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 "linux/virtio_pci_legacy.h"
18#include "virtio_pci_common.h"
19
20/* virtio config->get_features() implementation */
21static u64 vp_get_features(struct virtio_device *vdev)
22{
23 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
24
25 /* When someone needs more than 32 feature bits, we'll need to
26 * steal a bit to indicate that the rest are somewhere else. */
27 return vp_legacy_get_features(ldev: &vp_dev->ldev);
28}
29
30/* virtio config->finalize_features() implementation */
31static int vp_finalize_features(struct virtio_device *vdev)
32{
33 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
34
35 /* Give virtio_ring a chance to accept features. */
36 vring_transport_features(vdev);
37
38 /* Make sure we don't have any features > 32 bits! */
39 BUG_ON((u32)vdev->features != vdev->features);
40
41 /* We only support 32 feature bits. */
42 vp_legacy_set_features(ldev: &vp_dev->ldev, features: vdev->features);
43
44 return 0;
45}
46
47/* virtio config->get() implementation */
48static void vp_get(struct virtio_device *vdev, unsigned int offset,
49 void *buf, unsigned int len)
50{
51 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
52 void __iomem *ioaddr = vp_dev->ldev.ioaddr +
53 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +
54 offset;
55 u8 *ptr = buf;
56 int i;
57
58 for (i = 0; i < len; i++)
59 ptr[i] = ioread8(ioaddr + i);
60}
61
62/* the config->set() implementation. it's symmetric to the config->get()
63 * implementation */
64static void vp_set(struct virtio_device *vdev, unsigned int offset,
65 const void *buf, unsigned int len)
66{
67 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
68 void __iomem *ioaddr = vp_dev->ldev.ioaddr +
69 VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +
70 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 */
79static u8 vp_get_status(struct virtio_device *vdev)
80{
81 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
82 return vp_legacy_get_status(ldev: &vp_dev->ldev);
83}
84
85static 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 vp_legacy_set_status(ldev: &vp_dev->ldev, status);
91}
92
93static 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 vp_legacy_set_status(ldev: &vp_dev->ldev, status: 0);
98 /* Flush out the status write, and flush in device writes,
99 * including MSi-X interrupts, if any. */
100 vp_legacy_get_status(ldev: &vp_dev->ldev);
101 /* Flush pending VQ/configuration callbacks. */
102 vp_synchronize_vectors(vdev);
103}
104
105static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
106{
107 return vp_legacy_config_vector(ldev: &vp_dev->ldev, vector);
108}
109
110static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
111 struct virtio_pci_vq_info *info,
112 unsigned int index,
113 void (*callback)(struct virtqueue *vq),
114 const char *name,
115 bool ctx,
116 u16 msix_vec)
117{
118 struct virtqueue *vq;
119 u16 num;
120 int err;
121 u64 q_pfn;
122
123 /* Check if queue is either not available or already active. */
124 num = vp_legacy_get_queue_size(ldev: &vp_dev->ldev, idx: index);
125 if (!num || vp_legacy_get_queue_enable(ldev: &vp_dev->ldev, idx: index))
126 return ERR_PTR(error: -ENOENT);
127
128 info->msix_vector = msix_vec;
129
130 /* create the vring */
131 vq = vring_create_virtqueue(index, num,
132 VIRTIO_PCI_VRING_ALIGN, vdev: &vp_dev->vdev,
133 weak_barriers: true, may_reduce_num: false, ctx,
134 notify: vp_notify, callback, name);
135 if (!vq)
136 return ERR_PTR(error: -ENOMEM);
137
138 vq->num_max = num;
139
140 q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
141 if (q_pfn >> 32) {
142 dev_err(&vp_dev->pci_dev->dev,
143 "platform bug: legacy virtio-pci must not be used with RAM above 0x%llxGB\n",
144 0x1ULL << (32 + PAGE_SHIFT - 30));
145 err = -E2BIG;
146 goto out_del_vq;
147 }
148
149 /* activate the queue */
150 vp_legacy_set_queue_address(ldev: &vp_dev->ldev, index, queue_pfn: q_pfn);
151
152 vq->priv = (void __force *)vp_dev->ldev.ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
153
154 if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
155 msix_vec = vp_legacy_queue_vector(ldev: &vp_dev->ldev, idx: index, vector: msix_vec);
156 if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
157 err = -EBUSY;
158 goto out_deactivate;
159 }
160 }
161
162 return vq;
163
164out_deactivate:
165 vp_legacy_set_queue_address(ldev: &vp_dev->ldev, index, queue_pfn: 0);
166out_del_vq:
167 vring_del_virtqueue(vq);
168 return ERR_PTR(error: err);
169}
170
171static void del_vq(struct virtio_pci_vq_info *info)
172{
173 struct virtqueue *vq = info->vq;
174 struct virtio_pci_device *vp_dev = to_vp_device(vdev: vq->vdev);
175
176 if (vp_dev->msix_enabled) {
177 vp_legacy_queue_vector(ldev: &vp_dev->ldev, idx: vq->index,
178 VIRTIO_MSI_NO_VECTOR);
179 /* Flush the write out to device */
180 ioread8(vp_dev->ldev.ioaddr + VIRTIO_PCI_ISR);
181 }
182
183 /* Select and deactivate the queue */
184 vp_legacy_set_queue_address(ldev: &vp_dev->ldev, index: vq->index, queue_pfn: 0);
185
186 vring_del_virtqueue(vq);
187}
188
189static const struct virtio_config_ops virtio_pci_config_ops = {
190 .get = vp_get,
191 .set = vp_set,
192 .get_status = vp_get_status,
193 .set_status = vp_set_status,
194 .reset = vp_reset,
195 .find_vqs = vp_find_vqs,
196 .del_vqs = vp_del_vqs,
197 .synchronize_cbs = vp_synchronize_vectors,
198 .get_features = vp_get_features,
199 .finalize_features = vp_finalize_features,
200 .bus_name = vp_bus_name,
201 .set_vq_affinity = vp_set_vq_affinity,
202 .get_vq_affinity = vp_get_vq_affinity,
203};
204
205/* the PCI probing function */
206int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
207{
208 struct virtio_pci_legacy_device *ldev = &vp_dev->ldev;
209 struct pci_dev *pci_dev = vp_dev->pci_dev;
210 int rc;
211
212 ldev->pci_dev = pci_dev;
213
214 rc = vp_legacy_probe(ldev);
215 if (rc)
216 return rc;
217
218 vp_dev->isr = ldev->isr;
219 vp_dev->vdev.id = ldev->id;
220
221 vp_dev->vdev.config = &virtio_pci_config_ops;
222
223 vp_dev->config_vector = vp_config_vector;
224 vp_dev->setup_vq = setup_vq;
225 vp_dev->del_vq = del_vq;
226 vp_dev->is_legacy = true;
227
228 return 0;
229}
230
231void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
232{
233 struct virtio_pci_legacy_device *ldev = &vp_dev->ldev;
234
235 vp_legacy_remove(ldev);
236}
237