[PATCH 2/2] Enable Pass Through Feature in Intel IOMMU

[Fenghua Yu]

The patch set 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. In this mode, kernel uses swiotlb for DMA API functions but other VT-d
functionalities are enabled for KVM. By default, pass though mode is disabled in
kernel.

This second patch changes context mapping interface called in KVM vtd.c. KVM
always uses multi level translation page table in VT-d.


Signed-off-by: Fenghua Yu <fenghua.yu at intel.com>
Signed-off-by: Weidong Han <weidong.han at intel.com>
Signed-off-by: Allen Kay <allen.m.kay at intel.com>
Signed-off-by: David Woodhouse <david.woodhouse at intel.com>

---

 vtd.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)


diff --git a/virt/kvm/vtd.c b/virt/kvm/vtd.c
index a770874..7b753d7 100644
--- a/virt/kvm/vtd.c
+++ b/virt/kvm/vtd.c
@@ -124,7 +124,7 @@ int kvm_iommu_map_guest(struct kvm *kvm,
 			       pdev->bus->number, pdev->devfn);
 
 	r = intel_iommu_context_mapping(kvm->arch.intel_iommu_domain,
-					pdev);
+					pdev, CONTEXT_TT_MULTI_LEVEL);
 	if (r) {
 		printk(KERN_ERR "Domain context map for %s failed",
 		       pci_name(pdev));