1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2016-17 IBM Corp.
4 */
5
6 #define pr_fmt(fmt) "vas: " fmt
7
8 #include <linux/types.h>
9 #include <linux/mutex.h>
10 #include <linux/slab.h>
11 #include <linux/io.h>
12 #include <linux/log2.h>
13 #include <linux/rcupdate.h>
14 #include <linux/cred.h>
15 #include <linux/sched/mm.h>
16 #include <linux/mmu_context.h>
17 #include <asm/switch_to.h>
18 #include <asm/ppc-opcode.h>
19 #include "vas.h"
20 #include "copy-paste.h"
21
22 #define CREATE_TRACE_POINTS
23 #include "vas-trace.h"
24
25 /*
26 * Compute the paste address region for the window @window using the
27 * ->paste_base_addr and ->paste_win_id_shift we got from device tree.
28 */
vas_win_paste_addr(struct vas_window * window,u64 * addr,int * len)29 void vas_win_paste_addr(struct vas_window *window, u64 *addr, int *len)
30 {
31 int winid;
32 u64 base, shift;
33
34 base = window->vinst->paste_base_addr;
35 shift = window->vinst->paste_win_id_shift;
36 winid = window->winid;
37
38 *addr = base + (winid << shift);
39 if (len)
40 *len = PAGE_SIZE;
41
42 pr_debug("Txwin #%d: Paste addr 0x%llx\n", winid, *addr);
43 }
44
get_hvwc_mmio_bar(struct vas_window * window,u64 * start,int * len)45 static inline void get_hvwc_mmio_bar(struct vas_window *window,
46 u64 *start, int *len)
47 {
48 u64 pbaddr;
49
50 pbaddr = window->vinst->hvwc_bar_start;
51 *start = pbaddr + window->winid * VAS_HVWC_SIZE;
52 *len = VAS_HVWC_SIZE;
53 }
54
get_uwc_mmio_bar(struct vas_window * window,u64 * start,int * len)55 static inline void get_uwc_mmio_bar(struct vas_window *window,
56 u64 *start, int *len)
57 {
58 u64 pbaddr;
59
60 pbaddr = window->vinst->uwc_bar_start;
61 *start = pbaddr + window->winid * VAS_UWC_SIZE;
62 *len = VAS_UWC_SIZE;
63 }
64
65 /*
66 * Map the paste bus address of the given send window into kernel address
67 * space. Unlike MMIO regions (map_mmio_region() below), paste region must
68 * be mapped cache-able and is only applicable to send windows.
69 */
map_paste_region(struct vas_window * txwin)70 static void *map_paste_region(struct vas_window *txwin)
71 {
72 int len;
73 void *map;
74 char *name;
75 u64 start;
76
77 name = kasprintf(GFP_KERNEL, "window-v%d-w%d", txwin->vinst->vas_id,
78 txwin->winid);
79 if (!name)
80 goto free_name;
81
82 txwin->paste_addr_name = name;
83 vas_win_paste_addr(txwin, &start, &len);
84
85 if (!request_mem_region(start, len, name)) {
86 pr_devel("%s(): request_mem_region(0x%llx, %d) failed\n",
87 __func__, start, len);
88 goto free_name;
89 }
90
91 map = ioremap_cache(start, len);
92 if (!map) {
93 pr_devel("%s(): ioremap_cache(0x%llx, %d) failed\n", __func__,
94 start, len);
95 goto free_name;
96 }
97
98 pr_devel("Mapped paste addr 0x%llx to kaddr 0x%p\n", start, map);
99 return map;
100
101 free_name:
102 kfree(name);
103 return ERR_PTR(-ENOMEM);
104 }
105
map_mmio_region(char * name,u64 start,int len)106 static void *map_mmio_region(char *name, u64 start, int len)
107 {
108 void *map;
109
110 if (!request_mem_region(start, len, name)) {
111 pr_devel("%s(): request_mem_region(0x%llx, %d) failed\n",
112 __func__, start, len);
113 return NULL;
114 }
115
116 map = ioremap(start, len);
117 if (!map) {
118 pr_devel("%s(): ioremap(0x%llx, %d) failed\n", __func__, start,
119 len);
120 return NULL;
121 }
122
123 return map;
124 }
125
unmap_region(void * addr,u64 start,int len)126 static void unmap_region(void *addr, u64 start, int len)
127 {
128 iounmap(addr);
129 release_mem_region((phys_addr_t)start, len);
130 }
131
132 /*
133 * Unmap the paste address region for a window.
134 */
unmap_paste_region(struct vas_window * window)135 static void unmap_paste_region(struct vas_window *window)
136 {
137 int len;
138 u64 busaddr_start;
139
140 if (window->paste_kaddr) {
141 vas_win_paste_addr(window, &busaddr_start, &len);
142 unmap_region(window->paste_kaddr, busaddr_start, len);
143 window->paste_kaddr = NULL;
144 kfree(window->paste_addr_name);
145 window->paste_addr_name = NULL;
146 }
147 }
148
149 /*
150 * Unmap the MMIO regions for a window. Hold the vas_mutex so we don't
151 * unmap when the window's debugfs dir is in use. This serializes close
152 * of a window even on another VAS instance but since its not a critical
153 * path, just minimize the time we hold the mutex for now. We can add
154 * a per-instance mutex later if necessary.
155 */
unmap_winctx_mmio_bars(struct vas_window * window)156 static void unmap_winctx_mmio_bars(struct vas_window *window)
157 {
158 int len;
159 void *uwc_map;
160 void *hvwc_map;
161 u64 busaddr_start;
162
163 mutex_lock(&vas_mutex);
164
165 hvwc_map = window->hvwc_map;
166 window->hvwc_map = NULL;
167
168 uwc_map = window->uwc_map;
169 window->uwc_map = NULL;
170
171 mutex_unlock(&vas_mutex);
172
173 if (hvwc_map) {
174 get_hvwc_mmio_bar(window, &busaddr_start, &len);
175 unmap_region(hvwc_map, busaddr_start, len);
176 }
177
178 if (uwc_map) {
179 get_uwc_mmio_bar(window, &busaddr_start, &len);
180 unmap_region(uwc_map, busaddr_start, len);
181 }
182 }
183
184 /*
185 * Find the Hypervisor Window Context (HVWC) MMIO Base Address Region and the
186 * OS/User Window Context (UWC) MMIO Base Address Region for the given window.
187 * Map these bus addresses and save the mapped kernel addresses in @window.
188 */
map_winctx_mmio_bars(struct vas_window * window)189 static int map_winctx_mmio_bars(struct vas_window *window)
190 {
191 int len;
192 u64 start;
193
194 get_hvwc_mmio_bar(window, &start, &len);
195 window->hvwc_map = map_mmio_region("HVWCM_Window", start, len);
196
197 get_uwc_mmio_bar(window, &start, &len);
198 window->uwc_map = map_mmio_region("UWCM_Window", start, len);
199
200 if (!window->hvwc_map || !window->uwc_map) {
201 unmap_winctx_mmio_bars(window);
202 return -1;
203 }
204
205 return 0;
206 }
207
208 /*
209 * Reset all valid registers in the HV and OS/User Window Contexts for
210 * the window identified by @window.
