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425 lines
8.8 KiB
425 lines
8.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* VFIO-KVM bridge pseudo device |
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* |
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* Copyright (C) 2013 Red Hat, Inc. All rights reserved. |
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* Author: Alex Williamson <[email protected]> |
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*/ |
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#include <linux/errno.h> |
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#include <linux/file.h> |
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#include <linux/kvm_host.h> |
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#include <linux/list.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/slab.h> |
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#include <linux/uaccess.h> |
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#include <linux/vfio.h> |
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#include "vfio.h" |
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#ifdef CONFIG_SPAPR_TCE_IOMMU |
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#include <asm/kvm_ppc.h> |
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#endif |
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struct kvm_vfio_group { |
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struct list_head node; |
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struct vfio_group *vfio_group; |
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}; |
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struct kvm_vfio { |
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struct list_head group_list; |
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struct mutex lock; |
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bool noncoherent; |
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}; |
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static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep) |
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{ |
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struct vfio_group *vfio_group; |
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struct vfio_group *(*fn)(struct file *); |
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fn = symbol_get(vfio_group_get_external_user); |
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if (!fn) |
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return ERR_PTR(-EINVAL); |
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vfio_group = fn(filep); |
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symbol_put(vfio_group_get_external_user); |
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return vfio_group; |
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} |
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static bool kvm_vfio_external_group_match_file(struct vfio_group *group, |
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struct file *filep) |
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{ |
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bool ret, (*fn)(struct vfio_group *, struct file *); |
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fn = symbol_get(vfio_external_group_match_file); |
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if (!fn) |
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return false; |
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ret = fn(group, filep); |
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symbol_put(vfio_external_group_match_file); |
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return ret; |
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} |
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static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group) |
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{ |
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void (*fn)(struct vfio_group *); |
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fn = symbol_get(vfio_group_put_external_user); |
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if (!fn) |
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return; |
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fn(vfio_group); |
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symbol_put(vfio_group_put_external_user); |
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} |
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static void kvm_vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm) |
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{ |
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void (*fn)(struct vfio_group *, struct kvm *); |
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fn = symbol_get(vfio_group_set_kvm); |
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if (!fn) |
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return; |
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fn(group, kvm); |
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symbol_put(vfio_group_set_kvm); |
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} |
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static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group) |
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{ |
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long (*fn)(struct vfio_group *, unsigned long); |
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long ret; |
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fn = symbol_get(vfio_external_check_extension); |
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if (!fn) |
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return false; |
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ret = fn(vfio_group, VFIO_DMA_CC_IOMMU); |
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symbol_put(vfio_external_check_extension); |
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return ret > 0; |
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} |
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#ifdef CONFIG_SPAPR_TCE_IOMMU |
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static int kvm_vfio_external_user_iommu_id(struct vfio_group *vfio_group) |
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{ |
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int (*fn)(struct vfio_group *); |
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int ret = -EINVAL; |
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fn = symbol_get(vfio_external_user_iommu_id); |
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if (!fn) |
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return ret; |
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ret = fn(vfio_group); |
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symbol_put(vfio_external_user_iommu_id); |
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return ret; |
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} |
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static struct iommu_group *kvm_vfio_group_get_iommu_group( |
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struct vfio_group *group) |
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{ |
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int group_id = kvm_vfio_external_user_iommu_id(group); |
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if (group_id < 0) |
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return NULL; |
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return iommu_group_get_by_id(group_id); |
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} |
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static void kvm_spapr_tce_release_vfio_group(struct kvm *kvm, |
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struct vfio_group *vfio_group) |
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{ |
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struct iommu_group *grp = kvm_vfio_group_get_iommu_group(vfio_group); |
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if (WARN_ON_ONCE(!grp)) |
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return; |
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kvm_spapr_tce_release_iommu_group(kvm, grp); |
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iommu_group_put(grp); |
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} |
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#endif |
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/* |
