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 */
vp_get_features(struct virtio_device * vdev)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 */
vp_finalize_features(struct virtio_device * vdev)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 */
vp_get(struct virtio_device * vdev,unsigned offset,void * buf,unsigned len)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 */
vp_set(struct virtio_device * vdev,unsigned offset,const void * buf,unsigned len)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 */
vp_get_status(struct virtio_device * vdev)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
vp_set_status(struct virtio_device * vdev,u8 status)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
vp_reset(struct virtio_device * vdev)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
vp_config_vector(struct virtio_pci_device * vp_dev,u16 vector)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
setup_vq(struct virtio_pci_device * vp_dev,struct virtio_pci_vq_info * info,unsigned index,void (* callback)(struct virtqueue * vq),const char * name,bool ctx,u16 msix_vec)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
del_vq(struct virtio_pci_vq_info * info)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 */
virtio_pci_legacy_probe(struct virtio_pci_device * vp_dev)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
virtio_pci_legacy_remove(struct virtio_pci_device * vp_dev)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