1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * kvm nested virtualization support for s390x
4  *
5  * Copyright IBM Corp. 2016, 2018
6  *
7  *    Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com>
8  */
9 #include <linux/vmalloc.h>
10 #include <linux/kvm_host.h>
11 #include <linux/bug.h>
12 #include <linux/list.h>
13 #include <linux/bitmap.h>
14 #include <linux/sched/signal.h>
15 
16 #include <asm/gmap.h>
17 #include <asm/mmu_context.h>
18 #include <asm/sclp.h>
19 #include <asm/nmi.h>
20 #include <asm/dis.h>
21 #include <asm/fpu/api.h>
22 #include "kvm-s390.h"
23 #include "gaccess.h"
24 
25 struct vsie_page {
26 	struct kvm_s390_sie_block scb_s;	/* 0x0000 */
27 	/*
28 	 * the backup info for machine check. ensure it's at
29 	 * the same offset as that in struct sie_page!
30 	 */
31 	struct mcck_volatile_info mcck_info;    /* 0x0200 */
32 	/*
33 	 * The pinned original scb. Be aware that other VCPUs can modify
34 	 * it while we read from it. Values that are used for conditions or
35 	 * are reused conditionally, should be accessed via READ_ONCE.
36 	 */
37 	struct kvm_s390_sie_block *scb_o;	/* 0x0218 */
38 	/* the shadow gmap in use by the vsie_page */
39 	struct gmap *gmap;			/* 0x0220 */
40 	/* address of the last reported fault to guest2 */
41 	unsigned long fault_addr;		/* 0x0228 */
42 	/* calculated guest addresses of satellite control blocks */
43 	gpa_t sca_gpa;				/* 0x0230 */
44 	gpa_t itdba_gpa;			/* 0x0238 */
45 	gpa_t gvrd_gpa;				/* 0x0240 */
46 	gpa_t riccbd_gpa;			/* 0x0248 */
47 	gpa_t sdnx_gpa;				/* 0x0250 */
48 	__u8 reserved[0x0700 - 0x0258];		/* 0x0258 */
49 	struct kvm_s390_crypto_cb crycb;	/* 0x0700 */
50 	__u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE];	/* 0x0800 */
51 };
52 
53 /* trigger a validity icpt for the given scb */
set_validity_icpt(struct kvm_s390_sie_block * scb,__u16 reason_code)54 static int set_validity_icpt(struct kvm_s390_sie_block *scb,
55 			     __u16 reason_code)
56 {
57 	scb->ipa = 0x1000;
58 	scb->ipb = ((__u32) reason_code) << 16;
59 	scb->icptcode = ICPT_VALIDITY;
60 	return 1;
61 }
62 
63 /* mark the prefix as unmapped, this will block the VSIE */
prefix_unmapped(struct vsie_page * vsie_page)64 static void prefix_unmapped(struct vsie_page *vsie_page)
65 {
66 	atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20);
67 }
68 
69 /* mark the prefix as unmapped and wait until the VSIE has been left */
prefix_unmapped_sync(struct vsie_page * vsie_page)70 static void prefix_unmapped_sync(struct vsie_page *vsie_page)
71 {
72 	prefix_unmapped(vsie_page);
73 	if (vsie_page->scb_s.prog0c & PROG_IN_SIE)
74 		atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags);
75 	while (vsie_page->scb_s.prog0c & PROG_IN_SIE)
76 		cpu_relax();
77 }
78 
79 /* mark the prefix as mapped, this will allow the VSIE to run */
prefix_mapped(struct vsie_page * vsie_page)80 static void prefix_mapped(struct vsie_page *vsie_page)
81 {
82 	atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20);
83 }
84 
85 /* test if the prefix is mapped into the gmap shadow */
prefix_is_mapped(struct vsie_page * vsie_page)86 static int prefix_is_mapped(struct vsie_page *vsie_page)
87 {
88 	return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST);
89 }
90 
91 /* copy the updated intervention request bits into the shadow scb */
update_intervention_requests(struct vsie_page * vsie_page)92 static void update_intervention_requests(struct vsie_page *vsie_page)
93 {
94 	const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT;
95 	int cpuflags;
96 
97 	cpuflags = atomic_read(&vsie_page->scb_o->cpuflags);
98 	atomic_andnot(bits, &vsie_page->scb_s.cpuflags);
99 	atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags);
100 }
101 
102 /* shadow (filter and validate) the cpuflags  */
prepare_cpuflags(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)103 static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
104 {
105 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
106 	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
107 	int newflags, cpuflags = atomic_read(&scb_o->cpuflags);
108 
109 	/* we don't allow ESA/390 guests */
110 	if (!(cpuflags & CPUSTAT_ZARCH))
111 		return set_validity_icpt(scb_s, 0x0001U);
112 
113 	if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS))
114 		return set_validity_icpt(scb_s, 0x0001U);
115 	else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR))
116 		return set_validity_icpt(scb_s, 0x0007U);
117 
118 	/* intervention requests will be set later */
119 	newflags = CPUSTAT_ZARCH;
120 	if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8))
121 		newflags |= CPUSTAT_GED;
122 	if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) {
123 		if (cpuflags & CPUSTAT_GED)
124 			return set_validity_icpt(scb_s, 0x0001U);
125 		newflags |= CPUSTAT_GED2;
126 	}
127 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GPERE))
128 		newflags |= cpuflags & CPUSTAT_P;
129 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GSLS))
130 		newflags |= cpuflags & CPUSTAT_SM;
131 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IBS))
132 		newflags |= cpuflags & CPUSTAT_IBS;
133 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_KSS))
134 		newflags |= cpuflags & CPUSTAT_KSS;
135 
136 	atomic_set(&scb_s->cpuflags, newflags);
137 	return 0;
138 }
139 /* Copy to APCB FORMAT1 from APCB FORMAT0 */
setup_apcb10(struct kvm_vcpu * vcpu,struct kvm_s390_apcb1 * apcb_s,unsigned long apcb_o,struct kvm_s390_apcb1 * apcb_h)140 static int setup_apcb10(struct kvm_vcpu *vcpu, struct kvm_s390_apcb1 *apcb_s,
141 			unsigned long apcb_o, struct kvm_s390_apcb1 *apcb_h)
142 {
143 	struct kvm_s390_apcb0 tmp;
144 
145 	if (read_guest_real(vcpu, apcb_o, &tmp, sizeof(struct kvm_s390_apcb0)))
146 		return -EFAULT;
147 
148 	apcb_s->apm[0] = apcb_h->apm[0] & tmp.apm[0];
149 	apcb_s->aqm[0] = apcb_h->aqm[0] & tmp.aqm[0] & 0xffff000000000000UL;
150 	apcb_s->adm[0] = apcb_h->adm[0] & tmp.adm[0] & 0xffff000000000000UL;
151 
152 	return 0;
153 
154 }
155 
156 /**
157  * setup_apcb00 - Copy to APCB FORMAT0 from APCB FORMAT0
158  * @vcpu: pointer to the virtual CPU
159  * @apcb_s: pointer to start of apcb in the shadow crycb
160  * @apcb_o: pointer to start of original apcb in the guest2
161  * @apcb_h: pointer to start of apcb in the guest1
162  *
163  * Returns 0 and -EFAULT on error reading guest apcb
164  */
setup_apcb00(struct kvm_vcpu * vcpu,unsigned long * apcb_s,unsigned long apcb_o,unsigned long * apcb_h)165 static int setup_apcb00(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
166 			unsigned long apcb_o, unsigned long *apcb_h)
167 {
168 	if (read_guest_real(vcpu, apcb_o, apcb_s,
169 			    sizeof(struct kvm_s390_apcb0)))
170 		return -EFAULT;
171 
172 	bitmap_and(apcb_s, apcb_s, apcb_h, sizeof(struct kvm_s390_apcb0));
173 
174 	return 0;
175 }
176 
177 /**
178  * setup_apcb11 - Copy the FORMAT1 APCB from the guest to the shadow CRYCB
179  * @vcpu: pointer to the virtual CPU
180  * @apcb_s: pointer to start of apcb in the shadow crycb
181  * @apcb_o: pointer to start of original guest apcb
182  * @apcb_h: pointer to start of apcb in the host
183  *
184  * Returns 0 and -EFAULT on error reading guest apcb
185  */
setup_apcb11(struct kvm_vcpu * vcpu,unsigned long * apcb_s,unsigned long apcb_o,unsigned long * apcb_h)186 static int setup_apcb11(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
187 			unsigned long apcb_o,
188 			unsigned long *apcb_h)
189 {
190 	if (read_guest_real(vcpu, apcb_o, apcb_s,
191 			    sizeof(struct kvm_s390_apcb1)))
192 		return -EFAULT;
193 
194 	bitmap_and(apcb_s, apcb_s, apcb_h, sizeof(struct kvm_s390_apcb1));
195 
196 	return 0;
197 }
198 
199 /**
200  * setup_apcb - Create a shadow copy of the apcb.
