intr_remap: Call dmar_dev_scope_init() explicitly

Both DMA-remapping aswell as Interrupt-remapping depend on the
dmar dev scope to be initialized. When both DMA and
IRQ-remapping are enabled, we depend on DMA-remapping init code
to call dmar_dev_scope_init(). This resulted in not doing this
init when DMA-remapping was turned off but interrupt-remapping
turned on in the kernel config.

This caused interrupt routing to break with CONFIG_INTR_REMAP=y
and CONFIG_DMAR=n.

This issue was introduced by this commit:

 | commit 9d5ce73a64
 | Author: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
 | Date:   Tue Nov 10 19:46:16 2009 +0900
 |
 |    x86: intel-iommu: Convert detect_intel_iommu to use iommu_init hook

Fix this by calling dmar_dev_scope_init() explicitly from the
interrupt remapping code too.

Reported-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: yinghai@kernel.org
Cc: youquan.song@intel.com
Cc: joerg.roedel@amd.com
Cc: tony.luck@intel.com
Cc: dwmw2@infradead.org
Link: http://lkml.kernel.org/r/20110824001456.229207526@sbsiddha-desk.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/iommu/dmar.c

@@ -557,13 +557,17 @@ dmar_find_matched_drhd_unit(struct pci_dev *dev)
 
 int __init dmar_dev_scope_init(void)
 {
+	static int dmar_dev_scope_initialized;
 	struct dmar_drhd_unit *drhd, *drhd_n;
 	int ret = -ENODEV;
 
+	if (dmar_dev_scope_initialized)
+		return dmar_dev_scope_initialized;
+
 	list_for_each_entry_safe(drhd, drhd_n, &dmar_drhd_units, list) {
 		ret = dmar_parse_dev(drhd);
 		if (ret)
-			return ret;
+			goto fail;
 	}
 
 #ifdef CONFIG_DMAR
@@ -574,17 +578,22 @@ int __init dmar_dev_scope_init(void)
 		list_for_each_entry_safe(rmrr, rmrr_n, &dmar_rmrr_units, list) {
 			ret = rmrr_parse_dev(rmrr);
 			if (ret)
-				return ret;
+				goto fail;
 		}
 
 		list_for_each_entry_safe(atsr, atsr_n, &dmar_atsr_units, list) {
 			ret = atsr_parse_dev(atsr);
 			if (ret)
-				return ret;
+				goto fail;
 		}
 	}
 #endif
 
+	dmar_dev_scope_initialized = 1;
+	return 0;
+
+fail:
+	dmar_dev_scope_initialized = ret;
 	return ret;
 }
 

drivers/iommu/intel-iommu.c

@@ -3439,16 +3439,12 @@ int __init intel_iommu_init(void)
 		return 	-ENODEV;
 	}
 
-	if (dmar_dev_scope_init()) {
+	if (dmar_dev_scope_init() < 0) {
 		if (force_on)
 			panic("tboot: Failed to initialize DMAR device scope\n");
 		return 	-ENODEV;
 	}
 
-	/*
-	 * Check the need for DMA-remapping initialization now.
-	 * Above initialization will also be used by Interrupt-remapping.
-	 */
 	if (no_iommu || dmar_disabled)
 		return -ENODEV;
 

drivers/iommu/intr_remapping.c

@@ -773,6 +773,15 @@ int __init parse_ioapics_under_ir(void)
 	return ir_supported;
 }
 
+int ir_dev_scope_init(void)
+{
+	if (!intr_remapping_enabled)
+		return 0;
+
+	return dmar_dev_scope_init();
+}
+rootfs_initcall(ir_dev_scope_init);
+
 void disable_intr_remapping(void)
 {
 	struct dmar_drhd_unit *drhd;