diff -urN linux-2.4.21-pre5/arch/i386/kernel/io_apic.c linux-2.4.21-pre5-apic/arch/i386/kernel/io_apic.c
--- linux-2.4.21-pre5/arch/i386/kernel/io_apic.c	Sat Feb  1 19:42:12 2003
+++ linux-2.4.21-pre5-apic/arch/i386/kernel/io_apic.c	Sat Mar  1 09:38:18 2003
@@ -1313,6 +1313,34 @@
 
 static void mask_and_ack_level_ioapic_irq (unsigned int irq) { /* nothing */ }
 
+/*
+ * This function currently is only a helper for the i386 smp boot process where 
+ * we need to reprogram the ioredtbls to cater for the cpus which have come online
+ * so mask in all cases should simply be TARGET_CPUS
+ */
+void __devinit set_ioapic_logical_dest (unsigned long mask)
+{
+	struct IO_APIC_route_entry entry;
+	unsigned long flags;
+	int apic, pin;
+
+	if (skip_ioapic_setup == 1)
+		return;
+
+	spin_lock_irqsave(&ioapic_lock, flags);
+	for (apic = 0; apic < nr_ioapics; apic++) {
+		for (pin = 0; pin < nr_ioapic_registers[apic]; pin++) {
+			*(((int *)&entry)+0) = io_apic_read(apic, 0x10+pin*2);
+			*(((int *)&entry)+1) = io_apic_read(apic, 0x11+pin*2);
+			entry.dest.logical.logical_dest = mask;
+			io_apic_write(apic, 0x10 + 2 * pin, *(((int *)&entry) + 0));
+			io_apic_write(apic, 0x11 + 2 * pin, *(((int *)&entry) + 1));
+		}
+
+	}
+	spin_unlock_irqrestore(&ioapic_lock, flags);
+}
+
 static void set_ioapic_affinity (unsigned int irq, unsigned long mask)
 {
 	unsigned long flags;
diff -urN linux-2.4.21-pre5/arch/i386/kernel/smpboot.c linux-2.4.21-pre5-apic/arch/i386/kernel/smpboot.c
--- linux-2.4.21-pre5/arch/i386/kernel/smpboot.c	Sat Feb  1 19:42:12 2003
+++ linux-2.4.21-pre5-apic/arch/i386/kernel/smpboot.c	Sat Mar  1 09:41:38 2003
@@ -971,6 +971,8 @@
 extern int prof_old_multiplier[NR_CPUS];
 extern int prof_counter[NR_CPUS];
 
+extern void set_ioapic_logical_dest(unsigned long mask);
+
 static int boot_cpu_logical_apicid;
 /* Where the IO area was mapped on multiquad, always 0 otherwise */
 void *xquad_portio;
@@ -1223,5 +1225,6 @@
 		synchronize_tsc_bp();
 
 smp_done:
+	set_ioapic_logical_dest(cpu_online_map);
 	zap_low_mappings();
 }