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2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc 
 kernel/arch/powerpc/platforms/powernv/vas-window.c
....@@ -1,10 +1,6 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  * Copyright 2016-17 IBM Corp.
3
- *
4
- * This program is free software; you can redistribute it and/or
5
- * modify it under the terms of the GNU General Public License
6
- * as published by the Free Software Foundation; either version
7
- * 2 of the License, or (at your option) any later version.
84  */
95 
106 #define pr_fmt(fmt) "vas: " fmt
....@@ -16,6 +12,8 @@
1612 #include <linux/log2.h>
1713 #include <linux/rcupdate.h>
1814 #include <linux/cred.h>
15
+#include <linux/sched/mm.h>
16
+#include <linux/mmu_context.h>
1917 #include <asm/switch_to.h>
2018 #include <asm/ppc-opcode.h>
2119 #include "vas.h"
....@@ -28,7 +26,7 @@
2826  * Compute the paste address region for the window @window using the
2927  * ->paste_base_addr and ->paste_win_id_shift we got from device tree.
3028  */
31
-static void compute_paste_address(struct vas_window *window, u64 *addr, int *len)
29
+void vas_win_paste_addr(struct vas_window *window, u64 *addr, int *len)
3230 {
3331 	int winid;
3432 	u64 base, shift;
....@@ -43,16 +41,6 @@
4341 
4442 	pr_debug("Txwin #%d: Paste addr 0x%llx\n", winid, *addr);
4543 }
46
-
47
-u64 vas_win_paste_addr(struct vas_window *win)
48
-{
49
-	u64 addr;
50
-
51
-	compute_paste_address(win, &addr, NULL);
52
-
53
-	return addr;
54
-}
55
-EXPORT_SYMBOL(vas_win_paste_addr);
5644 
5745 static inline void get_hvwc_mmio_bar(struct vas_window *window,
5846 			u64 *start, int *len)
....@@ -92,7 +80,7 @@
9280 		goto free_name;
9381 
9482 	txwin->paste_addr_name = name;
95
-	compute_paste_address(txwin, &start, &len);
83
+	vas_win_paste_addr(txwin, &start, &len);
9684 
9785 	if (!request_mem_region(start, len, name)) {
9886 		pr_devel("%s(): request_mem_region(0x%llx, %d) failed\n",
....@@ -150,7 +138,7 @@
150138 	u64 busaddr_start;
151139 
152140 	if (window->paste_kaddr) {
153
-		compute_paste_address(window, &busaddr_start, &len);
141
+		vas_win_paste_addr(window, &busaddr_start, &len);
154142 		unmap_region(window->paste_kaddr, busaddr_start, len);
155143 		window->paste_kaddr = NULL;
156144 		kfree(window->paste_addr_name);
....@@ -198,7 +186,7 @@
198186  * OS/User Window Context (UWC) MMIO Base Address Region for the given window.
199187  * Map these bus addresses and save the mapped kernel addresses in @window.
200188  */
201
-int map_winctx_mmio_bars(struct vas_window *window)
189
+static int map_winctx_mmio_bars(struct vas_window *window)
202190 {
203191 	int len;
204192 	u64 start;
....@@ -226,7 +214,7 @@
226214  *	 registers are not sequential. And, we can only write to offsets
227215  *	 with valid registers.
228216  */
229
-void reset_window_regs(struct vas_window *window)
217
+static void reset_window_regs(struct vas_window *window)
230218 {
231219 	write_hvwc_reg(window, VREG(LPID), 0ULL);
232220 	write_hvwc_reg(window, VREG(PID), 0ULL);
....@@ -369,7 +357,8 @@
369357  *	as a one-time task? That could work for NX but what about other
370358  *	receivers?  Let the receivers tell us the rx-fifo buffers for now.
371359  */
372
-int init_winctx_regs(struct vas_window *window, struct vas_winctx *winctx)
360
+static void init_winctx_regs(struct vas_window *window,
361
+			     struct vas_winctx *winctx)
373362 {
374363 	u64 val;
375364 	int fifo_size;
....@@ -387,7 +376,7 @@
387376 	init_xlate_regs(window, winctx->user_win);
388377 
389378 	val = 0ULL;
390
-	val = SET_FIELD(VAS_FAULT_TX_WIN, val, 0);
379
+	val = SET_FIELD(VAS_FAULT_TX_WIN, val, winctx->fault_win_id);
391380 	write_hvwc_reg(window, VREG(FAULT_TX_WIN), val);
392381 
393382 	/* In PowerNV, interrupts go to HV. */
....@@ -414,7 +403,7 @@
414403 	 *
415404 	 * See also: Design note in function header.
