1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Virtio PCI driver - legacy device support
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.
8 * Copyright IBM Corp. 2007
9 * Copyright Red Hat, Inc. 2014
12 * Anthony Liguori <aliguori@us.ibm.com>
13 * Rusty Russell <rusty@rustcorp.com.au>
14 * Michael S. Tsirkin <mst@redhat.com>
17 #include "linux/virtio_pci_legacy.h"
18 #include "virtio_pci_common.h"
20 /* virtio config->get_features() implementation */
21 static u64 vp_get_features(struct virtio_device *vdev)
23 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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(&vp_dev->ldev);
30 /* virtio config->finalize_features() implementation */
31 static int vp_finalize_features(struct virtio_device *vdev)
33 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
35 /* Give virtio_ring a chance to accept features. */
36 vring_transport_features(vdev);
38 /* Make sure we don't have any features > 32 bits! */
39 BUG_ON((u32)vdev->features != vdev->features);
41 /* We only support 32 feature bits. */
42 vp_legacy_set_features(&vp_dev->ldev, vdev->features);
47 /* virtio config->get() implementation */
48 static void vp_get(struct virtio_device *vdev, unsigned int offset,
49 void *buf, unsigned int len)
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) +
58 for (i = 0; i < len; i++)
59 ptr[i] = ioread8(ioaddr + i);
62 /* the config->set() implementation. it's symmetric to the config->get()
64 static void vp_set(struct virtio_device *vdev, unsigned int offset,
65 const void *buf, unsigned int len)
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) +
74 for (i = 0; i < len; i++)
75 iowrite8(ptr[i], ioaddr + i);
78 /* config->{get,set}_status() implementations */
79 static u8 vp_get_status(struct virtio_device *vdev)
81 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
82 return vp_legacy_get_status(&vp_dev->ldev);
85 static void vp_set_status(struct virtio_device *vdev, u8 status)
87 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
88 /* We should never be setting status to 0. */
90 vp_legacy_set_status(&vp_dev->ldev, status);
93 static void vp_reset(struct virtio_device *vdev)
95 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
96 /* 0 status means a reset. */
97 vp_legacy_set_status(&vp_dev->ldev, 0);
98 /* Flush out the status write, and flush in device writes,
99 * including MSi-X interrupts, if any. */
100 vp_legacy_get_status(&vp_dev->ldev);
101 /* Flush pending VQ/configuration callbacks. */
102 vp_synchronize_vectors(vdev);
105 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
107 return vp_legacy_config_vector(&vp_dev->ldev, vector);
110 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
111 struct virtio_pci_vq_info *info,
113 void (*callback)(struct virtqueue *vq),
119 struct virtqueue *vq;
124 /* Check if queue is either not available or already active. */
125 num = vp_legacy_get_queue_size(&vp_dev->ldev, index);
126 if (!num || vp_legacy_get_queue_enable(&vp_dev->ldev, index))
127 return ERR_PTR(-ENOENT);
129 if (!size || size > num)
132 info->msix_vector = msix_vec;
134 /* create the vring */
135 vq = vring_create_virtqueue(index, size,
136 VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
138 vp_notify, callback, name);
140 return ERR_PTR(-ENOMEM);
144 q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
146 dev_err(&vp_dev->pci_dev->dev,
147 "platform bug: legacy virtio-pci must not be used with RAM above 0x%llxGB\n",
148 0x1ULL << (32 + PAGE_SHIFT - 30));
153 /* activate the queue */
154 vp_legacy_set_queue_address(&vp_dev->ldev, index, q_pfn);
156 vq->priv = (void __force *)vp_dev->ldev.ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
158 if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
159 msix_vec = vp_legacy_queue_vector(&vp_dev->ldev, index, msix_vec);
160 if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
169 vp_legacy_set_queue_address(&vp_dev->ldev, index, 0);
171 vring_del_virtqueue(vq);
175 static void del_vq(struct virtio_pci_vq_info *info)
177 struct virtqueue *vq = info->vq;
178 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
180 if (vp_dev->msix_enabled) {
181 vp_legacy_queue_vector(&vp_dev->ldev, vq->index,
182 VIRTIO_MSI_NO_VECTOR);
183 /* Flush the write out to device */
184 ioread8(vp_dev->ldev.ioaddr + VIRTIO_PCI_ISR);
187 /* Select and deactivate the queue */
188 vp_legacy_set_queue_address(&vp_dev->ldev, vq->index, 0);
190 vring_del_virtqueue(vq);
193 static const struct virtio_config_ops virtio_pci_config_ops = {
196 .get_status = vp_get_status,
197 .set_status = vp_set_status,
199 .find_vqs = vp_find_vqs,
200 .del_vqs = vp_del_vqs,
201 .synchronize_cbs = vp_synchronize_vectors,
202 .get_features = vp_get_features,
203 .finalize_features = vp_finalize_features,
204 .bus_name = vp_bus_name,
205 .set_vq_affinity = vp_set_vq_affinity,
206 .get_vq_affinity = vp_get_vq_affinity,
209 /* the PCI probing function */
210 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
212 struct virtio_pci_legacy_device *ldev = &vp_dev->ldev;
213 struct pci_dev *pci_dev = vp_dev->pci_dev;
216 ldev->pci_dev = pci_dev;
218 rc = vp_legacy_probe(ldev);
222 vp_dev->isr = ldev->isr;
223 vp_dev->vdev.id = ldev->id;
225 vp_dev->vdev.config = &virtio_pci_config_ops;
227 vp_dev->config_vector = vp_config_vector;
228 vp_dev->setup_vq = setup_vq;
229 vp_dev->del_vq = del_vq;
234 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
236 struct virtio_pci_legacy_device *ldev = &vp_dev->ldev;
238 vp_legacy_remove(ldev);