcpuinfo[i].vcpuid,
@@ -4630,10 +4652,11 @@ static void vcpupin(uint32_t domid, const char *vcpu, char *cpu)
         }
         libxl_vcpuinfo_list_free(vcpuinfo, nb_vcpu);
     }
-  vcpupin_out1:
+
+    rc = 0;
+ out:
     libxl_bitmap_dispose(&cpumap);
-  vcpupin_out:
-    ;
+    return rc;
 }
 
 int main_vcpupin(int argc, char **argv)
@@ -4644,8 +4667,7 @@ int main_vcpupin(int argc, char **argv)
         /* No options */
     }
 
-    vcpupin(find_domain(argv[optind]), argv[optind+1] , argv[optind+2]);
-    return 0;
+    return vcpupin(find_domain(argv[optind]), argv[optind+1] , argv[optind+2]);
 }
 
 static void vcpuset(uint32_t domid, const char* nr_vcpus, int check_host)

diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c
index 77092069aca9e0b0eddd65c88b935ff199ee1345..ebe0220fee5af1ea91c04c08bb1d33967c99caf7 100644 (file)
--- a/tools/libxl/xl_cmdtable.c
+++ b/tools/libxl/xl_cmdtable.c
@@ -211,7 +211,7 @@ struct cmd_spec cmd_table[] = {
       "[Domain, ...]",
     },
     { "vcpu-pin",
-      &main_vcpupin, 0, 1,
+      &main_vcpupin, 1, 1,
       "Set which CPUs a VCPU can use",
       "<Domain> <VCPU|all> <CPUs|all>",
     },