416405 	 */
417
-	val = __pa(winctx->rx_fifo);
406
+	val = winctx->rx_fifo;
418407 	val = SET_FIELD(VAS_PAGE_MIGRATION_SELECT, val, 0);
419408 	write_hvwc_reg(window, VREG(LFIFO_BAR), val);
420409 
....@@ -511,8 +500,6 @@
511500 	val = SET_FIELD(VAS_WINCTL_NX_WIN, val, winctx->nx_win);
512501 	val = SET_FIELD(VAS_WINCTL_OPEN, val, 1);
513502 	write_hvwc_reg(window, VREG(WINCTL), val);
514
-
515
-	return 0;
516503 }
517504 
518505 static void vas_release_window_id(struct ida *ida, int winid)
....@@ -750,7 +737,7 @@
750737 		 */
751738 		winctx->fifo_disable = true;
752739 		winctx->intr_disable = true;
753
-		winctx->rx_fifo = NULL;
740
+		winctx->rx_fifo = 0;
754741 	}
755742 
756743 	winctx->lnotify_lpid = rxattr->lnotify_lpid;
....@@ -762,6 +749,8 @@
762749 
763750 	winctx->min_scope = VAS_SCOPE_LOCAL;
764751 	winctx->max_scope = VAS_SCOPE_VECTORED_GROUP;
752
+	if (rxwin->vinst->virq)
753
+		winctx->irq_port = rxwin->vinst->irq_port;
765754 }
766755 
767756 static bool rx_win_args_valid(enum vas_cop_type cop,
....@@ -782,7 +771,7 @@
782771 	if (attr->rx_fifo_size > VAS_RX_FIFO_SIZE_MAX)
783772 		return false;
784773 
785
-	if (attr->wcreds_max > VAS_RX_WCREDS_MAX)
774
+	if (!attr->wcreds_max)
786775 		return false;
787776 
788777 	if (attr->nx_win) {
....@@ -827,7 +816,8 @@
827816 {
828817 	memset(rxattr, 0, sizeof(*rxattr));
829818 
830
-	if (cop == VAS_COP_TYPE_842 || cop == VAS_COP_TYPE_842_HIPRI) {
819
+	if (cop == VAS_COP_TYPE_842 || cop == VAS_COP_TYPE_842_HIPRI ||
820
+		cop == VAS_COP_TYPE_GZIP || cop == VAS_COP_TYPE_GZIP_HIPRI) {
831821 		rxattr->pin_win = true;
832822 		rxattr->nx_win = true;
833823 		rxattr->fault_win = false;
....@@ -841,9 +831,9 @@
841831 		rxattr->fault_win = true;
842832 		rxattr->notify_disable = true;
843833 		rxattr->rx_wcred_mode = true;
844
-		rxattr->tx_wcred_mode = true;
845834 		rxattr->rx_win_ord_mode = true;
846
-		rxattr->tx_win_ord_mode = true;
835
+		rxattr->rej_no_credit = true;
836
+		rxattr->tc_mode = VAS_THRESH_DISABLED;
847837 	} else if (cop == VAS_COP_TYPE_FTW) {
848838 		rxattr->user_win = true;
849839 		rxattr->intr_disable = true;
....@@ -887,9 +877,7 @@
887877 	rxwin->nx_win = rxattr->nx_win;
888878 	rxwin->user_win = rxattr->user_win;
889879 	rxwin->cop = cop;
890
-	rxwin->wcreds_max = rxattr->wcreds_max ?: VAS_WCREDS_DEFAULT;
891
-	if (rxattr->user_win)
892
-		rxwin->pid = task_pid_vnr(current);
880
+	rxwin->wcreds_max = rxattr->wcreds_max;
893881 
894882 	init_winctx_for_rxwin(rxwin, rxattr, &winctx);
895883 	init_winctx_regs(rxwin, &winctx);
....@@ -904,7 +892,8 @@
904892 {
905893 	memset(txattr, 0, sizeof(*txattr));
906894 
907
-	if (cop == VAS_COP_TYPE_842 || cop == VAS_COP_TYPE_842_HIPRI) {
895
+	if (cop == VAS_COP_TYPE_842 || cop == VAS_COP_TYPE_842_HIPRI ||
896
+		cop == VAS_COP_TYPE_GZIP || cop == VAS_COP_TYPE_GZIP_HIPRI) {
908897 		txattr->rej_no_credit = false;
909898 		txattr->rx_wcred_mode = true;
910899 		txattr->tx_wcred_mode = true;
....@@ -958,13 +947,22 @@
958947 	winctx->lpid = txattr->lpid;
959948 	winctx->pidr = txattr->pidr;
960949 	winctx->rx_win_id = txwin->rxwin->winid;
950
+	/*
951
+	 * IRQ and fault window setup is successful. Set fault window
952
+	 * for the send window so that ready to handle faults.
