From 03ea81550676296d94596e4337c771c6ba29f542 Mon Sep 17 00:00:00 2001
From: Weidong Han <weidong.han@intel.com>
Date: Fri, 17 Apr 2009 16:42:15 +0800
Subject: [PATCH] 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>
---
Documentation/kernel-parameters.txt | 3 +++
drivers/pci/intr_remapping.c | 11 +++++++++++
2 files changed, 14 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 33989d284ff0a..843cb6646d82a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1533,6 +1533,9 @@ and is between 256 and 4096 characters. It is defined in the file
noinitrd [RAM] Tells the kernel not to load any configured
initial RAM disk.
+ nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
+ remapping.
+
nointroute [IA-64]
nojitter [IA64] Disables jitter checking for ITC timers.
diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index 5c2142656e966..842039e4955b1 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;
--
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