xref: /openbmc/linux/drivers/vfio/pci/vfio_pci_igd.c (revision 0886196c)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * VFIO PCI Intel Graphics support
4  *
5  * Copyright (C) 2016 Red Hat, Inc.  All rights reserved.
6  *	Author: Alex Williamson <alex.williamson@redhat.com>
7  *
8  * Register a device specific region through which to provide read-only
9  * access to the Intel IGD opregion.  The register defining the opregion
10  * address is also virtualized to prevent user modification.
11  */
12 
13 #include <linux/io.h>
14 #include <linux/pci.h>
15 #include <linux/uaccess.h>
16 #include <linux/vfio.h>
17 
18 #include "vfio_pci_priv.h"
19 
20 #define OPREGION_SIGNATURE	"IntelGraphicsMem"
21 #define OPREGION_SIZE		(8 * 1024)
22 #define OPREGION_PCI_ADDR	0xfc
23 
24 #define OPREGION_RVDA		0x3ba
25 #define OPREGION_RVDS		0x3c2
26 #define OPREGION_VERSION	0x16
27 
28 struct igd_opregion_vbt {
29 	void *opregion;
30 	void *vbt_ex;
31 };
32 
33 /**
34  * igd_opregion_shift_copy() - Copy OpRegion to user buffer and shift position.
35  * @dst: User buffer ptr to copy to.
36  * @off: Offset to user buffer ptr. Increased by bytes on return.
37  * @src: Source buffer to copy from.
38  * @pos: Increased by bytes on return.
39  * @remaining: Decreased by bytes on return.
40  * @bytes: Bytes to copy and adjust off, pos and remaining.
41  *
42  * Copy OpRegion to offset from specific source ptr and shift the offset.
43  *
44  * Return: 0 on success, -EFAULT otherwise.
45  *
46  */
igd_opregion_shift_copy(char __user * dst,loff_t * off,void * src,loff_t * pos,size_t * remaining,size_t bytes)47 static inline unsigned long igd_opregion_shift_copy(char __user *dst,
48 						    loff_t *off,
49 						    void *src,
50 						    loff_t *pos,
51 						    size_t *remaining,
52 						    size_t bytes)
53 {
54 	if (copy_to_user(dst + (*off), src, bytes))
55 		return -EFAULT;
56 
57 	*off += bytes;
58 	*pos += bytes;
59 	*remaining -= bytes;
60 
61 	return 0;
62 }
63 
vfio_pci_igd_rw(struct vfio_pci_core_device * vdev,char __user * buf,size_t count,loff_t * ppos,bool iswrite)64 static ssize_t vfio_pci_igd_rw(struct vfio_pci_core_device *vdev,
65 			       char __user *buf, size_t count, loff_t *ppos,
66 			       bool iswrite)
67 {
68 	unsigned int i = VFIO_PCI_OFFSET_TO_INDEX(*ppos) - VFIO_PCI_NUM_REGIONS;
69 	struct igd_opregion_vbt *opregionvbt = vdev->region[i].data;
70 	loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK, off = 0;
71 	size_t remaining;
72 
73 	if (pos >= vdev->region[i].size || iswrite)
74 		return -EINVAL;
75 
76 	count = min_t(size_t, count, vdev->region[i].size - pos);
77 	remaining = count;
78 
79 	/* Copy until OpRegion version */
80 	if (remaining && pos < OPREGION_VERSION) {
81 		size_t bytes = min_t(size_t, remaining, OPREGION_VERSION - pos);
82 
83 		if (igd_opregion_shift_copy(buf, &off,
84 					    opregionvbt->opregion + pos, &pos,
85 					    &remaining, bytes))
86 			return -EFAULT;
87 	}
88 
89 	/* Copy patched (if necessary) OpRegion version */
90 	if (remaining && pos < OPREGION_VERSION + sizeof(__le16)) {
91 		size_t bytes = min_t(size_t, remaining,
92 				     OPREGION_VERSION + sizeof(__le16) - pos);
93 		__le16 version = *(__le16 *)(opregionvbt->opregion +
94 					     OPREGION_VERSION);
95 
96 		/* Patch to 2.1 if OpRegion 2.0 has extended VBT */
97 		if (le16_to_cpu(version) == 0x0200 && opregionvbt->vbt_ex)
98 			version = cpu_to_le16(0x0201);
99 
100 		if (igd_opregion_shift_copy(buf, &off,
101 					    (u8 *)&version +
102 					    (pos - OPREGION_VERSION),
103 					    &pos, &remaining, bytes))
104 			return -EFAULT;
105 	}
106 
107 	/* Copy until RVDA */
108 	if (remaining && pos < OPREGION_RVDA) {
109 		size_t bytes = min_t(size_t, remaining, OPREGION_RVDA - pos);
110 
111 		if (igd_opregion_shift_copy(buf, &off,
112 					    opregionvbt->opregion + pos, &pos,
113 					    &remaining, bytes))
114 			return -EFAULT;
115 	}
116 
117 	/* Copy modified (if necessary) RVDA */
118 	if (remaining && pos < OPREGION_RVDA + sizeof(__le64)) {
119 		size_t bytes = min_t(size_t, remaining,
120 				     OPREGION_RVDA + sizeof(__le64) - pos);
121 		__le64 rvda = cpu_to_le64(opregionvbt->vbt_ex ?