953
+	 */
954
+	if (txwin->vinst->virq)
955
+		winctx->fault_win_id = txwin->vinst->fault_win->winid;
961956 
962957 	winctx->dma_type = VAS_DMA_TYPE_INJECT;
963958 	winctx->tc_mode = txattr->tc_mode;
964959 	winctx->min_scope = VAS_SCOPE_LOCAL;
965960 	winctx->max_scope = VAS_SCOPE_VECTORED_GROUP;
961
+	if (txwin->vinst->virq)
962
+		winctx->irq_port = txwin->vinst->irq_port;
966963 
967
-	winctx->pswid = 0;
964
+	winctx->pswid = txattr->pswid ? txattr->pswid :
965
+			encode_pswid(txwin->vinst->vas_id, txwin->winid);
968966 }
969967 
970968 static bool tx_win_args_valid(enum vas_cop_type cop,
....@@ -979,9 +977,14 @@
979977 	if (attr->wcreds_max > VAS_TX_WCREDS_MAX)
980978 		return false;
981979 
982
-	if (attr->user_win &&
983
-			(cop != VAS_COP_TYPE_FTW || attr->rsvd_txbuf_count))
984
-		return false;
980
+	if (attr->user_win) {
981
+		if (attr->rsvd_txbuf_count)
982
+			return false;
983
+
984
+		if (cop != VAS_COP_TYPE_FTW && cop != VAS_COP_TYPE_GZIP &&
985
+			cop != VAS_COP_TYPE_GZIP_HIPRI)
986
+			return false;
987
+	}
985988 
986989 	return true;
987990 }
....@@ -1030,7 +1033,6 @@
10301033 	txwin->tx_win = 1;
10311034 	txwin->rxwin = rxwin;
10321035 	txwin->nx_win = txwin->rxwin->nx_win;
1033
-	txwin->pid = attr->pid;
10341036 	txwin->user_win = attr->user_win;
10351037 	txwin->wcreds_max = attr->wcreds_max ?: VAS_WCREDS_DEFAULT;
10361038 
....@@ -1054,12 +1056,59 @@
10541056 		}
10551057 	} else {
10561058 		/*
1057
-		 * A user mapping must ensure that context switch issues
1058
-		 * CP_ABORT for this thread.
1059
+		 * Interrupt hanlder or fault window setup failed. Means
1060
+		 * NX can not generate fault for page fault. So not
1061
+		 * opening for user space tx window.
10591062 		 */
1060
-		rc = set_thread_uses_vas();
1061
-		if (rc)
1063
+		if (!vinst->virq) {
1064
+			rc = -ENODEV;
10621065 			goto free_window;
1066
+		}
1067
+
1068
+		/*
1069
+		 * Window opened by a child thread may not be closed when
1070
+		 * it exits. So take reference to its pid and release it
1071
+		 * when the window is free by parent thread.
1072
+		 * Acquire a reference to the task's pid to make sure
1073
+		 * pid will not be re-used - needed only for multithread
1074
+		 * applications.
1075
+		 */
1076
+		txwin->pid = get_task_pid(current, PIDTYPE_PID);
1077
+		/*
1078
+		 * Acquire a reference to the task's mm.
1079
+		 */
1080
+		txwin->mm = get_task_mm(current);
1081
+
1082
+		if (!txwin->mm) {
1083
+			put_pid(txwin->pid);
1084
+			pr_err("VAS: pid(%d): mm_struct is not found\n",
1085
+					current->pid);
1086
+			rc = -EPERM;
1087
+			goto free_window;
1088
+		}
1089
+
1090
+		mmgrab(txwin->mm);
1091
+		mmput(txwin->mm);
1092
+		mm_context_add_vas_window(txwin->mm);
1093
+		/*
1094
+		 * Process closes window during exit. In the case of
1095
+		 * multithread application, the child thread can open
1096
+		 * window and can exit without closing it. so takes tgid
1097
+		 * reference until window closed to make sure tgid is not
1098
+		 * reused.
