intr-remap: allow disabling source id checking

Allow disabling the source id checking while programming the interrupt
remap table entry. Useful for debugging or working around the broken
source id checks on some platforms.

Signed-off-by: Chris Wright <chrisw@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

2 files changed, 27 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 2b2407d9a6d0..0afdd284d656 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1028,6 +1028,12 @@ and is between 256 and 4096 characters. It is defined in the file
                         result in a hardware IOTLB flush operation as opposed
                         to batching them for performance.
 
+        intremap=       [X86-64, Intel-IOMMU]
+                        Format: { on (default) | off | nosid }
+                        on      enable Interrupt Remapping (default)
+                        off     disable Interrupt Remapping
+                        nosid   disable Source ID checking
+
         inttest=        [IA64]
 
         iomem=          Disable strict checking of access to MMIO memory
@@ -1755,6 +1761,7 @@ and is between 256 and 4096 characters. It is defined in the file
 
         nointremap      [X86-64, Intel-IOMMU] Do not enable interrupt
                         remapping.
+                        [Deprecated - use intremap=off]
 
         nointroute      [IA-64]
 
diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index 1315ac688aa2..45478ef7dd74 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -21,6 +21,8 @@ static int ir_ioapic_num, ir_hpet_num;
 int intr_remapping_enabled;
 
 static int disable_intremap;
+static int disable_sourceid_checking;
+
 static __init int setup_nointremap(char *str)
 {
         disable_intremap = 1;
@@ -28,6 +30,22 @@ static __init int setup_nointremap(char *str)
 }
 early_param("nointremap", setup_nointremap);
 
+static __init int setup_intremap(char *str)
+{
+        if (!str)
+                return -EINVAL;
+
+        if (!strncmp(str, "on", 2))
+                disable_intremap = 0;
+        else if (!strncmp(str, "off", 3))
+                disable_intremap = 1;
+        else if (!strncmp(str, "nosid", 5))
+                disable_sourceid_checking = 1;
+
+        return 0;
+}
+early_param("intremap", setup_intremap);
+
 struct irq_2_iommu {
         struct intel_iommu *iommu;
         u16 irte_index;
@@ -453,6 +471,8 @@ int free_irte(int irq)
 static void set_irte_sid(struct irte *irte, unsigned int svt,
                          unsigned int sq, unsigned int sid)
 {
+        if (disable_sourceid_checking)
+                svt = SVT_NO_VERIFY;
         irte->svt = svt;
         irte->sq = sq;
         irte->sid = sid;