1 // SPDX-License-Identifier: GPL-2.0 OR MIT
2 /*
3  * Copyright 2016 VMware, Inc., Palo Alto, CA., USA
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the
7  * "Software"), to deal in the Software without restriction, including
8  * without limitation the rights to use, copy, modify, merge, publish,
9  * distribute, sub license, and/or sell copies of the Software, and to
10  * permit persons to whom the Software is furnished to do so, subject to
11  * the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the
14  * next paragraph) shall be included in all copies or substantial portions
15  * of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
20  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
21  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
22  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
23  * USE OR OTHER DEALINGS IN THE SOFTWARE.
24  *
25  */
26 
27 #include <linux/objtool.h>
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/slab.h>
31 #include <linux/cc_platform.h>
32 
33 #include <asm/hypervisor.h>
34 #include <drm/drm_ioctl.h>
35 
36 #include "vmwgfx_drv.h"
37 #include "vmwgfx_msg_x86.h"
38 #include "vmwgfx_msg_arm64.h"
39 #include "vmwgfx_mksstat.h"
40 
41 #define MESSAGE_STATUS_SUCCESS  0x0001
42 #define MESSAGE_STATUS_DORECV   0x0002
43 #define MESSAGE_STATUS_CPT      0x0010
44 #define MESSAGE_STATUS_HB       0x0080
45 
46 #define RPCI_PROTOCOL_NUM       0x49435052
47 #define GUESTMSG_FLAG_COOKIE    0x80000000
48 
49 #define RETRIES                 3
50 
51 #define VMW_HYPERVISOR_MAGIC    0x564D5868
52 
53 #define VMW_PORT_CMD_MSG        30
54 #define VMW_PORT_CMD_HB_MSG     0
55 #define VMW_PORT_CMD_OPEN_CHANNEL  (MSG_TYPE_OPEN << 16 | VMW_PORT_CMD_MSG)
56 #define VMW_PORT_CMD_CLOSE_CHANNEL (MSG_TYPE_CLOSE << 16 | VMW_PORT_CMD_MSG)
57 #define VMW_PORT_CMD_SENDSIZE   (MSG_TYPE_SENDSIZE << 16 | VMW_PORT_CMD_MSG)
58 #define VMW_PORT_CMD_RECVSIZE   (MSG_TYPE_RECVSIZE << 16 | VMW_PORT_CMD_MSG)
59 #define VMW_PORT_CMD_RECVSTATUS (MSG_TYPE_RECVSTATUS << 16 | VMW_PORT_CMD_MSG)
60 
61 #define VMW_PORT_CMD_MKS_GUEST_STATS   85
62 #define VMW_PORT_CMD_MKSGS_RESET       (0 << 16 | VMW_PORT_CMD_MKS_GUEST_STATS)
63 #define VMW_PORT_CMD_MKSGS_ADD_PPN     (1 << 16 | VMW_PORT_CMD_MKS_GUEST_STATS)
64 #define VMW_PORT_CMD_MKSGS_REMOVE_PPN  (2 << 16 | VMW_PORT_CMD_MKS_GUEST_STATS)
65 
66 #define HIGH_WORD(X) ((X & 0xFFFF0000) >> 16)
67 
68 #define MAX_USER_MSG_LENGTH	PAGE_SIZE
69 
70 static u32 vmw_msg_enabled = 1;
71 
72 enum rpc_msg_type {
73 	MSG_TYPE_OPEN,
74 	MSG_TYPE_SENDSIZE,
75 	MSG_TYPE_SENDPAYLOAD,
76 	MSG_TYPE_RECVSIZE,
77 	MSG_TYPE_RECVPAYLOAD,
78 	MSG_TYPE_RECVSTATUS,
79 	MSG_TYPE_CLOSE,
80 };
81 
82 struct rpc_channel {
83 	u16 channel_id;
84 	u32 cookie_high;
85 	u32 cookie_low;
86 };
87 
88 
89 
90 /**
91  * vmw_open_channel
92  *
93  * @channel: RPC channel
94  * @protocol:
95  *
96  * Returns: 0 on success
97  */
vmw_open_channel(struct rpc_channel * channel,unsigned int protocol)98 static int vmw_open_channel(struct rpc_channel *channel, unsigned int protocol)
99 {
100 	unsigned long eax, ebx, ecx, edx, si = 0, di = 0;
101 
102 	VMW_PORT(VMW_PORT_CMD_OPEN_CHANNEL,
103 		(protocol | GUESTMSG_FLAG_COOKIE), si, di,
104 		0,
105 		VMW_HYPERVISOR_MAGIC,
106 		eax, ebx, ecx, edx, si, di);
107 
108 	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
109 		return -EINVAL;
110 
111 	channel->channel_id  = HIGH_WORD(edx);
112 	channel->cookie_high = si;
113 	channel->cookie_low  = di;
114 
115 	return 0;
116 }
117 
118 
119 
120 /**
121  * vmw_close_channel
122  *
123  * @channel: RPC channel
124  *
125  * Returns: 0 on success
126  */
vmw_close_channel(struct rpc_channel * channel)127 static int vmw_close_channel(struct rpc_channel *channel)
128 {
129 	unsigned long eax, ebx, ecx, edx, si, di;
130 
131 	/* Set up additional parameters */
132 	si  = channel->cookie_high;
133 	di  = channel->cookie_low;
134 
135 	VMW_PORT(VMW_PORT_CMD_CLOSE_CHANNEL,
136 		0, si, di,
137 		channel->channel_id << 16,
138 		VMW_HYPERVISOR_MAGIC,
139 		eax, ebx, ecx, edx, si, di);
140 
141 	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
142 		return -EINVAL;
143 
144 	return 0;
145 }
146 
147 /**
148  * vmw_port_hb_out - Send the message payload either through the
149  * high-bandwidth port if available, or through the backdoor otherwise.
150  * @channel: The rpc channel.
151  * @msg: NULL-terminated message.
152  * @hb: Whether the high-bandwidth port is available.
153  *
154  * Return: The port status.