211 *
212 * NOTE: We cannot really use a for loop to reset window context. Not all
213 * offsets in a window context are valid registers and the valid
214 * registers are not sequential. And, we can only write to offsets
215 * with valid registers.
216 */
reset_window_regs(struct vas_window * window)217 static void reset_window_regs(struct vas_window *window)
218 {
219 write_hvwc_reg(window, VREG(LPID), 0ULL);
220 write_hvwc_reg(window, VREG(PID), 0ULL);
221 write_hvwc_reg(window, VREG(XLATE_MSR), 0ULL);
222 write_hvwc_reg(window, VREG(XLATE_LPCR), 0ULL);
223 write_hvwc_reg(window, VREG(XLATE_CTL), 0ULL);
224 write_hvwc_reg(window, VREG(AMR), 0ULL);
225 write_hvwc_reg(window, VREG(SEIDR), 0ULL);
226 write_hvwc_reg(window, VREG(FAULT_TX_WIN), 0ULL);
227 write_hvwc_reg(window, VREG(OSU_INTR_SRC_RA), 0ULL);
228 write_hvwc_reg(window, VREG(HV_INTR_SRC_RA), 0ULL);
229 write_hvwc_reg(window, VREG(PSWID), 0ULL);
230 write_hvwc_reg(window, VREG(LFIFO_BAR), 0ULL);
231 write_hvwc_reg(window, VREG(LDATA_STAMP_CTL), 0ULL);
232 write_hvwc_reg(window, VREG(LDMA_CACHE_CTL), 0ULL);
233 write_hvwc_reg(window, VREG(LRFIFO_PUSH), 0ULL);
234 write_hvwc_reg(window, VREG(CURR_MSG_COUNT), 0ULL);
235 write_hvwc_reg(window, VREG(LNOTIFY_AFTER_COUNT), 0ULL);
236 write_hvwc_reg(window, VREG(LRX_WCRED), 0ULL);
237 write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
238 write_hvwc_reg(window, VREG(TX_WCRED), 0ULL);
239 write_hvwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
240 write_hvwc_reg(window, VREG(LFIFO_SIZE), 0ULL);
241 write_hvwc_reg(window, VREG(WINCTL), 0ULL);
242 write_hvwc_reg(window, VREG(WIN_STATUS), 0ULL);
243 write_hvwc_reg(window, VREG(WIN_CTX_CACHING_CTL), 0ULL);
244 write_hvwc_reg(window, VREG(TX_RSVD_BUF_COUNT), 0ULL);
245 write_hvwc_reg(window, VREG(LRFIFO_WIN_PTR), 0ULL);
246 write_hvwc_reg(window, VREG(LNOTIFY_CTL), 0ULL);
247 write_hvwc_reg(window, VREG(LNOTIFY_PID), 0ULL);
248 write_hvwc_reg(window, VREG(LNOTIFY_LPID), 0ULL);
249 write_hvwc_reg(window, VREG(LNOTIFY_TID), 0ULL);
250 write_hvwc_reg(window, VREG(LNOTIFY_SCOPE), 0ULL);
251 write_hvwc_reg(window, VREG(NX_UTIL_ADDER), 0ULL);
252
253 /* Skip read-only registers: NX_UTIL and NX_UTIL_SE */
254
255 /*
256 * The send and receive window credit adder registers are also
257 * accessible from HVWC and have been initialized above. We don't
258 * need to initialize from the OS/User Window Context, so skip
259 * following calls:
260 *
261 * write_uwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
262 * write_uwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
263 */
264 }
265
266 /*
267 * Initialize window context registers related to Address Translation.
268 * These registers are common to send/receive windows although they
269 * differ for user/kernel windows. As we resolve the TODOs we may
270 * want to add fields to vas_winctx and move the initialization to
271 * init_vas_winctx_regs().
272 */
init_xlate_regs(struct vas_window * window,bool user_win)273 static void init_xlate_regs(struct vas_window *window, bool user_win)
274 {
275 u64 lpcr, val;
276
277 /*
278 * MSR_TA, MSR_US are false for both kernel and user.
279 * MSR_DR and MSR_PR are false for kernel.
280 */
281 val = 0ULL;
282 val = SET_FIELD(VAS_XLATE_MSR_HV, val, 1);
283 val = SET_FIELD(VAS_XLATE_MSR_SF, val, 1);
284 if (user_win) {
285 val = SET_FIELD(VAS_XLATE_MSR_DR, val, 1);
286 val = SET_FIELD(VAS_XLATE_MSR_PR, val, 1);
287 }
288 write_hvwc_reg(window, VREG(XLATE_MSR), val);
289
290 lpcr = mfspr(SPRN_LPCR);
291 val = 0ULL;
292 /*
293 * NOTE: From Section 5.7.8.1 Segment Lookaside Buffer of the
294 * Power ISA, v3.0B, Page size encoding is 0 = 4KB, 5 = 64KB.
295 *
296 * NOTE: From Section 1.3.1, Address Translation Context of the
297 * Nest MMU Workbook, LPCR_SC should be 0 for Power9.
298 */
299 val = SET_FIELD(VAS_XLATE_LPCR_PAGE_SIZE, val, 5);
300 val = SET_FIELD(VAS_XLATE_LPCR_ISL, val, lpcr & LPCR_ISL);
301 val = SET_FIELD(VAS_XLATE_LPCR_TC, val, lpcr & LPCR_TC);
302 val = SET_FIELD(VAS_XLATE_LPCR_SC, val, 0);
303 write_hvwc_reg(window, VREG(XLATE_LPCR), val);
304
305 /*
306 * Section 1.3.1 (Address translation Context) of NMMU workbook.
307 * 0b00 Hashed Page Table mode
308 * 0b01 Reserved
309 * 0b10 Radix on HPT
310 * 0b11 Radix on Radix
311 */
312 val = 0ULL;
313 val = SET_FIELD(VAS_XLATE_MODE, val, radix_enabled() ? 3 : 2);
314 write_hvwc_reg(window, VREG(XLATE_CTL), val);
315
316 /*
317 * TODO: Can we mfspr(AMR) even for user windows?
318 */
319 val = 0ULL;
320 val = SET_FIELD(VAS_AMR, val, mfspr(SPRN_AMR));
321 write_hvwc_reg(window, VREG(AMR), val);
322
323 val = 0ULL;
324 val = SET_FIELD(VAS_SEIDR, val, 0);
325 write_hvwc_reg(window, VREG(SEIDR), val);
326 }
327
328 /*
329 * Initialize Reserved Send Buffer Count for the send window. It involves
330 * writing to the register, reading it back to confirm that the hardware
331 * has enough buffers to reserve. See section 1.3.1.2.1 of VAS workbook.
332 *
333 * Since we can only make a best-effort attempt to fulfill the request,
334 * we don't return any errors if we cannot.
