[tip:x86/apic] x86, intr-remap: add option to disable interrupt remapping

From: tip-bot for Weidong Han
Date: Sun Apr 19 2009 - 04:27:27 EST


Commit-ID: 03ea81550676296d94596e4337c771c6ba29f542
Gitweb: http://git.kernel.org/tip/03ea81550676296d94596e4337c771c6ba29f542
Author: Weidong Han <weidong.han@xxxxxxxxx>
AuthorDate: Fri, 17 Apr 2009 16:42:15 +0800
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sun, 19 Apr 2009 10:21:54 +0200

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@xxxxxxxxx>
Signed-off-by: Weidong Han <weidong.han@xxxxxxxxx>
Acked-by: David Woodhouse <David.Woodhouse@xxxxxxxxx>
Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: allen.m.kay@xxxxxxxxx
Cc: fenghua.yu@xxxxxxxxx
LKML-Reference: <1239957736-6161-5-git-send-email-weidong.han@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>


---
Documentation/kernel-parameters.txt | 3 +++
drivers/pci/intr_remapping.c | 11 +++++++++++
2 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 33989d2..843cb66 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 5c21426..842039e 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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