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; 125 126 /* Select the queue we're interested in */ 127 iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 128 129 /* Check if queue is either not available or already active. */ 130 num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM); 131 if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN)) 132 return ERR_PTR(-ENOENT); 133 134 info->msix_vector = msix_vec; 135 136 /* create the vring */ 137 vq = vring_create_virtqueue(index, num, 138 VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev, 139 true, false, ctx, 140 vp_notify, callback, name); 141 if (!vq) 142 return ERR_PTR(-ENOMEM); 143 144 /* activate the queue */ 145 iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT, 146 vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 147 148 vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY; 149 150 if (msix_vec != VIRTIO_MSI_NO_VECTOR) { 151 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 152 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 153 if (msix_vec == VIRTIO_MSI_NO_VECTOR) { 154 err = -EBUSY; 155 goto out_deactivate; 156 } 157 } 158 159 return vq; 160 161 out_deactivate: 162 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 163 vring_del_virtqueue(vq); 164 return ERR_PTR(err); 165 } 166 167 static void del_vq(struct virtio_pci_vq_info *info) 168 { 169 struct virtqueue *vq = info->vq; 170 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 171 172 iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 173 174 if (vp_dev->msix_enabled) { 175 iowrite16(VIRTIO_MSI_NO_VECTOR, 176 vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 177 /* Flush the write out to device */ 178 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR); 179 } 180 181 /* Select and deactivate the queue */ 182 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 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 .get_features = vp_get_features, 196 .finalize_features = vp_finalize_features, 197 .bus_name = vp_bus_name, 198 .set_vq_affinity = vp_set_vq_affinity, 199 .get_vq_affinity = vp_get_vq_affinity, 200 }; 201 202 /* the PCI probing function */ 203 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) 204 { 205 struct pci_dev *pci_dev = vp_dev->pci_dev; 206 int rc; 207 208 /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */ 209 if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f) 210 return -ENODEV; 211 212 if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) { 213 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n", 214 VIRTIO_PCI_ABI_VERSION, pci_dev->revision); 215 return -ENODEV; 216 } 217 218 rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64)); 219 if (rc) { 220 rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32)); 221 } else { 222 /* 223 * The virtio ring base address is expressed as a 32-bit PFN, 224 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT. 225 */ 226 dma_set_coherent_mask(&pci_dev->dev, 227 DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT)); 228 } 229 230 if (rc) 231 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n"); 232 233 rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy"); 234 if (rc) 235 return rc; 236 237 rc = -ENOMEM; 238 vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0); 239 if (!vp_dev->ioaddr) 240 goto err_iomap; 241 242 vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR; 243 244 /* we use the subsystem vendor/device id as the virtio vendor/device 245 * id. this allows us to use the same PCI vendor/device id for all 246 * virtio devices and to identify the particular virtio driver by 247 * the subsystem ids */ 248 vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor; 249 vp_dev->vdev.id.device = pci_dev->subsystem_device; 250 251 vp_dev->vdev.config = &virtio_pci_config_ops; 252 253 vp_dev->config_vector = vp_config_vector; 254 vp_dev->setup_vq = setup_vq; 255 vp_dev->del_vq = del_vq; 256 257 return 0; 258 259 err_iomap: 260 pci_release_region(pci_dev, 0); 261 return rc; 262 } 263 264 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev) 265 { 266 struct pci_dev *pci_dev = vp_dev->pci_dev; 267 268 pci_iounmap(pci_dev, vp_dev->ioaddr); 269 pci_release_region(pci_dev, 0); 270 } 271