aboutsummaryrefslogtreecommitdiff
path: root/drivers/acpi/viot.c
blob: d2256326c73aea45b35f4e83fd71686c26039780 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
// SPDX-License-Identifier: GPL-2.0
/*
 * Virtual I/O topology
 *
 * The Virtual I/O Translation Table (VIOT) describes the topology of
 * para-virtual IOMMUs and the endpoints they manage. The OS uses it to
 * initialize devices in the right order, preventing endpoints from issuing DMA
 * before their IOMMU is ready.
 *
 * When binding a driver to a device, before calling the device driver's probe()
 * method, the driver infrastructure calls dma_configure(). At that point the
 * VIOT driver looks for an IOMMU associated to the device in the VIOT table.
 * If an IOMMU exists and has been initialized, the VIOT driver initializes the
 * device's IOMMU fwspec, allowing the DMA infrastructure to invoke the IOMMU
 * ops when the device driver configures DMA mappings. If an IOMMU exists and
 * hasn't yet been initialized, VIOT returns -EPROBE_DEFER to postpone probing
 * the device until the IOMMU is available.
 */
#define pr_fmt(fmt) "ACPI: VIOT: " fmt

#include <linux/acpi_viot.h>
#include <linux/dma-iommu.h>
#include <linux/fwnode.h>
#include <linux/iommu.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/platform_device.h>

struct viot_iommu {
	/* Node offset within the table */
	unsigned int			offset;
	struct fwnode_handle		*fwnode;
	struct list_head		list;
};

struct viot_endpoint {
	union {
		/* PCI range */
		struct {
			u16		segment_start;
			u16		segment_end;
			u16		bdf_start;
			u16		bdf_end;
		};
		/* MMIO */
		u64			address;
	};
	u32				endpoint_id;
	struct viot_iommu		*viommu;
	struct list_head		list;
};

static struct acpi_table_viot *viot;
static LIST_HEAD(viot_iommus);
static LIST_HEAD(viot_pci_ranges);
static LIST_HEAD(viot_mmio_endpoints);

static int __init viot_check_bounds(const struct acpi_viot_header *hdr)
{
	struct acpi_viot_header *start, *end, *hdr_end;

	start = ACPI_ADD_PTR(struct acpi_viot_header, viot,
			     max_t(size_t, sizeof(*viot), viot->node_offset));
	end = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->header.length);
	hdr_end = ACPI_ADD_PTR(struct acpi_viot_header, hdr, sizeof(*hdr));

	if (hdr < start || hdr_end > end) {
		pr_err(FW_BUG "Node pointer overflows\n");
		return -EOVERFLOW;
	}
	if (hdr->length < sizeof(*hdr)) {
		pr_err(FW_BUG "Empty node\n");
		return -EINVAL;
	}
	return 0;
}

static int __init viot_get_pci_iommu_fwnode(struct viot_iommu *viommu,
					    u16 segment, u16 bdf)
{
	struct pci_dev *pdev;
	struct fwnode_handle *fwnode;

	pdev = pci_get_domain_bus_and_slot(segment, PCI_BUS_NUM(bdf),
					   bdf & 0xff);
	if (!pdev) {
		pr_err("Could not find PCI IOMMU\n");
		return -ENODEV;
	}

	fwnode = pdev->dev.fwnode;
	if (!fwnode) {
		/*
		 * PCI devices aren't necessarily described by ACPI. Create a
		 * fwnode so the IOMMU subsystem can identify this device.
		 */
		fwnode = acpi_alloc_fwnode_static();
		if (!fwnode) {
			pci_dev_put(pdev);
			return -ENOMEM;
		}
		set_primary_fwnode(&pdev->dev, fwnode);
	}
	viommu->fwnode = pdev->dev.fwnode;
	pci_dev_put(pdev);
	return 0;
}

static int __init viot_get_mmio_iommu_fwnode(struct viot_iommu *viommu,
					     u64 address)
{
	struct acpi_device *adev;
	struct resource res = {
		.start	= address,
		.end	= address,
		.flags	= IORESOURCE_MEM,
	};

	adev = acpi_resource_consumer(&res);
	if (!adev) {
		pr_err("Could not find MMIO IOMMU\n");
		return -EINVAL;
	}
	viommu->fwnode = &adev->fwnode;
	return 0;
}

static struct viot_iommu * __init viot_get_iommu(unsigned int offset)
{
	int ret;
	struct viot_iommu *viommu;
	struct acpi_viot_header *hdr = ACPI_ADD_PTR(struct acpi_viot_header,
						    viot, offset);
	union {
		struct acpi_viot_virtio_iommu_pci pci;
		struct acpi_viot_virtio_iommu_mmio mmio;
	} *node = (void *)hdr;

	list_for_each_entry(viommu, &viot_iommus, list)
		if (viommu->offset == offset)
			return viommu;

	if (viot_check_bounds(hdr))
		return NULL;

	viommu = kzalloc(sizeof(*viommu), GFP_KERNEL);
	if (!viommu)
		return NULL;

	viommu->offset = offset;
	switch (hdr->type) {
	case ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI:
		if (hdr->length < sizeof(node->pci))
			goto err_free;

		ret = viot_get_pci_iommu_fwnode(viommu, node->pci.segment,
						node->pci.bdf);
		break;
	case ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO:
		if (hdr->length < sizeof(node->mmio))
			goto err_free;

		ret = viot_get_mmio_iommu_fwnode(viommu,
						 node->mmio.base_address);
		break;
	default:
		ret = -EINVAL;
	}
	if (ret)
		goto err_free;

	list_add(&viommu->list, &viot_iommus);
	return viommu;

err_free:
	kfree(viommu);
	return NULL;
}

static int __init viot_parse_node(const struct acpi_viot_header *hdr)
{
	int ret = -EINVAL;
	struct list_head *list;
	struct viot_endpoint *ep;
	union {
		struct acpi_viot_mmio mmio;
		struct acpi_viot_pci_range pci;
	} *node = (void *)hdr;

	if (viot_check_bounds(hdr))
		return -EINVAL;

	if (hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI ||
	    hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO)
		return 0;