1099
+		 */
1100
+		txwin->tgid = find_get_pid(task_tgid_vnr(current));
1101
+		/*
1102
+		 * Even a process that has no foreign real address mapping can
1103
+		 * use an unpaired COPY instruction (to no real effect). Issue
1104
+		 * CP_ABORT to clear any pending COPY and prevent a covert
1105
+		 * channel.
1106
+		 *
1107
+		 * __switch_to() will issue CP_ABORT on future context switches
1108
+		 * if process / thread has any open VAS window (Use
1109
+		 * current->mm->context.vas_windows).
1110
+		 */
1111
+		asm volatile(PPC_CP_ABORT);
10631112 	}
10641113 
10651114 	set_vinst_win(vinst, txwin);
....@@ -1142,6 +1191,7 @@
11421191 {
11431192 	u64 val;
11441193 	int creds, mode;
1194
+	int count = 0;
11451195 
11461196 	val = read_hvwc_reg(window, VREG(WINCTL));
11471197 	if (window->tx_win)
....@@ -1160,10 +1210,27 @@
11601210 		creds = GET_FIELD(VAS_LRX_WCRED, val);
11611211 	}
11621212 
1213
+	/*
1214
+	 * Takes around few milliseconds to complete all pending requests
1215
+	 * and return credits.
1216
+	 * TODO: Scan fault FIFO and invalidate CRBs points to this window
1217
+	 *       and issue CRB Kill to stop all pending requests. Need only
1218
+	 *       if there is a bug in NX or fault handling in kernel.
1219
+	 */
11631220 	if (creds < window->wcreds_max) {
11641221 		val = 0;
11651222 		set_current_state(TASK_UNINTERRUPTIBLE);
11661223 		schedule_timeout(msecs_to_jiffies(10));
1224
+		count++;
1225
+		/*
1226
+		 * Process can not close send window until all credits are
1227
+		 * returned.
1228
+		 */
1229
+		if (!(count % 1000))
1230
+			pr_warn_ratelimited("VAS: pid %d stuck. Waiting for credits returned for Window(%d). creds %d, Retries %d\n",
1231
+				vas_window_pid(window), window->winid,
1232
+				creds, count);
1233
+
11671234 		goto retry;
11681235 	}
11691236 }
....@@ -1177,6 +1244,7 @@
11771244 {
11781245 	int busy;
11791246 	u64 val;
1247
+	int count = 0;
11801248 
11811249 retry:
11821250 	val = read_hvwc_reg(window, VREG(WIN_STATUS));
....@@ -1184,7 +1252,16 @@
11841252 	if (busy) {
11851253 		val = 0;
11861254 		set_current_state(TASK_UNINTERRUPTIBLE);
1187
-		schedule_timeout(msecs_to_jiffies(5));
1255
+		schedule_timeout(msecs_to_jiffies(10));
1256
+		count++;
1257
+		/*
1258
+		 * Takes around few milliseconds to process all pending
1259
+		 * requests.
1260
+		 */
1261
+		if (!(count % 1000))
1262
+			pr_warn_ratelimited("VAS: pid %d stuck. Window (ID=%d) is in busy state. Retries %d\n",
1263
+				vas_window_pid(window), window->winid, count);
1264
+
11881265 		goto retry;
11891266 	}
11901267 }
....@@ -1249,19 +1326,29 @@
12491326 
12501327 	unmap_paste_region(window);
12511328 
1252
-	clear_vinst_win(window);
1253
-
12541329 	poll_window_busy_state(window);
12551330 
12561331 	unpin_close_window(window);
12571332 
12581333 	poll_window_credits(window);
12591334 
1335
+	clear_vinst_win(window);
1336
+
12601337 	poll_window_castout(window);
12611338 
12621339 	/* if send window, drop reference to matching receive window */
1263
-	if (window->tx_win)
1340
+	if (window->tx_win) {
1341
+		if (window->user_win) {
1342
+			/* Drop references to pid. tgid and mm */
1343
+			put_pid(window->pid);
1344
+			put_pid(window->tgid);
1345
+			if (window->mm) {
1346
+				mm_context_remove_vas_window(window->mm);
1347
+				mmdrop(window->mm);
1348
+			}
1349
+		}
12641350 		put_rx_win(window->rxwin);
1351
+	}
12651352 
12661353 	vas_window_free(window);
12671354 
....@@ -1270,10 +1357,88 @@
12701357 EXPORT_SYMBOL_GPL(vas_win_close);
12711358 
12721359 /*
1273
- * Return a system-wide unique window id for the window @win.
