New API: set-smp, get-smp

These calls allow you to change the number of virtual CPUs assigned to
the appliance.

This also adds a --smp option to virt-rescue.

generator/generator_actions.ml

@@ -1549,6 +1549,22 @@ C<^C> to kill the subprocess.");
    "\
 This returns the process group flag.");
 
+  ("set_smp", (RErr, [Int "smp"], []), -1, [FishAlias "smp"],
+   [],
+   "set number of virtual CPUs in appliance",
+   "\
+Change the number of virtual CPUs assigned to the appliance.  The
+default is C<1>.  Increasing this may improve performance, though
+often it has no effect.
+
+This function must be called before C<guestfs_launch>.");
+
+  ("get_smp", (RInt "smp", [], []), -1, [],
+   [],
+   "get number of virtual CPUs in appliance",
+   "\
+This returns the number of virtual CPUs assigned to the appliance.");
+
 ]
 
 (* daemon_functions are any functions which cause some action

rescue/virt-rescue.c

@@ -77,6 +77,7 @@ usage (int status)
              "  --network            Enable network\n"
              "  -r|--ro              Access read-only\n"
              "  --selinux            Enable SELinux\n"
+             "  --smp N              Enable SMP with N >= 2 virtual CPUs\n"
              "  -v|--verbose         Verbose messages\n"
              "  -V|--version         Display version and exit\n"
              "  -w|--rw              Mount read-write\n"
@@ -115,6 +116,7 @@ main (int argc, char *argv[])
     { "ro", 0, 0, 'r' },
     { "rw", 0, 0, 'w' },
     { "selinux", 0, 0, 0 },
+    { "smp", 1, 0, 0 },
     { "verbose", 0, 0, 'v' },
     { "version", 0, 0, 'V' },
     { 0, 0, 0, 0 }
@@ -128,6 +130,7 @@ main (int argc, char *argv[])
   const char *append = NULL;
   char *append_full;
   int memsize = 0;
+  int smp = 0;
 
   g = guestfs_create ();
   if (g == NULL) {
@@ -154,6 +157,17 @@ main (int argc, char *argv[])
           format = NULL;
         else
           format = optarg;
+      } else if (STREQ (long_options[option_index].name, "smp")) {
+        if (sscanf (optarg, "%u", &smp) != 1) {
+          fprintf (stderr, _("%s: could not parse --smp parameter '%s'\n"),
+                   program_name, optarg);
+          exit (EXIT_FAILURE);
+        }
+        if (smp < 1) {
+          fprintf (stderr, _("%s: --smp parameter '%s' should be >= 1\n"),
+                   program_name, optarg);
+          exit (EXIT_FAILURE);
+        }
       } else {
         fprintf (stderr, _("%s: unknown long option: %s (%d)\n"),
                  program_name, long_options[option_index].name, option_index);
@@ -270,6 +284,8 @@ main (int argc, char *argv[])
     guestfs_set_memsize (g, memsize);
   if (network)
     guestfs_set_network (g, 1);
+  if (smp >= 1)
+    guestfs_set_smp (g, smp);
 
   /* Kernel command line must include guestfs_rescue=1 (see
    * appliance/init) as well as other options.

rescue/virt-rescue.pod

@@ -175,6 +175,10 @@ See also L<guestfish(1)/OPENING DISKS FOR READ AND WRITE>.
 Enable SELinux in the rescue appliance.  You should read
 L<guestfs(3)/SELINUX> before using this option.
 
+=item B<--smp> N
+
+Enable N E<ge> 2 virtual CPUs in the rescue appliance.
+
 =item B<-v>
 
 =item B<--verbose>

src/guestfs-internal.h

@@ -170,6 +170,8 @@ struct guestfs_h
 
   int pgroup;                   /* Create process group for children? */
 
+  int smp;                      /* If > 1, -smp flag passed to qemu. */
+
   char *last_error;
   int last_errnum;              /* errno, or 0 if there was no errno */
 

src/guestfs.c

@@ -144,6 +144,9 @@ guestfs_create (void)
    */
   g->msg_next_serial = 0x00123400;
 
+  /* Default is uniprocessor appliance. */
+  g->smp = 1;
+
   /* Link the handles onto a global list. */
   gl_lock_lock (handles_lock);
   g->next = handles;
@@ -814,6 +817,24 @@ guestfs__get_pgroup (guestfs_h *g)
   return g->pgroup;
 }
 
+int
+guestfs__set_smp (guestfs_h *g, int v)
+{
+  if (v >= 1) {
+    g->smp = v;
+    return 0;
+  } else {
+    error (g, "invalid smp parameter: %d", v);
+    return -1;
+  }
+}
+
+int
+guestfs__get_smp (guestfs_h *g)
+{
+  return g->smp;
+}
+
 /* Note the private data area is allocated lazily, since the vast
  * majority of callers will never use it.  This means g->pda is
  * likely to be NULL.

src/launch.c

@@ -555,6 +555,12 @@ launch_appliance (guestfs_h *g)
 
     add_cmdline (g, "-nographic");
 
+    if (g->smp > 1) {
+      snprintf (buf, sizeof buf, "%d", g->smp);
+      add_cmdline (g, "-smp");
+      add_cmdline (g, buf);
+    }
+
     snprintf (buf, sizeof buf, "%d", g->memsize);
     add_cmdline (g, "-m");
     add_cmdline (g, buf);

test-tool/test-tool.c

@@ -206,6 +206,7 @@ main (int argc, char *argv[])
   printf ("guestfs_get_recovery_proc: %d\n",
           guestfs_get_recovery_proc (g));
   printf ("guestfs_get_selinux: %d\n", guestfs_get_selinux (g));
+  printf ("guestfs_get_smp: %d\n", guestfs_get_smp (g));
   printf ("guestfs_get_trace: %d\n", guestfs_get_trace (g));
   printf ("guestfs_get_verbose: %d\n", guestfs_get_verbose (g));