x86/apic: Handle XAPIC remap mode proper.

If remapping is in XAPIC mode, the setup code just skips X2APIC
initialization without checking max CPU APIC ID in system, which may
cause problem if system has a CPU with APIC ID bigger than 255.

Handle IR in XAPIC mode the same way as if remapping is disabled.

[ tglx: Split out from previous patch ]

Signed-off-by: Jiang Liu <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: [email protected]
Cc: H. Peter Anvin <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: HATAYAMA Daisuke <[email protected]>
Cc: Jan Beulich <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Oren Twaig <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index fa77be8d0b1715b46c310400e00d0982c589fb7e..04aec6bc7481d791ce7d8b1160887463925eef5c 100644 (file)
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1596,7 +1596,7 @@ static __init void try_to_enable_x2apic(int ir_stat)
        if (!x2apic_supported())
                return;
 
-       if (ir_stat < 0) {
+       if (ir_stat != IRQ_REMAP_X2APIC_MODE) {
                /* IR is required if there is APIC ID > 255 even when running
                 * under KVM
                 */
@@ -1613,10 +1613,6 @@ static __init void try_to_enable_x2apic(int ir_stat)
                 * only in physical mode
                 */
                x2apic_force_phys();
-
-       } else if (ir_stat == IRQ_REMAP_XAPIC_MODE) {
-               pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n");
-               return;
        }
 
        if (!x2apic_mode) {