335 *
336 * TODO: Reserved (aka dedicated) send buffers are not supported yet.
337 */
init_rsvd_tx_buf_count(struct vas_window * txwin,struct vas_winctx * winctx)338 static void init_rsvd_tx_buf_count(struct vas_window *txwin,
339 struct vas_winctx *winctx)
340 {
341 write_hvwc_reg(txwin, VREG(TX_RSVD_BUF_COUNT), 0ULL);
342 }
343
344 /*
345 * init_winctx_regs()
346 * Initialize window context registers for a receive window.
347 * Except for caching control and marking window open, the registers
348 * are initialized in the order listed in Section 3.1.4 (Window Context
349 * Cache Register Details) of the VAS workbook although they don't need
350 * to be.
351 *
352 * Design note: For NX receive windows, NX allocates the FIFO buffer in OPAL
353 * (so that it can get a large contiguous area) and passes that buffer
354 * to kernel via device tree. We now write that buffer address to the
355 * FIFO BAR. Would it make sense to do this all in OPAL? i.e have OPAL
356 * write the per-chip RX FIFO addresses to the windows during boot-up
357 * as a one-time task? That could work for NX but what about other
358 * receivers? Let the receivers tell us the rx-fifo buffers for now.
359 */
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)
362 {
363 u64 val;
364 int fifo_size;
365
366 reset_window_regs(window);
367
368 val = 0ULL;
369 val = SET_FIELD(VAS_LPID, val, winctx->lpid);
370 write_hvwc_reg(window, VREG(LPID), val);
371
372 val = 0ULL;
373 val = SET_FIELD(VAS_PID_ID, val, winctx->pidr);
374 write_hvwc_reg(window, VREG(PID), val);
375
376 init_xlate_regs(window, winctx->user_win);
377
378 val = 0ULL;
379 val = SET_FIELD(VAS_FAULT_TX_WIN, val, winctx->fault_win_id);
380 write_hvwc_reg(window, VREG(FAULT_TX_WIN), val);
381
382 /* In PowerNV, interrupts go to HV. */
383 write_hvwc_reg(window, VREG(OSU_INTR_SRC_RA), 0ULL);
384
385 val = 0ULL;
386 val = SET_FIELD(VAS_HV_INTR_SRC_RA, val, winctx->irq_port);
387 write_hvwc_reg(window, VREG(HV_INTR_SRC_RA), val);
388
389 val = 0ULL;
390 val = SET_FIELD(VAS_PSWID_EA_HANDLE, val, winctx->pswid);
391 write_hvwc_reg(window, VREG(PSWID), val);
392
393 write_hvwc_reg(window, VREG(SPARE1), 0ULL);
394 write_hvwc_reg(window, VREG(SPARE2), 0ULL);
395 write_hvwc_reg(window, VREG(SPARE3), 0ULL);
396
397 /*
398 * NOTE: VAS expects the FIFO address to be copied into the LFIFO_BAR
399 * register as is - do NOT shift the address into VAS_LFIFO_BAR
400 * bit fields! Ok to set the page migration select fields -
401 * VAS ignores the lower 10+ bits in the address anyway, because
402 * the minimum FIFO size is 1K?
403 *
404 * See also: Design note in function header.
405 */
406 val = __pa(winctx->rx_fifo);
407 val = SET_FIELD(VAS_PAGE_MIGRATION_SELECT, val, 0);
408 write_hvwc_reg(window, VREG(LFIFO_BAR), val);
409
410 val = 0ULL;
411 val = SET_FIELD(VAS_LDATA_STAMP, val, winctx->data_stamp);
412 write_hvwc_reg(window, VREG(LDATA_STAMP_CTL), val);
413
414 val = 0ULL;
415 val = SET_FIELD(VAS_LDMA_TYPE, val, winctx->dma_type);
416 val = SET_FIELD(VAS_LDMA_FIFO_DISABLE, val, winctx->fifo_disable);
417 write_hvwc_reg(window, VREG(LDMA_CACHE_CTL), val);
418
419 write_hvwc_reg(window, VREG(LRFIFO_PUSH), 0ULL);
420 write_hvwc_reg(window, VREG(CURR_MSG_COUNT), 0ULL);
421 write_hvwc_reg(window, VREG(LNOTIFY_AFTER_COUNT), 0ULL);
422
423 val = 0ULL;
424 val = SET_FIELD(VAS_LRX_WCRED, val, winctx->wcreds_max);
425 write_hvwc_reg(window, VREG(LRX_WCRED), val);
426
427 val = 0ULL;
428 val = SET_FIELD(VAS_TX_WCRED, val, winctx->wcreds_max);
429 write_hvwc_reg(window, VREG(TX_WCRED), val);
430
431 write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
432 write_hvwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
433
434 fifo_size = winctx->rx_fifo_size / 1024;
435
436 val = 0ULL;
437 val = SET_FIELD(VAS_LFIFO_SIZE, val, ilog2(fifo_size));
438 write_hvwc_reg(window, VREG(LFIFO_SIZE), val);
439
440 /* Update window control and caching control registers last so
441 * we mark the window open only after fully initializing it and
442 * pushing context to cache.
