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 */
vp_get_features(struct virtio_device * vdev)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 */
vp_finalize_features(struct virtio_device * vdev)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 */
vp_get(struct virtio_device * vdev,unsigned offset,void * buf,unsigned len)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 */
vp_set(struct virtio_device * vdev,unsigned offset,const void * buf,unsigned len)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 */
vp_get_status(struct virtio_device * vdev)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
vp_set_status(struct virtio_device * vdev,u8 status)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
vp_reset(struct virtio_device * vdev)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
vp_config_vector(struct virtio_pci_device * vp_dev,u16 vector)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
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)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
del_vq(struct virtio_pci_vq_info * info)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 */
virtio_pci_legacy_probe(struct virtio_pci_device * vp_dev)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
virtio_pci_legacy_remove(struct virtio_pci_device * vp_dev)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