x86: add x2apic config

Impact: cleanup

so could deselect x2apic
and INTR_REMAP will select x2apic

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1042d69b267d..bce241fe1d2d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -235,6 +235,20 @@ config SMP
 
           If you don't know what to do here, say N.
 
+config X86_X2APIC
+        bool "Support x2apic"
+        depends on X86_LOCAL_APIC && X86_64
+        ---help---
+          This enables x2apic support on CPUs that have this feature.
+
+          This allows 32-bit apic IDs (so it can support very large systems),
+          and accesses the local apic via MSRs not via mmio.
+
+          ( On certain CPU models you may need to enable INTR_REMAP too,
+            to get functional x2apic mode. )
+
+          If you don't know what to do here, say N.
+
 config SPARSE_IRQ
         bool "Support sparse irq numbering"
         depends on PCI_MSI || HT_IRQ
@@ -1828,6 +1842,7 @@ config DMAR_FLOPPY_WA
 config INTR_REMAP
         bool "Support for Interrupt Remapping (EXPERIMENTAL)"
         depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
+        select X86_X2APIC
         ---help---
           Supports Interrupt remapping for IO-APIC and MSI devices.
           To use x2apic mode in the CPU's which support x2APIC enhancements or