155  */
vmw_port_hb_out(struct rpc_channel * channel,const char * msg,bool hb)156 static unsigned long vmw_port_hb_out(struct rpc_channel *channel,
157 				     const char *msg, bool hb)
158 {
159 	unsigned long si, di, eax, ebx, ecx, edx;
160 	unsigned long msg_len = strlen(msg);
161 
162 	/* HB port can't access encrypted memory. */
163 	if (hb && !cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
164 		unsigned long bp = channel->cookie_high;
165 		u32 channel_id = (channel->channel_id << 16);
166 
167 		si = (uintptr_t) msg;
168 		di = channel->cookie_low;
169 
170 		VMW_PORT_HB_OUT(
171 			(MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
172 			msg_len, si, di,
173 			VMWARE_HYPERVISOR_HB | channel_id |
174 			VMWARE_HYPERVISOR_OUT,
175 			VMW_HYPERVISOR_MAGIC, bp,
176 			eax, ebx, ecx, edx, si, di);
177 
178 		return ebx;
179 	}
180 
181 	/* HB port not available. Send the message 4 bytes at a time. */
182 	ecx = MESSAGE_STATUS_SUCCESS << 16;
183 	while (msg_len && (HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS)) {
184 		unsigned int bytes = min_t(size_t, msg_len, 4);
185 		unsigned long word = 0;
186 
187 		memcpy(&word, msg, bytes);
188 		msg_len -= bytes;
189 		msg += bytes;
190 		si = channel->cookie_high;
191 		di = channel->cookie_low;
192 
193 		VMW_PORT(VMW_PORT_CMD_MSG | (MSG_TYPE_SENDPAYLOAD << 16),
194 			 word, si, di,
195 			 channel->channel_id << 16,
196 			 VMW_HYPERVISOR_MAGIC,
197 			 eax, ebx, ecx, edx, si, di);
198 	}
199 
200 	return ecx;
201 }
202 
203 /**
204  * vmw_port_hb_in - Receive the message payload either through the
205  * high-bandwidth port if available, or through the backdoor otherwise.
206  * @channel: The rpc channel.
207  * @reply: Pointer to buffer holding reply.
208  * @reply_len: Length of the reply.
209  * @hb: Whether the high-bandwidth port is available.
210  *
211  * Return: The port status.
212  */
vmw_port_hb_in(struct rpc_channel * channel,char * reply,unsigned long reply_len,bool hb)213 static unsigned long vmw_port_hb_in(struct rpc_channel *channel, char *reply,
214 				    unsigned long reply_len, bool hb)
215 {
216 	unsigned long si, di, eax, ebx, ecx, edx;
217 
218 	/* HB port can't access encrypted memory */
219 	if (hb && !cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
220 		unsigned long bp = channel->cookie_low;
221 		u32 channel_id = (channel->channel_id << 16);
222 
223 		si = channel->cookie_high;
224 		di = (uintptr_t) reply;
225 
226 		VMW_PORT_HB_IN(
227 			(MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
228 			reply_len, si, di,
229 			VMWARE_HYPERVISOR_HB | channel_id,
230 			VMW_HYPERVISOR_MAGIC, bp,
231 			eax, ebx, ecx, edx, si, di);
232 
233 		return ebx;
234 	}
235 
236 	/* HB port not available. Retrieve the message 4 bytes at a time. */
237 	ecx = MESSAGE_STATUS_SUCCESS << 16;
238 	while (reply_len) {
239 		unsigned int bytes = min_t(unsigned long, reply_len, 4);
240 
241 		si = channel->cookie_high;
242 		di = channel->cookie_low;
243 
244 		VMW_PORT(VMW_PORT_CMD_MSG | (MSG_TYPE_RECVPAYLOAD << 16),
245 			 MESSAGE_STATUS_SUCCESS, si, di,
246 			 channel->channel_id << 16,
247 			 VMW_HYPERVISOR_MAGIC,
248 			 eax, ebx, ecx, edx, si, di);
249 
250 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
251 			break;
252 
253 		memcpy(reply, &ebx, bytes);
254 		reply_len -= bytes;
255 		reply += bytes;
256 	}
257 
258 	return ecx;
259 }
260 
261 
262 /**
263  * vmw_send_msg: Sends a message to the host
264  *
265  * @channel: RPC channel
266  * @msg: NULL terminated string
267  *
268  * Returns: 0 on success
269  */
vmw_send_msg(struct rpc_channel * channel,const char * msg)270 static int vmw_send_msg(struct rpc_channel *channel, const char *msg)
271 {
272 	unsigned long eax, ebx, ecx, edx, si, di;
273 	size_t msg_len = strlen(msg);
274 	int retries = 0;
275 
276 	while (retries < RETRIES) {
277 		retries++;
278 
279 		/* Set up additional parameters */
280 		si  = channel->cookie_high;
281 		di  = channel->cookie_low;
282 
283 		VMW_PORT(VMW_PORT_CMD_SENDSIZE,
284 			msg_len, si, di,
285 			channel->channel_id << 16,
286 			VMW_HYPERVISOR_MAGIC,
287 			eax, ebx, ecx, edx, si, di);
288 
289 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
290 			/* Expected success. Give up. */
291 			return -EINVAL;
292 		}
293 
294 		/* Send msg */
295 		ebx = vmw_port_hb_out(channel, msg,
296 				      !!(HIGH_WORD(ecx) & MESSAGE_STATUS_HB));
297 
298 		if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) != 0) {
299 			return 0;
300 		} else if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) {
301 			/* A checkpoint occurred. Retry. */
302 			continue;
303 		} else {
304 			break;
305 		}
306 	}
307 
308 	return -EINVAL;
309 }
310 STACK_FRAME_NON_STANDARD(vmw_send_msg);
311 
312 
313 /**
314  * vmw_recv_msg: Receives a message from the host
315  *
316  * Note:  It is the caller's responsibility to call kfree() on msg.
