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-rw-r--r--arch/x86_64/kernel/aperture.c1
-rw-r--r--arch/x86_64/kernel/pci-dma.c3
-rw-r--r--arch/x86_64/kernel/pci-gart.c4
-rw-r--r--arch/x86_64/kernel/pci-swiotlb.c2
4 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86_64/kernel/aperture.c b/arch/x86_64/kernel/aperture.c
index 9ea723bab16..a195ef06ec5 100644
--- a/arch/x86_64/kernel/aperture.c
+++ b/arch/x86_64/kernel/aperture.c
@@ -209,6 +209,7 @@ void __init iommu_hole_init(void)
if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
continue;
+ iommu_detected = 1;
iommu_aperture = 1;
aper_order = (read_pci_config(0, num, 3, 0x90) >> 1) & 7;
diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c
index 33926c36725..7edd1a40fab 100644
--- a/arch/x86_64/kernel/pci-dma.c
+++ b/arch/x86_64/kernel/pci-dma.c
@@ -33,6 +33,9 @@ int panic_on_overflow __read_mostly = 0;
int force_iommu __read_mostly= 0;
#endif
+/* Set this to 1 if there is a HW IOMMU in the system */
+int iommu_detected __read_mostly = 0;
+
/* Dummy device used for NULL arguments (normally ISA). Better would
be probably a smaller DMA mask, but this is bug-to-bug compatible
to i386. */
diff --git a/arch/x86_64/kernel/pci-gart.c b/arch/x86_64/kernel/pci-gart.c
index 82a346e6e2e..4f67957d2b4 100644
--- a/arch/x86_64/kernel/pci-gart.c
+++ b/arch/x86_64/kernel/pci-gart.c
@@ -597,6 +597,10 @@ static int __init pci_iommu_init(void)
if (swiotlb)
return -ENODEV;
+ /* Did we detect a different HW IOMMU? */
+ if (iommu_detected && !iommu_aperture)
+ return -1;
+
if (no_iommu ||
(!force_iommu && end_pfn <= MAX_DMA32_PFN) ||
!iommu_aperture ||
diff --git a/arch/x86_64/kernel/pci-swiotlb.c b/arch/x86_64/kernel/pci-swiotlb.c
index 990ed67896f..ebdb77fe205 100644
--- a/arch/x86_64/kernel/pci-swiotlb.c
+++ b/arch/x86_64/kernel/pci-swiotlb.c
@@ -31,7 +31,7 @@ struct dma_mapping_ops swiotlb_dma_ops = {
void pci_swiotlb_init(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
- if (!iommu_aperture && !no_iommu &&
+ if (!iommu_detected && !no_iommu &&
(end_pfn > MAX_DMA32_PFN || force_iommu))
swiotlb = 1;
if (swiotlb) {