201  * @vcpu: pointer to the virtual CPU
202  * @crycb_s: pointer to shadow crycb
203  * @crycb_o: pointer to original guest crycb
204  * @crycb_h: pointer to the host crycb
205  * @fmt_o: format of the original guest crycb.
206  * @fmt_h: format of the host crycb.
207  *
208  * Checks the compatibility between the guest and host crycb and calls the
209  * appropriate copy function.
210  *
211  * Return 0 or an error number if the guest and host crycb are incompatible.
212  */
setup_apcb(struct kvm_vcpu * vcpu,struct kvm_s390_crypto_cb * crycb_s,const u32 crycb_o,struct kvm_s390_crypto_cb * crycb_h,int fmt_o,int fmt_h)213 static int setup_apcb(struct kvm_vcpu *vcpu, struct kvm_s390_crypto_cb *crycb_s,
214 	       const u32 crycb_o,
215 	       struct kvm_s390_crypto_cb *crycb_h,
216 	       int fmt_o, int fmt_h)
217 {
218 	struct kvm_s390_crypto_cb *crycb;
219 
220 	crycb = (struct kvm_s390_crypto_cb *) (unsigned long)crycb_o;
221 
222 	switch (fmt_o) {
223 	case CRYCB_FORMAT2:
224 		if ((crycb_o & PAGE_MASK) != ((crycb_o + 256) & PAGE_MASK))
225 			return -EACCES;
226 		if (fmt_h != CRYCB_FORMAT2)
227 			return -EINVAL;
228 		return setup_apcb11(vcpu, (unsigned long *)&crycb_s->apcb1,
229 				    (unsigned long) &crycb->apcb1,
230 				    (unsigned long *)&crycb_h->apcb1);
231 	case CRYCB_FORMAT1:
232 		switch (fmt_h) {
233 		case CRYCB_FORMAT2:
234 			return setup_apcb10(vcpu, &crycb_s->apcb1,
235 					    (unsigned long) &crycb->apcb0,
236 					    &crycb_h->apcb1);
237 		case CRYCB_FORMAT1:
238 			return setup_apcb00(vcpu,
239 					    (unsigned long *) &crycb_s->apcb0,
240 					    (unsigned long) &crycb->apcb0,
241 					    (unsigned long *) &crycb_h->apcb0);
242 		}
243 		break;
244 	case CRYCB_FORMAT0:
245 		if ((crycb_o & PAGE_MASK) != ((crycb_o + 32) & PAGE_MASK))
246 			return -EACCES;
247 
248 		switch (fmt_h) {
249 		case CRYCB_FORMAT2:
250 			return setup_apcb10(vcpu, &crycb_s->apcb1,
251 					    (unsigned long) &crycb->apcb0,
252 					    &crycb_h->apcb1);
253 		case CRYCB_FORMAT1:
254 		case CRYCB_FORMAT0:
255 			return setup_apcb00(vcpu,
256 					    (unsigned long *) &crycb_s->apcb0,
257 					    (unsigned long) &crycb->apcb0,
258 					    (unsigned long *) &crycb_h->apcb0);
259 		}
260 	}
261 	return -EINVAL;
262 }
263 
264 /**
265  * shadow_crycb - Create a shadow copy of the crycb block
266  * @vcpu: a pointer to the virtual CPU
267  * @vsie_page: a pointer to internal date used for the vSIE
268  *
269  * Create a shadow copy of the crycb block and setup key wrapping, if
270  * requested for guest 3 and enabled for guest 2.
271  *
272  * We accept format-1 or format-2, but we convert format-1 into format-2
273  * in the shadow CRYCB.
274  * Using format-2 enables the firmware to choose the right format when
275  * scheduling the SIE.
276  * There is nothing to do for format-0.
277  *
278  * This function centralize the issuing of set_validity_icpt() for all
279  * the subfunctions working on the crycb.
280  *
281  * Returns: - 0 if shadowed or nothing to do
282  *          - > 0 if control has to be given to guest 2
283  */
shadow_crycb(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)284 static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
285 {
286 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
287 	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
288 	const uint32_t crycbd_o = READ_ONCE(scb_o->crycbd);
289 	const u32 crycb_addr = crycbd_o & 0x7ffffff8U;
290 	unsigned long *b1, *b2;
291 	u8 ecb3_flags;
292 	u32 ecd_flags;
293 	int apie_h;
294 	int apie_s;
295 	int key_msk = test_kvm_facility(vcpu->kvm, 76);
296 	int fmt_o = crycbd_o & CRYCB_FORMAT_MASK;
297 	int fmt_h = vcpu->arch.sie_block->crycbd & CRYCB_FORMAT_MASK;
298 	int ret = 0;
299 
300 	scb_s->crycbd = 0;
301 
302 	apie_h = vcpu->arch.sie_block->eca & ECA_APIE;
303 	apie_s = apie_h & scb_o->eca;
304 	if (!apie_s && (!key_msk || (fmt_o == CRYCB_FORMAT0)))
305 		return 0;
306 
307 	if (!crycb_addr)
308 		return set_validity_icpt(scb_s, 0x0039U);
309 
310 	if (fmt_o == CRYCB_FORMAT1)
311 		if ((crycb_addr & PAGE_MASK) !=
312 		    ((crycb_addr + 128) & PAGE_MASK))
313 			return set_validity_icpt(scb_s, 0x003CU);
314 
315 	if (apie_s) {
316 		ret = setup_apcb(vcpu, &vsie_page->crycb, crycb_addr,
317 				 vcpu->kvm->arch.crypto.crycb,
318 				 fmt_o, fmt_h);
319 		if (ret)
320 			goto end;
321 		scb_s->eca |= scb_o->eca & ECA_APIE;
322 	}
323 
324 	/* we may only allow it if enabled for guest 2 */
325 	ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
326 		     (ECB3_AES | ECB3_DEA);
327 	ecd_flags = scb_o->ecd & vcpu->arch.sie_block->ecd & ECD_ECC;
328 	if (!ecb3_flags && !ecd_flags)
329 		goto end;
330 
331 	/* copy only the wrapping keys */
332 	if (read_guest_real(vcpu, crycb_addr + 72,
333 			    vsie_page->crycb.dea_wrapping_key_mask, 56))
334 		return set_validity_icpt(scb_s, 0x0035U);
335 
336 	scb_s->ecb3 |= ecb3_flags;