317  *
318  * @channel:  channel opened by vmw_open_channel
319  * @msg:  [OUT] message received from the host
320  * @msg_len: message length
321  */
vmw_recv_msg(struct rpc_channel * channel,void ** msg,size_t * msg_len)322 static int vmw_recv_msg(struct rpc_channel *channel, void **msg,
323 			size_t *msg_len)
324 {
325 	unsigned long eax, ebx, ecx, edx, si, di;
326 	char *reply;
327 	size_t reply_len;
328 	int retries = 0;
329 
330 
331 	*msg_len = 0;
332 	*msg = NULL;
333 
334 	while (retries < RETRIES) {
335 		retries++;
336 
337 		/* Set up additional parameters */
338 		si  = channel->cookie_high;
339 		di  = channel->cookie_low;
340 
341 		VMW_PORT(VMW_PORT_CMD_RECVSIZE,
342 			0, si, di,
343 			channel->channel_id << 16,
344 			VMW_HYPERVISOR_MAGIC,
345 			eax, ebx, ecx, edx, si, di);
346 
347 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
348 			DRM_ERROR("Failed to get reply size for host message.\n");
349 			return -EINVAL;
350 		}
351 
352 		/* No reply available.  This is okay. */
353 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_DORECV) == 0)
354 			return 0;
355 
356 		reply_len = ebx;
357 		reply     = kzalloc(reply_len + 1, GFP_KERNEL);
358 		if (!reply) {
359 			DRM_ERROR("Cannot allocate memory for host message reply.\n");
360 			return -ENOMEM;
361 		}
362 
363 
364 		/* Receive buffer */
365 		ebx = vmw_port_hb_in(channel, reply, reply_len,
366 				     !!(HIGH_WORD(ecx) & MESSAGE_STATUS_HB));
367 		if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) == 0) {
368 			kfree(reply);
369 			reply = NULL;
370 			if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) {
371 				/* A checkpoint occurred. Retry. */
372 				continue;
373 			}
374 
375 			return -EINVAL;
376 		}
377 
378 		reply[reply_len] = '\0';
379 
380 
381 		/* Ack buffer */
382 		si  = channel->cookie_high;
383 		di  = channel->cookie_low;
384 
385 		VMW_PORT(VMW_PORT_CMD_RECVSTATUS,
386 			MESSAGE_STATUS_SUCCESS, si, di,
387 			channel->channel_id << 16,
388 			VMW_HYPERVISOR_MAGIC,
389 			eax, ebx, ecx, edx, si, di);
390 
391 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
392 			kfree(reply);
393 			reply = NULL;
394 			if ((HIGH_WORD(ecx) & MESSAGE_STATUS_CPT) != 0) {
395 				/* A checkpoint occurred. Retry. */
396 				continue;
397 			}
398 
399 			return -EINVAL;
400 		}
401 
402 		break;
403 	}
404 
405 	if (!reply)
406 		return -EINVAL;
407 
408 	*msg_len = reply_len;
409 	*msg     = reply;
410 
411 	return 0;
412 }
413 STACK_FRAME_NON_STANDARD(vmw_recv_msg);
414 
415 
416 /**
417  * vmw_host_get_guestinfo: Gets a GuestInfo parameter
418  *
419  * Gets the value of a  GuestInfo.* parameter.  The value returned will be in
420  * a string, and it is up to the caller to post-process.
421  *
422  * @guest_info_param:  Parameter to get, e.g. GuestInfo.svga.gl3
423  * @buffer: if NULL, *reply_len will contain reply size.
424  * @length: size of the reply_buf.  Set to size of reply upon return
425  *
426  * Returns: 0 on success
427  */
vmw_host_get_guestinfo(const char * guest_info_param,char * buffer,size_t * length)428 int vmw_host_get_guestinfo(const char *guest_info_param,
429 			   char *buffer, size_t *length)
430 {
431 	struct rpc_channel channel;
432 	char *msg, *reply = NULL;
433 	size_t reply_len = 0;
434 
435 	if (!vmw_msg_enabled)
436 		return -ENODEV;
437 
438 	if (!guest_info_param || !length)
439 		return -EINVAL;
440 
441 	msg = kasprintf(GFP_KERNEL, "info-get %s", guest_info_param);
442 	if (!msg) {
443 		DRM_ERROR("Cannot allocate memory to get guest info \"%s\".",
444 			  guest_info_param);
445 		return -ENOMEM;
446 	}
447 
448 	if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM))
449 		goto out_open;
450 
451 	if (vmw_send_msg(&channel, msg) ||
452 	    vmw_recv_msg(&channel, (void *) &reply, &reply_len))
453 		goto out_msg;
454 
455 	vmw_close_channel(&channel);
456 	if (buffer && reply && reply_len > 0) {
457 		/* Remove reply code, which are the first 2 characters of
458 		 * the reply
459 		 */
460 		reply_len = max(reply_len - 2, (size_t) 0);
461 		reply_len = min(reply_len, *length);
462 
463 		if (reply_len > 0)
464 			memcpy(buffer, reply + 2, reply_len);
465 	}
466 
467 	*length = reply_len;
468 
469 	kfree(reply);
470 	kfree(msg);
471 
472 	return 0;
473 
474 out_msg:
475 	vmw_close_channel(&channel);
476 	kfree(reply);
477 out_open:
478 	*length = 0;
479 	kfree(msg);
480 	DRM_ERROR("Failed to get guest info \"%s\".", guest_info_param);
481 
482 	return -EINVAL;
483 }
484 
485 
486 /**
487  * vmw_host_printf: Sends a log message to the host
488  *
489  * @fmt: Regular printf format string and arguments
490  *
491  * Returns: 0 on success
492  */
493 __printf(1, 2)
vmw_host_printf(const char * fmt,...)494 int vmw_host_printf(const char *fmt, ...)
