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![Greg Edwards](/assets/img/avatar_default.png)
When determining the page size we could use to map with the IOMMU, the page size should also be aligned with the hva, not just the gfn. The gfn may not reflect the real alignment within the hugetlbfs file. Most of the time, this works fine. However, if the hugetlbfs file is backed by non-contiguous huge pages, a multi-huge page memslot starts at an unaligned offset within the hugetlbfs file, and the gfn is aligned with respect to the huge page size, kvm_host_page_size() will return the huge page size and we will use that to map with the IOMMU. When we later unpin that same memslot, the IOMMU returns the unmap size as the huge page size, and we happily unpin that many pfns in monotonically increasing order, not realizing we are spanning non-contiguous huge pages and partially unpin the wrong huge page. Ensure the IOMMU mapping page size is aligned with the hva corresponding to the gfn, which does reflect the alignment within the hugetlbfs file. Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Greg Edwards <gedwards@ddn.com> Cc: stable@vger.kernel.org Signed-off-by: Gleb Natapov <gleb@redhat.com>
359 lines
8.2 KiB
C
359 lines
8.2 KiB
C
/*
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* Copyright (c) 2006, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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* Place - Suite 330, Boston, MA 02111-1307 USA.
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*
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* Copyright (C) 2006-2008 Intel Corporation
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* Copyright IBM Corporation, 2008
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* Copyright 2010 Red Hat, Inc. and/or its affiliates.
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*
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* Author: Allen M. Kay <allen.m.kay@intel.com>
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* Author: Weidong Han <weidong.han@intel.com>
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* Author: Ben-Ami Yassour <benami@il.ibm.com>
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*/
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#include <linux/list.h>
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#include <linux/kvm_host.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/stat.h>
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#include <linux/dmar.h>
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#include <linux/iommu.h>
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#include <linux/intel-iommu.h>
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static bool allow_unsafe_assigned_interrupts;
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module_param_named(allow_unsafe_assigned_interrupts,
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allow_unsafe_assigned_interrupts, bool, S_IRUGO | S_IWUSR);
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MODULE_PARM_DESC(allow_unsafe_assigned_interrupts,
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"Enable device assignment on platforms without interrupt remapping support.");
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static int kvm_iommu_unmap_memslots(struct kvm *kvm);
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static void kvm_iommu_put_pages(struct kvm *kvm,
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gfn_t base_gfn, unsigned long npages);
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static pfn_t kvm_pin_pages(struct kvm_memory_slot *slot, gfn_t gfn,
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unsigned long size)
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{
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gfn_t end_gfn;
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pfn_t pfn;
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pfn = gfn_to_pfn_memslot(slot, gfn);
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end_gfn = gfn + (size >> PAGE_SHIFT);
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gfn += 1;
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if (is_error_noslot_pfn(pfn))
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return pfn;
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while (gfn < end_gfn)
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gfn_to_pfn_memslot(slot, gfn++);
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return pfn;
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}
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int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
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{
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gfn_t gfn, end_gfn;
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pfn_t pfn;
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int r = 0;
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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int flags;
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/* check if iommu exists and in use */
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if (!domain)
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return 0;
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gfn = slot->base_gfn;
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end_gfn = gfn + slot->npages;
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flags = IOMMU_READ;
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if (!(slot->flags & KVM_MEM_READONLY))
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flags |= IOMMU_WRITE;
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if (!kvm->arch.iommu_noncoherent)
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flags |= IOMMU_CACHE;
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while (gfn < end_gfn) {
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unsigned long page_size;
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/* Check if already mapped */
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if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn))) {
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gfn += 1;
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continue;
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}
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/* Get the page size we could use to map */
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page_size = kvm_host_page_size(kvm, gfn);
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/* Make sure the page_size does not exceed the memslot */
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while ((gfn + (page_size >> PAGE_SHIFT)) > end_gfn)
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page_size >>= 1;
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/* Make sure gfn is aligned to the page size we want to map */
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while ((gfn << PAGE_SHIFT) & (page_size - 1))
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page_size >>= 1;
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/* Make sure hva is aligned to the page size we want to map */
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while (__gfn_to_hva_memslot(slot, gfn) & (page_size - 1))
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page_size >>= 1;
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/*
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* Pin all pages we are about to map in memory. This is
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* important because we unmap and unpin in 4kb steps later.