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* Groups can use the same or different IOMMU domains. If the same then |
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* adding a new group may change the coherency of groups we've previously |
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* been told about. We don't want to care about any of that so we retest |
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* each group and bail as soon as we find one that's noncoherent. This |
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* means we only ever [un]register_noncoherent_dma once for the whole device. |
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*/ |
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static void kvm_vfio_update_coherency(struct kvm_device *dev) |
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{ |
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struct kvm_vfio *kv = dev->private; |
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bool noncoherent = false; |
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struct kvm_vfio_group *kvg; |
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mutex_lock(&kv->lock); |
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list_for_each_entry(kvg, &kv->group_list, node) { |
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if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) { |
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noncoherent = true; |
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break; |
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} |
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} |
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if (noncoherent != kv->noncoherent) { |
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kv->noncoherent = noncoherent; |
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if (kv->noncoherent) |
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kvm_arch_register_noncoherent_dma(dev->kvm); |
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else |
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kvm_arch_unregister_noncoherent_dma(dev->kvm); |
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} |
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mutex_unlock(&kv->lock); |
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} |
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static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) |
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{ |
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struct kvm_vfio *kv = dev->private; |
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struct vfio_group *vfio_group; |
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struct kvm_vfio_group *kvg; |
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int32_t __user *argp = (int32_t __user *)(unsigned long)arg; |
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struct fd f; |
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int32_t fd; |
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int ret; |
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switch (attr) { |
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case KVM_DEV_VFIO_GROUP_ADD: |
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if (get_user(fd, argp)) |
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return -EFAULT; |
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f = fdget(fd); |
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if (!f.file) |
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return -EBADF; |
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vfio_group = kvm_vfio_group_get_external_user(f.file); |
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fdput(f); |
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if (IS_ERR(vfio_group)) |
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return PTR_ERR(vfio_group); |
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mutex_lock(&kv->lock); |
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list_for_each_entry(kvg, &kv->group_list, node) { |
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if (kvg->vfio_group == vfio_group) { |
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mutex_unlock(&kv->lock); |
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kvm_vfio_group_put_external_user(vfio_group); |
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return -EEXIST; |
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} |
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} |
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kvg = kzalloc(sizeof(*kvg), GFP_KERNEL_ACCOUNT); |
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if (!kvg) { |
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mutex_unlock(&kv->lock); |
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kvm_vfio_group_put_external_user(vfio_group); |
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return -ENOMEM; |
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} |
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list_add_tail(&kvg->node, &kv->group_list); |
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kvg->vfio_group = vfio_group; |
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kvm_arch_start_assignment(dev->kvm); |
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mutex_unlock(&kv->lock); |
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kvm_vfio_group_set_kvm(vfio_group, dev->kvm); |
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kvm_vfio_update_coherency(dev); |
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return 0; |
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case KVM_DEV_VFIO_GROUP_DEL: |
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if (get_user(fd, argp)) |
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return -EFAULT; |
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f = fdget(fd); |
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if (!f.file) |
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return -EBADF; |
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ret = -ENOENT; |
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mutex_lock(&kv->lock); |
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list_for_each_entry(kvg, &kv->group_list, node) { |
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if (!kvm_vfio_external_group_match_file(kvg->vfio_group, |
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f.file)) |
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continue; |
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list_del(&kvg->node); |
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kvm_arch_end_assignment(dev->kvm); |
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#ifdef CONFIG_SPAPR_TCE_IOMMU |
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kvm_spapr_tce_release_vfio_group(dev->kvm, |
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kvg->vfio_group); |
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#endif |
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kvm_vfio_group_set_kvm(kvg->vfio_group, NULL); |
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kvm_vfio_group_put_external_user(kvg->vfio_group); |
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kfree(kvg); |
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ret = 0; |
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break; |
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} |
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mutex_unlock(&kv->lock); |
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fdput(f); |
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kvm_vfio_update_coherency(dev); |
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return ret; |
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#ifdef CONFIG_SPAPR_TCE_IOMMU |
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case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: { |
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struct kvm_vfio_spapr_tce param; |
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struct kvm_vfio *kv = dev->private; |
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struct vfio_group *vfio_group; |
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struct kvm_vfio_group *kvg; |
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struct fd f; |
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struct iommu_group *grp; |
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if (copy_from_user(¶m, (void __user *)arg, |
