From 522c68c4416de3cd3e11a9ff10d58e776a69ae1e Mon Sep 17 00:00:00 2001 From: Sheng Yang Date: Mon, 27 Apr 2009 20:35:43 +0800 Subject: KVM: Enable snooping control for supported hardware Memory aliases with different memory type is a problem for guest. For the guest without assigned device, the memory type of guest memory would always been the same as host(WB); but for the assigned device, some part of memory may be used as DMA and then set to uncacheable memory type(UC/WC), which would be a conflict of host memory type then be a potential issue. Snooping control can guarantee the cache correctness of memory go through the DMA engine of VT-d. [avi: fix build on ia64] Signed-off-by: Sheng Yang Signed-off-by: Avi Kivity --- virt/kvm/iommu.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) (limited to 'virt') diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c index 4c403750360..15147583abd 100644 --- a/virt/kvm/iommu.c +++ b/virt/kvm/iommu.c @@ -39,11 +39,16 @@ int kvm_iommu_map_pages(struct kvm *kvm, pfn_t pfn; int i, r = 0; struct iommu_domain *domain = kvm->arch.iommu_domain; + int flags; /* check if iommu exists and in use */ if (!domain) return 0; + flags = IOMMU_READ | IOMMU_WRITE; + if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY) + flags |= IOMMU_CACHE; + for (i = 0; i < npages; i++) { /* check if already mapped */ if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn))) @@ -53,8 +58,7 @@ int kvm_iommu_map_pages(struct kvm *kvm, r = iommu_map_range(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn), - PAGE_SIZE, - IOMMU_READ | IOMMU_WRITE); + PAGE_SIZE, flags); if (r) { printk(KERN_ERR "kvm_iommu_map_address:" "iommu failed to map pfn=%lx\n", pfn); @@ -88,7 +92,7 @@ int kvm_assign_device(struct kvm *kvm, { struct pci_dev *pdev = NULL; struct iommu_domain *domain = kvm->arch.iommu_domain; - int r; + int r, last_flags; /* check if iommu exists and in use */ if (!domain) @@ -107,12 +111,29 @@ int kvm_assign_device(struct kvm *kvm, return r; } + last_flags = kvm->arch.iommu_flags; + if (iommu_domain_has_cap(kvm->arch.iommu_domain, + IOMMU_CAP_CACHE_COHERENCY)) + kvm->arch.iommu_flags |= KVM_IOMMU_CACHE_COHERENCY; + + /* Check if need to update IOMMU page table for guest memory */ + if ((last_flags ^ kvm->arch.iommu_flags) == + KVM_IOMMU_CACHE_COHERENCY) { + kvm_iommu_unmap_memslots(kvm); + r = kvm_iommu_map_memslots(kvm); + if (r) + goto out_unmap; + } + printk(KERN_DEBUG "assign device: host bdf = %x:%x:%x\n", assigned_dev->host_busnr, PCI_SLOT(assigned_dev->host_devfn), PCI_FUNC(assigned_dev->host_devfn)); return 0; +out_unmap: + kvm_iommu_unmap_memslots(kvm); + return r; } int kvm_deassign_device(struct kvm *kvm, -- cgit v1.2.3