1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * handling interprocessor communication
4  *
5  * Copyright IBM Corp. 2008, 2013
6  *
7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
8  *               Christian Borntraeger <borntraeger@de.ibm.com>
9  *               Christian Ehrhardt <ehrhardt@de.ibm.com>
10  */
11 
12 #include <linux/kvm.h>
13 #include <linux/kvm_host.h>
14 #include <linux/slab.h>
15 #include <asm/sigp.h>
16 #include "gaccess.h"
17 #include "kvm-s390.h"
18 #include "trace.h"
19 
__sigp_sense(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u64 * reg)20 static int __sigp_sense(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
21 			u64 *reg)
22 {
23 	const bool stopped = kvm_s390_test_cpuflags(dst_vcpu, CPUSTAT_STOPPED);
24 	int rc;
25 	int ext_call_pending;
26 
27 	ext_call_pending = kvm_s390_ext_call_pending(dst_vcpu);
28 	if (!stopped && !ext_call_pending)
29 		rc = SIGP_CC_ORDER_CODE_ACCEPTED;
30 	else {
31 		*reg &= 0xffffffff00000000UL;
32 		if (ext_call_pending)
33 			*reg |= SIGP_STATUS_EXT_CALL_PENDING;
34 		if (stopped)
35 			*reg |= SIGP_STATUS_STOPPED;
36 		rc = SIGP_CC_STATUS_STORED;
37 	}
38 
39 	VCPU_EVENT(vcpu, 4, "sensed status of cpu %x rc %x", dst_vcpu->vcpu_id,
40 		   rc);
41 	return rc;
42 }
43 
__inject_sigp_emergency(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu)44 static int __inject_sigp_emergency(struct kvm_vcpu *vcpu,
45 				    struct kvm_vcpu *dst_vcpu)
46 {
47 	struct kvm_s390_irq irq = {
48 		.type = KVM_S390_INT_EMERGENCY,
49 		.u.emerg.code = vcpu->vcpu_id,
50 	};
51 	int rc = 0;
52 
53 	rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
54 	if (!rc)
55 		VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x",
56 			   dst_vcpu->vcpu_id);
57 
58 	return rc ? rc : SIGP_CC_ORDER_CODE_ACCEPTED;
59 }
60 
__sigp_emergency(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu)61 static int __sigp_emergency(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu)
62 {
63 	return __inject_sigp_emergency(vcpu, dst_vcpu);
64 }
65 
__sigp_conditional_emergency(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u16 asn,u64 * reg)66 static int __sigp_conditional_emergency(struct kvm_vcpu *vcpu,
67 					struct kvm_vcpu *dst_vcpu,
68 					u16 asn, u64 *reg)
69 {
70 	const u64 psw_int_mask = PSW_MASK_IO | PSW_MASK_EXT;
71 	u16 p_asn, s_asn;
72 	psw_t *psw;
73 	bool idle;
74 
75 	idle = is_vcpu_idle(vcpu);
76 	psw = &dst_vcpu->arch.sie_block->gpsw;
77 	p_asn = dst_vcpu->arch.sie_block->gcr[4] & 0xffff;  /* Primary ASN */
78 	s_asn = dst_vcpu->arch.sie_block->gcr[3] & 0xffff;  /* Secondary ASN */
79 
80 	/* Inject the emergency signal? */
81 	if (!is_vcpu_stopped(vcpu)
82 	    || (psw->mask & psw_int_mask) != psw_int_mask
83 	    || (idle && psw->addr != 0)
84 	    || (!idle && (asn == p_asn || asn == s_asn))) {
85 		return __inject_sigp_emergency(vcpu, dst_vcpu);
86 	} else {
87 		*reg &= 0xffffffff00000000UL;
88 		*reg |= SIGP_STATUS_INCORRECT_STATE;
89 		return SIGP_CC_STATUS_STORED;
90 	}
91 }
92 
__sigp_external_call(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u64 * reg)93 static int __sigp_external_call(struct kvm_vcpu *vcpu,
94 				struct kvm_vcpu *dst_vcpu, u64 *reg)
95 {
96 	struct kvm_s390_irq irq = {
97 		.type = KVM_S390_INT_EXTERNAL_CALL,
98 		.u.extcall.code = vcpu->vcpu_id,
99 	};
100 	int rc;
101 
102 	rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