122 					  OPREGION_SIZE : 0);
123 
124 		if (igd_opregion_shift_copy(buf, &off,
125 					    (u8 *)&rvda + (pos - OPREGION_RVDA),
126 					    &pos, &remaining, bytes))
127 			return -EFAULT;
128 	}
129 
130 	/* Copy the rest of OpRegion */
131 	if (remaining && pos < OPREGION_SIZE) {
132 		size_t bytes = min_t(size_t, remaining, OPREGION_SIZE - pos);
133 
134 		if (igd_opregion_shift_copy(buf, &off,
135 					    opregionvbt->opregion + pos, &pos,
136 					    &remaining, bytes))
137 			return -EFAULT;
138 	}
139 
140 	/* Copy extended VBT if exists */
141 	if (remaining &&
142 	    copy_to_user(buf + off, opregionvbt->vbt_ex + (pos - OPREGION_SIZE),
143 			 remaining))
144 		return -EFAULT;
145 
146 	*ppos += count;
147 
148 	return count;
149 }
150 
vfio_pci_igd_release(struct vfio_pci_core_device * vdev,struct vfio_pci_region * region)151 static void vfio_pci_igd_release(struct vfio_pci_core_device *vdev,
152 				 struct vfio_pci_region *region)
153 {
154 	struct igd_opregion_vbt *opregionvbt = region->data;
155 
156 	if (opregionvbt->vbt_ex)
157 		memunmap(opregionvbt->vbt_ex);
158 
159 	memunmap(opregionvbt->opregion);
160 	kfree(opregionvbt);
161 }
162 
163 static const struct vfio_pci_regops vfio_pci_igd_regops = {
164 	.rw		= vfio_pci_igd_rw,
165 	.release	= vfio_pci_igd_release,
166 };
167 
vfio_pci_igd_opregion_init(struct vfio_pci_core_device * vdev)168 static int vfio_pci_igd_opregion_init(struct vfio_pci_core_device *vdev)
169 {
170 	__le32 *dwordp = (__le32 *)(vdev->vconfig + OPREGION_PCI_ADDR);
171 	u32 addr, size;
172 	struct igd_opregion_vbt *opregionvbt;
173 	int ret;
174 	u16 version;
175 
176 	ret = pci_read_config_dword(vdev->pdev, OPREGION_PCI_ADDR, &addr);
177 	if (ret)
178 		return ret;
179 
180 	if (!addr || !(~addr))
181 		return -ENODEV;
182 
183 	opregionvbt = kzalloc(sizeof(*opregionvbt), GFP_KERNEL_ACCOUNT);
184 	if (!opregionvbt)
185 		return -ENOMEM;
186 
187 	opregionvbt->opregion = memremap(addr, OPREGION_SIZE, MEMREMAP_WB);
188 	if (!opregionvbt->opregion) {
189 		kfree(opregionvbt);
190 		return -ENOMEM;
191 	}
192 
193 	if (memcmp(opregionvbt->opregion, OPREGION_SIGNATURE, 16)) {
194 		memunmap(opregionvbt->opregion);
195 		kfree(opregionvbt);
196 		return -EINVAL;
197 	}
198 
199 	size = le32_to_cpu(*(__le32 *)(opregionvbt->opregion + 16));
200 	if (!size) {
201 		memunmap(opregionvbt->opregion);
202 		kfree(opregionvbt);
203 		return -EINVAL;
204 	}
205 
206 	size *= 1024; /* In KB */
207 
208 	/*
209 	 * OpRegion and VBT:
210 	 * When VBT data doesn't exceed 6KB, it's stored in Mailbox #4.
211 	 * When VBT data exceeds 6KB size, Mailbox #4 is no longer large enough
212 	 * to hold the VBT data, the Extended VBT region is introduced since
213 	 * OpRegion 2.0 to hold the VBT data. Since OpRegion 2.0, RVDA/RVDS are
214 	 * introduced to define the extended VBT data location and size.
