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-rw-r--r--arch/x86/include/asm/iommu.h1
-rw-r--r--arch/x86/kernel/pci-dma.c6
-rw-r--r--arch/x86/kernel/pci-swiotlb.c3
3 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index af326a2975b..fd6d21bbee6 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -6,6 +6,7 @@ extern void no_iommu_init(void);
extern struct dma_map_ops nommu_dma_ops;
extern int force_iommu, no_iommu;
extern int iommu_detected;
+extern int iommu_pass_through;
/* 10 seconds */
#define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 328592fb604..47630479b06 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -32,6 +32,8 @@ int no_iommu __read_mostly;
/* Set this to 1 if there is a HW IOMMU in the system */
int iommu_detected __read_mostly = 0;
+int iommu_pass_through;
+
dma_addr_t bad_dma_address __read_mostly = 0;
EXPORT_SYMBOL(bad_dma_address);
@@ -209,6 +211,10 @@ static __init int iommu_setup(char *p)
#ifdef CONFIG_SWIOTLB
if (!strncmp(p, "soft", 4))
swiotlb = 1;
+ if (!strncmp(p, "pt", 2)) {
+ iommu_pass_through = 1;
+ return 1;
+ }
#endif
gart_parse_options(p);
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index a1712f2b50f..6af96ee4420 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -71,7 +71,8 @@ void __init pci_swiotlb_init(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
#ifdef CONFIG_X86_64
- if (!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN)
+ if ((!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN) ||
+ iommu_pass_through)
swiotlb = 1;
#endif
if (swiotlb_force)