summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kvm/book3s_xive_template.c
blob: 0737acfd17f1ec04433d41bce26aaeae5beeeeed (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
/*
 * Copyright 2017 Benjamin Herrenschmidt, IBM Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 */

/* File to be included by other .c files */

#define XGLUE(a,b) a##b
#define GLUE(a,b) XGLUE(a,b)

/* Dummy interrupt used when taking interrupts out of a queue in H_CPPR */
#define XICS_DUMMY	1

static void GLUE(X_PFX,ack_pending)(struct kvmppc_xive_vcpu *xc)
{
	u8 cppr;
	u16 ack;

	/*
	 * Ensure any previous store to CPPR is ordered vs.
	 * the subsequent loads from PIPR or ACK.
	 */
	eieio();

	/* Perform the acknowledge OS to register cycle. */
	ack = be16_to_cpu(__x_readw(__x_tima + TM_SPC_ACK_OS_REG));

	/* Synchronize subsequent queue accesses */
	mb();

	/* XXX Check grouping level */

	/* Anything ? */
	if (!((ack >> 8) & TM_QW1_NSR_EO))
		return;

	/* Grab CPPR of the most favored pending interrupt */
	cppr = ack & 0xff;
	if (cppr < 8)
		xc->pending |= 1 << cppr;

#ifdef XIVE_RUNTIME_CHECKS
	/* Check consistency */
	if (cppr >= xc->hw_cppr)
		pr_warn("KVM-XIVE: CPU %d odd ack CPPR, got %d at %d\n",
			smp_processor_id(), cppr, xc->hw_cppr);
#endif

	/*
	 * Update our image of the HW CPPR. We don't yet modify
	 * xc->cppr, this will be done as we scan for interrupts
	 * in the queues.
	 */
	xc->hw_cppr = cppr;
}

static u8 GLUE(X_PFX,esb_load)(struct xive_irq_data *xd, u32 offset)
{
	u64 val;

	if (xd->flags & XIVE_IRQ_FLAG_SHIFT_BUG)
		offset |= offset << 4;

	val =__x_readq(__x_eoi_page(xd) + offset);
#ifdef __LITTLE_ENDIAN__
	val >>= 64-8;
#endif
	return (u8)val;
}


static void GLUE(X_PFX,source_eoi)(u32 hw_irq, struct xive_irq_data *xd)
{
	/* If the XIVE supports the new "store EOI facility, use it */
	if (xd->flags & XIVE_IRQ_FLAG_STORE_EOI)
		__x_writeq(0, __x_eoi_page(xd) + XIVE_ESB_STORE_EOI);
	else if (hw_irq && xd->flags & XIVE_IRQ_FLAG_EOI_FW)
		opal_int_eoi(hw_irq);
	else if (xd->flags & XIVE_IRQ_FLAG_LSI) {
		/*
		 * For LSIs the HW EOI cycle is used rather than PQ bits,
		 * as they are automatically re-triggred in HW when still
		 * pending.
		 */
		__x_readq(__x_eoi_page(xd) + XIVE_ESB_LOAD_EOI);
	} else {
		uint64_t eoi_val;

		/*
		 * Otherwise for EOI, we use the special MMIO that does
		 * a clear of both P and Q and returns the old Q,
		 * except for LSIs where we use the "EOI cycle" special
		 * load.
		 *
		 * This allows us to then do a re-trigger if Q was set
		 * rather than synthetizing an interrupt in software
		 */
		eoi_val = GLUE(X_PFX,esb_load)(xd, XIVE_ESB_SET_PQ_00);

		/* Re-trigger if needed */
		if ((eoi_val & 1) && __x_trig_page(xd))
			__x_writeq(0, __x_trig_page(xd));
	}
}

enum {
	scan_fetch,
	scan_poll,
	scan_eoi,
};

static u32 GLUE(X_PFX,scan_interrupts)(struct kvmppc_xive_vcpu *xc,
				       u8 pending, int scan_type)
{
	u32 hirq = 0;
	u8 prio = 0xff;

	/* Find highest pending priority */
	while ((xc->mfrr != 0xff || pending != 0) && hirq == 0) {
		struct xive_q *q;
		u32 idx, toggle;
		__be32 *qpage;