495 {
496 	va_list ap;
497 	struct rpc_channel channel;
498 	char *msg;
499 	char *log;
500 	int ret = 0;
501 
502 	if (!vmw_msg_enabled)
503 		return -ENODEV;
504 
505 	if (!fmt)
506 		return ret;
507 
508 	va_start(ap, fmt);
509 	log = kvasprintf(GFP_KERNEL, fmt, ap);
510 	va_end(ap);
511 	if (!log) {
512 		DRM_ERROR("Cannot allocate memory for the log message.\n");
513 		return -ENOMEM;
514 	}
515 
516 	msg = kasprintf(GFP_KERNEL, "log %s", log);
517 	if (!msg) {
518 		DRM_ERROR("Cannot allocate memory for host log message.\n");
519 		kfree(log);
520 		return -ENOMEM;
521 	}
522 
523 	if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM))
524 		goto out_open;
525 
526 	if (vmw_send_msg(&channel, msg))
527 		goto out_msg;
528 
529 	vmw_close_channel(&channel);
530 	kfree(msg);
531 	kfree(log);
532 
533 	return 0;
534 
535 out_msg:
536 	vmw_close_channel(&channel);
537 out_open:
538 	kfree(msg);
539 	kfree(log);
540 	DRM_ERROR("Failed to send host log message.\n");
541 
542 	return -EINVAL;
543 }
544 
545 
546 /**
547  * vmw_msg_ioctl: Sends and receveives a message to/from host from/to user-space
548  *
549  * Sends a message from user-space to host.
550  * Can also receive a result from host and return that to user-space.
551  *
552  * @dev: Identifies the drm device.
553  * @data: Pointer to the ioctl argument.
554  * @file_priv: Identifies the caller.
555  * Return: Zero on success, negative error code on error.
556  */
557 
vmw_msg_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)558 int vmw_msg_ioctl(struct drm_device *dev, void *data,
559 		  struct drm_file *file_priv)
560 {
561 	struct drm_vmw_msg_arg *arg =
562 			(struct drm_vmw_msg_arg *)data;
563 	struct rpc_channel channel;
564 	char *msg;
565 	int length;
566 
567 	msg = kmalloc(MAX_USER_MSG_LENGTH, GFP_KERNEL);
568 	if (!msg) {
569 		DRM_ERROR("Cannot allocate memory for log message.\n");
570 		return -ENOMEM;
571 	}
572 
573 	length = strncpy_from_user(msg, (void __user *)((unsigned long)arg->send),
574 				   MAX_USER_MSG_LENGTH);
575 	if (length < 0 || length >= MAX_USER_MSG_LENGTH) {
576 		DRM_ERROR("Userspace message access failure.\n");
577 		kfree(msg);
578 		return -EINVAL;
579 	}
580 
581 
582 	if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM)) {
583 		DRM_ERROR("Failed to open channel.\n");
584 		goto out_open;
585 	}
586 
587 	if (vmw_send_msg(&channel, msg)) {
588 		DRM_ERROR("Failed to send message to host.\n");
589 		goto out_msg;
590 	}
591 
592 	if (!arg->send_only) {
593 		char *reply = NULL;
594 		size_t reply_len = 0;
595 
596 		if (vmw_recv_msg(&channel, (void *) &reply, &reply_len)) {
597 			DRM_ERROR("Failed to receive message from host.\n");
598 			goto out_msg;
599 		}
600 		if (reply && reply_len > 0) {
601 			if (copy_to_user((void __user *)((unsigned long)arg->receive),
602 					 reply, reply_len)) {
603 				DRM_ERROR("Failed to copy message to userspace.\n");
604 				kfree(reply);
605 				goto out_msg;
606 			}
607 			arg->receive_len = (__u32)reply_len;
608 		}
609 		kfree(reply);
610 	}
611 
612 	vmw_close_channel(&channel);
613 	kfree(msg);
614 
615 	return 0;
616 
617 out_msg:
618 	vmw_close_channel(&channel);
619 out_open:
620 	kfree(msg);
621 
622 	return -EINVAL;
623 }
624 
625 /**
626  * reset_ppn_array: Resets a PPN64 array to INVALID_PPN64 content
627  *
628  * @arr: Array to reset.
629  * @size: Array length.
630  */
reset_ppn_array(PPN64 * arr,size_t size)631 static inline void reset_ppn_array(PPN64 *arr, size_t size)
632 {
633 	size_t i;
634 
635 	BUG_ON(!arr || size == 0);
636 
637 	for (i = 0; i < size; ++i)
638 		arr[i] = INVALID_PPN64;
639 }
640 
641 /**
642  * hypervisor_ppn_reset_all: Removes all mksGuestStat instance descriptors from
643  * the hypervisor. All related pages should be subsequently unpinned or freed.
644  *
645  */
hypervisor_ppn_reset_all(void)646 static inline void hypervisor_ppn_reset_all(void)
647 {
648 	unsigned long eax, ebx, ecx, edx, si = 0, di = 0;
649 
650 	VMW_PORT(VMW_PORT_CMD_MKSGS_RESET,
651 		0, si, di,
652 		0,
653 		VMW_HYPERVISOR_MAGIC,
654 		eax, ebx, ecx, edx, si, di);
655 }
656 
657 /**
658  * hypervisor_ppn_add: Adds a single mksGuestStat instance descriptor to the
659  * hypervisor. Any related userspace pages should be pinned in advance.
660  *
661  * @pfn: Physical page number of the instance descriptor
662  */
hypervisor_ppn_add(PPN64 pfn)663 static inline void hypervisor_ppn_add(PPN64 pfn)
664 {
665 	unsigned long eax, ebx, ecx, edx, si = 0, di = 0;
666 
667 	VMW_PORT(VMW_PORT_CMD_MKSGS_ADD_PPN,
668 		(unsigned long)pfn, si, di,
669 		0,
670 		VMW_HYPERVISOR_MAGIC,
671 		eax, ebx, ecx, edx, si, di);
672 }
673 
674 /**
675  * hypervisor_ppn_remove: Removes a single mksGuestStat instance descriptor from
676  * the hypervisor. All related pages should be subsequently unpinned or freed.
