xref: /linux/drivers/pci/ats.c (revision da923feefead2efc05ef21eb2a3f1058fe4c13ae) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * PCI Express I/O Virtualization (IOV) support
4  *   Address Translation Service 1.0
5  *   Page Request Interface added by Joerg Roedel <joerg.roedel@amd.com>
6  *   PASID support added by Joerg Roedel <joerg.roedel@amd.com>
7  *
8  * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
9  * Copyright (C) 2011 Advanced Micro Devices,
10  */
11 
12 #include <linux/export.h>
13 #include <linux/pci-ats.h>
14 #include <linux/pci.h>
15 #include <linux/slab.h>
16 
17 #include "pci.h"
18 
19 void pci_ats_init(struct pci_dev *dev)
20 {
21 	int pos;
22 
23 	if (pci_ats_disabled())
24 		return;
25 
26 	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
27 	if (!pos)
28 		return;
29 
30 	dev->ats_cap = pos;
31 }
32 
33 /**
34  * pci_ats_supported - check if the device can use ATS
35  * @dev: the PCI device
36  *
37  * Returns true if the device supports ATS and is allowed to use it, false
38  * otherwise.
39  */
40 bool pci_ats_supported(struct pci_dev *dev)
41 {
42 	if (!dev->ats_cap)
43 		return false;
44 
45 	return (dev->untrusted == 0);
46 }
47 EXPORT_SYMBOL_GPL(pci_ats_supported);
48 
49 /**
50  * pci_enable_ats - enable the ATS capability
51  * @dev: the PCI device
52  * @ps: the IOMMU page shift
53  *
54  * Returns 0 on success, or negative on failure.
55  */
56 int pci_enable_ats(struct pci_dev *dev, int ps)
57 {
58 	u16 ctrl;
59 	struct pci_dev *pdev;
60 
61 	if (!pci_ats_supported(dev))
62 		return -EINVAL;
63 
64 	if (WARN_ON(dev->ats_enabled))
65 		return -EBUSY;
66 
67 	if (ps < PCI_ATS_MIN_STU)
68 		return -EINVAL;
69 
70 	/*
71 	 * Note that enabling ATS on a VF fails unless it's already enabled
72 	 * with the same STU on the PF.
73 	 */
74 	ctrl = PCI_ATS_CTRL_ENABLE;
75 	if (dev->is_virtfn) {
76 		pdev = pci_physfn(dev);
77 		if (pdev->ats_stu != ps)
78 			return -EINVAL;
79 	} else {
80 		dev->ats_stu = ps;
81 		ctrl |= PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU);
82 	}
83 	pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
84 
85 	dev->ats_enabled = 1;
86 	return 0;
87 }
88 EXPORT_SYMBOL_GPL(pci_enable_ats);
89 
90 /**
91  * pci_disable_ats - disable the ATS capability
92  * @dev: the PCI device
93  */
94 void pci_disable_ats(struct pci_dev *dev)
95 {
96 	u16 ctrl;
97 
98 	if (WARN_ON(!dev->ats_enabled))
99 		return;
100 
101 	pci_read_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, &ctrl);
102 	ctrl &= ~PCI_ATS_CTRL_ENABLE;
103 	pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
104 
105 	dev->ats_enabled = 0;
106 }
107 EXPORT_SYMBOL_GPL(pci_disable_ats);
108 
109 void pci_restore_ats_state(struct pci_dev *dev)
110 {
111 	u16 ctrl;
112 
113 	if (!dev->ats_enabled)
114 		return;
115 
116 	ctrl = PCI_ATS_CTRL_ENABLE;
117 	if (!dev->is_virtfn)
118 		ctrl |= PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU);
119 	pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
120 }
121 
122 /**
123  * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
124  * @dev: the PCI device
125  *
126  * Returns the queue depth on success, or negative on failure.
127  *
128  * The ATS spec uses 0 in the Invalidate Queue Depth field to
129  * indicate that the function can accept 32 Invalidate Request.
130  * But here we use the `real' values (i.e. 1~32) for the Queue
131  * Depth; and 0 indicates the function shares the Queue with
132  * other functions (doesn't exclusively own a Queue).