337 	scb_s->ecd |= ecd_flags;
338 
339 	/* xor both blocks in one run */
340 	b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;
341 	b2 = (unsigned long *)
342 			    vcpu->kvm->arch.crypto.crycb->dea_wrapping_key_mask;
343 	/* as 56%8 == 0, bitmap_xor won't overwrite any data */
344 	bitmap_xor(b1, b1, b2, BITS_PER_BYTE * 56);
345 end:
346 	switch (ret) {
347 	case -EINVAL:
348 		return set_validity_icpt(scb_s, 0x0022U);
349 	case -EFAULT:
350 		return set_validity_icpt(scb_s, 0x0035U);
351 	case -EACCES:
352 		return set_validity_icpt(scb_s, 0x003CU);
353 	}
354 	scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT2;
355 	return 0;
356 }
357 
358 /* shadow (round up/down) the ibc to avoid validity icpt */
prepare_ibc(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)359 static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
360 {
361 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
362 	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
363 	/* READ_ONCE does not work on bitfields - use a temporary variable */
364 	const uint32_t __new_ibc = scb_o->ibc;
365 	const uint32_t new_ibc = READ_ONCE(__new_ibc) & 0x0fffU;
366 	__u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU;
367 
368 	scb_s->ibc = 0;
369 	/* ibc installed in g2 and requested for g3 */
370 	if (vcpu->kvm->arch.model.ibc && new_ibc) {
371 		scb_s->ibc = new_ibc;
372 		/* takte care of the minimum ibc level of the machine */
373 		if (scb_s->ibc < min_ibc)
374 			scb_s->ibc = min_ibc;
375 		/* take care of the maximum ibc level set for the guest */
376 		if (scb_s->ibc > vcpu->kvm->arch.model.ibc)
377 			scb_s->ibc = vcpu->kvm->arch.model.ibc;
378 	}
379 }
380 
381 /* unshadow the scb, copying parameters back to the real scb */
unshadow_scb(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)382 static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
383 {
384 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
385 	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
386 
387 	/* interception */
388 	scb_o->icptcode = scb_s->icptcode;
389 	scb_o->icptstatus = scb_s->icptstatus;
390 	scb_o->ipa = scb_s->ipa;
391 	scb_o->ipb = scb_s->ipb;
392 	scb_o->gbea = scb_s->gbea;
393 
394 	/* timer */
395 	scb_o->cputm = scb_s->cputm;
396 	scb_o->ckc = scb_s->ckc;
397 	scb_o->todpr = scb_s->todpr;
398 
399 	/* guest state */
400 	scb_o->gpsw = scb_s->gpsw;
401 	scb_o->gg14 = scb_s->gg14;
402 	scb_o->gg15 = scb_s->gg15;
403 	memcpy(scb_o->gcr, scb_s->gcr, 128);
404 	scb_o->pp = scb_s->pp;
405 
406 	/* branch prediction */
407 	if (test_kvm_facility(vcpu->kvm, 82)) {
408 		scb_o->fpf &= ~FPF_BPBC;
409 		scb_o->fpf |= scb_s->fpf & FPF_BPBC;
410 	}
411 
412 	/* interrupt intercept */
413 	switch (scb_s->icptcode) {
414 	case ICPT_PROGI:
415 	case ICPT_INSTPROGI:
416 	case ICPT_EXTINT:
417 		memcpy((void *)((u64)scb_o + 0xc0),
418 		       (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
419 		break;
420 	}
421 
422 	if (scb_s->ihcpu != 0xffffU)
423 		scb_o->ihcpu = scb_s->ihcpu;
424 }
425 
426 /*
427  * Setup the shadow scb by copying and checking the relevant parts of the g2
428  * provided scb.
429  *
430  * Returns: - 0 if the scb has been shadowed
431  *          - > 0 if control has to be given to guest 2
432  */
shadow_scb(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)433 static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
434 {
435 	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
436 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
437 	/* READ_ONCE does not work on bitfields - use a temporary variable */
438 	const uint32_t __new_prefix = scb_o->prefix;
439 	const uint32_t new_prefix = READ_ONCE(__new_prefix);
440 	const bool wants_tx = READ_ONCE(scb_o->ecb) & ECB_TE;
441 	bool had_tx = scb_s->ecb & ECB_TE;
442 	unsigned long new_mso = 0;
443 	int rc;
444 
445 	/* make sure we don't have any leftovers when reusing the scb */
446 	scb_s->icptcode = 0;
447 	scb_s->eca = 0;
448 	scb_s->ecb = 0;
449 	scb_s->ecb2 = 0;
450 	scb_s->ecb3 = 0;
451 	scb_s->ecd = 0;
452 	scb_s->fac = 0;
453 	scb_s->fpf = 0;
454 
455 	rc = prepare_cpuflags(vcpu, vsie_page);
456 	if (rc)
457 		goto out;
458 
459 	/* timer */
460 	scb_s->cputm = scb_o->cputm;
461 	scb_s->ckc = scb_o->ckc;
462 	scb_s->todpr = scb_o->todpr;
463 	scb_s->epoch = scb_o->epoch;
464 
465 	/* guest state */
466 	scb_s->gpsw = scb_o->gpsw;
467 	scb_s->gg14 = scb_o->gg14;
468 	scb_s->gg15 = scb_o->gg15;
469 	memcpy(scb_s->gcr, scb_o->gcr, 128);
470 	scb_s->pp = scb_o->pp;
471 
472 	/* interception / execution handling */
473 	scb_s->gbea = scb_o->gbea;
474 	scb_s->lctl = scb_o->lctl;
475 	scb_s->svcc = scb_o->svcc;
476 	scb_s->ictl = scb_o->ictl;
477 	/*
478 	 * SKEY handling functions can't deal with false setting of PTE invalid
479 	 * bits. Therefore we cannot provide interpretation and would later
480 	 * have to provide own emulation handlers.
