1 files changed, 18 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/mpparse.c b/arch/x86_64/kernel/mpparse.c
index 61ae57eb9e4c..0ec84909d846 100644
--- a/arch/x86_64/kernel/mpparse.c
+++ b/arch/x86_64/kernel/mpparse.c
@@ -649,6 +649,20 @@ static int mp_find_ioapic(int gsi)
         return -1;
 }
 
+static u8 uniq_ioapic_id(u8 id)
+{
+        int i;
+        DECLARE_BITMAP(used, 256);
+        bitmap_zero(used, 256);
+        for (i = 0; i < nr_ioapics; i++) {
+                struct mpc_config_ioapic *ia = &mp_ioapics[i];
+                __set_bit(ia->mpc_apicid, used);
+        }
+        if (!test_bit(id, used))
+                return id;
+        return find_first_zero_bit(used, 256);
+}
+
 void __init mp_register_ioapic(u8 id, u32 address, u32 gsi_base)
 {
         int idx = 0;
@@ -656,14 +670,14 @@ void __init mp_register_ioapic(u8 id, u32 address, u32 gsi_base)
         if (bad_ioapic(address))
                 return;
 
-        idx = nr_ioapics++;
+        idx = nr_ioapics;
 
         mp_ioapics[idx].mpc_type = MP_IOAPIC;
         mp_ioapics[idx].mpc_flags = MPC_APIC_USABLE;
         mp_ioapics[idx].mpc_apicaddr = address;
 
         set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
-        mp_ioapics[idx].mpc_apicid = id;
+        mp_ioapics[idx].mpc_apicid = uniq_ioapic_id(id);
         mp_ioapics[idx].mpc_apicver = 0;
         
         /* 
@@ -680,6 +694,8 @@ void __init mp_register_ioapic(u8 id, u32 address, u32 gsi_base)
                 mp_ioapics[idx].mpc_apicaddr,
                 mp_ioapic_routing[idx].gsi_start,
                 mp_ioapic_routing[idx].gsi_end);
+
+        nr_ioapics++;
 }
 
 void __init