diff --git a/hermit/arch/x86/kernel/entry.asm b/hermit/arch/x86/kernel/entry.asm
index 27b6ff9c5..ad5bb30e3 100644
--- a/hermit/arch/x86/kernel/entry.asm
+++ b/hermit/arch/x86/kernel/entry.asm
@@ -56,6 +56,7 @@ align 4
     global possible_cpus
     global timer_ticks
     global current_boot_id
+    global isle
     base dq 0
     limit dq 0
     cpu_freq dd 0
@@ -64,7 +65,7 @@ align 4
     possible_cpus dd 0
     timer_ticks dq 0
     current_boot_id dd 0
-    dummy dd 0
+    isle dd -1
     image_size dq 0
 
 ; Bootstrap page tables are used during the initialization.
diff --git a/hermit/kernel/main.c b/hermit/kernel/main.c
index cf78f655a..6d3b2376f 100644
--- a/hermit/kernel/main.c
+++ b/hermit/kernel/main.c
@@ -70,6 +70,7 @@ extern atomic_int64_t total_available_pages;
 
 extern atomic_int32_t cpu_online;
 extern atomic_int32_t possible_cpus;
+extern int32_t isle;
 
 static int foo(void* arg)
 {
@@ -111,7 +112,7 @@ static void print_status(void)
 	static spinlock_t status_lock = SPINLOCK_INIT;
 
 	spinlock_lock(&status_lock);
-	kprintf("CPU %d is now online (CR0 0x%zx, CR4 0x%zx)\n", CORE_ID, read_cr0(), read_cr4());
+	kprintf("CPU %d of isle %d is now online (CR0 0x%zx, CR4 0x%zx)\n", CORE_ID, isle, read_cr0(), read_cr4());
 	spinlock_unlock(&status_lock);
 }