481 	 */
482 	if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_KSS))
483 		scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
484 
485 	scb_s->icpua = scb_o->icpua;
486 
487 	if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_SM))
488 		new_mso = READ_ONCE(scb_o->mso) & 0xfffffffffff00000UL;
489 	/* if the hva of the prefix changes, we have to remap the prefix */
490 	if (scb_s->mso != new_mso || scb_s->prefix != new_prefix)
491 		prefix_unmapped(vsie_page);
492 	 /* SIE will do mso/msl validity and exception checks for us */
493 	scb_s->msl = scb_o->msl & 0xfffffffffff00000UL;
494 	scb_s->mso = new_mso;
495 	scb_s->prefix = new_prefix;
496 
497 	/* We have to definetly flush the tlb if this scb never ran */
498 	if (scb_s->ihcpu != 0xffffU)
499 		scb_s->ihcpu = scb_o->ihcpu;
500 
501 	/* MVPG and Protection Exception Interpretation are always available */
502 	scb_s->eca |= scb_o->eca & (ECA_MVPGI | ECA_PROTEXCI);
503 	/* Host-protection-interruption introduced with ESOP */
504 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_ESOP))
505 		scb_s->ecb |= scb_o->ecb & ECB_HOSTPROTINT;
506 	/*
507 	 * CPU Topology
508 	 * This facility only uses the utility field of the SCA and none of
509 	 * the cpu entries that are problematic with the other interpretation
510 	 * facilities so we can pass it through
511 	 */
512 	if (test_kvm_facility(vcpu->kvm, 11))
513 		scb_s->ecb |= scb_o->ecb & ECB_PTF;
514 	/* transactional execution */
515 	if (test_kvm_facility(vcpu->kvm, 73) && wants_tx) {
516 		/* remap the prefix is tx is toggled on */
517 		if (!had_tx)
518 			prefix_unmapped(vsie_page);
519 		scb_s->ecb |= ECB_TE;
520 	}
521 	/* specification exception interpretation */
522 	scb_s->ecb |= scb_o->ecb & ECB_SPECI;
523 	/* branch prediction */
524 	if (test_kvm_facility(vcpu->kvm, 82))
525 		scb_s->fpf |= scb_o->fpf & FPF_BPBC;
526 	/* SIMD */
527 	if (test_kvm_facility(vcpu->kvm, 129)) {
528 		scb_s->eca |= scb_o->eca & ECA_VX;
529 		scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT;
530 	}
531 	/* Run-time-Instrumentation */
532 	if (test_kvm_facility(vcpu->kvm, 64))
533 		scb_s->ecb3 |= scb_o->ecb3 & ECB3_RI;
534 	/* Instruction Execution Prevention */
535 	if (test_kvm_facility(vcpu->kvm, 130))
536 		scb_s->ecb2 |= scb_o->ecb2 & ECB2_IEP;
537 	/* Guarded Storage */
538 	if (test_kvm_facility(vcpu->kvm, 133)) {
539 		scb_s->ecb |= scb_o->ecb & ECB_GS;
540 		scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT;
541 	}
542 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF))
543 		scb_s->eca |= scb_o->eca & ECA_SII;
544 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB))
545 		scb_s->eca |= scb_o->eca & ECA_IB;
546 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))
547 		scb_s->eca |= scb_o->eca & ECA_CEI;
548 	/* Epoch Extension */
549 	if (test_kvm_facility(vcpu->kvm, 139)) {
550 		scb_s->ecd |= scb_o->ecd & ECD_MEF;
551 		scb_s->epdx = scb_o->epdx;
552 	}
553 
554 	/* etoken */
555 	if (test_kvm_facility(vcpu->kvm, 156))
556 		scb_s->ecd |= scb_o->ecd & ECD_ETOKENF;
557 
558 	scb_s->hpid = HPID_VSIE;
559 	scb_s->cpnc = scb_o->cpnc;
560 
561 	prepare_ibc(vcpu, vsie_page);
562 	rc = shadow_crycb(vcpu, vsie_page);
563 out:
564 	if (rc)
565 		unshadow_scb(vcpu, vsie_page);
566 	return rc;
567 }
568 
kvm_s390_vsie_gmap_notifier(struct gmap * gmap,unsigned long start,unsigned long end)569 void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
570 				 unsigned long end)
571 {
572 	struct kvm *kvm = gmap->private;
573 	struct vsie_page *cur;
574 	unsigned long prefix;
575 	struct page *page;
576 	int i;
577 
578 	if (!gmap_is_shadow(gmap))
579 		return;
580 	if (start >= 1UL << 31)
581 		/* We are only interested in prefix pages */
582 		return;
583 
584 	/*
585 	 * Only new shadow blocks are added to the list during runtime,
586 	 * therefore we can safely reference them all the time.
587 	 */
588 	for (i = 0; i < kvm->arch.vsie.page_count; i++) {
589 		page = READ_ONCE(kvm->arch.vsie.pages[i]);
590 		if (!page)
591 			continue;
592 		cur = page_to_virt(page);
593 		if (READ_ONCE(cur->gmap) != gmap)
594 			continue;
595 		prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT;
596 		/* with mso/msl, the prefix lies at an offset */
597 		prefix += cur->scb_s.mso;
598 		if (prefix <= end && start <= prefix + 2 * PAGE_SIZE - 1)
599 			prefix_unmapped_sync(cur);
600 	}
601 }
602 
603 /*
604  * Map the first prefix page and if tx is enabled also the second prefix page.
605  *
606  * The prefix will be protected, a gmap notifier will inform about unmaps.
607  * The shadow scb must not be executed until the prefix is remapped, this is
608  * guaranteed by properly handling PROG_REQUEST.
609  *
610  * Returns: - 0 on if successfully mapped or already mapped
611  *          - > 0 if control has to be given to guest 2
612  *          - -EAGAIN if the caller can retry immediately
613  *          - -ENOMEM if out of memory
614  */
map_prefix(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)615 static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
616 {
617 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
618 	u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
619 	int rc;
620 
621 	if (prefix_is_mapped(vsie_page))
622 		return 0;
623 
624 	/* mark it as mapped so we can catch any concurrent unmappers */
625 	prefix_mapped(vsie_page);
626 
627 	/* with mso/msl, the prefix lies at offset *mso* */
628 	prefix += scb_s->mso;
629 
630 	rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix, NULL);
631 	if (!rc && (scb_s->ecb & ECB_TE))
632 		rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
633 					   prefix + PAGE_SIZE, NULL);
634 	/*
635 	 * We don't have to mprotect, we will be called for all unshadows.
636 	 * SIE will detect if protection applies and trigger a validity.
637 	 */
638 	if (rc)
639 		prefix_unmapped(vsie_page);
640 	if (rc > 0 || rc == -EFAULT)
641 		rc = set_validity_icpt(scb_s, 0x0037U);
642 	return rc;
643 }
644 
645 /*
646  * Pin the guest page given by gpa and set hpa to the pinned host address.
647  * Will always be pinned writable.
648  *
649  * Returns: - 0 on success
650  *          - -EINVAL if the gpa is not valid guest storage
651  */
pin_guest_page(struct kvm * kvm,gpa_t gpa,hpa_t * hpa)652 static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
653 {
654 	struct page *page;
655 
656 	page = gfn_to_page(kvm, gpa_to_gfn(gpa));
657 	if (is_error_page(page))
658 		return -EINVAL;
659 	*hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK);
660 	return 0;
661 }
662 
663 /* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */
unpin_guest_page(struct kvm * kvm,gpa_t gpa,hpa_t hpa)664 static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa)
665 {
666 	kvm_release_pfn_dirty(hpa >> PAGE_SHIFT);
667 	/* mark the page always as dirty for migration */
668 	mark_page_dirty(kvm, gpa_to_gfn(gpa));
669 }
670 
671 /* unpin all blocks previously pinned by pin_blocks(), marking them dirty */
unpin_blocks(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)672 static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
673 {
674 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
675 	hpa_t hpa;
676 
677 	hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol;
678 	if (hpa) {
679 		unpin_guest_page(vcpu->kvm, vsie_page->sca_gpa, hpa);
680 		vsie_page->sca_gpa = 0;
681 		scb_s->scaol = 0;
682 		scb_s->scaoh = 0;
683 	}
684 
685 	hpa = scb_s->itdba;
686 	if (hpa) {
687 		unpin_guest_page(vcpu->kvm, vsie_page->itdba_gpa, hpa);
688 		vsie_page->itdba_gpa = 0;
689 		scb_s->itdba = 0;
690 	}
691 
692 	hpa = scb_s->gvrd;
693 	if (hpa) {
694 		unpin_guest_page(vcpu->kvm, vsie_page->gvrd_gpa, hpa);
695 		vsie_page->gvrd_gpa = 0;
696 		scb_s->gvrd = 0;
697 	}
698 
699 	hpa = scb_s->riccbd;
700 	if (hpa) {
701 		unpin_guest_page(vcpu->kvm, vsie_page->riccbd_gpa, hpa);
702 		vsie_page->riccbd_gpa = 0;
703 		scb_s->riccbd = 0;
704 	}
705 
706 	hpa = scb_s->sdnxo;
707 	if (hpa) {
708 		unpin_guest_page(vcpu->kvm, vsie_page->sdnx_gpa, hpa);
709 		vsie_page->sdnx_gpa = 0;
710 		scb_s->sdnxo = 0;
711 	}
712 }
713 
714 /*
715  * Instead of shadowing some blocks, we can simply forward them because the
716  * addresses in the scb are 64 bit long.