103 	if (rc == -EBUSY) {
104 		*reg &= 0xffffffff00000000UL;
105 		*reg |= SIGP_STATUS_EXT_CALL_PENDING;
106 		return SIGP_CC_STATUS_STORED;
107 	} else if (rc == 0) {
108 		VCPU_EVENT(vcpu, 4, "sent sigp ext call to cpu %x",
109 			   dst_vcpu->vcpu_id);
110 	}
111 
112 	return rc ? rc : SIGP_CC_ORDER_CODE_ACCEPTED;
113 }
114 
__sigp_stop(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu)115 static int __sigp_stop(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu)
116 {
117 	struct kvm_s390_irq irq = {
118 		.type = KVM_S390_SIGP_STOP,
119 	};
120 	int rc;
121 
122 	rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
123 	if (rc == -EBUSY)
124 		rc = SIGP_CC_BUSY;
125 	else if (rc == 0)
126 		VCPU_EVENT(vcpu, 4, "sent sigp stop to cpu %x",
127 			   dst_vcpu->vcpu_id);
128 
129 	return rc;
130 }
131 
__sigp_stop_and_store_status(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u64 * reg)132 static int __sigp_stop_and_store_status(struct kvm_vcpu *vcpu,
133 					struct kvm_vcpu *dst_vcpu, u64 *reg)
134 {
135 	struct kvm_s390_irq irq = {
136 		.type = KVM_S390_SIGP_STOP,
137 		.u.stop.flags = KVM_S390_STOP_FLAG_STORE_STATUS,
138 	};
139 	int rc;
140 
141 	rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
142 	if (rc == -EBUSY)
143 		rc = SIGP_CC_BUSY;
144 	else if (rc == 0)
145 		VCPU_EVENT(vcpu, 4, "sent sigp stop and store status to cpu %x",
146 			   dst_vcpu->vcpu_id);
147 
148 	return rc;
149 }
150 
__sigp_set_arch(struct kvm_vcpu * vcpu,u32 parameter,u64 * status_reg)151 static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter,
152 			   u64 *status_reg)
153 {
154 	*status_reg &= 0xffffffff00000000UL;
155 
156 	/* Reject set arch order, with czam we're always in z/Arch mode. */
157 	*status_reg |= SIGP_STATUS_INVALID_PARAMETER;
158 	return SIGP_CC_STATUS_STORED;
159 }
160 
__sigp_set_prefix(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u32 address,u64 * reg)161 static int __sigp_set_prefix(struct kvm_vcpu *vcpu, struct kvm_vcpu *dst_vcpu,
162 			     u32 address, u64 *reg)
163 {
164 	struct kvm_s390_irq irq = {
165 		.type = KVM_S390_SIGP_SET_PREFIX,
166 		.u.prefix.address = address & 0x7fffe000u,
167 	};
168 	int rc;
169 
170 	/*
171 	 * Make sure the new value is valid memory. We only need to check the
172 	 * first page, since address is 8k aligned and memory pieces are always
173 	 * at least 1MB aligned and have at least a size of 1MB.
174 	 */
175 	if (kvm_is_error_gpa(vcpu->kvm, irq.u.prefix.address)) {
176 		*reg &= 0xffffffff00000000UL;
177 		*reg |= SIGP_STATUS_INVALID_PARAMETER;
178 		return SIGP_CC_STATUS_STORED;
179 	}
180 
181 	rc = kvm_s390_inject_vcpu(dst_vcpu, &irq);
182 	if (rc == -EBUSY) {
183 		*reg &= 0xffffffff00000000UL;
184 		*reg |= SIGP_STATUS_INCORRECT_STATE;
185 		return SIGP_CC_STATUS_STORED;
186 	}
187 
188 	return rc;
189 }
190 
__sigp_store_status_at_addr(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u32 addr,u64 * reg)191 static int __sigp_store_status_at_addr(struct kvm_vcpu *vcpu,
192 				       struct kvm_vcpu *dst_vcpu,
193 				       u32 addr, u64 *reg)
194 {
195 	int rc;
196 
197 	if (!kvm_s390_test_cpuflags(dst_vcpu, CPUSTAT_STOPPED)) {
198 		*reg &= 0xffffffff00000000UL;
199 		*reg |= SIGP_STATUS_INCORRECT_STATE;
200 		return SIGP_CC_STATUS_STORED;
201 	}
202 
203 	addr &= 0x7ffffe00;
204 	rc = kvm_s390_store_status_unloaded(dst_vcpu, addr);
205 	if (rc == -EFAULT) {