133  */
134 int pci_ats_queue_depth(struct pci_dev *dev)
135 {
136 	u16 cap;
137 
138 	if (!dev->ats_cap)
139 		return -EINVAL;
140 
141 	if (dev->is_virtfn)
142 		return 0;
143 
144 	pci_read_config_word(dev, dev->ats_cap + PCI_ATS_CAP, &cap);
145 	return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) : PCI_ATS_MAX_QDEP;
146 }
147 
148 /**
149  * pci_ats_page_aligned - Return Page Aligned Request bit status.
150  * @pdev: the PCI device
151  *
152  * Returns 1, if the Untranslated Addresses generated by the device
153  * are always aligned or 0 otherwise.
154  *
155  * Per PCIe spec r4.0, sec 10.5.1.2, if the Page Aligned Request bit
156  * is set, it indicates the Untranslated Addresses generated by the
157  * device are always aligned to a 4096 byte boundary.
158  */
159 int pci_ats_page_aligned(struct pci_dev *pdev)
160 {
161 	u16 cap;
162 
163 	if (!pdev->ats_cap)
164 		return 0;
165 
166 	pci_read_config_word(pdev, pdev->ats_cap + PCI_ATS_CAP, &cap);
167 
168 	if (cap & PCI_ATS_CAP_PAGE_ALIGNED)
169 		return 1;
170 
171 	return 0;
172 }
173 
174 #ifdef CONFIG_PCI_PRI
175 void pci_pri_init(struct pci_dev *pdev)
176 {
177 	u16 status;
178 
179 	pdev->pri_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
180 
181 	if (!pdev->pri_cap)
182 		return;
183 
184 	pci_read_config_word(pdev, pdev->pri_cap + PCI_PRI_STATUS, &status);
185 	if (status & PCI_PRI_STATUS_PASID)
186 		pdev->pasid_required = 1;
187 }
188 
189 /**
190  * pci_enable_pri - Enable PRI capability
191  * @pdev: PCI device structure
192  * @reqs: outstanding requests
193  *
194  * Returns 0 on success, negative value on error
195  */
196 int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
197 {
198 	u16 control, status;
199 	u32 max_requests;
200 	int pri = pdev->pri_cap;
201 
202 	/*
203 	 * VFs must not implement the PRI Capability.  If their PF
204 	 * implements PRI, it is shared by the VFs, so if the PF PRI is
205 	 * enabled, it is also enabled for the VF.
206 	 */
207 	if (pdev->is_virtfn) {
208 		if (pci_physfn(pdev)->pri_enabled)
209 			return 0;
210 		return -EINVAL;
211 	}
212 
213 	if (WARN_ON(pdev->pri_enabled))
214 		return -EBUSY;
215 
216 	if (!pri)
217 		return -EINVAL;
218 
219 	pci_read_config_word(pdev, pri + PCI_PRI_STATUS, &status);
220 	if (!(status & PCI_PRI_STATUS_STOPPED))
221 		return -EBUSY;
222 
223 	pci_read_config_dword(pdev, pri + PCI_PRI_MAX_REQ, &max_requests);
224 	reqs = min(max_requests, reqs);
225 	pdev->pri_reqs_alloc = reqs;
226 	pci_write_config_dword(pdev, pri + PCI_PRI_ALLOC_REQ, reqs);
227 
228 	control = PCI_PRI_CTRL_ENABLE;
229 	pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);
230 
231 	pdev->pri_enabled = 1;
232 
233 	return 0;
234 }
235 
236 /**
237  * pci_disable_pri - Disable PRI capability
238  * @pdev: PCI device structure
239  *
240  * Only clears the enabled-bit, regardless of its former value
241  */
242 void pci_disable_pri(struct pci_dev *pdev)
243 {
244 	u16 control;
245 	int pri = pdev->pri_cap;
246 
247 	/* VFs share the PF PRI */
248 	if (pdev->is_virtfn)
249 		return;
250 