677  *
678  * @pfn: Physical page number of the instance descriptor
679  */
hypervisor_ppn_remove(PPN64 pfn)680 static inline void hypervisor_ppn_remove(PPN64 pfn)
681 {
682 	unsigned long eax, ebx, ecx, edx, si = 0, di = 0;
683 
684 	VMW_PORT(VMW_PORT_CMD_MKSGS_REMOVE_PPN,
685 		(unsigned long)pfn, si, di,
686 		0,
687 		VMW_HYPERVISOR_MAGIC,
688 		eax, ebx, ecx, edx, si, di);
689 }
690 
691 #if IS_ENABLED(CONFIG_DRM_VMWGFX_MKSSTATS)
692 
693 /* Order of the total number of pages used for kernel-internal mksGuestStat; at least 2 */
694 #define MKSSTAT_KERNEL_PAGES_ORDER 2
695 /* Header to the text description of mksGuestStat instance descriptor */
696 #define MKSSTAT_KERNEL_DESCRIPTION "vmwgfx"
697 
698 /* Kernel mksGuestStats counter names and desciptions; same order as enum mksstat_kern_stats_t */
699 static const char* const mksstat_kern_name_desc[MKSSTAT_KERN_COUNT][2] =
700 {
701 	{ "vmw_execbuf_ioctl", "vmw_execbuf_ioctl" },
702 };
703 
704 /**
705  * mksstat_init_record: Initializes an MKSGuestStatCounter-based record
706  * for the respective mksGuestStat index.
707  *
708  * @stat_idx: Index of the MKSGuestStatCounter-based mksGuestStat record.
709  * @pstat: Pointer to array of MKSGuestStatCounterTime.
710  * @pinfo: Pointer to array of MKSGuestStatInfoEntry.
711  * @pstrs: Pointer to current end of the name/description sequence.
712  * Return: Pointer to the new end of the names/description sequence.
713  */
714 
mksstat_init_record(mksstat_kern_stats_t stat_idx,MKSGuestStatCounterTime * pstat,MKSGuestStatInfoEntry * pinfo,char * pstrs)715 static inline char *mksstat_init_record(mksstat_kern_stats_t stat_idx,
716 	MKSGuestStatCounterTime *pstat, MKSGuestStatInfoEntry *pinfo, char *pstrs)
717 {
718 	char *const pstrd = pstrs + strlen(mksstat_kern_name_desc[stat_idx][0]) + 1;
719 	strcpy(pstrs, mksstat_kern_name_desc[stat_idx][0]);
720 	strcpy(pstrd, mksstat_kern_name_desc[stat_idx][1]);
721 
722 	pinfo[stat_idx].name.s = pstrs;
723 	pinfo[stat_idx].description.s = pstrd;
724 	pinfo[stat_idx].flags = MKS_GUEST_STAT_FLAG_NONE;
725 	pinfo[stat_idx].stat.counter = (MKSGuestStatCounter *)&pstat[stat_idx];
726 
727 	return pstrd + strlen(mksstat_kern_name_desc[stat_idx][1]) + 1;
728 }
729 
730 /**
731  * mksstat_init_record_time: Initializes an MKSGuestStatCounterTime-based record
732  * for the respective mksGuestStat index.
733  *
734  * @stat_idx: Index of the MKSGuestStatCounterTime-based mksGuestStat record.
735  * @pstat: Pointer to array of MKSGuestStatCounterTime.
736  * @pinfo: Pointer to array of MKSGuestStatInfoEntry.
737  * @pstrs: Pointer to current end of the name/description sequence.
738  * Return: Pointer to the new end of the names/description sequence.
739  */
740 
mksstat_init_record_time(mksstat_kern_stats_t stat_idx,MKSGuestStatCounterTime * pstat,MKSGuestStatInfoEntry * pinfo,char * pstrs)741 static inline char *mksstat_init_record_time(mksstat_kern_stats_t stat_idx,
742 	MKSGuestStatCounterTime *pstat, MKSGuestStatInfoEntry *pinfo, char *pstrs)
743 {
744 	char *const pstrd = pstrs + strlen(mksstat_kern_name_desc[stat_idx][0]) + 1;
745 	strcpy(pstrs, mksstat_kern_name_desc[stat_idx][0]);
746 	strcpy(pstrd, mksstat_kern_name_desc[stat_idx][1]);
747 
748 	pinfo[stat_idx].name.s = pstrs;
749 	pinfo[stat_idx].description.s = pstrd;
750 	pinfo[stat_idx].flags = MKS_GUEST_STAT_FLAG_TIME;
751 	pinfo[stat_idx].stat.counterTime = &pstat[stat_idx];
752 
753 	return pstrd + strlen(mksstat_kern_name_desc[stat_idx][1]) + 1;
754 }
755 
756 /**
757  * mksstat_init_kern_id: Creates a single mksGuestStat instance descriptor and
758  * kernel-internal counters. Adds PFN mapping to the hypervisor.
759  *
760  * Create a single mksGuestStat instance descriptor and corresponding structures
761  * for all kernel-internal counters. The corresponding PFNs are mapped with the
762  * hypervisor.
763  *
764  * @ppage: Output pointer to page containing the instance descriptor.
765  * Return: Zero on success, negative error code on error.
766  */
767 
mksstat_init_kern_id(struct page ** ppage)768 static int mksstat_init_kern_id(struct page **ppage)
769 {
770 	MKSGuestStatInstanceDescriptor *pdesc;
771 	MKSGuestStatCounterTime *pstat;
772 	MKSGuestStatInfoEntry *pinfo;
773 	char *pstrs, *pstrs_acc;
774 
775 	/* Allocate pages for the kernel-internal instance descriptor */
776 	struct page *page = alloc_pages(GFP_KERNEL | __GFP_ZERO, MKSSTAT_KERNEL_PAGES_ORDER);
777 
778 	if (!page)
779 		return -ENOMEM;
780 
781 	pdesc = page_address(page);
782 	pstat = vmw_mksstat_get_kern_pstat(pdesc);
783 	pinfo = vmw_mksstat_get_kern_pinfo(pdesc);
784 	pstrs = vmw_mksstat_get_kern_pstrs(pdesc);
785 
786 	/* Set up all kernel-internal counters and corresponding structures */
787 	pstrs_acc = pstrs;
788 	pstrs_acc = mksstat_init_record_time(MKSSTAT_KERN_EXECBUF, pstat, pinfo, pstrs_acc);
789 
790 	/* Add new counters above, in their order of appearance in mksstat_kern_stats_t */
791 
792 	BUG_ON(pstrs_acc - pstrs > PAGE_SIZE);
793 
794 	/* Set up the kernel-internal instance descriptor */
795 	pdesc->reservedMBZ = 0;
796 	pdesc->statStartVA = (uintptr_t)pstat;
797 	pdesc->strsStartVA = (uintptr_t)pstrs;
798 	pdesc->statLength = sizeof(*pstat) * MKSSTAT_KERN_COUNT;
799 	pdesc->infoLength = sizeof(*pinfo) * MKSSTAT_KERN_COUNT;
800 	pdesc->strsLength = pstrs_acc - pstrs;
801 	snprintf(pdesc->description, ARRAY_SIZE(pdesc->description) - 1, "%s pid=%d",
802 		MKSSTAT_KERNEL_DESCRIPTION, current->pid);
803 
804 	pdesc->statPPNs[0] = page_to_pfn(virt_to_page(pstat));
805 	reset_ppn_array(pdesc->statPPNs + 1, ARRAY_SIZE(pdesc->statPPNs) - 1);
806 
807 	pdesc->infoPPNs[0] = page_to_pfn(virt_to_page(pinfo));
808 	reset_ppn_array(pdesc->infoPPNs + 1, ARRAY_SIZE(pdesc->infoPPNs) - 1);
809 
810 	pdesc->strsPPNs[0] = page_to_pfn(virt_to_page(pstrs));
811 	reset_ppn_array(pdesc->strsPPNs + 1, ARRAY_SIZE(pdesc->strsPPNs) - 1);
812 
813 	*ppage = page;
814 
815 	hypervisor_ppn_add((PPN64)page_to_pfn(page));
816 
817 	return 0;
818 }
819 
820 /**
821  * vmw_mksstat_get_kern_slot: Acquires a slot for a single kernel-internal
822  * mksGuestStat instance descriptor.