206 		*reg &= 0xffffffff00000000UL;
207 		*reg |= SIGP_STATUS_INVALID_PARAMETER;
208 		rc = SIGP_CC_STATUS_STORED;
209 	}
210 	return rc;
211 }
212 
__sigp_sense_running(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u64 * reg)213 static int __sigp_sense_running(struct kvm_vcpu *vcpu,
214 				struct kvm_vcpu *dst_vcpu, u64 *reg)
215 {
216 	int rc;
217 
218 	if (!test_kvm_facility(vcpu->kvm, 9)) {
219 		*reg &= 0xffffffff00000000UL;
220 		*reg |= SIGP_STATUS_INVALID_ORDER;
221 		return SIGP_CC_STATUS_STORED;
222 	}
223 
224 	if (kvm_s390_test_cpuflags(dst_vcpu, CPUSTAT_RUNNING)) {
225 		/* running */
226 		rc = SIGP_CC_ORDER_CODE_ACCEPTED;
227 	} else {
228 		/* not running */
229 		*reg &= 0xffffffff00000000UL;
230 		*reg |= SIGP_STATUS_NOT_RUNNING;
231 		rc = SIGP_CC_STATUS_STORED;
232 	}
233 
234 	VCPU_EVENT(vcpu, 4, "sensed running status of cpu %x rc %x",
235 		   dst_vcpu->vcpu_id, rc);
236 
237 	return rc;
238 }
239 
__prepare_sigp_re_start(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u8 order_code)240 static int __prepare_sigp_re_start(struct kvm_vcpu *vcpu,
241 				   struct kvm_vcpu *dst_vcpu, u8 order_code)
242 {
243 	struct kvm_s390_local_interrupt *li = &dst_vcpu->arch.local_int;
244 	/* handle (RE)START in user space */
245 	int rc = -EOPNOTSUPP;
246 
247 	/* make sure we don't race with STOP irq injection */
248 	spin_lock(&li->lock);
249 	if (kvm_s390_is_stop_irq_pending(dst_vcpu))
250 		rc = SIGP_CC_BUSY;
251 	spin_unlock(&li->lock);
252 
253 	return rc;
254 }
255 
__prepare_sigp_cpu_reset(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu,u8 order_code)256 static int __prepare_sigp_cpu_reset(struct kvm_vcpu *vcpu,
257 				    struct kvm_vcpu *dst_vcpu, u8 order_code)
258 {
259 	/* handle (INITIAL) CPU RESET in user space */
260 	return -EOPNOTSUPP;
261 }
262 
__prepare_sigp_unknown(struct kvm_vcpu * vcpu,struct kvm_vcpu * dst_vcpu)263 static int __prepare_sigp_unknown(struct kvm_vcpu *vcpu,
264 				  struct kvm_vcpu *dst_vcpu)
265 {
266 	/* handle unknown orders in user space */
267 	return -EOPNOTSUPP;
268 }
269 
handle_sigp_dst(struct kvm_vcpu * vcpu,u8 order_code,u16 cpu_addr,u32 parameter,u64 * status_reg)270 static int handle_sigp_dst(struct kvm_vcpu *vcpu, u8 order_code,
271 			   u16 cpu_addr, u32 parameter, u64 *status_reg)
272 {
273 	int rc;
274 	struct kvm_vcpu *dst_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr);
275 
276 	if (!dst_vcpu)
277 		return SIGP_CC_NOT_OPERATIONAL;
278 
279 	/*
280 	 * SIGP RESTART, SIGP STOP, and SIGP STOP AND STORE STATUS orders
281 	 * are processed asynchronously. Until the affected VCPU finishes
282 	 * its work and calls back into KVM to clear the (RESTART or STOP)
283 	 * interrupt, we need to return any new non-reset orders "busy".
284 	 *
285 	 * This is important because a single VCPU could issue:
286 	 *  1) SIGP STOP $DESTINATION
287 	 *  2) SIGP SENSE $DESTINATION
288 	 *
289 	 * If the SIGP SENSE would not be rejected as "busy", it could
290 	 * return an incorrect answer as to whether the VCPU is STOPPED
291 	 * or OPERATING.
292 	 */
293 	if (order_code != SIGP_INITIAL_CPU_RESET &&
294 	    order_code != SIGP_CPU_RESET) {
295 		/*
296 		 * Lockless check. Both SIGP STOP and SIGP (RE)START
297 		 * properly synchronize everything while processing
298 		 * their orders, while the guest cannot observe a
299 		 * difference when issuing other orders from two
300 		 * different VCPUs.
