x86, AMD IOMMU: don't try to init IOMMU if early detect code did not detect one
This patch adds a check if the early detect code has found AMD IOMMU hardware
descriptions and does not try to initialize hardware if the check failed.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: iommu@lists.linux-foundation.org
Cc: bhavna.sarathy@amd.com
Cc: robert.richter@amd.com
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index c54c823..c970fac 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -101,6 +101,8 @@
u64 range_length;
} __attribute__((packed));
+static int __initdata amd_iommu_detected;
+
u16 amd_iommu_last_bdf;
struct list_head amd_iommu_unity_map;
unsigned amd_iommu_aperture_order = 26;
@@ -689,6 +691,9 @@
return 0;
}
+ if (!amd_iommu_detected)
+ return -ENODEV;
+
/*
* First parse ACPI tables to find the largest Bus/Dev/Func
* we need to handle. Upon this information the shared data
@@ -831,6 +836,7 @@
if (acpi_table_parse("IVRS", early_amd_iommu_detect) == 0) {
iommu_detected = 1;
+ amd_iommu_detected = 1;
#ifdef CONFIG_GART_IOMMU
gart_iommu_aperture_disabled = 1;
gart_iommu_aperture = 0;