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 u16 msix_vec) 120 { 121 struct virtqueue *vq; 122 u16 num; 123 int err; 124 125 /* Select the queue we're interested in */ 126 iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 127 128 /* Check if queue is either not available or already active. */ 129 num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM); 130 if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN)) 131 return ERR_PTR(-ENOENT); 132 133 info->msix_vector = msix_vec; 134 135 /* create the vring */ 136 vq = vring_create_virtqueue(index, num, 137 VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev, 138 true, false, vp_notify, callback, name); 139 if (!vq) 140 return ERR_PTR(-ENOMEM); 141 142 /* activate the queue */ 143 iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT, 144 vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 145 146 vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY; 147 148 if (msix_vec != VIRTIO_MSI_NO_VECTOR) { 149 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 150 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 151 if (msix_vec == VIRTIO_MSI_NO_VECTOR) { 152 err = -EBUSY; 153 goto out_deactivate; 154 } 155 } 156 157 return vq; 158 159 out_deactivate: 160 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 161 vring_del_virtqueue(vq); 162 return ERR_PTR(err); 163 } 164 165 static void del_vq(struct virtio_pci_vq_info *info) 166 { 167 struct virtqueue *vq = info->vq; 168 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 169 170 iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 171 172 if (vp_dev->msix_enabled) { 173 iowrite16(VIRTIO_MSI_NO_VECTOR, 174 vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 175 /* Flush the write out to device */ 176 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR); 177 } 178 179 /* Select and deactivate the queue */ 180 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 181 182 vring_del_virtqueue(vq); 183 } 184 185 static const struct virtio_config_ops virtio_pci_config_ops = { 186 .get = vp_get, 187 .set = vp_set, 188 .get_status = vp_get_status, 189 .set_status = vp_set_status, 190 .reset = vp_reset, 191 .find_vqs = vp_find_vqs, 192 .del_vqs = vp_del_vqs, 193 .get_features = vp_get_features, 194 .finalize_features = vp_finalize_features, 195 .bus_name = vp_bus_name, 196 .set_vq_affinity = vp_set_vq_affinity, 197 .get_vq_affinity = vp_get_vq_affinity, 198 }; 199 200 /* the PCI probing function */ 201 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) 202 { 203 struct pci_dev *pci_dev = vp_dev->pci_dev; 204 int rc; 205 206 /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */ 207 if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f) 208 return -ENODEV; 209 210 if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) { 211 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n", 212 VIRTIO_PCI_ABI_VERSION, pci_dev->revision); 213 return -ENODEV; 214 } 215 216 rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64)); 217 if (rc) { 218 rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32)); 219 } else { 220 /* 221 * The virtio ring base address is expressed as a 32-bit PFN, 222 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT. 223 */ 224 dma_set_coherent_mask(&pci_dev->dev, 225 DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT)); 226 } 227 228 if (rc) 229 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n"); 230 231 rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy"); 232 if (rc) 233 return rc; 234 235 rc = -ENOMEM; 236 vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0); 237 if (!vp_dev->ioaddr) 238 goto err_iomap; 239 240 vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR; 241 242 /* we use the subsystem vendor/device id as the virtio vendor/device 243 * id. this allows us to use the same PCI vendor/device id for all 244 * virtio devices and to identify the particular virtio driver by 245 * the subsystem ids */ 246 vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor; 247 vp_dev->vdev.id.device = pci_dev->subsystem_device; 248 249 vp_dev->vdev.config = &virtio_pci_config_ops; 250 251 vp_dev->config_vector = vp_config_vector; 252 vp_dev->setup_vq = setup_vq; 253 vp_dev->del_vq = del_vq; 254 255 return 0; 256 257 err_iomap: 258 pci_release_region(pci_dev, 0); 259 return rc; 260 } 261 262 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev) 263 { 264 struct pci_dev *pci_dev = vp_dev->pci_dev; 265 266 pci_iounmap(pci_dev, vp_dev->ioaddr); 267 pci_release_region(pci_dev, 0); 268 } 269