intel-iommu: Unify hardware and software passthrough support
This makes the hardware passthrough mode work a lot more like the software version, so that the behaviour of a kernel with 'iommu=pt' is the same whether the hardware supports passthrough or not. In particular: - We use a single si_domain for the pass-through devices. - 32-bit devices can be taken out of the pass-through domain so that they don't have to use swiotlb. - Devices will work again after being removed from a KVM guest. - A potential oops on OOM (in init_context_pass_through()) is fixed. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
parent
0815565adf
commit
19943b0e30
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@ -71,9 +71,8 @@ void __init pci_swiotlb_init(void)
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{
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/* don't initialize swiotlb if iommu=off (no_iommu=1) */
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#ifdef CONFIG_X86_64
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if ((!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN) ||
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iommu_pass_through)
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swiotlb = 1;
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if ((!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN))
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swiotlb = 1;
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#endif
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if (swiotlb_force)
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swiotlb = 1;
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@ -251,7 +251,8 @@ static inline int first_pte_in_page(struct dma_pte *pte)
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* 2. It maps to each iommu if successful.
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* 3. Each iommu mapps to this domain if successful.
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*/
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struct dmar_domain *si_domain;
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static struct dmar_domain *si_domain;
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static int hw_pass_through = 1;
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/* devices under the same p2p bridge are owned in one domain */
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#define DOMAIN_FLAG_P2P_MULTIPLE_DEVICES (1 << 0)
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@ -1948,14 +1949,24 @@ static int iommu_prepare_identity_map(struct pci_dev *pdev,
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struct dmar_domain *domain;
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int ret;
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printk(KERN_INFO
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"IOMMU: Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
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pci_name(pdev), start, end);
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domain = get_domain_for_dev(pdev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
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if (!domain)
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return -ENOMEM;
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/* For _hardware_ passthrough, don't bother. But for software
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passthrough, we do it anyway -- it may indicate a memory
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range which is reserved in E820, so which didn't get set
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up to start with in si_domain */
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if (domain == si_domain && hw_pass_through) {
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printk("Ignoring identity map for HW passthrough device %s [0x%Lx - 0x%Lx]\n",
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pci_name(pdev), start, end);
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return 0;
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}
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printk(KERN_INFO
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"IOMMU: Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
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pci_name(pdev), start, end);
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ret = iommu_domain_identity_map(domain, start, end);
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if (ret)
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goto error;
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@ -2006,23 +2017,6 @@ static inline void iommu_prepare_isa(void)
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}
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#endif /* !CONFIG_DMAR_FLPY_WA */
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/* Initialize each context entry as pass through.*/
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static int __init init_context_pass_through(void)
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{
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struct pci_dev *pdev = NULL;
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struct dmar_domain *domain;
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int ret;
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for_each_pci_dev(pdev) {
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domain = get_domain_for_dev(pdev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
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ret = domain_context_mapping(domain, pdev,
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CONTEXT_TT_PASS_THROUGH);
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if (ret)
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return ret;
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}
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return 0;
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}
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static int md_domain_init(struct dmar_domain *domain, int guest_width);
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static int __init si_domain_work_fn(unsigned long start_pfn,
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@ -2037,7 +2031,7 @@ static int __init si_domain_work_fn(unsigned long start_pfn,
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}
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static int si_domain_init(void)
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static int si_domain_init(int hw)
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{
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struct dmar_drhd_unit *drhd;
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struct intel_iommu *iommu;
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@ -2064,6 +2058,9 @@ static int si_domain_init(void)
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si_domain->flags = DOMAIN_FLAG_STATIC_IDENTITY;
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if (hw)
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return 0;
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for_each_online_node(nid) {
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work_with_active_regions(nid, si_domain_work_fn, &ret);
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if (ret)
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@ -2155,24 +2152,26 @@ static int iommu_should_identity_map(struct pci_dev *pdev, int startup)
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return 1;
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}
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static int iommu_prepare_static_identity_mapping(void)
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static int iommu_prepare_static_identity_mapping(int hw)
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{
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struct pci_dev *pdev = NULL;
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int ret;
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ret = si_domain_init();
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ret = si_domain_init(hw);
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if (ret)
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return -EFAULT;
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for_each_pci_dev(pdev) {
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if (iommu_should_identity_map(pdev, 1)) {
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printk(KERN_INFO "IOMMU: identity mapping for device %s\n",
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pci_name(pdev));
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printk(KERN_INFO "IOMMU: %s identity mapping for device %s\n",
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hw ? "hardware" : "software", pci_name(pdev));
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ret = domain_context_mapping(si_domain, pdev,
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hw ? CONTEXT_TT_PASS_THROUGH :
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CONTEXT_TT_MULTI_LEVEL);
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if (ret)
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return ret;
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ret = domain_add_dev_info(si_domain, pdev);
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if (ret)
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return ret;
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@ -2189,14 +2188,6 @@ int __init init_dmars(void)
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struct pci_dev *pdev;
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struct intel_iommu *iommu;
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int i, ret;
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int pass_through = 1;
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/*
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* In case pass through can not be enabled, iommu tries to use identity
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* mapping.
