x86, intr-remap: add option to disable interrupt remapping

Add option "nointremap" to disable interrupt remapping.

[ Impact: add new boot option ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Weidong Han <weidong.han@intel.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: allen.m.kay@intel.com
Cc: fenghua.yu@intel.com
LKML-Reference: <1239957736-6161-5-git-send-email-weidong.han@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index 5c2142656e96..842039e4955b 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -15,6 +15,14 @@ static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
 static int ir_ioapic_num;
 int intr_remapping_enabled;
 
+static int disable_intremap;
+static __init int setup_nointremap(char *str)
+{
+        disable_intremap = 1;
+        return 0;
+}
+early_param("nointremap", setup_nointremap);
+
 struct irq_2_iommu {
         struct intel_iommu *iommu;
         u16 irte_index;
@@ -506,6 +514,9 @@ int __init intr_remapping_supported(void)
 {
         struct dmar_drhd_unit *drhd;
 
+        if (disable_intremap)
+                return 0;
+
         for_each_drhd_unit(drhd) {
                 struct intel_iommu *iommu = drhd->iommu;