		/*
		 * If pending is 0 this will return 0xff which is what
		 * we want
		 */
		prio = ffs(pending) - 1;

		/* Don't scan past the guest cppr */
		if (prio >= xc->cppr || prio > 7) {
			if (xc->mfrr < xc->cppr) {
				prio = xc->mfrr;
				hirq = XICS_IPI;
			}
			break;
		}

		/* Grab queue and pointers */
		q = &xc->queues[prio];
		idx = q->idx;
		toggle = q->toggle;

		/*
		 * Snapshot the queue page. The test further down for EOI
		 * must use the same "copy" that was used by __xive_read_eq
		 * since qpage can be set concurrently and we don't want
		 * to miss an EOI.
		 */
		qpage = READ_ONCE(q->qpage);

skip_ipi:
		/*
		 * Try to fetch from the queue. Will return 0 for a
		 * non-queueing priority (ie, qpage = 0).
		 */
		hirq = __xive_read_eq(qpage, q->msk, &idx, &toggle);

		/*
		 * If this was a signal for an MFFR change done by
		 * H_IPI we skip it. Additionally, if we were fetching
		 * we EOI it now, thus re-enabling reception of a new
		 * such signal.
		 *
		 * We also need to do that if prio is 0 and we had no
		 * page for the queue. In this case, we have non-queued
		 * IPI that needs to be EOId.
		 *
		 * This is safe because if we have another pending MFRR
		 * change that wasn't observed above, the Q bit will have
		 * been set and another occurrence of the IPI will trigger.
		 */
		if (hirq == XICS_IPI || (prio == 0 && !qpage)) {
			if (scan_type == scan_fetch) {
				GLUE(X_PFX,source_eoi)(xc->vp_ipi,
						       &xc->vp_ipi_data);
				q->idx = idx;
				q->toggle = toggle;
			}
			/* Loop back on same queue with updated idx/toggle */
#ifdef XIVE_RUNTIME_CHECKS
			WARN_ON(hirq && hirq != XICS_IPI);
#endif
			if (hirq)
				goto skip_ipi;
		}

		/* If it's the dummy interrupt, continue searching */
		if (hirq == XICS_DUMMY)
			goto skip_ipi;

		/* Clear the pending bit if the queue is now empty */
		if (!hirq) {
			pending &= ~(1 << prio);

			/*
			 * Check if the queue count needs adjusting due to
			 * interrupts being moved away.
			 */
			if (atomic_read(&q->pending_count)) {
				int p = atomic_xchg(&q->pending_count, 0);
				if (p) {
#ifdef XIVE_RUNTIME_CHECKS
					WARN_ON(p > atomic_read(&q->count));
#endif
					atomic_sub(p, &q->count);
				}
			}
		}

		/*
		 * If the most favoured prio we found pending is less
		 * favored (or equal) than a pending IPI, we return
		 * the IPI instead.
		 */
		if (prio >= xc->mfrr && xc->mfrr < xc->cppr) {
			prio = xc->mfrr;
			hirq = XICS_IPI;
			break;
		}

		/* If fetching, update queue pointers */
		if (scan_type == scan_fetch) {
			q->idx = idx;
			q->toggle = toggle;
		}
	}

	/* If we are just taking a "peek", do nothing else */
	if (scan_type == scan_poll)
		return hirq;

	/* Update the pending bits */
	xc->pending = pending;

	/*
	 * If this is an EOI that's it, no CPPR adjustment done here,
	 * all we needed was cleanup the stale pending bits and check
	 * if there's anything left.
	 */
	if (scan_type == scan_eoi)
		return hirq;

