1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2023 Intel Corporation. 4 */ 5 #include <linux/vfio.h> 6 #include <linux/iommufd.h> 7 8 #include "vfio.h" 9 10 static dev_t device_devt; 11 12 void vfio_init_device_cdev(struct vfio_device *device) 13 { 14 device->device.devt = MKDEV(MAJOR(device_devt), device->index); 15 cdev_init(&device->cdev, &vfio_device_fops); 16 device->cdev.owner = THIS_MODULE; 17 } 18 19 /* 20 * device access via the fd opened by this function is blocked until 21 * .open_device() is called successfully during BIND_IOMMUFD. 22 */ 23 int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep) 24 { 25 struct vfio_device *device = container_of(inode->i_cdev, 26 struct vfio_device, cdev); 27 struct vfio_device_file *df; 28 int ret; 29 30 /* Paired with the put in vfio_device_fops_release() */ 31 if (!vfio_device_try_get_registration(device)) 32 return -ENODEV; 33 34 df = vfio_allocate_device_file(device); 35 if (IS_ERR(df)) { 36 ret = PTR_ERR(df); 37 goto err_put_registration; 38 } 39 40 filep->private_data = df; 41 42 /* 43 * Use the pseudo fs inode on the device to link all mmaps 44 * to the same address space, allowing us to unmap all vmas 45 * associated to this device using unmap_mapping_range(). 46 */ 47 filep->f_mapping = device->inode->i_mapping; 48 49 return 0; 50 51 err_put_registration: 52 vfio_device_put_registration(device); 53 return ret; 54 } 55 56 static void vfio_df_get_kvm_safe(struct vfio_device_file *df) 57 { 58 spin_lock(&df->kvm_ref_lock); 59 vfio_device_get_kvm_safe(df->device, df->kvm); 60 spin_unlock(&df->kvm_ref_lock); 61 } 62 63 long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, 64 struct vfio_device_bind_iommufd __user *arg) 65 { 66 struct vfio_device *device = df->device; 67 struct vfio_device_bind_iommufd bind; 68 unsigned long minsz; 69 int ret; 70 71 static_assert(__same_type(arg->out_devid, df->devid)); 72 73 minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid); 74 75 if (copy_from_user(&bind, arg, minsz)) 76 return -EFAULT; 77 78 if (bind.argsz < minsz || bind.flags || bind.iommufd < 0) 79 return -EINVAL; 80 81 /* BIND_IOMMUFD only allowed for cdev fds */ 82 if (df->group) 83 return -EINVAL; 84 85 ret = vfio_device_block_group(device); 86 if (ret) 87 return ret; 88 89 mutex_lock(&device->dev_set->lock); 90 /* one device cannot be bound twice */ 91 if (df->access_granted) { 92 ret = -EINVAL; 93 goto out_unlock; 94 } 95 96 df->iommufd = iommufd_ctx_from_fd(bind.iommufd); 97 if (IS_ERR(df->iommufd)) { 98 ret = PTR_ERR(df->iommufd); 99 df->iommufd = NULL; 100 goto out_unlock; 101 } 102 103 /* 104 * Before the device open, get the KVM pointer currently 105 * associated with the device file (if there is) and obtain 106 * a reference. This reference is held until device closed. 107 * Save the pointer in the device for use by drivers. 108 */ 109 vfio_df_get_kvm_safe(df); 110 111 ret = vfio_df_open(df); 112 if (ret) 113 goto out_put_kvm; 114 115 ret = copy_to_user(&arg->out_devid, &df->devid, 116 sizeof(df->devid)) ? -EFAULT : 0; 117 if (ret) 118 goto out_close_device; 119 120 device->cdev_opened = true; 121 /* 122 * Paired with smp_load_acquire() in vfio_device_fops::ioctl/ 123 * read/write/mmap 124 */ 125 smp_store_release(&df->access_granted, true); 126 mutex_unlock(&device->dev_set->lock); 127 return 0; 128 129 out_close_device: 130 vfio_df_close(df); 131 out_put_kvm: 132 vfio_device_put_kvm(device); 133 iommufd_ctx_put(df->iommufd); 134 df->iommufd = NULL; 135 out_unlock: 136 mutex_unlock(&device->dev_set->lock); 137 vfio_device_unblock_group(device); 138 return ret; 139 } 140 141 void vfio_df_unbind_iommufd(struct vfio_device_file *df) 142 { 143 struct vfio_device *device = df->device; 144 145 /* 146 * In the time of close, there is no contention with another one 147 * changing this flag. So read df->access_granted without lock 148 * and no smp_load_acquire() is ok. 149 */ 150 if (!df->access_granted) 151 return; 152 153 mutex_lock(&device->dev_set->lock); 154 vfio_df_close(df); 155 vfio_device_put_kvm(device); 156 iommufd_ctx_put(df->iommufd); 157 device->cdev_opened = false; 158 mutex_unlock(&device->dev_set->lock); 159 vfio_device_unblock_group(device); 160 } 161 162 int vfio_df_ioctl_attach_pt(struct vfio_device_file *df, 163 struct vfio_device_attach_iommufd_pt __user *arg) 164 { 165 struct vfio_device *device = df->device; 166 struct vfio_device_attach_iommufd_pt attach; 167 unsigned long minsz; 168 int ret; 169 170 minsz = offsetofend(struct vfio_device_attach_iommufd_pt, pt_id); 171 172 if (copy_from_user(&attach, arg, minsz)) 173 return -EFAULT; 174 175 if (attach.argsz < minsz || attach.flags) 176 return -EINVAL; 177 178 mutex_lock(&device->dev_set->lock); 179 ret = device->ops->attach_ioas(device, &attach.pt_id); 180 if (ret) 181 goto out_unlock; 182 183 if (copy_to_user(&arg->pt_id, &attach.pt_id, sizeof(attach.pt_id))) { 184 ret = -EFAULT; 185 goto out_detach; 186 } 187 mutex_unlock(&device->dev_set->lock); 188 189 return 0; 190 191 out_detach: 192 device->ops->detach_ioas(device); 193 out_unlock: 194 mutex_unlock(&device->dev_set->lock); 195 return ret; 196 } 197 198 int vfio_df_ioctl_detach_pt(struct vfio_device_file *df, 199 struct vfio_device_detach_iommufd_pt __user *arg) 200 { 201 struct vfio_device *device = df->device; 202 struct vfio_device_detach_iommufd_pt detach; 203 unsigned long minsz; 204 205 minsz = offsetofend(struct vfio_device_detach_iommufd_pt, flags); 206 207 if (copy_from_user(&detach, arg, minsz)) 208 return -EFAULT; 209 210 if (detach.argsz < minsz || detach.flags) 211 return -EINVAL; 212 213 mutex_lock(&device->dev_set->lock); 214 device->ops->detach_ioas(device); 215 mutex_unlock(&device->dev_set->lock); 216 217 return 0; 218 } 219 220 static char *vfio_device_devnode(const struct device *dev, umode_t *mode) 221 { 222 return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev)); 223 } 224 225 int vfio_cdev_init(struct class *device_class) 226 { 227 device_class->devnode = vfio_device_devnode; 228 return alloc_chrdev_region(&device_devt, 0, 229 MINORMASK + 1, "vfio-dev"); 230 } 231 232 void vfio_cdev_cleanup(void) 233 { 234 unregister_chrdev_region(device_devt, MINORMASK + 1); 235 } 236