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sizeof(struct kvm_vfio_spapr_tce))) |
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return -EFAULT; |
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f = fdget(param.groupfd); |
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if (!f.file) |
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return -EBADF; |
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vfio_group = kvm_vfio_group_get_external_user(f.file); |
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fdput(f); |
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if (IS_ERR(vfio_group)) |
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return PTR_ERR(vfio_group); |
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grp = kvm_vfio_group_get_iommu_group(vfio_group); |
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if (WARN_ON_ONCE(!grp)) { |
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kvm_vfio_group_put_external_user(vfio_group); |
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return -EIO; |
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} |
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ret = -ENOENT; |
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mutex_lock(&kv->lock); |
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list_for_each_entry(kvg, &kv->group_list, node) { |
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if (kvg->vfio_group != vfio_group) |
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continue; |
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ret = kvm_spapr_tce_attach_iommu_group(dev->kvm, |
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param.tablefd, grp); |
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break; |
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} |
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mutex_unlock(&kv->lock); |
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iommu_group_put(grp); |
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kvm_vfio_group_put_external_user(vfio_group); |
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return ret; |
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} |
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#endif /* CONFIG_SPAPR_TCE_IOMMU */ |
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} |
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return -ENXIO; |
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} |
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static int kvm_vfio_set_attr(struct kvm_device *dev, |
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struct kvm_device_attr *attr) |
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{ |
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switch (attr->group) { |
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case KVM_DEV_VFIO_GROUP: |
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return kvm_vfio_set_group(dev, attr->attr, attr->addr); |
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} |
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return -ENXIO; |
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} |
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static int kvm_vfio_has_attr(struct kvm_device *dev, |
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struct kvm_device_attr *attr) |
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{ |
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switch (attr->group) { |
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case KVM_DEV_VFIO_GROUP: |
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switch (attr->attr) { |
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case KVM_DEV_VFIO_GROUP_ADD: |
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case KVM_DEV_VFIO_GROUP_DEL: |
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#ifdef CONFIG_SPAPR_TCE_IOMMU |
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case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: |
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#endif |
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return 0; |
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} |
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break; |
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} |
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return -ENXIO; |
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} |
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static void kvm_vfio_destroy(struct kvm_device *dev) |
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{ |
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struct kvm_vfio *kv = dev->private; |
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struct kvm_vfio_group *kvg, *tmp; |
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list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) { |
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#ifdef CONFIG_SPAPR_TCE_IOMMU |
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kvm_spapr_tce_release_vfio_group(dev->kvm, kvg->vfio_group); |
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#endif |
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kvm_vfio_group_set_kvm(kvg->vfio_group, NULL); |
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kvm_vfio_group_put_external_user(kvg->vfio_group); |
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list_del(&kvg->node); |
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kfree(kvg); |
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kvm_arch_end_assignment(dev->kvm); |
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} |
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kvm_vfio_update_coherency(dev); |
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kfree(kv); |
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kfree(dev); /* alloc by kvm_ioctl_create_device, free by .destroy */ |
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} |
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static int kvm_vfio_create(struct kvm_device *dev, u32 type); |
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static struct kvm_device_ops kvm_vfio_ops = { |
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.name = "kvm-vfio", |
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.create = kvm_vfio_create, |
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.destroy = kvm_vfio_destroy, |
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.set_attr = kvm_vfio_set_attr, |
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.has_attr = kvm_vfio_has_attr, |
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}; |
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static int kvm_vfio_create(struct kvm_device *dev, u32 type) |
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{ |
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struct kvm_device *tmp; |
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struct kvm_vfio *kv; |
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/* Only one VFIO "device" per VM */ |
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list_for_each_entry(tmp, &dev->kvm->devices, vm_node) |
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if (tmp->ops == &kvm_vfio_ops) |
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return -EBUSY; |
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kv = kzalloc(sizeof(*kv), GFP_KERNEL_ACCOUNT); |
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if (!kv) |
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return -ENOMEM; |
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INIT_LIST_HEAD(&kv->group_list); |
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mutex_init(&kv->lock); |
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dev->private = kv; |
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return 0; |
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} |
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int kvm_vfio_ops_init(void) |
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{ |
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return kvm_register_device_ops(&kvm_vfio_ops, KVM_DEV_TYPE_VFIO); |
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} |
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void kvm_vfio_ops_exit(void) |
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{ |
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kvm_unregister_device_ops(KVM_DEV_TYPE_VFIO); |
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}
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