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(vp_dev) + offset; 56 u8 *ptr = buf; 57 int i; 58 59 for (i = 0; i < len; i++) 60 ptr[i] = ioread8(ioaddr + i); 61 } 62 63 /* the config->set() implementation. it's symmetric to the config->get() 64 * implementation */ 65 static void vp_set(struct virtio_device *vdev, unsigned offset, 66 const void *buf, unsigned len) 67 { 68 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 69 void __iomem *ioaddr = vp_dev->ioaddr + 70 VIRTIO_PCI_CONFIG(vp_dev) + 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 ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS); 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 iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_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 iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS); 98 /* Flush out the status write, and flush in device writes, 99 * including MSi-X interrupts, if any. */ 100 ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS); 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 /* Setup the vector used for configuration events */ 108 iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); 109 /* Verify we had enough resources to assign the vector */ 110 /* Will also flush the write out to device */ 111 return ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); 112 } 113 114 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev, 115 struct virtio_pci_vq_info *info, 116 unsigned index, 117 void (*callback)(struct virtqueue *vq), 118 const char *name, 119 bool ctx, 120 u16 msix_vec) 121 { 122 struct virtqueue *vq; 123 u16 num; 124 int err; 125 u64 q_pfn; 126 127 /* Select the queue we're interested in */ 128 iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 129 130 /* Check if queue is either not available or already active. */ 131 num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM); 132 if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN)) 133 return ERR_PTR(-ENOENT); 134 135 info->msix_vector = msix_vec; 136 137 /* create the vring */ 138 vq = vring_create_virtqueue(index, num, 139 VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev, 140 true, false, ctx, 141 vp_notify, callback, name); 142 if (!vq) 143 return ERR_PTR(-ENOMEM); 144 145 q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT; 146 if (q_pfn >> 32) { 147 dev_err(&vp_dev->pci_dev->dev, 148 "platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n", 149 0x1ULL << (32 + PAGE_SHIFT - 30)); 150 err = -E2BIG; 151 goto out_del_vq; 152 } 153 154 /* activate the queue */ 155 iowrite32(q_pfn, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 156 157 vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY; 158 159 if (msix_vec != VIRTIO_MSI_NO_VECTOR) { 160 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 161 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 162 if (msix_vec == VIRTIO_MSI_NO_VECTOR) { 163 err = -EBUSY; 164 goto out_deactivate; 165 } 166 } 167 168 return vq; 169 170 out_deactivate: 171 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 172 out_del_vq: 173 vring_del_virtqueue(vq); 174 return ERR_PTR(err); 175 } 176 177 static void del_vq(struct virtio_pci_vq_info *info) 178 { 179 struct virtqueue *vq = info->vq; 180 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 181 182 iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 183 184 if (vp_dev->msix_enabled) { 185 iowrite16(VIRTIO_MSI_NO_VECTOR, 186 vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 187 /* Flush the write out to device */ 188 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR); 189 } 190 191 /* Select and deactivate the queue */ 192 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 193 194 vring_del_virtqueue(vq); 195 } 196 197 static const struct virtio_config_ops virtio_pci_config_ops = { 198 .get = vp_get, 199 .set = vp_set, 200 .get_status = vp_get_status, 201 .set_status = vp_set_status, 202 .reset = vp_reset, 203 .find_vqs = vp_find_vqs, 204 .del_vqs = vp_del_vqs, 205 .get_features = vp_get_features, 206 .finalize_features = vp_finalize_features, 207 .bus_name = vp_bus_name, 208 .set_vq_affinity = vp_set_vq_affinity, 209 .get_vq_affinity = vp_get_vq_affinity, 210 }; 211 212 /* the PCI probing function */ 213 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) 214 { 215 struct pci_dev *pci_dev = vp_dev->pci_dev; 216 int rc; 217 218 /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */ 219 if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f) 220 return -ENODEV; 221 222 if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) { 223 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n", 224 VIRTIO_PCI_ABI_VERSION, pci_dev->revision); 225 return -ENODEV; 226 } 227 228 rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64)); 229 if (rc) { 230 rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32)); 231 } else { 232 /* 233 * The virtio ring base address is expressed as a 32-bit PFN, 234 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT. 235 */ 236 dma_set_coherent_mask(&pci_dev->dev, 237 DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT)); 238 } 239 240 if (rc) 241 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n"); 242 243 rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy"); 244 if (rc) 245 return rc; 246 247 rc = -ENOMEM; 248 vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0); 249 if (!vp_dev->ioaddr) 250 goto err_iomap; 251 252 vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR; 253 254 /* we use the subsystem vendor/device id as the virtio vendor/device 255 * id. this allows us to use the same PCI vendor/device id for all 256 * virtio devices and to identify the particular virtio driver by 257 * the subsystem ids */ 258 vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor; 259 vp_dev->vdev.id.device = pci_dev->subsystem_device; 260 261 vp_dev->vdev.config = &virtio_pci_config_ops; 262 263 vp_dev->config_vector = vp_config_vector; 264 vp_dev->setup_vq = setup_vq; 265 vp_dev->del_vq = del_vq; 266 267 return 0; 268 269 err_iomap: 270 pci_release_region(pci_dev, 0); 271 return rc; 272 } 273 274 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev) 275 { 276 struct pci_dev *pci_dev = vp_dev->pci_dev; 277 278 pci_iounmap(pci_dev, vp_dev->ioaddr); 279 pci_release_region(pci_dev, 0); 280 } 281