	/*
	 * If we found an interrupt, adjust what the guest CPPR should
	 * be as if we had just fetched that interrupt from HW.
	 *
	 * Note: This can only make xc->cppr smaller as the previous
	 * loop will only exit with hirq != 0 if prio is lower than
	 * the current xc->cppr. Thus we don't need to re-check xc->mfrr
	 * for pending IPIs.
	 */
	if (hirq)
		xc->cppr = prio;
	/*
	 * If it was an IPI the HW CPPR might have been lowered too much
	 * as the HW interrupt we use for IPIs is routed to priority 0.
	 *
	 * We re-sync it here.
	 */
	if (xc->cppr != xc->hw_cppr) {
		xc->hw_cppr = xc->cppr;
		__x_writeb(xc->cppr, __x_tima + TM_QW1_OS + TM_CPPR);
	}

	return hirq;
}

X_STATIC unsigned long GLUE(X_PFX,h_xirr)(struct kvm_vcpu *vcpu)
{
	struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
	u8 old_cppr;
	u32 hirq;

	pr_devel("H_XIRR\n");

	xc->GLUE(X_STAT_PFX,h_xirr)++;

	/* First collect pending bits from HW */
	GLUE(X_PFX,ack_pending)(xc);

	pr_devel(" new pending=0x%02x hw_cppr=%d cppr=%d\n",
		 xc->pending, xc->hw_cppr, xc->cppr);

	/* Grab previous CPPR and reverse map it */
	old_cppr = xive_prio_to_guest(xc->cppr);

	/* Scan for actual interrupts */
	hirq = GLUE(X_PFX,scan_interrupts)(xc, xc->pending, scan_fetch);

	pr_devel(" got hirq=0x%x hw_cppr=%d cppr=%d\n",
		 hirq, xc->hw_cppr, xc->cppr);

#ifdef XIVE_RUNTIME_CHECKS
	/* That should never hit */
	if (hirq & 0xff000000)
		pr_warn("XIVE: Weird guest interrupt number 0x%08x\n", hirq);
#endif

	/*
	 * XXX We could check if the interrupt is masked here and
	 * filter it. If we chose to do so, we would need to do:
	 *
	 *    if (masked) {
	 *        lock();
	 *        if (masked) {
	 *            old_Q = true;
	 *            hirq = 0;
	 *        }
	 *        unlock();
	 *    }
	 */

	/* Return interrupt and old CPPR in GPR4 */
	vcpu->arch.regs.gpr[4] = hirq | (old_cppr << 24);

	return H_SUCCESS;
}

X_STATIC unsigned long GLUE(X_PFX,h_ipoll)(struct kvm_vcpu *vcpu, unsigned long server)
{
	struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
	u8 pending = xc->pending;
	u32 hirq;

	pr_devel("H_IPOLL(server=%ld)\n", server);

	xc->GLUE(X_STAT_PFX,h_ipoll)++;

	/* Grab the target VCPU if not the current one */
	if (xc->server_num != server) {
		vcpu = kvmppc_xive_find_server(vcpu->kvm, server);
		if (!vcpu)
			return H_PARAMETER;
		xc = vcpu->arch.xive_vcpu;

		/* Scan all priorities */
		pending = 0xff;
	} else {
		/* Grab pending interrupt if any */
		__be64 qw1 = __x_readq(__x_tima + TM_QW1_OS);
		u8 pipr = be64_to_cpu(qw1) & 0xff;
		if (pipr < 8)
			pending |= 1 << pipr;
	}

	hirq = GLUE(X_PFX,scan_interrupts)(xc, pending, scan_poll);

	/* Return interrupt and old CPPR in GPR4 */
	vcpu->arch.regs.gpr[4] = hirq | (xc->cppr << 24);

	return H_SUCCESS;
}

static void GLUE(X_PFX,push_pending_to_hw)(struct kvmppc_xive_vcpu *xc)
{
	u8 pending, prio;

	pending = xc->pending;
	if (xc->mfrr != 0xff) {
		if (xc->mfrr < 8)
			pending |= 1 << xc->mfrr;
		else
			pending |= 0x80;
	}
	if (!pending)
		return;
	prio = ffs(pending) - 1;

	__x_writeb(prio, __x_tima + TM_SPC_SET_OS_PENDING);
}

static void GLUE(X_PFX,scan_for_rerouted_irqs)(struct kvmppc_xive *xive,
					       struct kvmppc_xive_vcpu *xc)
{
	unsigned int prio;

