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>

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]
 

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;