823  *
824  * Find a slot for a single kernel-internal mksGuestStat instance descriptor.
825  * In case no such was already present, allocate a new one and set up a kernel-
826  * internal mksGuestStat instance descriptor for the former.
827  *
828  * @pid: Process for which a slot is sought.
829  * @dev_priv: Identifies the drm private device.
830  * Return: Non-negative slot on success, negative error code on error.
831  */
832 
vmw_mksstat_get_kern_slot(pid_t pid,struct vmw_private * dev_priv)833 int vmw_mksstat_get_kern_slot(pid_t pid, struct vmw_private *dev_priv)
834 {
835 	const size_t base = (u32)hash_32(pid, MKSSTAT_CAPACITY_LOG2);
836 	size_t i;
837 
838 	for (i = 0; i < ARRAY_SIZE(dev_priv->mksstat_kern_pids); ++i) {
839 		const size_t slot = (i + base) % ARRAY_SIZE(dev_priv->mksstat_kern_pids);
840 
841 		/* Check if an instance descriptor for this pid is already present */
842 		if (pid == (pid_t)atomic_read(&dev_priv->mksstat_kern_pids[slot]))
843 			return (int)slot;
844 
845 		/* Set up a new instance descriptor for this pid */
846 		if (!atomic_cmpxchg(&dev_priv->mksstat_kern_pids[slot], 0, MKSSTAT_PID_RESERVED)) {
847 			const int ret = mksstat_init_kern_id(&dev_priv->mksstat_kern_pages[slot]);
848 
849 			if (!ret) {
850 				/* Reset top-timer tracking for this slot */
851 				dev_priv->mksstat_kern_top_timer[slot] = MKSSTAT_KERN_COUNT;
852 
853 				atomic_set(&dev_priv->mksstat_kern_pids[slot], pid);
854 				return (int)slot;
855 			}
856 
857 			atomic_set(&dev_priv->mksstat_kern_pids[slot], 0);
858 			return ret;
859 		}
860 	}
861 
862 	return -ENOSPC;
863 }
864 
865 #endif
866 
867 /**
868  * vmw_mksstat_cleanup_descriptor: Frees a single userspace-originating
869  * mksGuestStat instance-descriptor page and unpins all related user pages.
870  *
871  * Unpin all user pages realated to this instance descriptor and free
872  * the instance-descriptor page itself.
873  *
874  * @page: Page of the instance descriptor.
875  */
876 
vmw_mksstat_cleanup_descriptor(struct page * page)877 static void vmw_mksstat_cleanup_descriptor(struct page *page)
878 {
879 	MKSGuestStatInstanceDescriptor *pdesc = page_address(page);
880 	size_t i;
881 
882 	for (i = 0; i < ARRAY_SIZE(pdesc->statPPNs) && pdesc->statPPNs[i] != INVALID_PPN64; ++i)
883 		unpin_user_page(pfn_to_page(pdesc->statPPNs[i]));
884 
885 	for (i = 0; i < ARRAY_SIZE(pdesc->infoPPNs) && pdesc->infoPPNs[i] != INVALID_PPN64; ++i)
886 		unpin_user_page(pfn_to_page(pdesc->infoPPNs[i]));
887 
888 	for (i = 0; i < ARRAY_SIZE(pdesc->strsPPNs) && pdesc->strsPPNs[i] != INVALID_PPN64; ++i)
889 		unpin_user_page(pfn_to_page(pdesc->strsPPNs[i]));
890 
891 	__free_page(page);
892 }
893 
894 /**
895  * vmw_mksstat_remove_all: Resets all mksGuestStat instance descriptors
896  * from the hypervisor.
897  *
898  * Discard all hypervisor PFN mappings, containing active mksGuestState instance
899  * descriptors, unpin the related userspace pages and free the related kernel pages.
900  *
901  * @dev_priv: Identifies the drm private device.
902  * Return: Zero on success, negative error code on error.