	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
	if (!ep)
		return -ENOMEM;

	switch (hdr->type) {
	case ACPI_VIOT_NODE_PCI_RANGE:
		if (hdr->length < sizeof(node->pci)) {
			pr_err(FW_BUG "Invalid PCI node size\n");
			goto err_free;
		}

		ep->segment_start = node->pci.segment_start;
		ep->segment_end = node->pci.segment_end;
		ep->bdf_start = node->pci.bdf_start;
		ep->bdf_end = node->pci.bdf_end;
		ep->endpoint_id = node->pci.endpoint_start;
		ep->viommu = viot_get_iommu(node->pci.output_node);
		list = &viot_pci_ranges;
		break;
	case ACPI_VIOT_NODE_MMIO:
		if (hdr->length < sizeof(node->mmio)) {
			pr_err(FW_BUG "Invalid MMIO node size\n");
			goto err_free;
		}

		ep->address = node->mmio.base_address;
		ep->endpoint_id = node->mmio.endpoint;
		ep->viommu = viot_get_iommu(node->mmio.output_node);
		list = &viot_mmio_endpoints;
		break;
	default:
		pr_warn("Unsupported node %x\n", hdr->type);
		ret = 0;
		goto err_free;
	}

	if (!ep->viommu) {
		pr_warn("No IOMMU node found\n");
		/*
		 * A future version of the table may use the node for other
		 * purposes. Keep parsing.
		 */
		ret = 0;
		goto err_free;
	}

	list_add(&ep->list, list);
	return 0;

err_free:
	kfree(ep);
	return ret;
}

/**
 * acpi_viot_init - Parse the VIOT table
 *
 * Parse the VIOT table, prepare the list of endpoints to be used during DMA
 * setup of devices.
 */
void __init acpi_viot_init(void)
{
	int i;
	acpi_status status;
	struct acpi_table_header *hdr;
	struct acpi_viot_header *node;

	status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);
	if (ACPI_FAILURE(status)) {
		if (status != AE_NOT_FOUND) {
			const char *msg = acpi_format_exception(status);

			pr_err("Failed to get table, %s\n", msg);
		}
		return;
	}

	viot = (void *)hdr;

	node = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->node_offset);
	for (i = 0; i < viot->node_count; i++) {
		if (viot_parse_node(node))
			return;

		node = ACPI_ADD_PTR(struct acpi_viot_header, node,
				    node->length);
	}

	acpi_put_table(hdr);
}

static int viot_dev_iommu_init(struct device *dev, struct viot_iommu *viommu,
			       u32 epid)
{
	const struct iommu_ops *ops;

	if (!viommu)
		return -ENODEV;

	/* We're not translating ourself */
	if (viommu->fwnode == dev->fwnode)
		return -EINVAL;

	ops = iommu_ops_from_fwnode(viommu->fwnode);
	if (!ops)
		return IS_ENABLED(CONFIG_VIRTIO_IOMMU) ?
			-EPROBE_DEFER : -ENODEV;

	return acpi_iommu_fwspec_init(dev, epid, viommu->fwnode, ops);
}

static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)
{
	u32 epid;
	struct viot_endpoint *ep;
	u32 domain_nr = pci_domain_nr(pdev->bus);

	list_for_each_entry(ep, &viot_pci_ranges, list) {
		if (domain_nr >= ep->segment_start &&
		    domain_nr <= ep->segment_end &&
		    dev_id >= ep->bdf_start &&
		    dev_id <= ep->bdf_end) {
			epid = ((domain_nr - ep->segment_start) << 16) +
				dev_id - ep->bdf_start + ep->endpoint_id;

			/*
			 * If we found a PCI range managed by the viommu, we're
			 * the one that has to request ACS.
			 */
			pci_request_acs();

			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
						   epid);
		}
	}
	return -ENODEV;
}

static int viot_mmio_dev_iommu_init(struct platform_device *pdev)
{
	struct resource *mem;
	struct viot_endpoint *ep;

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem)
		return -ENODEV;

	list_for_each_entry(ep, &viot_mmio_endpoints, list) {
		if (ep->address == mem->start)
			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
						   ep->endpoint_id);
	}
	return -ENODEV;
}

/**
 * viot_iommu_configure - Setup IOMMU ops for an endpoint described by VIOT
 * @dev: the endpoint
 *
 * Return: 0 on success, <0 on failure
 */
int viot_iommu_configure(struct device *dev)
{
	if (dev_is_pci(dev))
		return pci_for_each_dma_alias(to_pci_dev(dev),
					      viot_pci_dev_iommu_init, NULL);
	else if (dev_is_platform(dev))
		return viot_mmio_dev_iommu_init(to_platform_device(dev));
	return -ENODEV;
}