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 */
 20static 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 */
 30static 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 */
 47static 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 */
 63static 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 */
 78static 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
 84static 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
 92static 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
104static 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
113static 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
169out_deactivate:
170	iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
171out_del_vq:
172	vring_del_virtqueue(vq);
173	return ERR_PTR(err);
174}
175
176static 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
196static 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 */
212int 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
268err_iomap:
269	pci_release_region(pci_dev, 0);
270	return rc;
271}
272
273void 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}