From 4ed0d3e6c64cfd9ba4ceb2099b10d1cf8ece4320 Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Fri, 24 Apr 2009 17:30:20 -0700 Subject: Intel IOMMU Pass Through Support The patch adds kernel parameter intel_iommu=pt to set up pass through mode in context mapping entry. This disables DMAR in linux kernel; but KVM still runs on VT-d and interrupt remapping still works. In this mode, kernel uses swiotlb for DMA API functions but other VT-d functionalities are enabled for KVM. KVM always uses multi level translation page table in VT-d. By default, pass though mode is disabled in kernel. This is useful when people don't want to enable VT-d DMAR in kernel but still want to use KVM and interrupt remapping for reasons like DMAR performance concern or debug purpose. Signed-off-by: Fenghua Yu Acked-by: Weidong Han Signed-off-by: David Woodhouse --- arch/x86/kernel/pci-dma.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/x86/kernel/pci-dma.c') diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 745579bc825..8cad0d85424 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -160,6 +160,8 @@ again: return page_address(page); } +extern int iommu_pass_through; + /* * See for the iommu kernel parameter * documentation. @@ -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); -- cgit v1.2.3-18-g5258 From aed5d5f4c5ea5da01a774e42cff08c4b4fa59072 Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Thu, 30 Apr 2009 17:57:11 -0700 Subject: Fix !CONFIG_DMAR build failure introduced by Intel IOMMU Pass Through Support This updated patch should fix the compiling errors and remove the extern iommu_pass_through from drivers/pci/intel-iommu.c file. Signed-off-by: Fenghua Yu Signed-off-by: David Woodhouse --- arch/x86/kernel/pci-dma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/pci-dma.c') diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 8cad0d85424..049005e8217 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); @@ -160,8 +162,6 @@ again: return page_address(page); } -extern int iommu_pass_through; - /* * See for the iommu kernel parameter * documentation. -- cgit v1.2.3-18-g5258 From 3238c0c4d68d9a9022b411a11a4b933fbdb53a14 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Wed, 1 Jul 2009 18:56:16 +0100 Subject: intel-iommu: Make iommu=pt work on i386 too Signed-off-by: David Woodhouse --- arch/x86/kernel/pci-dma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/pci-dma.c') diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 47630479b06..1a041bcf506 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -211,11 +211,11 @@ static __init int iommu_setup(char *p) #ifdef CONFIG_SWIOTLB if (!strncmp(p, "soft", 4)) swiotlb = 1; +#endif if (!strncmp(p, "pt", 2)) { iommu_pass_through = 1; return 1; } -#endif gart_parse_options(p); -- cgit v1.2.3-18-g5258