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(&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(&vp_dev->ldev, 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(&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(&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(&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);
103}
104
105static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
106{
107	return vp_legacy_config_vector(&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(&vp_dev->ldev, index);
125	if (!num || vp_legacy_get_queue_enable(&vp_dev->ldev, index))
126		return ERR_PTR(-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, &vp_dev->vdev,
133				    true, false, ctx,
134				    vp_notify, callback, name);
135	if (!vq)
136		return ERR_PTR(-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(&vp_dev->ldev, index, 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(&vp_dev->ldev, index, 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(&vp_dev->ldev, index, 0);
166out_del_vq:
167	vring_del_virtqueue(vq);
168	return ERR_PTR(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(vq->vdev);
175
176	if (vp_dev->msix_enabled) {
177		vp_legacy_queue_vector(&vp_dev->ldev, 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(&vp_dev->ldev, vq->index, 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}