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authorFenghua Yu <fenghua.yu@intel.com>2009-04-24 17:30:20 -0700
committerDavid Woodhouse <David.Woodhouse@intel.com>2009-04-29 06:54:34 +0100
commit4ed0d3e6c64cfd9ba4ceb2099b10d1cf8ece4320 (patch)
tree950bacfaf57040aafbcc2ea9b52eb171d35c23bd /arch/ia64/kernel
parent091069740304c979f957ceacec39c461d0192158 (diff)
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 <fenghua.yu@intel.com> Acked-by: Weidong Han <weidong@intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'arch/ia64/kernel')
-rw-r--r--arch/ia64/kernel/pci-swiotlb.c2
1 files changed, 1 insertions, 1 deletions
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");