215 	 * OpRegion 2.0: RVDA defines the absolute physical address of the
216 	 *   extended VBT data, RVDS defines the VBT data size.
217 	 * OpRegion 2.1 and above: RVDA defines the relative address of the
218 	 *   extended VBT data to OpRegion base, RVDS defines the VBT data size.
219 	 *
220 	 * Due to the RVDA definition diff in OpRegion VBT (also the only diff
221 	 * between 2.0 and 2.1), exposing OpRegion and VBT as a contiguous range
222 	 * for OpRegion 2.0 and above makes it possible to support the
223 	 * non-contiguous VBT through a single vfio region. From r/w ops view,
224 	 * only contiguous VBT after OpRegion with version 2.1+ is exposed,
225 	 * regardless the host OpRegion is 2.0 or non-contiguous 2.1+. The r/w
226 	 * ops will on-the-fly shift the actural offset into VBT so that data at
227 	 * correct position can be returned to the requester.
228 	 */
229 	version = le16_to_cpu(*(__le16 *)(opregionvbt->opregion +
230 					  OPREGION_VERSION));
231 	if (version >= 0x0200) {
232 		u64 rvda = le64_to_cpu(*(__le64 *)(opregionvbt->opregion +
233 						   OPREGION_RVDA));
234 		u32 rvds = le32_to_cpu(*(__le32 *)(opregionvbt->opregion +
235 						   OPREGION_RVDS));
236 
237 		/* The extended VBT is valid only when RVDA/RVDS are non-zero */
238 		if (rvda && rvds) {
239 			size += rvds;
240 
241 			/*
242 			 * Extended VBT location by RVDA:
243 			 * Absolute physical addr for 2.0.
244 			 * Relative addr to OpRegion header for 2.1+.
245 			 */
246 			if (version == 0x0200)
247 				addr = rvda;
248 			else
249 				addr += rvda;
250 
251 			opregionvbt->vbt_ex = memremap(addr, rvds, MEMREMAP_WB);
252 			if (!opregionvbt->vbt_ex) {
253 				memunmap(opregionvbt->opregion);
254 				kfree(opregionvbt);
255 				return -ENOMEM;
256 			}
257 		}
258 	}
259 
260 	ret = vfio_pci_core_register_dev_region(vdev,
261 		PCI_VENDOR_ID_INTEL | VFIO_REGION_TYPE_PCI_VENDOR_TYPE,
262 		VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION, &vfio_pci_igd_regops,
263 		size, VFIO_REGION_INFO_FLAG_READ, opregionvbt);
264 	if (ret) {
265 		if (opregionvbt->vbt_ex)
266 			memunmap(opregionvbt->vbt_ex);
267 
268 		memunmap(opregionvbt->opregion);
269 		kfree(opregionvbt);
270 		return ret;
271 	}
272 
273 	/* Fill vconfig with the hw value and virtualize register */
274 	*dwordp = cpu_to_le32(addr);
275 	memset(vdev->pci_config_map + OPREGION_PCI_ADDR,
276 	       PCI_CAP_ID_INVALID_VIRT, 4);
277 
278 	return ret;
279 }
280 
vfio_pci_igd_cfg_rw(struct vfio_pci_core_device * vdev,char __user * buf,size_t count,loff_t * ppos,bool iswrite)281 static ssize_t vfio_pci_igd_cfg_rw(struct vfio_pci_core_device *vdev,
282 				   char __user *buf, size_t count, loff_t *ppos,
283 				   bool iswrite)
284 {
285 	unsigned int i = VFIO_PCI_OFFSET_TO_INDEX(*ppos) - VFIO_PCI_NUM_REGIONS;
286 	struct pci_dev *pdev = vdev->region[i].data;
287 	loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
288 	size_t size;
289 	int ret;
290 
291 	if (pos >= vdev->region[i].size || iswrite)
292 		return -EINVAL;
293 
294 	size = count = min(count, (size_t)(vdev->region[i].size - pos));
295 
296 	if ((pos & 1) && size) {
297 		u8 val;
298 
299 		ret = pci_user_read_config_byte(pdev, pos, &val);
300 		if (ret)
301 			return ret;
302 
303 		if (copy_to_user(buf + count - size, &val, 1))
304 			return -EFAULT;
305 
306 		pos++;
307 		size--;
308 	}
309 
310 	if ((pos & 3) && size > 2) {
311 		u16 val;
312 		__le16 lval;
313 