	/* For each priority that is now masked */
	for (prio = xc->cppr; prio < KVMPPC_XIVE_Q_COUNT; prio++) {
		struct xive_q *q = &xc->queues[prio];
		struct kvmppc_xive_irq_state *state;
		struct kvmppc_xive_src_block *sb;
		u32 idx, toggle, entry, irq, hw_num;
		struct xive_irq_data *xd;
		__be32 *qpage;
		u16 src;

		idx = q->idx;
		toggle = q->toggle;
		qpage = READ_ONCE(q->qpage);
		if (!qpage)
			continue;

		/* For each interrupt in the queue */
		for (;;) {
			entry = be32_to_cpup(qpage + idx);

			/* No more ? */
			if ((entry >> 31) == toggle)
				break;
			irq = entry & 0x7fffffff;

			/* Skip dummies and IPIs */
			if (irq == XICS_DUMMY || irq == XICS_IPI)
				goto next;
			sb = kvmppc_xive_find_source(xive, irq, &src);
			if (!sb)
				goto next;
			state = &sb->irq_state[src];

			/* Has it been rerouted ? */
			if (xc->server_num == state->act_server)
				goto next;

			/*
			 * Allright, it *has* been re-routed, kill it from
			 * the queue.
			 */
			qpage[idx] = cpu_to_be32((entry & 0x80000000) | XICS_DUMMY);

			/* Find the HW interrupt */
			kvmppc_xive_select_irq(state, &hw_num, &xd);

			/* If it's not an LSI, set PQ to 11 the EOI will force a resend */
			if (!(xd->flags & XIVE_IRQ_FLAG_LSI))
				GLUE(X_PFX,esb_load)(xd, XIVE_ESB_SET_PQ_11);

			/* EOI the source */
			GLUE(X_PFX,source_eoi)(hw_num, xd);

		next:
			idx = (idx + 1) & q->msk;
			if (idx == 0)
				toggle ^= 1;
		}
	}
}

X_STATIC int GLUE(X_PFX,h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr)
{
	struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
	struct kvmppc_xive *xive = vcpu->kvm->arch.xive;
	u8 old_cppr;

	pr_devel("H_CPPR(cppr=%ld)\n", cppr);

	xc->GLUE(X_STAT_PFX,h_cppr)++;

	/* Map CPPR */
	cppr = xive_prio_from_guest(cppr);

	/* Remember old and update SW state */
	old_cppr = xc->cppr;
	xc->cppr = cppr;

	/*
	 * Order the above update of xc->cppr with the subsequent
	 * read of xc->mfrr inside push_pending_to_hw()
	 */
	smp_mb();

	if (cppr > old_cppr) {
		/*
		 * We are masking less, we need to look for pending things
		 * to deliver and set VP pending bits accordingly to trigger
		 * a new interrupt otherwise we might miss MFRR changes for
		 * which we have optimized out sending an IPI signal.
		 */
		GLUE(X_PFX,push_pending_to_hw)(xc);
	} else {
		/*
		 * We are masking more, we need to check the queue for any
		 * interrupt that has been routed to another CPU, take
		 * it out (replace it with the dummy) and retrigger it.
		 *
		 * This is necessary since those interrupts may otherwise
		 * never be processed, at least not until this CPU restores
		 * its CPPR.
		 *
		 * This is in theory racy vs. HW adding new interrupts to
		 * the queue. In practice this works because the interesting
		 * cases are when the guest has done a set_xive() to move the
		 * interrupt away, which flushes the xive, followed by the
		 * target CPU doing a H_CPPR. So any new interrupt coming into
		 * the queue must still be routed to us and isn't a source
		 * of concern.
		 */
		GLUE(X_PFX,scan_for_rerouted_irqs)(xive, xc);
	}

	/* Apply new CPPR */
	xc->hw_cppr = cppr;
	__x_writeb(cppr, __x_tima + TM_QW1_OS + TM_CPPR);

	return H_SUCCESS;
}

X_STATIC int GLUE(X_PFX,h_eoi)(struct kvm_vcpu *vcpu, unsigned long xirr)
{
	struct kvmppc_xive *xive = vcpu->kvm->arch.xive;
	struct kvmppc_xive_src_block *sb;
	struct kvmppc_xive_irq_state *state;
	struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
	struct xive_irq_data *xd;
	u8 new_cppr = xirr >> 24;
	u32 irq = xirr & 0x00ffffff, hw_num;
	u16 src;
	int rc = 0;

	pr_devel("H_EOI(xirr=%08lx)\n", xirr);

	xc->GLUE(X_STAT_PFX,h_eoi)++;

	xc->cppr = xive_prio_from_guest(new_cppr);

