1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Virtio PCI driver - legacy device support 4 * 5 * This module allows virtio devices to be used over a virtual PCI device. 6 * This can be used with QEMU based VMMs like KVM or Xen. 7 * 8 * Copyright IBM Corp. 2007 9 * Copyright Red Hat, Inc. 2014 10 * 11 * Authors: 12 * Anthony Liguori <aliguori@us.ibm.com> 13 * Rusty Russell <rusty@rustcorp.com.au> 14 * Michael S. Tsirkin <mst@redhat.com> 15 */ 16 17 #include "virtio_pci_common.h" 18 19 /* virtio config->get_features() implementation */ 20 static u64 vp_get_features(struct virtio_device *vdev) 21 { 22 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 23 24 /* When someone needs more than 32 feature bits, we'll need to 25 * steal a bit to indicate that the rest are somewhere else. */ 26 return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES); 27 } 28 29 /* virtio config->finalize_features() implementation */ 30 static int vp_finalize_features(struct virtio_device *vdev) 31 { 32 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 33 34 /* Give virtio_ring a chance to accept features. */ 35 vring_transport_features(vdev); 36 37 /* Make sure we don't have any features > 32 bits! */ 38 BUG_ON((u32)vdev->features != vdev->features); 39 40 /* We only support 32 feature bits. */ 41 iowrite32(vdev->features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES); 42 43 return 0; 44 } 45 46 /* virtio config->get() implementation */ 47 static void vp_get(struct virtio_device *vdev, unsigned offset, 48 void *buf, unsigned len) 49 { 50 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 51 void __iomem *ioaddr = vp_dev->ioaddr + 52 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) + 53 offset; 54 u8 *ptr = buf; 55 int i; 56 57 for (i = 0; i < len; i++) 58 ptr[i] = ioread8(ioaddr + i); 59 } 60 61 /* the config->set() implementation. it's symmetric to the config->get() 62 * implementation */ 63 static void vp_set(struct virtio_device *vdev, unsigned offset, 64 const void *buf, unsigned len) 65 { 66 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 67 void __iomem *ioaddr = vp_dev->ioaddr + 68 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) + 69 offset; 70 const u8 *ptr = buf; 71 int i; 72 73 for (i = 0; i < len; i++) 74 iowrite8(ptr[i], ioaddr + i); 75 } 76 77 /* config->{get,set}_status() implementations */ 78 static u8 vp_get_status(struct virtio_device *vdev) 79 { 80 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 81 return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS); 82 } 83 84 static void vp_set_status(struct virtio_device *vdev, u8 status) 85 { 86 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 87 /* We should never be setting status to 0. */ 88 BUG_ON(status == 0); 89 iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS); 90 } 91 92 static void vp_reset(struct virtio_device *vdev) 93 { 94 struct virtio_pci_device *vp_dev = to_vp_device(vdev); 95 /* 0 status means a reset. */ 96 iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS); 97 /* Flush out the status write, and flush in device writes, 98 * including MSi-X interrupts, if any. */ 99 ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS); 100 /* Flush pending VQ/configuration callbacks. */ 101 vp_synchronize_vectors(vdev); 102 } 103 104 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) 105 { 106 /* Setup the vector used for configuration events */ 107 iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); 108 /* Verify we had enough resources to assign the vector */ 109 /* Will also flush the write out to device */ 110 return ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); 111 } 112 113 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev, 114 struct virtio_pci_vq_info *info, 115 unsigned index, 116 void (*callback)(struct virtqueue *vq), 117 const char *name, 118 bool ctx, 119 u16 msix_vec) 120 { 121 struct virtqueue *vq; 122 u16 num; 123 int err; 124 u64 q_pfn; 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 q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT; 145 if (q_pfn >> 32) { 146 dev_err(&vp_dev->pci_dev->dev, 147 "platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n", 148 0x1ULL << (32 + PAGE_SHIFT - 30)); 149 err = -E2BIG; 150 goto out_del_vq; 151 } 152 153 /* activate the queue */ 154 iowrite32(q_pfn, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 155 156 vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY; 157 158 if (msix_vec != VIRTIO_MSI_NO_VECTOR) { 159 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 160 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 161 if (msix_vec == VIRTIO_MSI_NO_VECTOR) { 162 err = -EBUSY; 163 goto out_deactivate; 164 } 165 } 166 167 return vq; 168 169 out_deactivate: 170 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 171 out_del_vq: 172 vring_del_virtqueue(vq); 173 return ERR_PTR(err); 174 } 175 176 static void del_vq(struct virtio_pci_vq_info *info) 177 { 178 struct virtqueue *vq = info->vq; 179 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); 180 181 iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); 182 183 if (vp_dev->msix_enabled) { 184 iowrite16(VIRTIO_MSI_NO_VECTOR, 185 vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); 186 /* Flush the write out to device */ 187 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR); 188 } 189 190 /* Select and deactivate the queue */ 191 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); 192 193 vring_del_virtqueue(vq); 194 } 195 196 static const struct virtio_config_ops virtio_pci_config_ops = { 197 .get = vp_get, 198 .set = vp_set, 199 .get_status = vp_get_status, 200 .set_status = vp_set_status, 201 .reset = vp_reset, 202 .find_vqs = vp_find_vqs, 203 .del_vqs = vp_del_vqs, 204 .get_features = vp_get_features, 205 .finalize_features = vp_finalize_features, 206 .bus_name = vp_bus_name, 207 .set_vq_affinity = vp_set_vq_affinity, 208 .get_vq_affinity = vp_get_vq_affinity, 209 }; 210 211 /* the PCI probing function */ 212 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) 213 { 214 struct pci_dev *pci_dev = vp_dev->pci_dev; 215 int rc; 216 217 /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */ 218 if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f) 219 return -ENODEV; 220 221 if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) { 222 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n", 223 VIRTIO_PCI_ABI_VERSION, pci_dev->revision); 224 return -ENODEV; 225 } 226 227 rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64)); 228 if (rc) { 229 rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32)); 230 } else { 231 /* 232 * The virtio ring base address is expressed as a 32-bit PFN, 233 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT. 234 */ 235 dma_set_coherent_mask(&pci_dev->dev, 236 DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT)); 237 } 238 239 if (rc) 240 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n"); 241 242 rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy"); 243 if (rc) 244 return rc; 245 246 rc = -ENOMEM; 247 vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0); 248 if (!vp_dev->ioaddr) 249 goto err_iomap; 250 251 vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR; 252 253 /* we use the subsystem vendor/device id as the virtio vendor/device 254 * id. this allows us to use the same PCI vendor/device id for all 255 * virtio devices and to identify the particular virtio driver by 256 * the subsystem ids */ 257 vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor; 258 vp_dev->vdev.id.device = pci_dev->subsystem_device; 259 260 vp_dev->vdev.config = &virtio_pci_config_ops; 261 262 vp_dev->config_vector = vp_config_vector; 263 vp_dev->setup_vq = setup_vq; 264 vp_dev->del_vq = del_vq; 265 266 return 0; 267 268 err_iomap: 269 pci_release_region(pci_dev, 0); 270 return rc; 271 } 272 273 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev) 274 { 275 struct pci_dev *pci_dev = vp_dev->pci_dev; 276 277 pci_iounmap(pci_dev, vp_dev->ioaddr); 278 pci_release_region(pci_dev, 0); 279 } 280