443 */
444
445 write_hvwc_reg(window, VREG(WIN_STATUS), 0ULL);
446
447 init_rsvd_tx_buf_count(window, winctx);
448
449 /* for a send window, point to the matching receive window */
450 val = 0ULL;
451 val = SET_FIELD(VAS_LRX_WIN_ID, val, winctx->rx_win_id);
452 write_hvwc_reg(window, VREG(LRFIFO_WIN_PTR), val);
453
454 write_hvwc_reg(window, VREG(SPARE4), 0ULL);
455
456 val = 0ULL;
457 val = SET_FIELD(VAS_NOTIFY_DISABLE, val, winctx->notify_disable);
458 val = SET_FIELD(VAS_INTR_DISABLE, val, winctx->intr_disable);
459 val = SET_FIELD(VAS_NOTIFY_EARLY, val, winctx->notify_early);
460 val = SET_FIELD(VAS_NOTIFY_OSU_INTR, val, winctx->notify_os_intr_reg);
461 write_hvwc_reg(window, VREG(LNOTIFY_CTL), val);
462
463 val = 0ULL;
464 val = SET_FIELD(VAS_LNOTIFY_PID, val, winctx->lnotify_pid);
465 write_hvwc_reg(window, VREG(LNOTIFY_PID), val);
466
467 val = 0ULL;
468 val = SET_FIELD(VAS_LNOTIFY_LPID, val, winctx->lnotify_lpid);
469 write_hvwc_reg(window, VREG(LNOTIFY_LPID), val);
470
471 val = 0ULL;
472 val = SET_FIELD(VAS_LNOTIFY_TID, val, winctx->lnotify_tid);
473 write_hvwc_reg(window, VREG(LNOTIFY_TID), val);
474
475 val = 0ULL;
476 val = SET_FIELD(VAS_LNOTIFY_MIN_SCOPE, val, winctx->min_scope);
477 val = SET_FIELD(VAS_LNOTIFY_MAX_SCOPE, val, winctx->max_scope);
478 write_hvwc_reg(window, VREG(LNOTIFY_SCOPE), val);
479
480 /* Skip read-only registers NX_UTIL and NX_UTIL_SE */
481
482 write_hvwc_reg(window, VREG(SPARE5), 0ULL);
483 write_hvwc_reg(window, VREG(NX_UTIL_ADDER), 0ULL);
484 write_hvwc_reg(window, VREG(SPARE6), 0ULL);
485
486 /* Finally, push window context to memory and... */
487 val = 0ULL;
488 val = SET_FIELD(VAS_PUSH_TO_MEM, val, 1);
489 write_hvwc_reg(window, VREG(WIN_CTX_CACHING_CTL), val);
490
491 /* ... mark the window open for business */
492 val = 0ULL;
493 val = SET_FIELD(VAS_WINCTL_REJ_NO_CREDIT, val, winctx->rej_no_credit);
494 val = SET_FIELD(VAS_WINCTL_PIN, val, winctx->pin_win);
495 val = SET_FIELD(VAS_WINCTL_TX_WCRED_MODE, val, winctx->tx_wcred_mode);
496 val = SET_FIELD(VAS_WINCTL_RX_WCRED_MODE, val, winctx->rx_wcred_mode);
497 val = SET_FIELD(VAS_WINCTL_TX_WORD_MODE, val, winctx->tx_word_mode);
498 val = SET_FIELD(VAS_WINCTL_RX_WORD_MODE, val, winctx->rx_word_mode);
499 val = SET_FIELD(VAS_WINCTL_FAULT_WIN, val, winctx->fault_win);
500 val = SET_FIELD(VAS_WINCTL_NX_WIN, val, winctx->nx_win);
501 val = SET_FIELD(VAS_WINCTL_OPEN, val, 1);
502 write_hvwc_reg(window, VREG(WINCTL), val);
503 }
504
vas_release_window_id(struct ida * ida,int winid)505 static void vas_release_window_id(struct ida *ida, int winid)
506 {
507 ida_free(ida, winid);
508 }
509
vas_assign_window_id(struct ida * ida)510 static int vas_assign_window_id(struct ida *ida)
511 {
512 int winid = ida_alloc_max(ida, VAS_WINDOWS_PER_CHIP - 1, GFP_KERNEL);
513
514 if (winid == -ENOSPC) {
515 pr_err("Too many (%d) open windows\n", VAS_WINDOWS_PER_CHIP);
516 return -EAGAIN;
517 }
518
519 return winid;
520 }
521
vas_window_free(struct vas_window * window)522 static void vas_window_free(struct vas_window *window)
523 {
524 int winid = window->winid;
525 struct vas_instance *vinst = window->vinst;
526
527 unmap_winctx_mmio_bars(window);
528
529 vas_window_free_dbgdir(window);
530
531 kfree(window);
532
533 vas_release_window_id(&vinst->ida, winid);
534 }
535
vas_window_alloc(struct vas_instance * vinst)536 static struct vas_window *vas_window_alloc(struct vas_instance *vinst)
537 {
538 int winid;
539 struct vas_window *window;
540
541 winid = vas_assign_window_id(&vinst->ida);
542 if (winid < 0)
543 return ERR_PTR(winid);
544
545 window = kzalloc(sizeof(*window), GFP_KERNEL);
546 if (!window)
547 goto out_free;
548
549 window->vinst = vinst;
550 window->winid = winid;
551
552 if (map_winctx_mmio_bars(window))
553 goto out_free;
554
555 vas_window_init_dbgdir(window);
556
557 return window;
558
559 out_free:
560 kfree(window);
561 vas_release_window_id(&vinst->ida, winid);
562 return ERR_PTR(-ENOMEM);
563 }
564
put_rx_win(struct vas_window * rxwin)565 static void put_rx_win(struct vas_window *rxwin)
566 {
567 /* Better not be a send window! */
568 WARN_ON_ONCE(rxwin->tx_win);
569
570 atomic_dec(&rxwin->num_txwins);
571 }
572
573 /*
574 * Find the user space receive window given the @pswid.
575 * - We must have a valid vasid and it must belong to this instance.
576 * (so both send and receive windows are on the same VAS instance)
577 * - The window must refer to an OPEN, FTW, RECEIVE window.
578 *
579 * NOTE: We access ->windows[] table and assume that vinst->mutex is held.
580 */
get_user_rxwin(struct vas_instance * vinst,u32 pswid)581 static struct vas_window *get_user_rxwin(struct vas_instance *vinst, u32 pswid)
582 {
583 int vasid, winid;
584 struct vas_window *rxwin;
585
586 decode_pswid(pswid, &vasid, &winid);
587
588 if (vinst->vas_id != vasid)
589 return ERR_PTR(-EINVAL);
590
591 rxwin = vinst->windows[winid];
592
593 if (!rxwin || rxwin->tx_win || rxwin->cop != VAS_COP_TYPE_FTW)
594 return ERR_PTR(-EINVAL);
595
596 return rxwin;
597 }
598
599 /*
600 * Get the VAS receive window associated with NX engine identified
601 * by @cop and if applicable, @pswid.
602 *
603 * See also function header of set_vinst_win().
604 */
get_vinst_rxwin(struct vas_instance * vinst,enum vas_cop_type cop,u32 pswid)605 static struct vas_window *get_vinst_rxwin(struct vas_instance *vinst,
606 enum vas_cop_type cop, u32 pswid)
607 {
608 struct vas_window *rxwin;
609
610 mutex_lock(&vinst->mutex);
611
612 if (cop == VAS_COP_TYPE_FTW)
613 rxwin = get_user_rxwin(vinst, pswid);
614 else
615 rxwin = vinst->rxwin[cop] ?: ERR_PTR(-EINVAL);
616
617 if (!IS_ERR(rxwin))
618 atomic_inc(&rxwin->num_txwins);
619
620 mutex_unlock(&vinst->mutex);
621
622 return rxwin;
623 }
624
625 /*
626 * We have two tables of windows in a VAS instance. The first one,
627 * ->windows[], contains all the windows in the instance and allows
628 * looking up a window by its id. It is used to look up send windows
629 * during fault handling and receive windows when pairing user space
630 * send/receive windows.
631 *
632 * The second table, ->rxwin[], contains receive windows that are
633 * associated with NX engines. This table has VAS_COP_TYPE_MAX
634 * entries and is used to look up a receive window by its
635 * coprocessor type.
636 *
637 * Here, we save @window in the ->windows[] table. If it is a receive
638 * window, we also save the window in the ->rxwin[] table.
639 */
set_vinst_win(struct vas_instance * vinst,struct vas_window * window)640 static void set_vinst_win(struct vas_instance *vinst,
641 struct vas_window *window)
642 {
643 int id = window->winid;
644
645 mutex_lock(&vinst->mutex);
646
647 /*
648 * There should only be one receive window for a coprocessor type
649 * unless its a user (FTW) window.