903  */
904 
vmw_mksstat_remove_all(struct vmw_private * dev_priv)905 int vmw_mksstat_remove_all(struct vmw_private *dev_priv)
906 {
907 	int ret = 0;
908 	size_t i;
909 
910 	/* Discard all PFN mappings with the hypervisor */
911 	hypervisor_ppn_reset_all();
912 
913 	/* Discard all userspace-originating instance descriptors and unpin all related pages */
914 	for (i = 0; i < ARRAY_SIZE(dev_priv->mksstat_user_pids); ++i) {
915 		const pid_t pid0 = (pid_t)atomic_read(&dev_priv->mksstat_user_pids[i]);
916 
917 		if (!pid0)
918 			continue;
919 
920 		if (pid0 != MKSSTAT_PID_RESERVED) {
921 			const pid_t pid1 = atomic_cmpxchg(&dev_priv->mksstat_user_pids[i], pid0, MKSSTAT_PID_RESERVED);
922 
923 			if (!pid1)
924 				continue;
925 
926 			if (pid1 == pid0) {
927 				struct page *const page = dev_priv->mksstat_user_pages[i];
928 
929 				BUG_ON(!page);
930 
931 				dev_priv->mksstat_user_pages[i] = NULL;
932 				atomic_set(&dev_priv->mksstat_user_pids[i], 0);
933 
934 				vmw_mksstat_cleanup_descriptor(page);
935 				continue;
936 			}
937 		}
938 
939 		ret = -EAGAIN;
940 	}
941 
942 #if IS_ENABLED(CONFIG_DRM_VMWGFX_MKSSTATS)
943 	/* Discard all kernel-internal instance descriptors and free all related pages */
944 	for (i = 0; i < ARRAY_SIZE(dev_priv->mksstat_kern_pids); ++i) {
945 		const pid_t pid0 = (pid_t)atomic_read(&dev_priv->mksstat_kern_pids[i]);
946 
947 		if (!pid0)
948 			continue;
949 
950 		if (pid0 != MKSSTAT_PID_RESERVED) {
951 			const pid_t pid1 = atomic_cmpxchg(&dev_priv->mksstat_kern_pids[i], pid0, MKSSTAT_PID_RESERVED);
952 
953 			if (!pid1)
954 				continue;
955 
956 			if (pid1 == pid0) {
957 				struct page *const page = dev_priv->mksstat_kern_pages[i];
958 
959 				BUG_ON(!page);
960 
961 				dev_priv->mksstat_kern_pages[i] = NULL;
962 				atomic_set(&dev_priv->mksstat_kern_pids[i], 0);
963 
964 				__free_pages(page, MKSSTAT_KERNEL_PAGES_ORDER);
965 				continue;
966 			}
967 		}
968 
969 		ret = -EAGAIN;
970 	}
971 
972 #endif
973 	return ret;
974 }
975 
976 /**
977  * vmw_mksstat_reset_ioctl: Resets all mksGuestStat instance descriptors
978  * from the hypervisor.
979  *
980  * Discard all hypervisor PFN mappings, containing active mksGuestStat instance
981  * descriptors, unpin the related userspace pages and free the related kernel pages.
982  *
983  * @dev: Identifies the drm device.
984  * @data: Pointer to the ioctl argument.
985  * @file_priv: Identifies the caller; unused.
986  * Return: Zero on success, negative error code on error.
987  */
988 
vmw_mksstat_reset_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)989 int vmw_mksstat_reset_ioctl(struct drm_device *dev, void *data,
990 				struct drm_file *file_priv)
991 {
992 	struct vmw_private *const dev_priv = vmw_priv(dev);
993 	return vmw_mksstat_remove_all(dev_priv);
994 }
995 
996 /**
997  * vmw_mksstat_add_ioctl: Creates a single userspace-originating mksGuestStat
998  * instance descriptor and registers that with the hypervisor.
999  *
1000  * Create a hypervisor PFN mapping, containing a single mksGuestStat instance
1001  * descriptor and pin the corresponding userspace pages.
1002  *
1003  * @dev: Identifies the drm device.
1004  * @data: Pointer to the ioctl argument.
1005  * @file_priv: Identifies the caller; unused.
1006  * Return: Zero on success, negative error code on error.
1007  */
1008 
vmw_mksstat_add_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)1009 int vmw_mksstat_add_ioctl(struct drm_device *dev, void *data,
1010 				struct drm_file *file_priv)
1011 {
1012 	struct drm_vmw_mksstat_add_arg *arg =
1013 		(struct drm_vmw_mksstat_add_arg *) data;
1014 
1015 	struct vmw_private *const dev_priv = vmw_priv(dev);
1016 
1017 	struct page *page;
1018 	MKSGuestStatInstanceDescriptor *pdesc;
1019 	const size_t num_pages_stat = PFN_UP(arg->stat_len);
1020 	const size_t num_pages_info = PFN_UP(arg->info_len);
1021 	const size_t num_pages_strs = PFN_UP(arg->strs_len);
1022 	long desc_len;
1023 	long nr_pinned_stat;
1024 	long nr_pinned_info;
1025 	long nr_pinned_strs;
1026 	struct page *pages_stat[ARRAY_SIZE(pdesc->statPPNs)];
1027 	struct page *pages_info[ARRAY_SIZE(pdesc->infoPPNs)];
1028 	struct page *pages_strs[ARRAY_SIZE(pdesc->strsPPNs)];
1029 	size_t i, slot;
1030 
1031 	arg->id = -1;
1032 
1033 	if (!arg->stat || !arg->info || !arg->strs)
1034 		return -EINVAL;
1035 
1036 	if (!arg->stat_len || !arg->info_len || !arg->strs_len)
1037 		return -EINVAL;
1038 
1039 	if (!arg->description)
1040 		return -EINVAL;
1041 
1042 	if (num_pages_stat > ARRAY_SIZE(pdesc->statPPNs) ||
1043 		num_pages_info > ARRAY_SIZE(pdesc->infoPPNs) ||
1044 		num_pages_strs > ARRAY_SIZE(pdesc->strsPPNs))
1045 		return -EINVAL;
1046 
1047 	/* Find an available slot in the mksGuestStats user array and reserve it */
1048 	for (slot = 0; slot < ARRAY_SIZE(dev_priv->mksstat_user_pids); ++slot)