717  *
718  * This works as long as the data lies in one page. If blocks ever exceed one
719  * page, we have to fall back to shadowing.
720  *
721  * As we reuse the sca, the vcpu pointers contained in it are invalid. We must
722  * therefore not enable any facilities that access these pointers (e.g. SIGPIF).
723  *
724  * Returns: - 0 if all blocks were pinned.
725  *          - > 0 if control has to be given to guest 2
726  *          - -ENOMEM if out of memory
727  */
pin_blocks(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)728 static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
729 {
730 	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
731 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
732 	hpa_t hpa;
733 	gpa_t gpa;
734 	int rc = 0;
735 
736 	gpa = READ_ONCE(scb_o->scaol) & ~0xfUL;
737 	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
738 		gpa |= (u64) READ_ONCE(scb_o->scaoh) << 32;
739 	if (gpa) {
740 		if (gpa < 2 * PAGE_SIZE)
741 			rc = set_validity_icpt(scb_s, 0x0038U);
742 		else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu))
743 			rc = set_validity_icpt(scb_s, 0x0011U);
744 		else if ((gpa & PAGE_MASK) !=
745 			 ((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK))
746 			rc = set_validity_icpt(scb_s, 0x003bU);
747 		if (!rc) {
748 			rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
749 			if (rc)
750 				rc = set_validity_icpt(scb_s, 0x0034U);
751 		}
752 		if (rc)
753 			goto unpin;
754 		vsie_page->sca_gpa = gpa;
755 		scb_s->scaoh = (u32)((u64)hpa >> 32);
756 		scb_s->scaol = (u32)(u64)hpa;
757 	}
758 
759 	gpa = READ_ONCE(scb_o->itdba) & ~0xffUL;
760 	if (gpa && (scb_s->ecb & ECB_TE)) {
761 		if (gpa < 2 * PAGE_SIZE) {
762 			rc = set_validity_icpt(scb_s, 0x0080U);
763 			goto unpin;
764 		}
765 		/* 256 bytes cannot cross page boundaries */
766 		rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
767 		if (rc) {
768 			rc = set_validity_icpt(scb_s, 0x0080U);
769 			goto unpin;
770 		}
771 		vsie_page->itdba_gpa = gpa;
772 		scb_s->itdba = hpa;
773 	}
774 
775 	gpa = READ_ONCE(scb_o->gvrd) & ~0x1ffUL;
776 	if (gpa && (scb_s->eca & ECA_VX) && !(scb_s->ecd & ECD_HOSTREGMGMT)) {
777 		if (gpa < 2 * PAGE_SIZE) {
778 			rc = set_validity_icpt(scb_s, 0x1310U);
779 			goto unpin;
780 		}
781 		/*
782 		 * 512 bytes vector registers cannot cross page boundaries
783 		 * if this block gets bigger, we have to shadow it.
784 		 */
785 		rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
786 		if (rc) {
787 			rc = set_validity_icpt(scb_s, 0x1310U);
788 			goto unpin;
789 		}
790 		vsie_page->gvrd_gpa = gpa;
791 		scb_s->gvrd = hpa;
792 	}
793 
794 	gpa = READ_ONCE(scb_o->riccbd) & ~0x3fUL;
795 	if (gpa && (scb_s->ecb3 & ECB3_RI)) {
796 		if (gpa < 2 * PAGE_SIZE) {
797 			rc = set_validity_icpt(scb_s, 0x0043U);
798 			goto unpin;
799 		}
800 		/* 64 bytes cannot cross page boundaries */
801 		rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
802 		if (rc) {
803 			rc = set_validity_icpt(scb_s, 0x0043U);
804 			goto unpin;
805 		}
806 		/* Validity 0x0044 will be checked by SIE */
807 		vsie_page->riccbd_gpa = gpa;
808 		scb_s->riccbd = hpa;
809 	}
810 	if (((scb_s->ecb & ECB_GS) && !(scb_s->ecd & ECD_HOSTREGMGMT)) ||
811 	    (scb_s->ecd & ECD_ETOKENF)) {
812 		unsigned long sdnxc;
813 
814 		gpa = READ_ONCE(scb_o->sdnxo) & ~0xfUL;
815 		sdnxc = READ_ONCE(scb_o->sdnxo) & 0xfUL;
816 		if (!gpa || gpa < 2 * PAGE_SIZE) {
817 			rc = set_validity_icpt(scb_s, 0x10b0U);
818 			goto unpin;
819 		}
820 		if (sdnxc < 6 || sdnxc > 12) {
821 			rc = set_validity_icpt(scb_s, 0x10b1U);
822 			goto unpin;
823 		}
824 		if (gpa & ((1 << sdnxc) - 1)) {
825 			rc = set_validity_icpt(scb_s, 0x10b2U);
826 			goto unpin;
827 		}
828 		/* Due to alignment rules (checked above) this cannot
829 		 * cross page boundaries
830 		 */
831 		rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
832 		if (rc) {
833 			rc = set_validity_icpt(scb_s, 0x10b0U);
834 			goto unpin;
835 		}
836 		vsie_page->sdnx_gpa = gpa;
837 		scb_s->sdnxo = hpa | sdnxc;
838 	}
839 	return 0;
840 unpin:
841 	unpin_blocks(vcpu, vsie_page);
842 	return rc;
843 }
844 
845 /* unpin the scb provided by guest 2, marking it as dirty */
unpin_scb(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page,gpa_t gpa)846 static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
847 		      gpa_t gpa)
848 {
849 	hpa_t hpa = (hpa_t) vsie_page->scb_o;
850 
851 	if (hpa)
852 		unpin_guest_page(vcpu->kvm, gpa, hpa);
853 	vsie_page->scb_o = NULL;
854 }
855 
856 /*
857  * Pin the scb at gpa provided by guest 2 at vsie_page->scb_o.
858  *
859  * Returns: - 0 if the scb was pinned.
860  *          - > 0 if control has to be given to guest 2
861  */
pin_scb(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page,gpa_t gpa)862 static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
863 		   gpa_t gpa)
864 {
865 	hpa_t hpa;
866 	int rc;
867 
868 	rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
869 	if (rc) {
870 		rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
871 		WARN_ON_ONCE(rc);
872 		return 1;
873 	}
874 	vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa;
875 	return 0;
876 }
877 
878 /*
879  * Inject a fault into guest 2.
880  *
881  * Returns: - > 0 if control has to be given to guest 2
882  *            < 0 if an error occurred during injection.
883  */
inject_fault(struct kvm_vcpu * vcpu,__u16 code,__u64 vaddr,bool write_flag)884 static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr,
885 			bool write_flag)
886 {
887 	struct kvm_s390_pgm_info pgm = {
888 		.code = code,
889 		.trans_exc_code =
890 			/* 0-51: virtual address */
891 			(vaddr & 0xfffffffffffff000UL) |
892 			/* 52-53: store / fetch */
893 			(((unsigned int) !write_flag) + 1) << 10,
894 			/* 62-63: asce id (alway primary == 0) */
895 		.exc_access_id = 0, /* always primary */
896 		.op_access_id = 0, /* not MVPG */
897 	};
898 	int rc;
899 
900 	if (code == PGM_PROTECTION)
901 		pgm.trans_exc_code |= 0x4UL;
902 
903 	rc = kvm_s390_inject_prog_irq(vcpu, &pgm);
904 	return rc ? rc : 1;
905 }
906 
907 /*
908  * Handle a fault during vsie execution on a gmap shadow.