650 */
651 if (!window->user_win && !window->tx_win) {
652 WARN_ON_ONCE(vinst->rxwin[window->cop]);
653 vinst->rxwin[window->cop] = window;
654 }
655
656 WARN_ON_ONCE(vinst->windows[id] != NULL);
657 vinst->windows[id] = window;
658
659 mutex_unlock(&vinst->mutex);
660 }
661
662 /*
663 * Clear this window from the table(s) of windows for this VAS instance.
664 * See also function header of set_vinst_win().
665 */
clear_vinst_win(struct vas_window * window)666 static void clear_vinst_win(struct vas_window *window)
667 {
668 int id = window->winid;
669 struct vas_instance *vinst = window->vinst;
670
671 mutex_lock(&vinst->mutex);
672
673 if (!window->user_win && !window->tx_win) {
674 WARN_ON_ONCE(!vinst->rxwin[window->cop]);
675 vinst->rxwin[window->cop] = NULL;
676 }
677
678 WARN_ON_ONCE(vinst->windows[id] != window);
679 vinst->windows[id] = NULL;
680
681 mutex_unlock(&vinst->mutex);
682 }
683
init_winctx_for_rxwin(struct vas_window * rxwin,struct vas_rx_win_attr * rxattr,struct vas_winctx * winctx)684 static void init_winctx_for_rxwin(struct vas_window *rxwin,
685 struct vas_rx_win_attr *rxattr,
686 struct vas_winctx *winctx)
687 {
688 /*
689 * We first zero (memset()) all fields and only set non-zero fields.
690 * Following fields are 0/false but maybe deserve a comment:
691 *
692 * ->notify_os_intr_reg In powerNV, send intrs to HV
693 * ->notify_disable False for NX windows
694 * ->intr_disable False for Fault Windows
695 * ->xtra_write False for NX windows
696 * ->notify_early NA for NX windows
697 * ->rsvd_txbuf_count NA for Rx windows
698 * ->lpid, ->pid, ->tid NA for Rx windows
699 */
700
701 memset(winctx, 0, sizeof(struct vas_winctx));
702
703 winctx->rx_fifo = rxattr->rx_fifo;
704 winctx->rx_fifo_size = rxattr->rx_fifo_size;
705 winctx->wcreds_max = rxwin->wcreds_max;
706 winctx->pin_win = rxattr->pin_win;
707
708 winctx->nx_win = rxattr->nx_win;
709 winctx->fault_win = rxattr->fault_win;
710 winctx->user_win = rxattr->user_win;
711 winctx->rej_no_credit = rxattr->rej_no_credit;
712 winctx->rx_word_mode = rxattr->rx_win_ord_mode;
713 winctx->tx_word_mode = rxattr->tx_win_ord_mode;
714 winctx->rx_wcred_mode = rxattr->rx_wcred_mode;
715 winctx->tx_wcred_mode = rxattr->tx_wcred_mode;
716 winctx->notify_early = rxattr->notify_early;
717
718 if (winctx->nx_win) {
719 winctx->data_stamp = true;
720 winctx->intr_disable = true;
721 winctx->pin_win = true;
722
723 WARN_ON_ONCE(winctx->fault_win);
724 WARN_ON_ONCE(!winctx->rx_word_mode);
725 WARN_ON_ONCE(!winctx->tx_word_mode);
726 WARN_ON_ONCE(winctx->notify_after_count);
727 } else if (winctx->fault_win) {
728 winctx->notify_disable = true;
729 } else if (winctx->user_win) {
730 /*
731 * Section 1.8.1 Low Latency Core-Core Wake up of
732 * the VAS workbook:
733 *
734 * - disable credit checks ([tr]x_wcred_mode = false)
735 * - disable FIFO writes
736 * - enable ASB_Notify, disable interrupt
737 */
738 winctx->fifo_disable = true;
739 winctx->intr_disable = true;
740 winctx->rx_fifo = NULL;
741 }
742
743 winctx->lnotify_lpid = rxattr->lnotify_lpid;
744 winctx->lnotify_pid = rxattr->lnotify_pid;
745 winctx->lnotify_tid = rxattr->lnotify_tid;
746 winctx->pswid = rxattr->pswid;
747 winctx->dma_type = VAS_DMA_TYPE_INJECT;
748 winctx->tc_mode = rxattr->tc_mode;
749
750 winctx->min_scope = VAS_SCOPE_LOCAL;
751 winctx->max_scope = VAS_SCOPE_VECTORED_GROUP;
752 if (rxwin->vinst->virq)
753 winctx->irq_port = rxwin->vinst->irq_port;
754 }
755
rx_win_args_valid(enum vas_cop_type cop,struct vas_rx_win_attr * attr)756 static bool rx_win_args_valid(enum vas_cop_type cop,
757 struct vas_rx_win_attr *attr)
758 {
759 pr_debug("Rxattr: fault %d, notify %d, intr %d, early %d, fifo %d\n",
760 attr->fault_win, attr->notify_disable,
761 attr->intr_disable, attr->notify_early,
762 attr->rx_fifo_size);
763
764 if (cop >= VAS_COP_TYPE_MAX)
765 return false;
766
767 if (cop != VAS_COP_TYPE_FTW &&
768 attr->rx_fifo_size < VAS_RX_FIFO_SIZE_MIN)
769 return false;
770
771 if (attr->rx_fifo_size > VAS_RX_FIFO_SIZE_MAX)
772 return false;
773
774 if (!attr->wcreds_max)
775 return false;
776
777 if (attr->nx_win) {
778 /* cannot be fault or user window if it is nx */
779 if (attr->fault_win || attr->user_win)
780 return false;
781 /*
782 * Section 3.1.4.32: NX Windows must not disable notification,
783 * and must not enable interrupts or early notification.
784 */
785 if (attr->notify_disable || !attr->intr_disable ||
786 attr->notify_early)
787 return false;
788 } else if (attr->fault_win) {
789 /* cannot be both fault and user window */
790 if (attr->user_win)
791 return false;
792
793 /*
794 * Section 3.1.4.32: Fault windows must disable notification
795 * but not interrupts.
796 */
797 if (!attr->notify_disable || attr->intr_disable)
798 return false;
799
800 } else if (attr->user_win) {
801 /*
802 * User receive windows are only for fast-thread-wakeup
803 * (FTW). They don't need a FIFO and must disable interrupts
804 */
805 if (attr->rx_fifo || attr->rx_fifo_size || !attr->intr_disable)
806 return false;
807 } else {
808 /* Rx window must be one of NX or Fault or User window. */
809 return false;
810 }
811
812 return true;
813 }
814
vas_init_rx_win_attr(struct vas_rx_win_attr * rxattr,enum vas_cop_type cop)815 void vas_init_rx_win_attr(struct vas_rx_win_attr *rxattr, enum vas_cop_type cop)
816 {
817 memset(rxattr, 0, sizeof(*rxattr));
818
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) {
821 rxattr->pin_win = true;
822 rxattr->nx_win = true;
823 rxattr->fault_win = false;
824 rxattr->intr_disable = true;
825 rxattr->rx_wcred_mode = true;
826 rxattr->tx_wcred_mode = true;
827 rxattr->rx_win_ord_mode = true;
828 rxattr->tx_win_ord_mode = true;
829 } else if (cop == VAS_COP_TYPE_FAULT) {
830 rxattr->pin_win = true;
831 rxattr->fault_win = true;
832 rxattr->notify_disable = true;
833 rxattr->rx_wcred_mode = true;
834 rxattr->rx_win_ord_mode = true;
835 rxattr->rej_no_credit = true;
836 rxattr->tc_mode = VAS_THRESH_DISABLED;
837 } else if (cop == VAS_COP_TYPE_FTW) {
838 rxattr->user_win = true;
839 rxattr->intr_disable = true;
840
841 /*
842 * As noted in the VAS Workbook we disable credit checks.
