From c1cbebeec4a6be1c1fb54fbf2395ade2534b03c4 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joerg.roedel@amd.com>
Date: Thu, 3 Jul 2008 19:35:10 +0200
Subject: [PATCH] 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>
---
arch/x86/kernel/amd_iommu_init.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index c54c82305af41..c970fac6fdc60 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -101,6 +101,8 @@ struct ivmd_header {
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 @@ int __init amd_iommu_init(void)
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 @@ void __init amd_iommu_detect(void)
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;
--
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