	/*
	 * IPIs are synthetized from MFRR and thus don't need
	 * any special EOI handling. The underlying interrupt
	 * used to signal MFRR changes is EOId when fetched from
	 * the queue.
	 */
	if (irq == XICS_IPI || irq == 0) {
		/*
		 * This barrier orders the setting of xc->cppr vs.
		 * subsquent test of xc->mfrr done inside
		 * scan_interrupts and push_pending_to_hw
		 */
		smp_mb();
		goto bail;
	}

	/* Find interrupt source */
	sb = kvmppc_xive_find_source(xive, irq, &src);
	if (!sb) {
		pr_devel(" source not found !\n");
		rc = H_PARAMETER;
		/* Same as above */
		smp_mb();
		goto bail;
	}
	state = &sb->irq_state[src];
	kvmppc_xive_select_irq(state, &hw_num, &xd);

	state->in_eoi = true;

	/*
	 * This barrier orders both setting of in_eoi above vs,
	 * subsequent test of guest_priority, and the setting
	 * of xc->cppr vs. subsquent test of xc->mfrr done inside
	 * scan_interrupts and push_pending_to_hw
	 */
	smp_mb();

again:
	if (state->guest_priority == MASKED) {
		arch_spin_lock(&sb->lock);
		if (state->guest_priority != MASKED) {
			arch_spin_unlock(&sb->lock);
			goto again;
		}
		pr_devel(" EOI on saved P...\n");

		/* Clear old_p, that will cause unmask to perform an EOI */
		state->old_p = false;

		arch_spin_unlock(&sb->lock);
	} else {
		pr_devel(" EOI on source...\n");

		/* Perform EOI on the source */
		GLUE(X_PFX,source_eoi)(hw_num, xd);

		/* If it's an emulated LSI, check level and resend */
		if (state->lsi && state->asserted)
			__x_writeq(0, __x_trig_page(xd));

	}

	/*
	 * This barrier orders the above guest_priority check
	 * and spin_lock/unlock with clearing in_eoi below.
	 *
	 * It also has to be a full mb() as it must ensure
	 * the MMIOs done in source_eoi() are completed before
	 * state->in_eoi is visible.
	 */
	mb();
	state->in_eoi = false;
bail:

	/* Re-evaluate pending IRQs and update HW */
	GLUE(X_PFX,scan_interrupts)(xc, xc->pending, scan_eoi);
	GLUE(X_PFX,push_pending_to_hw)(xc);
	pr_devel(" after scan pending=%02x\n", xc->pending);

	/* Apply new CPPR */
	xc->hw_cppr = xc->cppr;
	__x_writeb(xc->cppr, __x_tima + TM_QW1_OS + TM_CPPR);

	return rc;
}

X_STATIC int GLUE(X_PFX,h_ipi)(struct kvm_vcpu *vcpu, unsigned long server,
			       unsigned long mfrr)
{
	struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;

	pr_devel("H_IPI(server=%08lx,mfrr=%ld)\n", server, mfrr);

	xc->GLUE(X_STAT_PFX,h_ipi)++;

	/* Find target */
	vcpu = kvmppc_xive_find_server(vcpu->kvm, server);
	if (!vcpu)
		return H_PARAMETER;
	xc = vcpu->arch.xive_vcpu;

	/* Locklessly write over MFRR */
	xc->mfrr = mfrr;

	/*
	 * The load of xc->cppr below and the subsequent MMIO store
	 * to the IPI must happen after the above mfrr update is
	 * globally visible so that:
	 *
	 * - Synchronize with another CPU doing an H_EOI or a H_CPPR
	 *   updating xc->cppr then reading xc->mfrr.
	 *
	 * - The target of the IPI sees the xc->mfrr update
	 */
	mb();

	/* Shoot the IPI if most favored than target cppr */
	if (mfrr < xc->cppr)
		__x_writeq(0, __x_trig_page(&xc->vp_ipi_data));

	return H_SUCCESS;
}