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 unsigned index, 116 void (*callback)(struct virtqueue *vq), 117 const char *name, 118 u16 msix_vec) 119 { 120 struct virtqueue *vq; 121 u16 num; 122 int err; 123 124 /* Select the queue we're interested in */ 125 iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 126 127 /* Check if queue is either not available or already active. */ 128 num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM); 129 if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN)) 130 return ERR_PTR(-ENOENT); 131 132 /* create the vring */ 133 vq = vring_create_virtqueue(index, num, 134 VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev, 135 true, false, vp_notify, callback, name); 136 if (!vq) 137 return ERR_PTR(-ENOMEM); 138 139 /* activate the queue */ 140 iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT, 141 vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 142 143 vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY; 144 145 if (msix_vec != VIRTIO_MSI_NO_VECTOR) { 146 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 147 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 148 if (msix_vec == VIRTIO_MSI_NO_VECTOR) { 149 err = -EBUSY; 150 goto out_deactivate; 151 } 152 } 153 154 return vq; 155 156 out_deactivate: 157 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 158 vring_del_virtqueue(vq); 159 return ERR_PTR(err); 160 } 161 162 static void del_vq(struct virtqueue *vq) 163 { 164 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 165 166 iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 167 168 if (vp_dev->pci_dev->msix_enabled) { 169 iowrite16(VIRTIO_MSI_NO_VECTOR, 170 vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 171 /* Flush the write out to device */ 172 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR); 173 } 174 175 /* Select and deactivate the queue */ 176 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 177 178 vring_del_virtqueue(vq); 179 } 180 181 static const struct virtio_config_ops virtio_pci_config_ops = { 182 .get = vp_get, 183 .set = vp_set, 184 .get_status = vp_get_status, 185 .set_status = vp_set_status, 186 .reset = vp_reset, 187 .find_vqs = vp_find_vqs, 188 .del_vqs = vp_del_vqs, 189 .get_features = vp_get_features, 190 .finalize_features = vp_finalize_features, 191 .bus_name = vp_bus_name, 192 .set_vq_affinity = vp_set_vq_affinity, 193 .get_vq_affinity = vp_get_vq_affinity, 194 }; 195 196 /* the PCI probing function */ 197 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) 198 { 199 struct pci_dev *pci_dev = vp_dev->pci_dev; 200 int rc; 201 202 /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */ 203 if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f) 204 return -ENODEV; 205 206 if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) { 207 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n", 208 VIRTIO_PCI_ABI_VERSION, pci_dev->revision); 209 return -ENODEV; 210 } 211 212 rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64)); 213 if (rc) { 214 rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32)); 215 } else { 216 /* 217 * The virtio ring base address is expressed as a 32-bit PFN, 218 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT. 219 */ 220 dma_set_coherent_mask(&pci_dev->dev, 221 DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT)); 222 } 223 224 if (rc) 225 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n"); 226 227 rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy"); 228 if (rc) 229 return rc; 230 231 rc = -ENOMEM; 232 vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0); 233 if (!vp_dev->ioaddr) 234 goto err_iomap; 235 236 vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR; 237 238 /* we use the subsystem vendor/device id as the virtio vendor/device 239 * id. this allows us to use the same PCI vendor/device id for all 240 * virtio devices and to identify the particular virtio driver by 241 * the subsystem ids */ 242 vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor; 243 vp_dev->vdev.id.device = pci_dev->subsystem_device; 244 245 vp_dev->vdev.config = &virtio_pci_config_ops; 246 247 vp_dev->config_vector = vp_config_vector; 248 vp_dev->setup_vq = setup_vq; 249 vp_dev->del_vq = del_vq; 250 251 return 0; 252 253 err_iomap: 254 pci_release_region(pci_dev, 0); 255 return rc; 256 } 257 258 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev) 259 { 260 struct pci_dev *pci_dev = vp_dev->pci_dev; 261 262 pci_iounmap(pci_dev, vp_dev->ioaddr); 263 pci_release_region(pci_dev, 0); 264 } 265