843 * If we enable credit checks in the future, we must also
844 * implement a mechanism to return the user credits or new
845 * paste operations will fail.
846 */
847 }
848 }
849 EXPORT_SYMBOL_GPL(vas_init_rx_win_attr);
850
vas_rx_win_open(int vasid,enum vas_cop_type cop,struct vas_rx_win_attr * rxattr)851 struct vas_window *vas_rx_win_open(int vasid, enum vas_cop_type cop,
852 struct vas_rx_win_attr *rxattr)
853 {
854 struct vas_window *rxwin;
855 struct vas_winctx winctx;
856 struct vas_instance *vinst;
857
858 trace_vas_rx_win_open(current, vasid, cop, rxattr);
859
860 if (!rx_win_args_valid(cop, rxattr))
861 return ERR_PTR(-EINVAL);
862
863 vinst = find_vas_instance(vasid);
864 if (!vinst) {
865 pr_devel("vasid %d not found!\n", vasid);
866 return ERR_PTR(-EINVAL);
867 }
868 pr_devel("Found instance %d\n", vasid);
869
870 rxwin = vas_window_alloc(vinst);
871 if (IS_ERR(rxwin)) {
872 pr_devel("Unable to allocate memory for Rx window\n");
873 return rxwin;
874 }
875
876 rxwin->tx_win = false;
877 rxwin->nx_win = rxattr->nx_win;
878 rxwin->user_win = rxattr->user_win;
879 rxwin->cop = cop;
880 rxwin->wcreds_max = rxattr->wcreds_max;
881
882 init_winctx_for_rxwin(rxwin, rxattr, &winctx);
883 init_winctx_regs(rxwin, &winctx);
884
885 set_vinst_win(vinst, rxwin);
886
887 return rxwin;
888 }
889 EXPORT_SYMBOL_GPL(vas_rx_win_open);
890
vas_init_tx_win_attr(struct vas_tx_win_attr * txattr,enum vas_cop_type cop)891 void vas_init_tx_win_attr(struct vas_tx_win_attr *txattr, enum vas_cop_type cop)
892 {
893 memset(txattr, 0, sizeof(*txattr));
894
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) {
897 txattr->rej_no_credit = false;
898 txattr->rx_wcred_mode = true;
899 txattr->tx_wcred_mode = true;
900 txattr->rx_win_ord_mode = true;
901 txattr->tx_win_ord_mode = true;
902 } else if (cop == VAS_COP_TYPE_FTW) {
903 txattr->user_win = true;
904 }
905 }
906 EXPORT_SYMBOL_GPL(vas_init_tx_win_attr);
907
init_winctx_for_txwin(struct vas_window * txwin,struct vas_tx_win_attr * txattr,struct vas_winctx * winctx)908 static void init_winctx_for_txwin(struct vas_window *txwin,
909 struct vas_tx_win_attr *txattr,
910 struct vas_winctx *winctx)
911 {
912 /*
913 * We first zero all fields and only set non-zero ones. Following
914 * are some fields set to 0/false for the stated reason:
915 *
916 * ->notify_os_intr_reg In powernv, send intrs to HV
917 * ->rsvd_txbuf_count Not supported yet.
918 * ->notify_disable False for NX windows
919 * ->xtra_write False for NX windows
920 * ->notify_early NA for NX windows
921 * ->lnotify_lpid NA for Tx windows
922 * ->lnotify_pid NA for Tx windows
923 * ->lnotify_tid NA for Tx windows
924 * ->tx_win_cred_mode Ignore for now for NX windows
925 * ->rx_win_cred_mode Ignore for now for NX windows
926 */
927 memset(winctx, 0, sizeof(struct vas_winctx));
928
929 winctx->wcreds_max = txwin->wcreds_max;
930
931 winctx->user_win = txattr->user_win;
932 winctx->nx_win = txwin->rxwin->nx_win;
933 winctx->pin_win = txattr->pin_win;
934 winctx->rej_no_credit = txattr->rej_no_credit;
935 winctx->rsvd_txbuf_enable = txattr->rsvd_txbuf_enable;
936
937 winctx->rx_wcred_mode = txattr->rx_wcred_mode;
938 winctx->tx_wcred_mode = txattr->tx_wcred_mode;
939 winctx->rx_word_mode = txattr->rx_win_ord_mode;
940 winctx->tx_word_mode = txattr->tx_win_ord_mode;
941 winctx->rsvd_txbuf_count = txattr->rsvd_txbuf_count;
942
943 winctx->intr_disable = true;
944 if (winctx->nx_win)
945 winctx->data_stamp = true;
946
947 winctx->lpid = txattr->lpid;
948 winctx->pidr = txattr->pidr;
949 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;
956
957 winctx->dma_type = VAS_DMA_TYPE_INJECT;
958 winctx->tc_mode = txattr->tc_mode;
959 winctx->min_scope = VAS_SCOPE_LOCAL;
960 winctx->max_scope = VAS_SCOPE_VECTORED_GROUP;
961 if (txwin->vinst->virq)
962 winctx->irq_port = txwin->vinst->irq_port;
963
964 winctx->pswid = txattr->pswid ? txattr->pswid :
965 encode_pswid(txwin->vinst->vas_id, txwin->winid);
966 }
967
tx_win_args_valid(enum vas_cop_type cop,struct vas_tx_win_attr * attr)968 static bool tx_win_args_valid(enum vas_cop_type cop,
969 struct vas_tx_win_attr *attr)
970 {
971 if (attr->tc_mode != VAS_THRESH_DISABLED)
972 return false;
973
974 if (cop > VAS_COP_TYPE_MAX)
975 return false;
976
977 if (attr->wcreds_max > VAS_TX_WCREDS_MAX)
978 return false;
979
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 }
988
989 return true;
990 }
991
vas_tx_win_open(int vasid,enum vas_cop_type cop,struct vas_tx_win_attr * attr)992 struct vas_window *vas_tx_win_open(int vasid, enum vas_cop_type cop,
993 struct vas_tx_win_attr *attr)
994 {
995 int rc;
996 struct vas_window *txwin;
997 struct vas_window *rxwin;
998 struct vas_winctx winctx;
999 struct vas_instance *vinst;
1000
1001 trace_vas_tx_win_open(current, vasid, cop, attr);
1002
1003 if (!tx_win_args_valid(cop, attr))
1004 return ERR_PTR(-EINVAL);
1005
1006 /*
1007 * If caller did not specify a vasid but specified the PSWID of a
1008 * receive window (applicable only to FTW windows), use the vasid
1009 * from that receive window.