909  *
910  * Returns: - 0 if the fault was resolved
911  *          - > 0 if control has to be given to guest 2
912  *          - < 0 if an error occurred
913  */
handle_fault(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)914 static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
915 {
916 	int rc;
917 
918 	if (current->thread.gmap_int_code == PGM_PROTECTION)
919 		/* we can directly forward all protection exceptions */
920 		return inject_fault(vcpu, PGM_PROTECTION,
921 				    current->thread.gmap_addr, 1);
922 
923 	rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
924 				   current->thread.gmap_addr, NULL);
925 	if (rc > 0) {
926 		rc = inject_fault(vcpu, rc,
927 				  current->thread.gmap_addr,
928 				  current->thread.gmap_write_flag);
929 		if (rc >= 0)
930 			vsie_page->fault_addr = current->thread.gmap_addr;
931 	}
932 	return rc;
933 }
934 
935 /*
936  * Retry the previous fault that required guest 2 intervention. This avoids
937  * one superfluous SIE re-entry and direct exit.
938  *
939  * Will ignore any errors. The next SIE fault will do proper fault handling.
940  */
handle_last_fault(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)941 static void handle_last_fault(struct kvm_vcpu *vcpu,
942 			      struct vsie_page *vsie_page)
943 {
944 	if (vsie_page->fault_addr)
945 		kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
946 				      vsie_page->fault_addr, NULL);
947 	vsie_page->fault_addr = 0;
948 }
949 
clear_vsie_icpt(struct vsie_page * vsie_page)950 static inline void clear_vsie_icpt(struct vsie_page *vsie_page)
951 {
952 	vsie_page->scb_s.icptcode = 0;
953 }
954 
955 /* rewind the psw and clear the vsie icpt, so we can retry execution */
retry_vsie_icpt(struct vsie_page * vsie_page)956 static void retry_vsie_icpt(struct vsie_page *vsie_page)
957 {
958 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
959 	int ilen = insn_length(scb_s->ipa >> 8);
960 
961 	/* take care of EXECUTE instructions */
962 	if (scb_s->icptstatus & 1) {
963 		ilen = (scb_s->icptstatus >> 4) & 0x6;
964 		if (!ilen)
965 			ilen = 4;
966 	}
967 	scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, ilen);
968 	clear_vsie_icpt(vsie_page);
969 }
970 
971 /*
972  * Try to shadow + enable the guest 2 provided facility list.
973  * Retry instruction execution if enabled for and provided by guest 2.
974  *
975  * Returns: - 0 if handled (retry or guest 2 icpt)
976  *          - > 0 if control has to be given to guest 2
977  */
handle_stfle(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)978 static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
979 {
980 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
981 	__u32 fac = READ_ONCE(vsie_page->scb_o->fac) & 0x7ffffff8U;
982 
983 	if (fac && test_kvm_facility(vcpu->kvm, 7)) {
984 		retry_vsie_icpt(vsie_page);
985 		if (read_guest_real(vcpu, fac, &vsie_page->fac,
986 				    sizeof(vsie_page->fac)))
987 			return set_validity_icpt(scb_s, 0x1090U);
988 		scb_s->fac = (__u32)(__u64) &vsie_page->fac;
989 	}
990 	return 0;
991 }
992 
993 /*
994  * Get a register for a nested guest.
995  * @vcpu the vcpu of the guest
996  * @vsie_page the vsie_page for the nested guest
997  * @reg the register number, the upper 4 bits are ignored.
998  * returns: the value of the register.
999  */
vsie_get_register(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page,u8 reg)1000 static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, u8 reg)
1001 {
1002 	/* no need to validate the parameter and/or perform error handling */
1003 	reg &= 0xf;
1004 	switch (reg) {
1005 	case 15:
1006 		return vsie_page->scb_s.gg15;
1007 	case 14:
1008 		return vsie_page->scb_s.gg14;
1009 	default:
1010 		return vcpu->run->s.regs.gprs[reg];
1011 	}
1012 }
1013 
vsie_handle_mvpg(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)1014 static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
1015 {
1016 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
1017 	unsigned long pei_dest, pei_src, src, dest, mask, prefix;
1018 	u64 *pei_block = &vsie_page->scb_o->mcic;
1019 	int edat, rc_dest, rc_src;
1020 	union ctlreg0 cr0;
1021 
1022 	cr0.val = vcpu->arch.sie_block->gcr[0];
1023 	edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
1024 	mask = _kvm_s390_logical_to_effective(&scb_s->gpsw, PAGE_MASK);
1025 	prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
1026 
1027 	dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask;
1028 	dest = _kvm_s390_real_to_abs(prefix, dest) + scb_s->mso;
1029 	src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask;
1030 	src = _kvm_s390_real_to_abs(prefix, src) + scb_s->mso;
1031 
1032 	rc_dest = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, dest, &pei_dest);
1033 	rc_src = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, src, &pei_src);
1034 	/*
1035 	 * Either everything went well, or something non-critical went wrong
1036 	 * e.g. because of a race. In either case, simply retry.
1037 	 */
1038 	if (rc_dest == -EAGAIN || rc_src == -EAGAIN || (!rc_dest && !rc_src)) {
1039 		retry_vsie_icpt(vsie_page);
1040 		return -EAGAIN;
1041 	}
1042 	/* Something more serious went wrong, propagate the error */
1043 	if (rc_dest < 0)
1044 		return rc_dest;
1045 	if (rc_src < 0)
1046 		return rc_src;
1047 
1048 	/* The only possible suppressing exception: just deliver it */
1049 	if (rc_dest == PGM_TRANSLATION_SPEC || rc_src == PGM_TRANSLATION_SPEC) {
1050 		clear_vsie_icpt(vsie_page);
1051 		rc_dest = kvm_s390_inject_program_int(vcpu, PGM_TRANSLATION_SPEC);
1052 		WARN_ON_ONCE(rc_dest);
1053 		return 1;
1054 	}
1055 
1056 	/*
1057 	 * Forward the PEI intercept to the guest if it was a page fault, or
1058 	 * also for segment and region table faults if EDAT applies.
1059 	 */
1060 	if (edat) {
1061 		rc_dest = rc_dest == PGM_ASCE_TYPE ? rc_dest : 0;
1062 		rc_src = rc_src == PGM_ASCE_TYPE ? rc_src : 0;
1063 	} else {
1064 		rc_dest = rc_dest != PGM_PAGE_TRANSLATION ? rc_dest : 0;
1065 		rc_src = rc_src != PGM_PAGE_TRANSLATION ? rc_src : 0;
1066 	}
1067 	if (!rc_dest && !rc_src) {
1068 		pei_block[0] = pei_dest;
1069 		pei_block[1] = pei_src;
1070 		return 1;
1071 	}
1072 
1073 	retry_vsie_icpt(vsie_page);
1074 
1075 	/*
1076 	 * The host has edat, and the guest does not, or it was an ASCE type
1077 	 * exception. The host needs to inject the appropriate DAT interrupts
1078 	 * into the guest.
1079 	 */
1080 	if (rc_dest)
1081 		return inject_fault(vcpu, rc_dest, dest, 1);
1082 	return inject_fault(vcpu, rc_src, src, 0);
1083 }
1084 
1085 /*
1086  * Run the vsie on a shadow scb and a shadow gmap, without any further
1087  * sanity checks, handling SIE faults.
1088  *
1089  * Returns: - 0 everything went fine
1090  *          - > 0 if control has to be given to guest 2
1091  *          - < 0 if an error occurred
1092  */
do_vsie_run(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)1093 static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
1094 	__releases(vcpu->kvm->srcu)
1095 	__acquires(vcpu->kvm->srcu)
1096 {
1097 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
1098 	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
1099 	int guest_bp_isolation;
1100 	int rc = 0;
1101 
1102 	handle_last_fault(vcpu, vsie_page);
1103 
1104 	kvm_vcpu_srcu_read_unlock(vcpu);
1105 
1106 	/* save current guest state of bp isolation override */
1107 	guest_bp_isolation = test_thread_flag(TIF_ISOLATE_BP_GUEST);
1108 
1109 	/*
1110 	 * The guest is running with BPBC, so we have to force it on for our
1111 	 * nested guest. This is done by enabling BPBC globally, so the BPBC
1112 	 * control in the SCB (which the nested guest can modify) is simply
1113 	 * ignored.
