1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Virtio PCI driver - legacy device support 4 * 5 * This module allows virtio devices to be used over a virtual PCI device. 6 * This can be used with QEMU based VMMs like KVM or Xen. 7 * 8 * Copyright IBM Corp. 2007 9 * Copyright Red Hat, Inc. 2014 10 * 11 * Authors: 12 * Anthony Liguori <aliguori@us.ibm.com> 13 * Rusty Russell <rusty@rustcorp.com.au> 14 * Michael S. Tsirkin <mst@redhat.com> 15 */ 16 17 #include "linux/virtio_pci_legacy.h" 18 #include "virtio_pci_common.h" 19 20 /* virtio config->get_features() implementation */ 21 static u64 vp_get_features(struct virtio_device *vdev) 22 { 23 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 24 25 /* When someone needs more than 32 feature bits, we'll need to 26 * steal a bit to indicate that the rest are somewhere else. */ 27 return vp_legacy_get_features(&vp_dev->ldev); 28 } 29 30 /* virtio config->finalize_features() implementation */ 31 static int vp_finalize_features(struct virtio_device *vdev) 32 { 33 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 34 35 /* Give virtio_ring a chance to accept features. */ 36 vring_transport_features(vdev); 37 38 /* Make sure we don't have any features > 32 bits! */ 39 BUG_ON((u32)vdev->features != vdev->features); 40 41 /* We only support 32 feature bits. */ 42 vp_legacy_set_features(&vp_dev->ldev, vdev->features); 43 44 return 0; 45 } 46 47 /* virtio config->get() implementation */ 48 static void vp_get(struct virtio_device *vdev, unsigned int offset, 49 void *buf, unsigned int len) 50 { 51 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 52 void __iomem *ioaddr = vp_dev->ldev.ioaddr + 53 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) + 54 offset; 55 u8 *ptr = buf; 56 int i; 57 58 for (i = 0; i < len; i++) 59 ptr[i] = ioread8(ioaddr + i); 60 } 61 62 /* the config->set() implementation. it's symmetric to the config->get() 63 * implementation */ 64 static void vp_set(struct virtio_device *vdev, unsigned int offset, 65 const void *buf, unsigned int len) 66 { 67 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 68 void __iomem *ioaddr = vp_dev->ldev.ioaddr + 69 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) + 70 offset; 71 const u8 *ptr = buf; 72 int i; 73 74 for (i = 0; i < len; i++) 75 iowrite8(ptr[i], ioaddr + i); 76 } 77 78 /* config->{get,set}_status() implementations */ 79 static u8 vp_get_status(struct virtio_device *vdev) 80 { 81 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 82 return vp_legacy_get_status(&vp_dev->ldev); 83 } 84 85 static void vp_set_status(struct virtio_device *vdev, u8 status) 86 { 87 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 88 /* We should never be setting status to 0. */ 89 BUG_ON(status == 0); 90 vp_legacy_set_status(&vp_dev->ldev, status); 91 } 92 93 static void vp_reset(struct virtio_device *vdev) 94 { 95 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 96 /* 0 status means a reset. */ 97 vp_legacy_set_status(&vp_dev->ldev, 0); 98 /* Flush out the status write, and flush in device writes, 99 * including MSi-X interrupts, if any. */ 100 vp_legacy_get_status(&vp_dev->ldev); 101 /* Flush pending VQ/configuration callbacks. */ 102 vp_synchronize_vectors(vdev); 103 } 104 105 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) 106 { 107 return vp_legacy_config_vector(&vp_dev->ldev, vector); 108 } 109 110 