1360
+ * Return credit for the given window.
1361
+ * Send windows and fault window uses credit mechanism as follows:
1362
+ *
1363
+ * Send windows:
1364
+ * - The default number of credits available for each send window is
1365
+ *   1024. It means 1024 requests can be issued asynchronously at the
1366
+ *   same time. If the credit is not available, that request will be
1367
+ *   returned with RMA_Busy.
1368
+ * - One credit is taken when NX request is issued.
1369
+ * - This credit is returned after NX processed that request.
1370
+ * - If NX encounters translation error, kernel will return the
1371
+ *   credit on the specific send window after processing the fault CRB.
1372
+ *
1373
+ * Fault window:
1374
+ * - The total number credits available is FIFO_SIZE/CRB_SIZE.
1375
+ *   Means 4MB/128 in the current implementation. If credit is not
1376
+ *   available, RMA_Reject is returned.
1377
+ * - A credit is taken when NX pastes CRB in fault FIFO.
1378
+ * - The kernel with return credit on fault window after reading entry
1379
+ *   from fault FIFO.
12741380  */
1275
-u32 vas_win_id(struct vas_window *win)
1381
+void vas_return_credit(struct vas_window *window, bool tx)
12761382 {
1277
-	return encode_pswid(win->vinst->vas_id, win->winid);
1383
+	uint64_t val;
1384
+
1385
+	val = 0ULL;
1386
+	if (tx) { /* send window */
1387
+		val = SET_FIELD(VAS_TX_WCRED, val, 1);
1388
+		write_hvwc_reg(window, VREG(TX_WCRED_ADDER), val);
1389
+	} else {
1390
+		val = SET_FIELD(VAS_LRX_WCRED, val, 1);
1391
+		write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), val);
1392
+	}
12781393 }
1279
-EXPORT_SYMBOL_GPL(vas_win_id);
1394
+
1395
+struct vas_window *vas_pswid_to_window(struct vas_instance *vinst,
1396
+		uint32_t pswid)
1397
+{
1398
+	struct vas_window *window;
1399
+	int winid;
1400
+
1401
+	if (!pswid) {
1402
+		pr_devel("%s: called for pswid 0!\n", __func__);
1403
+		return ERR_PTR(-ESRCH);
1404
+	}
1405
+
1406
+	decode_pswid(pswid, NULL, &winid);
1407
+
1408
+	if (winid >= VAS_WINDOWS_PER_CHIP)
1409
+		return ERR_PTR(-ESRCH);
1410
+
1411
+	/*
1412
+	 * If application closes the window before the hardware
1413
+	 * returns the fault CRB, we should wait in vas_win_close()
1414
+	 * for the pending requests. so the window must be active
1415
+	 * and the process alive.
1416
+	 *
1417
+	 * If its a kernel process, we should not get any faults and
1418
+	 * should not get here.
1419
+	 */
1420
+	window = vinst->windows[winid];
1421
+
1422
+	if (!window) {
1423
+		pr_err("PSWID decode: Could not find window for winid %d pswid %d vinst 0x%p\n",
1424
+			winid, pswid, vinst);
1425
+		return NULL;
1426
+	}
1427
+
1428
+	/*
1429
+	 * Do some sanity checks on the decoded window.  Window should be
1430
+	 * NX GZIP user send window. FTW windows should not incur faults
1431
+	 * since their CRBs are ignored (not queued on FIFO or processed
1432
+	 * by NX).
1433
+	 */
1434
+	if (!window->tx_win || !window->user_win || !window->nx_win ||
1435
+			window->cop == VAS_COP_TYPE_FAULT ||
1436
+			window->cop == VAS_COP_TYPE_FTW) {
1437
+		pr_err("PSWID decode: id %d, tx %d, user %d, nx %d, cop %d\n",
1438
+			winid, window->tx_win, window->user_win,
1439
+			window->nx_win, window->cop);
1440
+		WARN_ON(1);
1441
+	}
1442
+
1443
+	return window;
1444
+}