1 /* 2 * Virtio PCI driver - legacy device support 3 * 4 * This module allows virtio devices to be used over a virtual PCI device. 5 * This can be used with QEMU based VMMs like KVM or Xen. 6 * 7 * Copyright IBM Corp. 2007 8 * Copyright Red Hat, Inc. 2014 9 * 10 * Authors: 11 * Anthony Liguori <aliguori@us.ibm.com> 12 * Rusty Russell <rusty@rustcorp.com.au> 13 * Michael S. Tsirkin <mst@redhat.com> 14 * 15 * This work is licensed under the terms of the GNU GPL, version 2 or later. 16 * See the COPYING file in the top-level directory. 17 * 18 */ 19 20 #include "virtio_pci_common.h" 21 22 /* virtio config->get_features() implementation */ 23 static u64 vp_get_features(struct virtio_device *vdev) 24 { 25 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 26 27 /* When someone needs more than 32 feature bits, we'll need to 28 * steal a bit to indicate that the rest are somewhere else. */ 29 return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES); 30 } 31 32 /* virtio config->finalize_features() implementation */ 33 static int vp_finalize_features(struct virtio_device *vdev) 34 { 35 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 36 37 /* Give virtio_ring a chance to accept features. */ 38 vring_transport_features(vdev); 39 40 /* Make sure we don't have any features > 32 bits! */ 41 BUG_ON((u32)vdev->features != vdev->features); 42 43 /* We only support 32 feature bits. */ 44 iowrite32(vdev->features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES); 45 46 return 0; 47 } 48 49 /* virtio config->get() implementation */ 50 static void vp_get(struct virtio_device *vdev, unsigned offset, 51 void *buf, unsigned len) 52 { 53 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 54 void __iomem *ioaddr = vp_dev->ioaddr + 55 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) + 56 offset; 57 u8 *ptr = buf; 58 int i; 59 60 for (i = 0; i < len; i++) 61 ptr[i] = ioread8(ioaddr + i); 62 } 63 64 /* the config->set() implementation. it's symmetric to the config->get() 65 * implementation */ 66 static void vp_set(struct virtio_device *vdev, unsigned offset, 67 const void *buf, unsigned len) 68 { 69 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 70 void __iomem *ioaddr = vp_dev->ioaddr + 71 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) + 72 offset; 73 const u8 *ptr = buf; 74 int i; 75 76 for (i = 0; i < len; i++) 77 iowrite8(ptr[i], ioaddr + i); 78 } 79 80 /* config->{get,set}_status() implementations */ 81 static u8 vp_get_status(struct virtio_device *vdev) 82 { 83 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 84 return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS); 85 } 86 87 static void vp_set_status(struct virtio_device *vdev, u8 status) 88 { 89 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 90 /* We should never be setting status to 0. */ 91 BUG_ON(status == 0); 92 iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS); 93 } 94 95 static void vp_reset(struct virtio_device *vdev) 96 { 97 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 98 /* 0 status means a reset. */ 99 iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS); 100 /* Flush out the status write, and flush in device writes, 101 * including MSi-X interrupts, if any. */ 102 ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS); 103 /* Flush pending VQ/configuration callbacks. */ 104 vp_synchronize_vectors(vdev); 105 } 106 107 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) 108 { 109 /* Setup the vector used for configuration events */ 110 iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); 111 /* Verify we had enough resources to assign the vector */ 112 /* Will also flush the write out to device */ 113 return ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); 114 } 115 116 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev, 117 struct virtio_pci_vq_info *info, 118 unsigned index, 119 void (*callback)(struct virtqueue *vq), 120 const char *name, 121 bool ctx, 122 u16 msix_vec) 123 { 124 struct virtqueue *vq; 125 u16 num; 126 int err; 127 u64 q_pfn; 128 129 /* Select the queue we're interested in */ 130 iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 131 132 /* Check if queue is either not available or already active. */ 133 num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM); 134 if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN)) 