251 	if (WARN_ON(!pdev->pri_enabled))
252 		return;
253 
254 	if (!pri)
255 		return;
256 
257 	pci_read_config_word(pdev, pri + PCI_PRI_CTRL, &control);
258 	control &= ~PCI_PRI_CTRL_ENABLE;
259 	pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);
260 
261 	pdev->pri_enabled = 0;
262 }
263 EXPORT_SYMBOL_GPL(pci_disable_pri);
264 
265 /**
266  * pci_restore_pri_state - Restore PRI
267  * @pdev: PCI device structure
268  */
269 void pci_restore_pri_state(struct pci_dev *pdev)
270 {
271 	u16 control = PCI_PRI_CTRL_ENABLE;
272 	u32 reqs = pdev->pri_reqs_alloc;
273 	int pri = pdev->pri_cap;
274 
275 	if (pdev->is_virtfn)
276 		return;
277 
278 	if (!pdev->pri_enabled)
279 		return;
280 
281 	if (!pri)
282 		return;
283 
284 	pci_write_config_dword(pdev, pri + PCI_PRI_ALLOC_REQ, reqs);
285 	pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);
286 }
287 
288 /**
289  * pci_reset_pri - Resets device's PRI state
290  * @pdev: PCI device structure
291  *
292  * The PRI capability must be disabled before this function is called.
293  * Returns 0 on success, negative value on error.
294  */
295 int pci_reset_pri(struct pci_dev *pdev)
296 {
297 	u16 control;
298 	int pri = pdev->pri_cap;
299 
300 	if (pdev->is_virtfn)
301 		return 0;
302 
303 	if (WARN_ON(pdev->pri_enabled))
304 		return -EBUSY;
305 
306 	if (!pri)
307 		return -EINVAL;
308 
309 	control = PCI_PRI_CTRL_RESET;
310 	pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);
311 
312 	return 0;
313 }
314 
315 /**
316  * pci_prg_resp_pasid_required - Return PRG Response PASID Required bit
317  *				 status.
318  * @pdev: PCI device structure
319  *
320  * Returns 1 if PASID is required in PRG Response Message, 0 otherwise.
321  */
322 int pci_prg_resp_pasid_required(struct pci_dev *pdev)
323 {
324 	if (pdev->is_virtfn)
325 		pdev = pci_physfn(pdev);
326 
327 	return pdev->pasid_required;
328 }
329 
330 /**
331  * pci_pri_supported - Check if PRI is supported.
332  * @pdev: PCI device structure
333  *
334  * Returns true if PRI capability is present, false otherwise.
335  */
336 bool pci_pri_supported(struct pci_dev *pdev)
337 {
338 	/* VFs share the PF PRI */
339 	if (pci_physfn(pdev)->pri_cap)
340 		return true;
341 	return false;
342 }
343 EXPORT_SYMBOL_GPL(pci_pri_supported);
344 #endif /* CONFIG_PCI_PRI */
345 
346 #ifdef CONFIG_PCI_PASID
347 void pci_pasid_init(struct pci_dev *pdev)
348 {
349 	pdev->pasid_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
350 }
351 
352 /**
353  * pci_enable_pasid - Enable the PASID capability
354  * @pdev: PCI device structure
355  * @features: Features to enable
356  *
357  * Returns 0 on success, negative value on error. This function checks
358  * whether the features are actually supported by the device and returns
359  * an error if not.
360  */
361 int pci_enable_pasid(struct pci_dev *pdev, int features)
362 {
363 	u16 control, supported;
364 	int pasid = pdev->pasid_cap;
365 
366 	/*
367 	 * VFs must not implement the PASID Capability, but if a PF
368 	 * supports PASID, its VFs share the PF PASID configuration.