314 		ret = pci_user_read_config_word(pdev, pos, &val);
315 		if (ret)
316 			return ret;
317 
318 		lval = cpu_to_le16(val);
319 		if (copy_to_user(buf + count - size, &lval, 2))
320 			return -EFAULT;
321 
322 		pos += 2;
323 		size -= 2;
324 	}
325 
326 	while (size > 3) {
327 		u32 val;
328 		__le32 lval;
329 
330 		ret = pci_user_read_config_dword(pdev, pos, &val);
331 		if (ret)
332 			return ret;
333 
334 		lval = cpu_to_le32(val);
335 		if (copy_to_user(buf + count - size, &lval, 4))
336 			return -EFAULT;
337 
338 		pos += 4;
339 		size -= 4;
340 	}
341 
342 	while (size >= 2) {
343 		u16 val;
344 		__le16 lval;
345 
346 		ret = pci_user_read_config_word(pdev, pos, &val);
347 		if (ret)
348 			return ret;
349 
350 		lval = cpu_to_le16(val);
351 		if (copy_to_user(buf + count - size, &lval, 2))
352 			return -EFAULT;
353 
354 		pos += 2;
355 		size -= 2;
356 	}
357 
358 	while (size) {
359 		u8 val;
360 
361 		ret = pci_user_read_config_byte(pdev, pos, &val);
362 		if (ret)
363 			return ret;
364 
365 		if (copy_to_user(buf + count - size, &val, 1))
366 			return -EFAULT;
367 
368 		pos++;
369 		size--;
370 	}
371 
372 	*ppos += count;
373 
374 	return count;
375 }
376 
vfio_pci_igd_cfg_release(struct vfio_pci_core_device * vdev,struct vfio_pci_region * region)377 static void vfio_pci_igd_cfg_release(struct vfio_pci_core_device *vdev,
378 				     struct vfio_pci_region *region)
379 {
380 	struct pci_dev *pdev = region->data;
381 
382 	pci_dev_put(pdev);
383 }
384 
385 static const struct vfio_pci_regops vfio_pci_igd_cfg_regops = {
386 	.rw		= vfio_pci_igd_cfg_rw,
387 	.release	= vfio_pci_igd_cfg_release,
388 };
389 
vfio_pci_igd_cfg_init(struct vfio_pci_core_device * vdev)390 static int vfio_pci_igd_cfg_init(struct vfio_pci_core_device *vdev)
391 {
392 	struct pci_dev *host_bridge, *lpc_bridge;
393 	int ret;
394 
395 	host_bridge = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));
396 	if (!host_bridge)
397 		return -ENODEV;
398 
399 	if (host_bridge->vendor != PCI_VENDOR_ID_INTEL ||
400 	    host_bridge->class != (PCI_CLASS_BRIDGE_HOST << 8)) {
401 		pci_dev_put(host_bridge);
402 		return -EINVAL;
403 	}
404 
405 	ret = vfio_pci_core_register_dev_region(vdev,
406 		PCI_VENDOR_ID_INTEL | VFIO_REGION_TYPE_PCI_VENDOR_TYPE,
407 		VFIO_REGION_SUBTYPE_INTEL_IGD_HOST_CFG,
408 		&vfio_pci_igd_cfg_regops, host_bridge->cfg_size,
409 		VFIO_REGION_INFO_FLAG_READ, host_bridge);
410 	if (ret) {
411 		pci_dev_put(host_bridge);
412 		return ret;
413 	}
414 
415 	lpc_bridge = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0x1f, 0));
416 	if (!lpc_bridge)
417 		return -ENODEV;
418 
419 	if (lpc_bridge->vendor != PCI_VENDOR_ID_INTEL ||
420 	    lpc_bridge->class != (PCI_CLASS_BRIDGE_ISA << 8)) {
421 		pci_dev_put(lpc_bridge);
422 		return -EINVAL;
423 	}
424 
425 	ret = vfio_pci_core_register_dev_region(vdev,
426 		PCI_VENDOR_ID_INTEL | VFIO_REGION_TYPE_PCI_VENDOR_TYPE,
427 		VFIO_REGION_SUBTYPE_INTEL_IGD_LPC_CFG,
428 		&vfio_pci_igd_cfg_regops, lpc_bridge->cfg_size,
429 		VFIO_REGION_INFO_FLAG_READ, lpc_bridge);
430 	if (ret) {
431 		pci_dev_put(lpc_bridge);
432 		return ret;
433 	}
434 
435 	return 0;
436 }
437 
vfio_pci_igd_init(struct vfio_pci_core_device * vdev)438 int vfio_pci_igd_init(struct vfio_pci_core_device *vdev)
439 {
440 	int ret;
441 
442 	ret = vfio_pci_igd_opregion_init(vdev);
443 	if (ret)
444 		return ret;
445 
446 	ret = vfio_pci_igd_cfg_init(vdev);
447 	if (ret)
448 		return ret;
449 
450 	return 0;
451 }
452