1114 	 */
1115 	if (test_kvm_facility(vcpu->kvm, 82) &&
1116 	    vcpu->arch.sie_block->fpf & FPF_BPBC)
1117 		set_thread_flag(TIF_ISOLATE_BP_GUEST);
1118 
1119 	local_irq_disable();
1120 	guest_enter_irqoff();
1121 	local_irq_enable();
1122 
1123 	/*
1124 	 * Simulate a SIE entry of the VCPU (see sie64a), so VCPU blocking
1125 	 * and VCPU requests also hinder the vSIE from running and lead
1126 	 * to an immediate exit. kvm_s390_vsie_kick() has to be used to
1127 	 * also kick the vSIE.
1128 	 */
1129 	vcpu->arch.sie_block->prog0c |= PROG_IN_SIE;
1130 	barrier();
1131 	if (test_cpu_flag(CIF_FPU))
1132 		load_fpu_regs();
1133 	if (!kvm_s390_vcpu_sie_inhibited(vcpu))
1134 		rc = sie64a(scb_s, vcpu->run->s.regs.gprs);
1135 	barrier();
1136 	vcpu->arch.sie_block->prog0c &= ~PROG_IN_SIE;
1137 
1138 	local_irq_disable();
1139 	guest_exit_irqoff();
1140 	local_irq_enable();
1141 
1142 	/* restore guest state for bp isolation override */
1143 	if (!guest_bp_isolation)
1144 		clear_thread_flag(TIF_ISOLATE_BP_GUEST);
1145 
1146 	kvm_vcpu_srcu_read_lock(vcpu);
1147 
1148 	if (rc == -EINTR) {
1149 		VCPU_EVENT(vcpu, 3, "%s", "machine check");
1150 		kvm_s390_reinject_machine_check(vcpu, &vsie_page->mcck_info);
1151 		return 0;
1152 	}
1153 
1154 	if (rc > 0)
1155 		rc = 0; /* we could still have an icpt */
1156 	else if (rc == -EFAULT)
1157 		return handle_fault(vcpu, vsie_page);
1158 
1159 	switch (scb_s->icptcode) {
1160 	case ICPT_INST:
1161 		if (scb_s->ipa == 0xb2b0)
1162 			rc = handle_stfle(vcpu, vsie_page);
1163 		break;
1164 	case ICPT_STOP:
1165 		/* stop not requested by g2 - must have been a kick */
1166 		if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT))
1167 			clear_vsie_icpt(vsie_page);
1168 		break;
1169 	case ICPT_VALIDITY:
1170 		if ((scb_s->ipa & 0xf000) != 0xf000)
1171 			scb_s->ipa += 0x1000;
1172 		break;
1173 	case ICPT_PARTEXEC:
1174 		if (scb_s->ipa == 0xb254)
1175 			rc = vsie_handle_mvpg(vcpu, vsie_page);
1176 		break;
1177 	}
1178 	return rc;
1179 }
1180 
release_gmap_shadow(struct vsie_page * vsie_page)1181 static void release_gmap_shadow(struct vsie_page *vsie_page)
1182 {
1183 	if (vsie_page->gmap)
1184 		gmap_put(vsie_page->gmap);
1185 	WRITE_ONCE(vsie_page->gmap, NULL);
1186 	prefix_unmapped(vsie_page);
1187 }
1188 
acquire_gmap_shadow(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)1189 static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
1190 			       struct vsie_page *vsie_page)
1191 {
1192 	unsigned long asce;
1193 	union ctlreg0 cr0;
1194 	struct gmap *gmap;
1195 	int edat;
1196 
1197 	asce = vcpu->arch.sie_block->gcr[1];
1198 	cr0.val = vcpu->arch.sie_block->gcr[0];
1199 	edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
1200 	edat += edat && test_kvm_facility(vcpu->kvm, 78);
1201 
1202 	/*
1203 	 * ASCE or EDAT could have changed since last icpt, or the gmap
1204 	 * we're holding has been unshadowed. If the gmap is still valid,
1205 	 * we can safely reuse it.
1206 	 */
1207 	if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat))
1208 		return 0;
1209 
1210 	/* release the old shadow - if any, and mark the prefix as unmapped */
1211 	release_gmap_shadow(vsie_page);
1212 	gmap = gmap_shadow(vcpu->arch.gmap, asce, edat);
1213 	if (IS_ERR(gmap))
1214 		return PTR_ERR(gmap);
1215 	gmap->private = vcpu->kvm;
1216 	WRITE_ONCE(vsie_page->gmap, gmap);
1217 	return 0;
1218 }
1219 
1220 /*
1221  * Register the shadow scb at the VCPU, e.g. for kicking out of vsie.
1222  */
register_shadow_scb(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)1223 static void register_shadow_scb(struct kvm_vcpu *vcpu,
1224 				struct vsie_page *vsie_page)
1225 {
1226 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
1227 
1228 	WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
1229 	/*
1230 	 * External calls have to lead to a kick of the vcpu and
1231 	 * therefore the vsie -> Simulate Wait state.
1232 	 */
1233 	kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT);
1234 	/*
1235 	 * We have to adjust the g3 epoch by the g2 epoch. The epoch will
1236 	 * automatically be adjusted on tod clock changes via kvm_sync_clock.
1237 	 */
1238 	preempt_disable();
1239 	scb_s->epoch += vcpu->kvm->arch.epoch;
1240 
1241 	if (scb_s->ecd & ECD_MEF) {
1242 		scb_s->epdx += vcpu->kvm->arch.epdx;
1243 		if (scb_s->epoch < vcpu->kvm->arch.epoch)
1244 			scb_s->epdx += 1;
1245 	}
1246 
1247 	preempt_enable();
1248 }
1249 
1250 /*
1251  * Unregister a shadow scb from a VCPU.
1252  */
unregister_shadow_scb(struct kvm_vcpu * vcpu)1253 static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
1254 {
1255 	kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT);
1256 	WRITE_ONCE(vcpu->arch.vsie_block, NULL);
1257 }
1258 
1259 /*
1260  * Run the vsie on a shadowed scb, managing the gmap shadow, handling
1261  * prefix pages and faults.
1262  *
1263  * Returns: - 0 if no errors occurred
1264  *          - > 0 if control has to be given to guest 2
1265  *          - -ENOMEM if out of memory
1266  */
vsie_run(struct kvm_vcpu * vcpu,struct vsie_page * vsie_page)1267 static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
1268 {
1269 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
1270 	int rc = 0;
1271 
1272 	while (1) {
1273 		rc = acquire_gmap_shadow(vcpu, vsie_page);
1274 		if (!rc)
1275 			rc = map_prefix(vcpu, vsie_page);
1276 		if (!rc) {
1277 			gmap_enable(vsie_page->gmap);
1278 			update_intervention_requests(vsie_page);
1279 			rc = do_vsie_run(vcpu, vsie_page);
1280 			gmap_enable(vcpu->arch.gmap);
1281 		}
1282 		atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20);
1283 
1284 		if (rc == -EAGAIN)
1285 			rc = 0;
1286 		if (rc || scb_s->icptcode || signal_pending(current) ||
1287 		    kvm_s390_vcpu_has_irq(vcpu, 0) ||
1288 		    kvm_s390_vcpu_sie_inhibited(vcpu))
1289 			break;
1290 		cond_resched();
1291 	}
1292 
1293 	if (rc == -EFAULT) {
1294 		/*
1295 		 * Addressing exceptions are always presentes as intercepts.