369 	 */
370 	if (pdev->is_virtfn) {
371 		if (pci_physfn(pdev)->pasid_enabled)
372 			return 0;
373 		return -EINVAL;
374 	}
375 
376 	if (WARN_ON(pdev->pasid_enabled))
377 		return -EBUSY;
378 
379 	if (!pdev->eetlp_prefix_path && !pdev->pasid_no_tlp)
380 		return -EINVAL;
381 
382 	if (!pasid)
383 		return -EINVAL;
384 
385 	if (!pci_acs_path_enabled(pdev, NULL, PCI_ACS_RR | PCI_ACS_UF))
386 		return -EINVAL;
387 
388 	pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
389 	supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
390 
391 	/* User wants to enable anything unsupported? */
392 	if ((supported & features) != features)
393 		return -EINVAL;
394 
395 	control = PCI_PASID_CTRL_ENABLE | features;
396 	pdev->pasid_features = features;
397 
398 	pci_write_config_word(pdev, pasid + PCI_PASID_CTRL, control);
399 
400 	pdev->pasid_enabled = 1;
401 
402 	return 0;
403 }
404 EXPORT_SYMBOL_GPL(pci_enable_pasid);
405 
406 /**
407  * pci_disable_pasid - Disable the PASID capability
408  * @pdev: PCI device structure
409  */
410 void pci_disable_pasid(struct pci_dev *pdev)
411 {
412 	u16 control = 0;
413 	int pasid = pdev->pasid_cap;
414 
415 	/* VFs share the PF PASID configuration */
416 	if (pdev->is_virtfn)
417 		return;
418 
419 	if (WARN_ON(!pdev->pasid_enabled))
420 		return;
421 
422 	if (!pasid)
423 		return;
424 
425 	pci_write_config_word(pdev, pasid + PCI_PASID_CTRL, control);
426 
427 	pdev->pasid_enabled = 0;
428 }
429 EXPORT_SYMBOL_GPL(pci_disable_pasid);
430 
431 /**
432  * pci_restore_pasid_state - Restore PASID capabilities
433  * @pdev: PCI device structure
434  */
435 void pci_restore_pasid_state(struct pci_dev *pdev)
436 {
437 	u16 control;
438 	int pasid = pdev->pasid_cap;
439 
440 	if (pdev->is_virtfn)
441 		return;
442 
443 	if (!pdev->pasid_enabled)
444 		return;
445 
446 	if (!pasid)
447 		return;
448 
449 	control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features;
450 	pci_write_config_word(pdev, pasid + PCI_PASID_CTRL, control);
451 }
452 
453 /**
454  * pci_pasid_features - Check which PASID features are supported
455  * @pdev: PCI device structure
456  *
457  * Returns a negative value when no PASI capability is present.
458  * Otherwise is returns a bitmask with supported features. Current
459  * features reported are:
460  * PCI_PASID_CAP_EXEC - Execute permission supported
461  * PCI_PASID_CAP_PRIV - Privileged mode supported
462  */
463 int pci_pasid_features(struct pci_dev *pdev)
464 {
465 	u16 supported;
466 	int pasid;
467 
468 	if (pdev->is_virtfn)
469 		pdev = pci_physfn(pdev);
470 
471 	pasid = pdev->pasid_cap;
472 	if (!pasid)
473 		return -EINVAL;
474 
475 	pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
476 
477 	supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
478 
479 	return supported;
480 }
481 EXPORT_SYMBOL_GPL(pci_pasid_features);
482 
483 #define PASID_NUMBER_SHIFT	8
484 #define PASID_NUMBER_MASK	(0x1f << PASID_NUMBER_SHIFT)
485 /**
486  * pci_max_pasids - Get maximum number of PASIDs supported by device
487  * @pdev: PCI device structure
488  *
489  * Returns negative value when PASID capability is not present.
490  * Otherwise it returns the number of supported PASIDs.
491  */
492 int pci_max_pasids(struct pci_dev *pdev)
493 {
494 	u16 supported;
495 	int pasid;
496 
497 	if (pdev->is_virtfn)
498 		pdev = pci_physfn(pdev);
499 
500 	pasid = pdev->pasid_cap;
501 	if (!pasid)
502 		return -EINVAL;
503 
504 	pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
505 
506 	supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
507 
508 	return (1 << supported);
509 }
510 EXPORT_SYMBOL_GPL(pci_max_pasids);
511 #endif /* CONFIG_PCI_PASID */
512