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev, 111 struct virtio_pci_vq_info *info, 112 unsigned int index, 113 void (*callback)(struct virtqueue *vq), 114 const char *name, 115 bool ctx, 116 u16 msix_vec) 117 { 118 struct virtqueue *vq; 119 u16 num; 120 int err; 121 u64 q_pfn; 122 123 /* Check if queue is either not available or already active. */ 124 num = vp_legacy_get_queue_size(&vp_dev->ldev, index); 125 if (!num || vp_legacy_get_queue_enable(&vp_dev->ldev, index)) 126 return ERR_PTR(-ENOENT); 127 128 info->msix_vector = msix_vec; 129 130 /* create the vring */ 131 vq = vring_create_virtqueue(index, num, 132 VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev, 133 true, false, ctx, 134 vp_notify, callback, name); 135 if (!vq) 136 return ERR_PTR(-ENOMEM); 137 138 q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT; 139 if (q_pfn >> 32) { 140 dev_err(&vp_dev->pci_dev->dev, 141 "platform bug: legacy virtio-pci must not be used with RAM above 0x%llxGB\n", 142 0x1ULL << (32 + PAGE_SHIFT - 30)); 143 err = -E2BIG; 144 goto out_del_vq; 145 } 146 147 /* activate the queue */ 148 vp_legacy_set_queue_address(&vp_dev->ldev, index, q_pfn); 149 150 vq->priv = (void __force *)vp_dev->ldev.ioaddr + VIRTIO_PCI_QUEUE_NOTIFY; 151 152 if (msix_vec != VIRTIO_MSI_NO_VECTOR) { 153 msix_vec = vp_legacy_queue_vector(&vp_dev->ldev, index, msix_vec); 154 if (msix_vec == VIRTIO_MSI_NO_VECTOR) { 155 err = -EBUSY; 156 goto out_deactivate; 157 } 158 } 159 160 return vq; 161 162 out_deactivate: 163 vp_legacy_set_queue_address(&vp_dev->ldev, index, 0); 164 out_del_vq: 165 vring_del_virtqueue(vq); 166 return ERR_PTR(err); 167 } 168 169 static void del_vq(struct virtio_pci_vq_info *info) 170 { 171 struct virtqueue *vq = info->vq; 172 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 173 174 if (vp_dev->msix_enabled) { 175 vp_legacy_queue_vector(&vp_dev->ldev, vq->index, 176 VIRTIO_MSI_NO_VECTOR); 177 /* Flush the write out to device */ 178 ioread8(vp_dev->ldev.ioaddr + VIRTIO_PCI_ISR); 179 } 180 181 /* Select and deactivate the queue */ 182 vp_legacy_set_queue_address(&vp_dev->ldev, vq->index, 0); 183 184 vring_del_virtqueue(vq); 185 } 186 187 static const struct virtio_config_ops virtio_pci_config_ops = { 188 .get = vp_get, 189 .set = vp_set, 190 .get_status = vp_get_status, 191 .set_status = vp_set_status, 192 .reset = vp_reset, 193 .find_vqs = vp_find_vqs, 194 .del_vqs = vp_del_vqs, 195 .synchronize_cbs = vp_synchronize_vectors, 196 .get_features = vp_get_features, 197 .finalize_features = vp_finalize_features, 198 .bus_name = vp_bus_name, 199 .set_vq_affinity = vp_set_vq_affinity, 200 .get_vq_affinity = vp_get_vq_affinity, 201 }; 202 203 /* the PCI probing function */ 204 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) 205 { 206 struct virtio_pci_legacy_device *ldev = &vp_dev->ldev; 207 struct pci_dev *pci_dev = vp_dev->pci_dev; 208 int rc; 209 210 ldev->pci_dev = pci_dev; 211 212 rc = vp_legacy_probe(ldev); 213 if (rc) 214 return rc; 215 216 vp_dev->isr = ldev->isr; 217 vp_dev->vdev.id = ldev->id; 218 219 vp_dev->vdev.config = &virtio_pci_config_ops; 220 221 vp_dev->config_vector = vp_config_vector; 222 vp_dev->setup_vq = setup_vq; 223 vp_dev->del_vq = del_vq; 224 225 return 0; 226 } 227 228 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev) 229 { 230 struct virtio_pci_legacy_device *ldev = &vp_dev->ldev; 231 232 vp_legacy_remove(ldev); 233 } 234