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/ia64/include/asm/iommu.h | 1 + arch/ia64/kernel/pci-swiotlb.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/ia64') diff --git a/arch/ia64/include/asm/iommu.h b/arch/ia64/include/asm/iommu.h index 0490794fe4aa..37d41ca5645a 100644 --- a/arch/ia64/include/asm/iommu.h +++ b/arch/ia64/include/asm/iommu.h @@ -9,6 +9,7 @@ extern void pci_iommu_shutdown(void); extern void no_iommu_init(void); extern int force_iommu, no_iommu; extern int iommu_detected; +extern int iommu_pass_through; extern void iommu_dma_init(void); extern void machvec_init(const char *name); diff --git a/arch/ia64/kernel/pci-swiotlb.c b/arch/ia64/kernel/pci-swiotlb.c index 285aae8431c6..223abb134105 100644 --- a/arch/ia64/kernel/pci-swiotlb.c +++ b/arch/ia64/kernel/pci-swiotlb.c @@ -46,7 +46,7 @@ void __init swiotlb_dma_init(void) void __init pci_swiotlb_init(void) { - if (!iommu_detected) { + if (!iommu_detected || iommu_pass_through) { #ifdef CONFIG_IA64_GENERIC swiotlb = 1; printk(KERN_INFO "PCI-DMA: Re-initialize machine vector.\n"); -- cgit v1.2.3 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/ia64/kernel/pci-dma.c | 2 ++ arch/x86/kernel/pci-dma.c | 4 ++-- drivers/pci/intel-iommu.c | 1 - 3 files changed, 4 insertions(+), 3 deletions(-) (limited to 'arch/ia64') diff --git a/arch/ia64/kernel/pci-dma.c b/arch/ia64/kernel/pci-dma.c index eb987386f691..ecdde25d0d18 100644 --- a/arch/ia64/kernel/pci-dma.c +++ b/arch/ia64/kernel/pci-dma.c @@ -32,6 +32,8 @@ int force_iommu __read_mostly = 1; int force_iommu __read_mostly; #endif +int iommu_pass_through; + /* 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/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 8cad0d854242..049005e82178 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. diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 13121821db7f..d3edd6aa82ce 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -288,7 +288,6 @@ int dmar_disabled = 1; static int __initdata dmar_map_gfx = 1; static int dmar_forcedac; static int intel_iommu_strict; -int iommu_pass_through; #define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1)) static DEFINE_SPINLOCK(device_domain_lock); -- cgit v1.2.3 From 008fe148cb0fb51d266baabe2c09997b21cf90c6 Mon Sep 17 00:00:00 2001 From: "Luck, Tony" Date: Tue, 26 May 2009 15:45:12 -0700 Subject: intel-iommu: Fix one last ia64 build problem in Pass Through Support On ia64 with CONFIG_DMAR=n and CONFIG_SWIOTLB=y (as used in arch/ia64/configs/tiger_defconfig) there is still a link error with iommu_pass_through listed as an undefined symbol: arch/ia64/kernel/built-in.o: In function `pci_swiotlb_init': (.init.text+0x7f70): undefined reference to `iommu_pass_through' Fix it by #defining iommu_pass_through away in asm/iommu.h Signed-off-by: Tony Luck Signed-off-by: David Woodhouse --- arch/ia64/include/asm/iommu.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/ia64') diff --git a/arch/ia64/include/asm/iommu.h b/arch/ia64/include/asm/iommu.h index 37d41ca5645a..745e095fe82e 100644 --- a/arch/ia64/include/asm/iommu.h +++ b/arch/ia64/include/asm/iommu.h @@ -9,7 +9,11 @@ extern void pci_iommu_shutdown(void); extern void no_iommu_init(void); extern int force_iommu, no_iommu; extern int iommu_detected; +#ifdef CONFIG_DMAR extern int iommu_pass_through; +#else +#define iommu_pass_through (0) +#endif extern void iommu_dma_init(void); extern void machvec_init(const char *name); -- cgit v1.2.3