1296 		 * As addressing exceptions are suppressing and our guest 3 PSW
1297 		 * points at the responsible instruction, we have to
1298 		 * forward the PSW and set the ilc. If we can't read guest 3
1299 		 * instruction, we can use an arbitrary ilc. Let's always use
1300 		 * ilen = 4 for now, so we can avoid reading in guest 3 virtual
1301 		 * memory. (we could also fake the shadow so the hardware
1302 		 * handles it).
1303 		 */
1304 		scb_s->icptcode = ICPT_PROGI;
1305 		scb_s->iprcc = PGM_ADDRESSING;
1306 		scb_s->pgmilc = 4;
1307 		scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4);
1308 		rc = 1;
1309 	}
1310 	return rc;
1311 }
1312 
1313 /*
1314  * Get or create a vsie page for a scb address.
1315  *
1316  * Returns: - address of a vsie page (cached or new one)
1317  *          - NULL if the same scb address is already used by another VCPU
1318  *          - ERR_PTR(-ENOMEM) if out of memory
1319  */
get_vsie_page(struct kvm * kvm,unsigned long addr)1320 static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
1321 {
1322 	struct vsie_page *vsie_page;
1323 	struct page *page;
1324 	int nr_vcpus;
1325 
1326 	rcu_read_lock();
1327 	page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
1328 	rcu_read_unlock();
1329 	if (page) {
1330 		if (page_ref_inc_return(page) == 2)
1331 			return page_to_virt(page);
1332 		page_ref_dec(page);
1333 	}
1334 
1335 	/*
1336 	 * We want at least #online_vcpus shadows, so every VCPU can execute
1337 	 * the VSIE in parallel.
1338 	 */
1339 	nr_vcpus = atomic_read(&kvm->online_vcpus);
1340 
1341 	mutex_lock(&kvm->arch.vsie.mutex);
1342 	if (kvm->arch.vsie.page_count < nr_vcpus) {
1343 		page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO | GFP_DMA);
1344 		if (!page) {
1345 			mutex_unlock(&kvm->arch.vsie.mutex);
1346 			return ERR_PTR(-ENOMEM);
1347 		}
1348 		page_ref_inc(page);
1349 		kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;
1350 		kvm->arch.vsie.page_count++;
1351 	} else {
1352 		/* reuse an existing entry that belongs to nobody */
1353 		while (true) {
1354 			page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
1355 			if (page_ref_inc_return(page) == 2)
1356 				break;
1357 			page_ref_dec(page);
1358 			kvm->arch.vsie.next++;
1359 			kvm->arch.vsie.next %= nr_vcpus;
1360 		}
1361 		radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
1362 	}
1363 	page->index = addr;
1364 	/* double use of the same address */
1365 	if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
1366 		page_ref_dec(page);
1367 		mutex_unlock(&kvm->arch.vsie.mutex);
1368 		return NULL;
1369 	}
1370 	mutex_unlock(&kvm->arch.vsie.mutex);
1371 
1372 	vsie_page = page_to_virt(page);
1373 	memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));
1374 	release_gmap_shadow(vsie_page);
1375 	vsie_page->fault_addr = 0;
1376 	vsie_page->scb_s.ihcpu = 0xffffU;
1377 	return vsie_page;
1378 }
1379 
1380 /* put a vsie page acquired via get_vsie_page */
put_vsie_page(struct kvm * kvm,struct vsie_page * vsie_page)1381 static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page)
1382 {
1383 	struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT);
1384 
1385 	page_ref_dec(page);
1386 }
1387 
kvm_s390_handle_vsie(struct kvm_vcpu * vcpu)1388 int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
1389 {
1390 	struct vsie_page *vsie_page;
1391 	unsigned long scb_addr;
1392 	int rc;
1393 
1394 	vcpu->stat.instruction_sie++;
1395 	if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2))
1396 		return -EOPNOTSUPP;
1397 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
1398 		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
1399 
1400 	BUILD_BUG_ON(sizeof(struct vsie_page) != PAGE_SIZE);
1401 	scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL);
1402 
1403 	/* 512 byte alignment */
1404 	if (unlikely(scb_addr & 0x1ffUL))
1405 		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
1406 
1407 	if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0) ||
1408 	    kvm_s390_vcpu_sie_inhibited(vcpu))
1409 		return 0;
1410 
1411 	vsie_page = get_vsie_page(vcpu->kvm, scb_addr);
1412 	if (IS_ERR(vsie_page))
1413 		return PTR_ERR(vsie_page);
1414 	else if (!vsie_page)
1415 		/* double use of sie control block - simply do nothing */
1416 		return 0;
1417 
1418 	rc = pin_scb(vcpu, vsie_page, scb_addr);
1419 	if (rc)
1420 		goto out_put;
1421 	rc = shadow_scb(vcpu, vsie_page);
1422 	if (rc)
1423 		goto out_unpin_scb;
1424 	rc = pin_blocks(vcpu, vsie_page);
1425 	if (rc)
1426 		goto out_unshadow;
1427 	register_shadow_scb(vcpu, vsie_page);
1428 	rc = vsie_run(vcpu, vsie_page);
1429 	unregister_shadow_scb(vcpu);
1430 	unpin_blocks(vcpu, vsie_page);
1431 out_unshadow:
1432 	unshadow_scb(vcpu, vsie_page);
1433 out_unpin_scb:
1434 	unpin_scb(vcpu, vsie_page, scb_addr);
1435 out_put:
1436 	put_vsie_page(vcpu->kvm, vsie_page);
1437 
1438 	return rc < 0 ? rc : 0;
1439 }
1440 
1441 /* Init the vsie data structures. To be called when a vm is initialized. */
kvm_s390_vsie_init(struct kvm * kvm)1442 void kvm_s390_vsie_init(struct kvm *kvm)
1443 {
1444 	mutex_init(&kvm->arch.vsie.mutex);
1445 	INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL_ACCOUNT);
1446 }
1447 
1448 /* Destroy the vsie data structures. To be called when a vm is destroyed. */
kvm_s390_vsie_destroy(struct kvm * kvm)1449 void kvm_s390_vsie_destroy(struct kvm *kvm)
1450 {
1451 	struct vsie_page *vsie_page;
1452 	struct page *page;
1453 	int i;
1454 
1455 	mutex_lock(&kvm->arch.vsie.mutex);
1456 	for (i = 0; i < kvm->arch.vsie.page_count; i++) {
1457 		page = kvm->arch.vsie.pages[i];
1458 		kvm->arch.vsie.pages[i] = NULL;
1459 		vsie_page = page_to_virt(page);
1460 		release_gmap_shadow(vsie_page);
1461 		/* free the radix tree entry */
1462 		radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
1463 		__free_page(page);
1464 	}
1465 	kvm->arch.vsie.page_count = 0;
1466 	mutex_unlock(&kvm->arch.vsie.mutex);
1467 }
1468 
kvm_s390_vsie_kick(struct kvm_vcpu * vcpu)1469 void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)
1470 {
1471 	struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block);
1472 
1473 	/*
1474 	 * Even if the VCPU lets go of the shadow sie block reference, it is
1475 	 * still valid in the cache. So we can safely kick it.
1476 	 */
1477 	if (scb) {
1478 		atomic_or(PROG_BLOCK_SIE, &scb->prog20);
1479 		if (scb->prog0c & PROG_IN_SIE)
1480 			atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags);
1481 	}
1482 }
1483