1010 */
1011 if (vasid == -1 && attr->pswid)
1012 decode_pswid(attr->pswid, &vasid, NULL);
1013
1014 vinst = find_vas_instance(vasid);
1015 if (!vinst) {
1016 pr_devel("vasid %d not found!\n", vasid);
1017 return ERR_PTR(-EINVAL);
1018 }
1019
1020 rxwin = get_vinst_rxwin(vinst, cop, attr->pswid);
1021 if (IS_ERR(rxwin)) {
1022 pr_devel("No RxWin for vasid %d, cop %d\n", vasid, cop);
1023 return rxwin;
1024 }
1025
1026 txwin = vas_window_alloc(vinst);
1027 if (IS_ERR(txwin)) {
1028 rc = PTR_ERR(txwin);
1029 goto put_rxwin;
1030 }
1031
1032 txwin->cop = cop;
1033 txwin->tx_win = 1;
1034 txwin->rxwin = rxwin;
1035 txwin->nx_win = txwin->rxwin->nx_win;
1036 txwin->user_win = attr->user_win;
1037 txwin->wcreds_max = attr->wcreds_max ?: VAS_WCREDS_DEFAULT;
1038
1039 init_winctx_for_txwin(txwin, attr, &winctx);
1040
1041 init_winctx_regs(txwin, &winctx);
1042
1043 /*
1044 * If its a kernel send window, map the window address into the
1045 * kernel's address space. For user windows, user must issue an
1046 * mmap() to map the window into their address space.
1047 *
1048 * NOTE: If kernel ever resubmits a user CRB after handling a page
1049 * fault, we will need to map this into kernel as well.
1050 */
1051 if (!txwin->user_win) {
1052 txwin->paste_kaddr = map_paste_region(txwin);
1053 if (IS_ERR(txwin->paste_kaddr)) {
1054 rc = PTR_ERR(txwin->paste_kaddr);
1055 goto free_window;
1056 }
1057 } else {
1058 /*
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.
1062 */
1063 if (!vinst->virq) {
1064 rc = -ENODEV;
1065 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. Expects parent
1097 * thread to use and close the window. So do not need
1098 * to take pid reference for parent thread.
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);
1112 }
1113
1114 set_vinst_win(vinst, txwin);
1115
1116 return txwin;
1117
1118 free_window:
1119 vas_window_free(txwin);
1120
1121 put_rxwin:
1122 put_rx_win(rxwin);
1123 return ERR_PTR(rc);
1124
1125 }
1126 EXPORT_SYMBOL_GPL(vas_tx_win_open);
1127
vas_copy_crb(void * crb,int offset)1128 int vas_copy_crb(void *crb, int offset)
1129 {
1130 return vas_copy(crb, offset);
1131 }
1132 EXPORT_SYMBOL_GPL(vas_copy_crb);
1133
1134 #define RMA_LSMP_REPORT_ENABLE PPC_BIT(53)
vas_paste_crb(struct vas_window * txwin,int offset,bool re)1135 int vas_paste_crb(struct vas_window *txwin, int offset, bool re)
1136 {
1137 int rc;
1138 void *addr;
1139 uint64_t val;
1140
1141 trace_vas_paste_crb(current, txwin);
1142
1143 /*
1144 * Only NX windows are supported for now and hardware assumes
1145 * report-enable flag is set for NX windows. Ensure software
1146 * complies too.
1147 */
1148 WARN_ON_ONCE(txwin->nx_win && !re);
1149
1150 addr = txwin->paste_kaddr;
1151 if (re) {
1152 /*
1153 * Set the REPORT_ENABLE bit (equivalent to writing
1154 * to 1K offset of the paste address)
1155 */
1156 val = SET_FIELD(RMA_LSMP_REPORT_ENABLE, 0ULL, 1);
1157 addr += val;
1158 }
1159
1160 /*
1161 * Map the raw CR value from vas_paste() to an error code (there
1162 * is just pass or fail for now though).
1163 */
1164 rc = vas_paste(addr, offset);
1165 if (rc == 2)
1166 rc = 0;
1167 else
1168 rc = -EINVAL;
1169
1170 pr_debug("Txwin #%d: Msg count %llu\n", txwin->winid,
1171 read_hvwc_reg(txwin, VREG(LRFIFO_PUSH)));
1172
1173 return rc;
1174 }
1175 EXPORT_SYMBOL_GPL(vas_paste_crb);
1176
1177 /*
1178 * If credit checking is enabled for this window, poll for the return
1179 * of window credits (i.e for NX engines to process any outstanding CRBs).
1180 * Since NX-842 waits for the CRBs to be processed before closing the
1181 * window, we should not have to wait for too long.
1182 *
1183 * TODO: We retry in 10ms intervals now. We could/should probably peek at
1184 * the VAS_LRFIFO_PUSH_OFFSET register to get an estimate of pending
1185 * CRBs on the FIFO and compute the delay dynamically on each retry.
1186 * But that is not really needed until we support NX-GZIP access from
1187 * user space. (NX-842 driver waits for CSB and Fast thread-wakeup
1188 * doesn't use credit checking).
1189 */
poll_window_credits(struct vas_window * window)1190 static void poll_window_credits(struct vas_window *window)
1191 {
1192 u64 val;
1193 int creds, mode;
1194 int count = 0;
1195
1196 val = read_hvwc_reg(window, VREG(WINCTL));
1197 if (window->tx_win)
1198 mode = GET_FIELD(VAS_WINCTL_TX_WCRED_MODE, val);
1199 else
1200 mode = GET_FIELD(VAS_WINCTL_RX_WCRED_MODE, val);
1201
1202 if (!mode)
1203 return;
1204 retry:
1205 if (window->tx_win) {
1206 val = read_hvwc_reg(window, VREG(TX_WCRED));
1207 creds = GET_FIELD(VAS_TX_WCRED, val);
1208 } else {
1209 val = read_hvwc_reg(window, VREG(LRX_WCRED));
1210 creds = GET_FIELD(VAS_LRX_WCRED, val);
1211 }
1212
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 */
1220 if (creds < window->wcreds_max) {
1221 val = 0;
1222 set_current_state(TASK_UNINTERRUPTIBLE);
1223 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
1234 goto retry;
1235 }
1236 }
1237
1238 /*
1239 * Wait for the window to go to "not-busy" state. It should only take a
1240 * short time to queue a CRB, so window should not be busy for too long.
1241 * Trying 5ms intervals.