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*/
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pfn = kvm_pin_pages(slot, gfn, page_size);
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if (is_error_noslot_pfn(pfn)) {
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gfn += 1;
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continue;
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}
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/* Map into IO address space */
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r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
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page_size, flags);
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if (r) {
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printk(KERN_ERR "kvm_iommu_map_address:"
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"iommu failed to map pfn=%llx\n", pfn);
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goto unmap_pages;
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}
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gfn += page_size >> PAGE_SHIFT;
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}
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return 0;
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unmap_pages:
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kvm_iommu_put_pages(kvm, slot->base_gfn, gfn);
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return r;
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}
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static int kvm_iommu_map_memslots(struct kvm *kvm)
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{
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int idx, r = 0;
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struct kvm_memslots *slots;
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struct kvm_memory_slot *memslot;
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if (kvm->arch.iommu_noncoherent)
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kvm_arch_register_noncoherent_dma(kvm);
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idx = srcu_read_lock(&kvm->srcu);
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slots = kvm_memslots(kvm);
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kvm_for_each_memslot(memslot, slots) {
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r = kvm_iommu_map_pages(kvm, memslot);
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if (r)
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break;
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}
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srcu_read_unlock(&kvm->srcu, idx);
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return r;
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}
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int kvm_assign_device(struct kvm *kvm,
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struct kvm_assigned_dev_kernel *assigned_dev)
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{
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struct pci_dev *pdev = NULL;
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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int r;
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bool noncoherent;
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/* check if iommu exists and in use */
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if (!domain)
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return 0;
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pdev = assigned_dev->dev;
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if (pdev == NULL)
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return -ENODEV;
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r = iommu_attach_device(domain, &pdev->dev);
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if (r) {
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dev_err(&pdev->dev, "kvm assign device failed ret %d", r);
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return r;
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}
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noncoherent = !iommu_domain_has_cap(kvm->arch.iommu_domain,
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IOMMU_CAP_CACHE_COHERENCY);
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/* Check if need to update IOMMU page table for guest memory */
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if (noncoherent != kvm->arch.iommu_noncoherent) {
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kvm_iommu_unmap_memslots(kvm);
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kvm->arch.iommu_noncoherent = noncoherent;
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r = kvm_iommu_map_memslots(kvm);
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if (r)
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goto out_unmap;
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}
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pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
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dev_info(&pdev->dev, "kvm assign device\n");
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return 0;
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out_unmap:
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kvm_iommu_unmap_memslots(kvm);
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return r;
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}
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int kvm_deassign_device(struct kvm *kvm,
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struct kvm_assigned_dev_kernel *assigned_dev)
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{
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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struct pci_dev *pdev = NULL;
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/* check if iommu exists and in use */
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if (!domain)
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return 0;
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pdev = assigned_dev->dev;
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if (pdev == NULL)
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return -ENODEV;
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iommu_detach_device(domain, &pdev->dev);
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pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
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dev_info(&pdev->dev, "kvm deassign device\n");
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return 0;
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}
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int kvm_iommu_map_guest(struct kvm *kvm)
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{
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int r;
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if (!iommu_present(&pci_bus_type)) {
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printk(KERN_ERR "%s: iommu not found\n", __func__);
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return -ENODEV;
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}
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mutex_lock(&kvm->slots_lock);
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kvm->arch.iommu_domain = iommu_domain_alloc(&pci_bus_type);
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if (!kvm->arch.iommu_domain) {
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r = -ENOMEM;
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goto out_unlock;
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}
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if (!allow_unsafe_assigned_interrupts &&
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!iommu_domain_has_cap(kvm->arch.iommu_domain,
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IOMMU_CAP_INTR_REMAP)) {
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printk(KERN_WARNING "%s: No interrupt remapping support,"
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" disallowing device assignment."
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" Re-enble with \"allow_unsafe_assigned_interrupts=1\""
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" module option.\n", __func__);
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iommu_domain_free(kvm->arch.iommu_domain);
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kvm->arch.iommu_domain = NULL;
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r = -EPERM;
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goto out_unlock;
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}
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r = kvm_iommu_map_memslots(kvm);
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if (r)
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kvm_iommu_unmap_memslots(kvm);
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out_unlock:
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mutex_unlock(&kvm->slots_lock);
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return r;
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}
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static void kvm_unpin_pages(struct kvm *kvm, pfn_t pfn, unsigned long npages)
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{
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unsigned long i;
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for (i = 0; i < npages; ++i)
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kvm_release_pfn_clean(pfn + i);
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}
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static void kvm_iommu_put_pages(struct kvm *kvm,
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gfn_t base_gfn, unsigned long npages)
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{
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struct iommu_domain *domain;
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gfn_t end_gfn, gfn;
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pfn_t pfn;
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u64 phys;
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domain = kvm->arch.iommu_domain;
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end_gfn = base_gfn + npages;
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gfn = base_gfn;
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/* check if iommu exists and in use */
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if (!domain)
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return;
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while (gfn < end_gfn) {
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unsigned long unmap_pages;
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size_t size;
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/* Get physical address */
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phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
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if (!phys) {
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gfn++;
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continue;
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}
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pfn = phys >> PAGE_SHIFT;
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/* Unmap address from IO address space */
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size = iommu_unmap(domain, gfn_to_gpa(gfn), PAGE_SIZE);
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unmap_pages = 1ULL << get_order(size);
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/* Unpin all pages we just unmapped to not leak any memory */
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kvm_unpin_pages(kvm, pfn, unmap_pages);
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gfn += unmap_pages;
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}
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}
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void kvm_iommu_unmap_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
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{
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kvm_iommu_put_pages(kvm, slot->base_gfn, slot->npages);
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}
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static int kvm_iommu_unmap_memslots(struct kvm *kvm)
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{
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int idx;
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struct kvm_memslots *slots;
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struct kvm_memory_slot *memslot;
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idx = srcu_read_lock(&kvm->srcu);
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slots = kvm_memslots(kvm);
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kvm_for_each_memslot(memslot, slots)
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kvm_iommu_unmap_pages(kvm, memslot);
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srcu_read_unlock(&kvm->srcu, idx);
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if (kvm->arch.iommu_noncoherent)
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kvm_arch_unregister_noncoherent_dma(kvm);
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return 0;
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}
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int kvm_iommu_unmap_guest(struct kvm *kvm)
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{
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struct iommu_domain *domain = kvm->arch.iommu_domain;
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/* check if iommu exists and in use */
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if (!domain)
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return 0;
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mutex_lock(&kvm->slots_lock);
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kvm_iommu_unmap_memslots(kvm);
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kvm->arch.iommu_domain = NULL;
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kvm->arch.iommu_noncoherent = false;
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mutex_unlock(&kvm->slots_lock);
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iommu_domain_free(domain);
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return 0;
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}
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