301 		 */
302 		if (kvm_s390_is_stop_irq_pending(dst_vcpu) ||
303 		    kvm_s390_is_restart_irq_pending(dst_vcpu))
304 			return SIGP_CC_BUSY;
305 	}
306 
307 	switch (order_code) {
308 	case SIGP_SENSE:
309 		vcpu->stat.instruction_sigp_sense++;
310 		rc = __sigp_sense(vcpu, dst_vcpu, status_reg);
311 		break;
312 	case SIGP_EXTERNAL_CALL:
313 		vcpu->stat.instruction_sigp_external_call++;
314 		rc = __sigp_external_call(vcpu, dst_vcpu, status_reg);
315 		break;
316 	case SIGP_EMERGENCY_SIGNAL:
317 		vcpu->stat.instruction_sigp_emergency++;
318 		rc = __sigp_emergency(vcpu, dst_vcpu);
319 		break;
320 	case SIGP_STOP:
321 		vcpu->stat.instruction_sigp_stop++;
322 		rc = __sigp_stop(vcpu, dst_vcpu);
323 		break;
324 	case SIGP_STOP_AND_STORE_STATUS:
325 		vcpu->stat.instruction_sigp_stop_store_status++;
326 		rc = __sigp_stop_and_store_status(vcpu, dst_vcpu, status_reg);
327 		break;
328 	case SIGP_STORE_STATUS_AT_ADDRESS:
329 		vcpu->stat.instruction_sigp_store_status++;
330 		rc = __sigp_store_status_at_addr(vcpu, dst_vcpu, parameter,
331 						 status_reg);
332 		break;
333 	case SIGP_SET_PREFIX:
334 		vcpu->stat.instruction_sigp_prefix++;
335 		rc = __sigp_set_prefix(vcpu, dst_vcpu, parameter, status_reg);
336 		break;
337 	case SIGP_COND_EMERGENCY_SIGNAL:
338 		vcpu->stat.instruction_sigp_cond_emergency++;
339 		rc = __sigp_conditional_emergency(vcpu, dst_vcpu, parameter,
340 						  status_reg);
341 		break;
342 	case SIGP_SENSE_RUNNING:
343 		vcpu->stat.instruction_sigp_sense_running++;
344 		rc = __sigp_sense_running(vcpu, dst_vcpu, status_reg);
345 		break;
346 	case SIGP_START:
347 		vcpu->stat.instruction_sigp_start++;
348 		rc = __prepare_sigp_re_start(vcpu, dst_vcpu, order_code);
349 		break;
350 	case SIGP_RESTART:
351 		vcpu->stat.instruction_sigp_restart++;
352 		rc = __prepare_sigp_re_start(vcpu, dst_vcpu, order_code);
353 		break;
354 	case SIGP_INITIAL_CPU_RESET:
355 		vcpu->stat.instruction_sigp_init_cpu_reset++;
356 		rc = __prepare_sigp_cpu_reset(vcpu, dst_vcpu, order_code);
357 		break;
358 	case SIGP_CPU_RESET:
359 		vcpu->stat.instruction_sigp_cpu_reset++;
360 		rc = __prepare_sigp_cpu_reset(vcpu, dst_vcpu, order_code);
361 		break;
362 	default:
363 		vcpu->stat.instruction_sigp_unknown++;
364 		rc = __prepare_sigp_unknown(vcpu, dst_vcpu);
365 	}
366 
367 	if (rc == -EOPNOTSUPP)
368 		VCPU_EVENT(vcpu, 4,
369 			   "sigp order %u -> cpu %x: handled in user space",
370 			   order_code, dst_vcpu->vcpu_id);
371 
372 	return rc;
373 }
374 
handle_sigp_order_in_user_space(struct kvm_vcpu * vcpu,u8 order_code,u16 cpu_addr)375 static int handle_sigp_order_in_user_space(struct kvm_vcpu *vcpu, u8 order_code,
376 					   u16 cpu_addr)
377 {
378 	if (!vcpu->kvm->arch.user_sigp)
379 		return 0;
380 
381 	switch (order_code) {
382 	case SIGP_SENSE:
383 	case SIGP_EXTERNAL_CALL:
384 	case SIGP_EMERGENCY_SIGNAL:
385 	case SIGP_COND_EMERGENCY_SIGNAL:
386 	case SIGP_SENSE_RUNNING:
387 		return 0;
388 	/* update counters as we're directly dropping to user space */
389 	case SIGP_STOP:
390 		vcpu->stat.instruction_sigp_stop++;
391 		break;
392 	case SIGP_STOP_AND_STORE_STATUS:
393 		vcpu->stat.instruction_sigp_stop_store_status++;
394 		break;
395 	case SIGP_STORE_STATUS_AT_ADDRESS:
396 		vcpu->stat.instruction_sigp_store_status++;
397 		break;
398 	case SIGP_STORE_ADDITIONAL_STATUS:
399 		vcpu->stat.instruction_sigp_store_adtl_status++;
400 		break;
401 	case SIGP_SET_PREFIX:
402 		vcpu->stat.instruction_sigp_prefix++;
403 		break;
404 	case SIGP_START:
405 		vcpu->stat.instruction_sigp_start++;
406 		break;
407 	case SIGP_RESTART:
408 		vcpu->stat.instruction_sigp_restart++;
409 		break;
410 	case SIGP_INITIAL_CPU_RESET:
411 		vcpu->stat.instruction_sigp_init_cpu_reset++;
412 		break;
413 	case SIGP_CPU_RESET:
414 		vcpu->stat.instruction_sigp_cpu_reset++;
415 		break;
416 	default:
417 		vcpu->stat.instruction_sigp_unknown++;
418 	}
419 	VCPU_EVENT(vcpu, 3, "SIGP: order %u for CPU %d handled in userspace",
420 		   order_code, cpu_addr);
421 
422 	return 1;
423 }
424 
kvm_s390_handle_sigp(struct kvm_vcpu * vcpu)425 int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu)
426 {
427 	int r1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
428 	int r3 = vcpu->arch.sie_block->ipa & 0x000f;
429 	u32 parameter;
430 	u16 cpu_addr = vcpu->run->s.regs.gprs[r3];
431 	u8 order_code;
432 	int rc;
433 
434 	/* sigp in userspace can exit */
435 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
436 		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
437 
438 	order_code = kvm_s390_get_base_disp_rs(vcpu, NULL);
439 	if (handle_sigp_order_in_user_space(vcpu, order_code, cpu_addr))
440 		return -EOPNOTSUPP;
441 
442 	if (r1 % 2)
443 		parameter = vcpu->run->s.regs.gprs[r1];
444 	else
445 		parameter = vcpu->run->s.regs.gprs[r1 + 1];
446 
447 	trace_kvm_s390_handle_sigp(vcpu, order_code, cpu_addr, parameter);
448 	switch (order_code) {
449 	case SIGP_SET_ARCHITECTURE:
450 		vcpu->stat.instruction_sigp_arch++;
451 		rc = __sigp_set_arch(vcpu, parameter,
452 				     &vcpu->run->s.regs.gprs[r1]);
453 		break;
454 	default:
455 		rc = handle_sigp_dst(vcpu, order_code, cpu_addr,
456 				     parameter,
457 				     &vcpu->run->s.regs.gprs[r1]);
458 	}
459 
460 	if (rc < 0)
461 		return rc;
462 
463 	kvm_s390_set_psw_cc(vcpu, rc);
464 	return 0;
465 }
466 
467 /*
468  * Handle SIGP partial execution interception.
469  *
470  * This interception will occur at the source cpu when a source cpu sends an
471  * external call to a target cpu and the target cpu has the WAIT bit set in
472  * its cpuflags. Interception will occurr after the interrupt indicator bits at
473  * the target cpu have been set. All error cases will lead to instruction
474  * interception, therefore nothing is to be checked or prepared.
475  */
kvm_s390_handle_sigp_pei(struct kvm_vcpu * vcpu)476 int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu)
477 {
478 	int r3 = vcpu->arch.sie_block->ipa & 0x000f;
479 	u16 cpu_addr = vcpu->run->s.regs.gprs[r3];
480 	struct kvm_vcpu *dest_vcpu;
481 	u8 order_code = kvm_s390_get_base_disp_rs(vcpu, NULL);
482 
483 	if (order_code == SIGP_EXTERNAL_CALL) {
484 		trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr);
485 
486 		dest_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr);
487 		BUG_ON(dest_vcpu == NULL);
488 
489 		kvm_s390_vcpu_wakeup(dest_vcpu);
490 		kvm_s390_set_psw_cc(vcpu, SIGP_CC_ORDER_CODE_ACCEPTED);
491 		return 0;
492 	}
493 
494 	return -EOPNOTSUPP;
495 }
496