1242 */
poll_window_busy_state(struct vas_window * window)1243 static void poll_window_busy_state(struct vas_window *window)
1244 {
1245 int busy;
1246 u64 val;
1247 int count = 0;
1248
1249 retry:
1250 val = read_hvwc_reg(window, VREG(WIN_STATUS));
1251 busy = GET_FIELD(VAS_WIN_BUSY, val);
1252 if (busy) {
1253 val = 0;
1254 set_current_state(TASK_UNINTERRUPTIBLE);
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
1265 goto retry;
1266 }
1267 }
1268
1269 /*
1270 * Have the hardware cast a window out of cache and wait for it to
1271 * be completed.
1272 *
1273 * NOTE: It can take a relatively long time to cast the window context
1274 * out of the cache. It is not strictly necessary to cast out if:
1275 *
1276 * - we clear the "Pin Window" bit (so hardware is free to evict)
1277 *
1278 * - we re-initialize the window context when it is reassigned.
1279 *
1280 * We do the former in vas_win_close() and latter in vas_win_open().
1281 * So, ignoring the cast-out for now. We can add it as needed. If
1282 * casting out becomes necessary we should consider offloading the
1283 * job to a worker thread, so the window close can proceed quickly.
1284 */
poll_window_castout(struct vas_window * window)1285 static void poll_window_castout(struct vas_window *window)
1286 {
1287 /* stub for now */
1288 }
1289
1290 /*
1291 * Unpin and close a window so no new requests are accepted and the
1292 * hardware can evict this window from cache if necessary.
1293 */
unpin_close_window(struct vas_window * window)1294 static void unpin_close_window(struct vas_window *window)
1295 {
1296 u64 val;
1297
1298 val = read_hvwc_reg(window, VREG(WINCTL));
1299 val = SET_FIELD(VAS_WINCTL_PIN, val, 0);
1300 val = SET_FIELD(VAS_WINCTL_OPEN, val, 0);
1301 write_hvwc_reg(window, VREG(WINCTL), val);
1302 }
1303
1304 /*
1305 * Close a window.
1306 *
1307 * See Section 1.12.1 of VAS workbook v1.05 for details on closing window:
1308 * - Disable new paste operations (unmap paste address)
1309 * - Poll for the "Window Busy" bit to be cleared
1310 * - Clear the Open/Enable bit for the Window.
1311 * - Poll for return of window Credits (implies FIFO empty for Rx win?)
1312 * - Unpin and cast window context out of cache
1313 *
1314 * Besides the hardware, kernel has some bookkeeping of course.
1315 */
vas_win_close(struct vas_window * window)1316 int vas_win_close(struct vas_window *window)
1317 {
1318 if (!window)
1319 return 0;
1320
1321 if (!window->tx_win && atomic_read(&window->num_txwins) != 0) {
1322 pr_devel("Attempting to close an active Rx window!\n");
1323 WARN_ON_ONCE(1);
1324 return -EBUSY;
1325 }
1326
1327 unmap_paste_region(window);
1328
1329 poll_window_busy_state(window);
1330
1331 unpin_close_window(window);
1332
1333 poll_window_credits(window);
1334
1335 clear_vinst_win(window);
1336
1337 poll_window_castout(window);
1338
1339 /* if send window, drop reference to matching receive window */
1340 if (window->tx_win) {
1341 if (window->user_win) {
1342 /* Drop references to pid and mm */
1343 put_pid(window->pid);
1344 if (window->mm) {
1345 mm_context_remove_vas_window(window->mm);
1346 mmdrop(window->mm);
1347 }
1348 }
1349 put_rx_win(window->rxwin);
1350 }
1351
1352 vas_window_free(window);
1353
1354 return 0;
1355 }
1356 EXPORT_SYMBOL_GPL(vas_win_close);
1357
1358 /*
1359 * Return credit for the given window.
1360 * Send windows and fault window uses credit mechanism as follows:
1361 *
1362 * Send windows:
1363 * - The default number of credits available for each send window is
1364 * 1024. It means 1024 requests can be issued asynchronously at the
1365 * same time. If the credit is not available, that request will be
1366 * returned with RMA_Busy.
1367 * - One credit is taken when NX request is issued.
1368 * - This credit is returned after NX processed that request.
1369 * - If NX encounters translation error, kernel will return the
1370 * credit on the specific send window after processing the fault CRB.
1371 *
1372 * Fault window:
1373 * - The total number credits available is FIFO_SIZE/CRB_SIZE.
1374 * Means 4MB/128 in the current implementation. If credit is not
1375 * available, RMA_Reject is returned.
1376 * - A credit is taken when NX pastes CRB in fault FIFO.
1377 * - The kernel with return credit on fault window after reading entry
1378 * from fault FIFO.
1379 */
vas_return_credit(struct vas_window * window,bool tx)1380 void vas_return_credit(struct vas_window *window, bool tx)
1381 {
1382 uint64_t val;
1383
1384 val = 0ULL;
1385 if (tx) { /* send window */
1386 val = SET_FIELD(VAS_TX_WCRED, val, 1);
1387 write_hvwc_reg(window, VREG(TX_WCRED_ADDER), val);
1388 } else {
1389 val = SET_FIELD(VAS_LRX_WCRED, val, 1);
1390 write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), val);
1391 }
1392 }
1393
vas_pswid_to_window(struct vas_instance * vinst,uint32_t pswid)1394 struct vas_window *vas_pswid_to_window(struct vas_instance *vinst,
1395 uint32_t pswid)
1396 {
1397 struct vas_window *window;
1398 int winid;
1399
1400 if (!pswid) {
1401 pr_devel("%s: called for pswid 0!\n", __func__);
1402 return ERR_PTR(-ESRCH);
1403 }
1404
1405 decode_pswid(pswid, NULL, &winid);
1406
1407 if (winid >= VAS_WINDOWS_PER_CHIP)
1408 return ERR_PTR(-ESRCH);
1409
1410 /*
1411 * If application closes the window before the hardware
1412 * returns the fault CRB, we should wait in vas_win_close()
1413 * for the pending requests. so the window must be active
1414 * and the process alive.
1415 *
1416 * If its a kernel process, we should not get any faults and
1417 * should not get here.
1418 */
1419 window = vinst->windows[winid];
1420
1421 if (!window) {
1422 pr_err("PSWID decode: Could not find window for winid %d pswid %d vinst 0x%p\n",
1423 winid, pswid, vinst);
1424 return NULL;
1425 }
1426
1427 /*
1428 * Do some sanity checks on the decoded window. Window should be
1429 * NX GZIP user send window. FTW windows should not incur faults
1430 * since their CRBs are ignored (not queued on FIFO or processed
1431 * by NX).
1432 */
1433 if (!window->tx_win || !window->user_win || !window->nx_win ||
1434 window->cop == VAS_COP_TYPE_FAULT ||
1435 window->cop == VAS_COP_TYPE_FTW) {
1436 pr_err("PSWID decode: id %d, tx %d, user %d, nx %d, cop %d\n",
1437 winid, window->tx_win, window->user_win,
1438 window->nx_win, window->cop);
1439 WARN_ON(1);
1440 }
1441
1442 return window;
1443 }
1444
