[PATCH v4 3/5] iommu/x86: Add architectural MSI reserved region helper

[Yu Zhang]

Intel and AMD IOMMU drivers both reserve the x86 architectural MSI
address window from normal IOVA mappings, but each open-codes the range
and its allocation attributes.

Add iommu_alloc_resv_x86_msi_region() to encapsulate those details, and
convert the Intel and AMD drivers to use it.

Signed-off-by: Yu Zhang <zhang...@linux.microsoft.com>
---
 arch/x86/include/asm/iommu.h | 14 ++++++++++++++
 drivers/iommu/amd/iommu.c    |  6 +-----
 drivers/iommu/intel/iommu.c  |  6 +-----
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index 3be2451e7bc8..6404f4fbeae8 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -4,6 +4,11 @@
 
 #include <linux/acpi.h>
 
+#ifdef CONFIG_IOMMU_API
+#include <linux/iommu.h>
+#include <linux/sizes.h>
+#endif
+
 #include <asm/e820/api.h>
 
 extern int force_iommu, no_iommu;
@@ -21,6 +26,15 @@ extern bool x86_swiotlb_enable;
 /* 10 seconds */
 #define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
 
+#ifdef CONFIG_IOMMU_API
+static inline struct iommu_resv_region *
+iommu_alloc_resv_x86_msi_region(void)
+{
+       return iommu_alloc_resv_region(0xfee00000, SZ_1M, 0,
+                                      IOMMU_RESV_MSI, GFP_KERNEL);
+}
+#endif
+
 static inline int __init
 arch_rmrr_sanity_check(struct acpi_dmar_reserved_memory *rmrr)
 {
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 4dc306a4b5c6..b9bbd9aa99a8 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -50,8 +50,6 @@
 #define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28))
 
 /* Reserved IOVA ranges */
-#define MSI_RANGE_START                (0xfee00000)
-#define MSI_RANGE_END          (0xfeefffff)
 #define HT_RANGE_START         (0xfd00000000ULL)
 #define HT_RANGE_END           (0xffffffffffULL)
 
@@ -3140,9 +3138,7 @@ static void amd_iommu_get_resv_regions(struct device *dev,
                list_add_tail(&region->list, head);
        }
 
-       region = iommu_alloc_resv_region(MSI_RANGE_START,
-                                        MSI_RANGE_END - MSI_RANGE_START + 1,
-                                        0, IOMMU_RESV_MSI, GFP_KERNEL);
+       region = iommu_alloc_resv_x86_msi_region();
        if (!region)
                return;
        list_add_tail(&region->list, head);
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 2e3b3ab216f8..c4de4bbcb065 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -39,8 +39,6 @@
 #define IS_ISA_DEVICE(pdev) ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA)
 #define IS_AZALIA(pdev) ((pdev)->vendor == 0x8086 && (pdev)->device == 0x3a3e)
 
-#define IOAPIC_RANGE_START     (0xfee00000)
-#define IOAPIC_RANGE_END       (0xfeefffff)
 #define IOVA_START_ADDR                (0x1000)
 
 #define DEFAULT_DOMAIN_ADDRESS_WIDTH 57
@@ -3459,9 +3457,7 @@ static void intel_iommu_get_resv_regions(struct device 
*device,
        }
 #endif /* CONFIG_INTEL_IOMMU_FLOPPY_WA */
 
-       reg = iommu_alloc_resv_region(IOAPIC_RANGE_START,
-                                     IOAPIC_RANGE_END - IOAPIC_RANGE_START + 1,
-                                     0, IOMMU_RESV_MSI, GFP_KERNEL);
+       reg = iommu_alloc_resv_x86_msi_region();
        if (!reg)
                return;
        list_add_tail(&reg->list, head);
-- 
2.52.0