Introduce -smp , maxcpus= flag to specify maximum number of CPUS.

Follow on patch will use it to determine the size of the MADT and
other BIOS tables.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/fw_cfg.c

@@ -279,6 +279,7 @@ void *fw_cfg_init(uint32_t ctl_port, uint32_t data_port,
     fw_cfg_add_bytes(s, FW_CFG_UUID, qemu_uuid, 16);
     fw_cfg_add_i16(s, FW_CFG_NOGRAPHIC, (uint16_t)(display_type == DT_NOGRAPHIC));
     fw_cfg_add_i16(s, FW_CFG_NB_CPUS, (uint16_t)smp_cpus);
+    fw_cfg_add_i16(s, FW_CFG_MAX_CPUS, (uint16_t)max_cpus);
     fw_cfg_add_i16(s, FW_CFG_BOOT_MENU, (uint16_t)boot_menu);
 
     register_savevm("fw_cfg", -1, 1, fw_cfg_save, fw_cfg_load, s);

hw/fw_cfg.h

@@ -16,6 +16,7 @@
 #define FW_CFG_BOOT_DEVICE      0x0c
 #define FW_CFG_NUMA             0x0d
 #define FW_CFG_BOOT_MENU        0x0e
+#define FW_CFG_MAX_CPUS         0x0f
 #define FW_CFG_MAX_ENTRY        0x10
 
 #define FW_CFG_WRITE_CHANNEL    0x4000

qemu-options.hx

@@ -39,7 +39,10 @@ Select CPU model (-cpu ? for list and additional feature selection)
 ETEXI
 
 DEF("smp", HAS_ARG, QEMU_OPTION_smp,
-    "-smp n          set the number of CPUs to 'n' [default=1]\n")
+    "-smp n[,maxcpus=cpus]\n"
+    "                set the number of CPUs to 'n' [default=1]\n"
+    "                maxcpus= maximum number of total cpus, including\n"
+    "                offline CPUs for hotplug etc.\n")
 STEXI
 @item -smp @var{n}
 Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255

sysemu.h

@@ -121,6 +121,7 @@ extern int usb_enabled;
 extern int virtio_balloon;
 extern const char *virtio_balloon_devaddr;
 extern int smp_cpus;
+extern int max_cpus;
 extern int cursor_hide;
 extern int graphic_rotate;
 extern int no_quit;

vl.c

@@ -222,6 +222,7 @@ int rtc_td_hack = 0;
 int usb_enabled = 0;
 int singlestep = 0;
 int smp_cpus = 1;
+int max_cpus = 0;
 const char *vnc_display;
 int acpi_enabled = 1;
 int no_hpet = 0;
@@ -5453,12 +5454,29 @@ int main(int argc, char **argv, char **envp)
                 add_device_config(DEV_GENERIC, optarg);
                 break;
             case QEMU_OPTION_smp:
-                smp_cpus = atoi(optarg);
+            {
+                char *p;
+                char option[128];
+                smp_cpus = strtol(optarg, &p, 10);
                 if (smp_cpus < 1) {
                     fprintf(stderr, "Invalid number of CPUs\n");
                     exit(1);
                 }
+                if (*p++ != ',')
+                    break;
+                if (get_param_value(option, 128, "maxcpus", p))
+                    max_cpus = strtol(option, NULL, 0);
+                if (max_cpus < smp_cpus) {
+                    fprintf(stderr, "maxcpus must be equal to or greater than "
+                            "smp\n");
+                    exit(1);
+                }
+                if (max_cpus > 255) {
+                    fprintf(stderr, "Unsupported number of maxcpus\n");
+                    exit(1);
+                }
                 break;
+            }
 	    case QEMU_OPTION_vnc:
                 display_type = DT_VNC;
 		vnc_display = optarg;
@@ -5639,6 +5657,13 @@ int main(int argc, char **argv, char **envp)
     }
 #endif
 
+    /*
+     * Default to max_cpus = smp_cpus, in case the user doesn't
+     * specify a max_cpus value.
+     */
+    if (!max_cpus)
+        max_cpus = smp_cpus;
+
     machine->max_cpus = machine->max_cpus ?: 1; /* Default to UP */
     if (smp_cpus > machine->max_cpus) {
         fprintf(stderr, "Number of SMP cpus requested (%d), exceeds max cpus "