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*/
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if (iommu_pass_through)
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iommu_identity_mapping = 1;
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/*
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* for each drhd
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@ -2250,14 +2241,8 @@ int __init init_dmars(void)
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goto error;
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}
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if (!ecap_pass_through(iommu->ecap))
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pass_through = 0;
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hw_pass_through = 0;
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}
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if (iommu_pass_through)
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if (!pass_through) {
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printk(KERN_INFO
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"Pass Through is not supported by hardware.\n");
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iommu_pass_through = 0;
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}
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/*
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* Start from the sane iommu hardware state.
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@ -2312,63 +2297,56 @@ int __init init_dmars(void)
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}
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}
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/*
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* If pass through is set and enabled, context entries of all pci
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* devices are intialized by pass through translation type.
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*/
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if (iommu_pass_through) {
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ret = init_context_pass_through();
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if (ret) {
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printk(KERN_ERR "IOMMU: Pass through init failed.\n");
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iommu_pass_through = 0;
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}
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}
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if (iommu_pass_through)
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iommu_identity_mapping = 1;
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#ifdef CONFIG_DMAR_BROKEN_GFX_WA
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else
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iommu_identity_mapping = 2;
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#endif
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/*
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* If pass through is not set or not enabled, setup context entries for
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* identity mappings for rmrr, gfx, and isa and may fall back to static
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* identity mapping if iommu_identity_mapping is set.
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*/
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if (!iommu_pass_through) {
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#ifdef CONFIG_DMAR_BROKEN_GFX_WA
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if (!iommu_identity_mapping)
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iommu_identity_mapping = 2;
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#endif
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if (iommu_identity_mapping)
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iommu_prepare_static_identity_mapping();
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/*
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* For each rmrr
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* for each dev attached to rmrr
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* do
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* locate drhd for dev, alloc domain for dev
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* allocate free domain
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* allocate page table entries for rmrr
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* if context not allocated for bus
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* allocate and init context
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* set present in root table for this bus
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* init context with domain, translation etc
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* endfor
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* endfor
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*/
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printk(KERN_INFO "IOMMU: Setting RMRR:\n");
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for_each_rmrr_units(rmrr) {
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for (i = 0; i < rmrr->devices_cnt; i++) {
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pdev = rmrr->devices[i];
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/*
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* some BIOS lists non-exist devices in DMAR
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* table.
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*/
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if (!pdev)
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continue;
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ret = iommu_prepare_rmrr_dev(rmrr, pdev);
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if (ret)
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printk(KERN_ERR
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"IOMMU: mapping reserved region failed\n");
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}
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if (iommu_identity_mapping) {
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ret = iommu_prepare_static_identity_mapping(hw_pass_through);
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if (ret) {
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printk(KERN_CRIT "Failed to setup IOMMU pass-through\n");
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goto error;
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}
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iommu_prepare_isa();
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}
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/*
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* For each rmrr
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* for each dev attached to rmrr
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* do
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* locate drhd for dev, alloc domain for dev
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* allocate free domain
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* allocate page table entries for rmrr
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* if context not allocated for bus
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* allocate and init context
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* set present in root table for this bus
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* init context with domain, translation etc
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* endfor
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* endfor
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*/
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printk(KERN_INFO "IOMMU: Setting RMRR:\n");
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for_each_rmrr_units(rmrr) {
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for (i = 0; i < rmrr->devices_cnt; i++) {
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pdev = rmrr->devices[i];
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/*
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* some BIOS lists non-exist devices in DMAR
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* table.
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*/
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if (!pdev)
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continue;
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ret = iommu_prepare_rmrr_dev(rmrr, pdev);
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if (ret)
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printk(KERN_ERR
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"IOMMU: mapping reserved region failed\n");
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}
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}
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iommu_prepare_isa();
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/*
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* for each drhd
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@ -2536,7 +2514,10 @@ static int iommu_no_mapping(struct device *dev)
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ret = domain_add_dev_info(si_domain, pdev);
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if (ret)
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return 0;
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ret = domain_context_mapping(si_domain, pdev, CONTEXT_TT_MULTI_LEVEL);
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ret = domain_context_mapping(si_domain, pdev,
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hw_pass_through ?
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CONTEXT_TT_PASS_THROUGH :
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CONTEXT_TT_MULTI_LEVEL);
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if (!ret) {
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printk(KERN_INFO "64bit %s uses identity mapping\n",
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pci_name(pdev));
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@ -3202,7 +3183,7 @@ int __init intel_iommu_init(void)
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* Check the need for DMA-remapping initialization now.
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* Above initialization will also be used by Interrupt-remapping.
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*/
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if (no_iommu || (swiotlb && !iommu_pass_through) || dmar_disabled)
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if (no_iommu || swiotlb || dmar_disabled)
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return -ENODEV;
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iommu_init_mempool();
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@ -3222,14 +3203,7 @@ int __init intel_iommu_init(void)
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init_timer(&unmap_timer);
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force_iommu = 1;
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if (!iommu_pass_through) {
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printk(KERN_INFO
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"Multi-level page-table translation for DMAR.\n");
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dma_ops = &intel_dma_ops;
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} else
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printk(KERN_INFO
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"DMAR: Pass through translation for DMAR.\n");
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dma_ops = &intel_dma_ops;
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init_iommu_sysfs();
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