1049 		if (!atomic_cmpxchg(&dev_priv->mksstat_user_pids[slot], 0, MKSSTAT_PID_RESERVED))
1050 			break;
1051 
1052 	if (slot == ARRAY_SIZE(dev_priv->mksstat_user_pids))
1053 		return -ENOSPC;
1054 
1055 	BUG_ON(dev_priv->mksstat_user_pages[slot]);
1056 
1057 	/* Allocate a page for the instance descriptor */
1058 	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
1059 
1060 	if (!page) {
1061 		atomic_set(&dev_priv->mksstat_user_pids[slot], 0);
1062 		return -ENOMEM;
1063 	}
1064 
1065 	/* Set up the instance descriptor */
1066 	pdesc = page_address(page);
1067 
1068 	pdesc->reservedMBZ = 0;
1069 	pdesc->statStartVA = arg->stat;
1070 	pdesc->strsStartVA = arg->strs;
1071 	pdesc->statLength = arg->stat_len;
1072 	pdesc->infoLength = arg->info_len;
1073 	pdesc->strsLength = arg->strs_len;
1074 	desc_len = strncpy_from_user(pdesc->description, u64_to_user_ptr(arg->description),
1075 		ARRAY_SIZE(pdesc->description) - 1);
1076 
1077 	if (desc_len < 0) {
1078 		atomic_set(&dev_priv->mksstat_user_pids[slot], 0);
1079 		__free_page(page);
1080 		return -EFAULT;
1081 	}
1082 
1083 	reset_ppn_array(pdesc->statPPNs, ARRAY_SIZE(pdesc->statPPNs));
1084 	reset_ppn_array(pdesc->infoPPNs, ARRAY_SIZE(pdesc->infoPPNs));
1085 	reset_ppn_array(pdesc->strsPPNs, ARRAY_SIZE(pdesc->strsPPNs));
1086 
1087 	/* Pin mksGuestStat user pages and store those in the instance descriptor */
1088 	nr_pinned_stat = pin_user_pages_fast(arg->stat, num_pages_stat, FOLL_LONGTERM, pages_stat);
1089 	if (num_pages_stat != nr_pinned_stat)
1090 		goto err_pin_stat;
1091 
1092 	for (i = 0; i < num_pages_stat; ++i)
1093 		pdesc->statPPNs[i] = page_to_pfn(pages_stat[i]);
1094 
1095 	nr_pinned_info = pin_user_pages_fast(arg->info, num_pages_info, FOLL_LONGTERM, pages_info);
1096 	if (num_pages_info != nr_pinned_info)
1097 		goto err_pin_info;
1098 
1099 	for (i = 0; i < num_pages_info; ++i)
1100 		pdesc->infoPPNs[i] = page_to_pfn(pages_info[i]);
1101 
1102 	nr_pinned_strs = pin_user_pages_fast(arg->strs, num_pages_strs, FOLL_LONGTERM, pages_strs);
1103 	if (num_pages_strs != nr_pinned_strs)
1104 		goto err_pin_strs;
1105 
1106 	for (i = 0; i < num_pages_strs; ++i)
1107 		pdesc->strsPPNs[i] = page_to_pfn(pages_strs[i]);
1108 
1109 	/* Send the descriptor to the host via a hypervisor call. The mksGuestStat
1110 	   pages will remain in use until the user requests a matching remove stats
1111 	   or a stats reset occurs. */
1112 	hypervisor_ppn_add((PPN64)page_to_pfn(page));
1113 
1114 	dev_priv->mksstat_user_pages[slot] = page;
1115 	atomic_set(&dev_priv->mksstat_user_pids[slot], task_pgrp_vnr(current));
1116 
1117 	arg->id = slot;
1118 
1119 	DRM_DEV_INFO(dev->dev, "pid=%d arg.description='%.*s' id=%zu\n", current->pid, (int)desc_len, pdesc->description, slot);
1120 
1121 	return 0;
1122 
1123 err_pin_strs:
1124 	if (nr_pinned_strs > 0)
1125 		unpin_user_pages(pages_strs, nr_pinned_strs);
1126 
1127 err_pin_info:
1128 	if (nr_pinned_info > 0)
1129 		unpin_user_pages(pages_info, nr_pinned_info);
1130 
1131 err_pin_stat:
1132 	if (nr_pinned_stat > 0)
1133 		unpin_user_pages(pages_stat, nr_pinned_stat);
1134 
1135 	atomic_set(&dev_priv->mksstat_user_pids[slot], 0);
1136 	__free_page(page);
1137 	return -ENOMEM;
1138 }
1139 
1140 /**
1141  * vmw_mksstat_remove_ioctl: Removes a single userspace-originating mksGuestStat
1142  * instance descriptor from the hypervisor.
1143  *
1144  * Discard a hypervisor PFN mapping, containing a single mksGuestStat instance
1145  * descriptor and unpin the corresponding userspace pages.
1146  *
1147  * @dev: Identifies the drm device.
1148  * @data: Pointer to the ioctl argument.
1149  * @file_priv: Identifies the caller; unused.
1150  * Return: Zero on success, negative error code on error.
1151  */
1152 
vmw_mksstat_remove_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)1153 int vmw_mksstat_remove_ioctl(struct drm_device *dev, void *data,
1154 				struct drm_file *file_priv)
1155 {
1156 	struct drm_vmw_mksstat_remove_arg *arg =
1157 		(struct drm_vmw_mksstat_remove_arg *) data;
1158 
1159 	struct vmw_private *const dev_priv = vmw_priv(dev);
1160 
1161 	const size_t slot = arg->id;
1162 	pid_t pgid, pid;
1163 
1164 	if (slot >= ARRAY_SIZE(dev_priv->mksstat_user_pids))
1165 		return -EINVAL;
1166 
1167 	DRM_DEV_INFO(dev->dev, "pid=%d arg.id=%zu\n", current->pid, slot);
1168 
1169 	pgid = task_pgrp_vnr(current);
1170 	pid = atomic_cmpxchg(&dev_priv->mksstat_user_pids[slot], pgid, MKSSTAT_PID_RESERVED);
1171 
1172 	if (!pid)
1173 		return 0;
1174 
1175 	if (pid == pgid) {
1176 		struct page *const page = dev_priv->mksstat_user_pages[slot];
1177 
1178 		BUG_ON(!page);
1179 
1180 		dev_priv->mksstat_user_pages[slot] = NULL;
1181 		atomic_set(&dev_priv->mksstat_user_pids[slot], 0);
1182 
1183 		hypervisor_ppn_remove((PPN64)page_to_pfn(page));
1184 
1185 		vmw_mksstat_cleanup_descriptor(page);
1186 		return 0;
1187 	}
1188 
1189 	return -EAGAIN;
1190 }
1191