135 return ERR_PTR(-ENOENT); 136 137 info->msix_vector = msix_vec; 138 139 /* create the vring */ 140 vq = vring_create_virtqueue(index, num, 141 VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev, 142 true, false, ctx, 143 vp_notify, callback, name); 144 if (!vq) 145 return ERR_PTR(-ENOMEM); 146 147 q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT; 148 if (q_pfn >> 32) { 149 dev_err(&vp_dev->pci_dev->dev, 150 "platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n", 151 0x1ULL << (32 + PAGE_SHIFT - 30)); 152 err = -E2BIG; 153 goto out_del_vq; 154 } 155 156 /* activate the queue */ 157 iowrite32(q_pfn, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 158 159 vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY; 160 161 if (msix_vec != VIRTIO_MSI_NO_VECTOR) { 162 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 163 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 164 if (msix_vec == VIRTIO_MSI_NO_VECTOR) { 165 err = -EBUSY; 166 goto out_deactivate; 167 } 168 } 169 170 return vq; 171 172 out_deactivate: 173 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 174 out_del_vq: 175 vring_del_virtqueue(vq); 176 return ERR_PTR(err); 177 } 178 179 static void del_vq(struct virtio_pci_vq_info *info) 180 { 181 struct virtqueue *vq = info->vq; 182 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 183 184 iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 185 186 if (vp_dev->msix_enabled) { 187 iowrite16(VIRTIO_MSI_NO_VECTOR, 188 vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 189 /* Flush the write out to device */ 190 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR); 191 } 192 193 /* Select and deactivate the queue */ 194 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 195 196 vring_del_virtqueue(vq); 197 } 198 199 static const struct virtio_config_ops virtio_pci_config_ops = { 200 .get = vp_get, 201 .set = vp_set, 202 .get_status = vp_get_status, 203 .set_status = vp_set_status, 204 .reset = vp_reset, 205 .find_vqs = vp_find_vqs, 206 .del_vqs = vp_del_vqs, 207 .get_features = vp_get_features, 208 .finalize_features = vp_finalize_features, 209 .bus_name = vp_bus_name, 210 .set_vq_affinity = vp_set_vq_affinity, 211 .get_vq_affinity = vp_get_vq_affinity, 212 }; 213 214 /* the PCI probing function */ 215 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) 216 { 217 struct pci_dev *pci_dev = vp_dev->pci_dev; 218 int rc; 219 220 /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */ 221 if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f) 222 return -ENODEV; 223 224 if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) { 225 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n", 226 VIRTIO_PCI_ABI_VERSION, pci_dev->revision); 227 return -ENODEV; 228 } 229 230 rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64)); 231 if (rc) { 232 rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32)); 233 } else { 234 /* 235 * The virtio ring base address is expressed as a 32-bit PFN, 236 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT. 237 */ 238 dma_set_coherent_mask(&pci_dev->dev, 239 DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT)); 240 } 241 242 if (rc) 243 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n"); 244 245 rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy"); 246 if (rc) 247 return rc; 248 249 rc = -ENOMEM; 250 vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0); 251 if (!vp_dev->ioaddr) 252 goto err_iomap; 253 254 vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR; 255 256 /* we use the subsystem vendor/device id as the virtio vendor/device 257 * id. this allows us to use the same PCI vendor/device id for all 258 * virtio devices and to identify the particular virtio driver by 259 * the subsystem ids */ 260 vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor; 261 vp_dev->vdev.id.device = pci_dev->subsystem_device; 262 263 vp_dev->vdev.config = &virtio_pci_config_ops; 264 265 vp_dev->config_vector = vp_config_vector; 266 vp_dev->setup_vq = setup_vq; 267 vp_dev->del_vq = del_vq; 268 269 return 0; 270 271 err_iomap: 272 pci_release_region(pci_dev, 0); 273 return rc; 274 } 275 276 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev) 277 { 278 struct pci_dev *pci_dev = vp_dev->pci_dev; 279 280 pci_iounmap(pci_dev, vp_dev->ioaddr); 281 pci_release_region(pci_dev, 0); 282 } 283