xref: /linux/arch/powerpc/kvm/book3s_hv_nested.c (revision 44f57d78)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright IBM Corporation, 2018
4  * Authors Suraj Jitindar Singh <sjitindarsingh@gmail.com>
5  *	   Paul Mackerras <paulus@ozlabs.org>
6  *
7  * Description: KVM functions specific to running nested KVM-HV guests
8  * on Book3S processors (specifically POWER9 and later).
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/kvm_host.h>
13 #include <linux/llist.h>
14 
15 #include <asm/kvm_ppc.h>
16 #include <asm/kvm_book3s.h>
17 #include <asm/mmu.h>
18 #include <asm/pgtable.h>
19 #include <asm/pgalloc.h>
20 #include <asm/pte-walk.h>
21 #include <asm/reg.h>
22 
23 static struct patb_entry *pseries_partition_tb;
24 
25 static void kvmhv_update_ptbl_cache(struct kvm_nested_guest *gp);
26 static void kvmhv_free_memslot_nest_rmap(struct kvm_memory_slot *free);
27 
28 void kvmhv_save_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
29 {
30 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
31 
32 	hr->pcr = vc->pcr;
33 	hr->dpdes = vc->dpdes;
34 	hr->hfscr = vcpu->arch.hfscr;
35 	hr->tb_offset = vc->tb_offset;
36 	hr->dawr0 = vcpu->arch.dawr;
37 	hr->dawrx0 = vcpu->arch.dawrx;
38 	hr->ciabr = vcpu->arch.ciabr;
39 	hr->purr = vcpu->arch.purr;
40 	hr->spurr = vcpu->arch.spurr;
41 	hr->ic = vcpu->arch.ic;
42 	hr->vtb = vc->vtb;
43 	hr->srr0 = vcpu->arch.shregs.srr0;
44 	hr->srr1 = vcpu->arch.shregs.srr1;
45 	hr->sprg[0] = vcpu->arch.shregs.sprg0;
46 	hr->sprg[1] = vcpu->arch.shregs.sprg1;
47 	hr->sprg[2] = vcpu->arch.shregs.sprg2;
48 	hr->sprg[3] = vcpu->arch.shregs.sprg3;
49 	hr->pidr = vcpu->arch.pid;
50 	hr->cfar = vcpu->arch.cfar;
51 	hr->ppr = vcpu->arch.ppr;
52 }
53 
54 static void byteswap_pt_regs(struct pt_regs *regs)
55 {
56 	unsigned long *addr = (unsigned long *) regs;
57 
58 	for (; addr < ((unsigned long *) (regs + 1)); addr++)
59 		*addr = swab64(*addr);
60 }
61 
62 static void byteswap_hv_regs(struct hv_guest_state *hr)
63 {
64 	hr->version = swab64(hr->version);
65 	hr->lpid = swab32(hr->lpid);
66 	hr->vcpu_token = swab32(hr->vcpu_token);
67 	hr->lpcr = swab64(hr->lpcr);
68 	hr->pcr = swab64(hr->pcr);
69 	hr->amor = swab64(hr->amor);
70 	hr->dpdes = swab64(hr->dpdes);
71 	hr->hfscr = swab64(hr->hfscr);
72 	hr->tb_offset = swab64(hr->tb_offset);
73 	hr->dawr0 = swab64(hr->dawr0);
74 	hr->dawrx0 = swab64(hr->dawrx0);
75 	hr->ciabr = swab64(hr->ciabr);
76 	hr->hdec_expiry = swab64(hr->hdec_expiry);
77 	hr->purr = swab64(hr->purr);
78 	hr->spurr = swab64(hr->spurr);
79 	hr->ic = swab64(hr->ic);
80 	hr->vtb = swab64(hr->vtb);
81 	hr->hdar = swab64(hr->hdar);
82 	hr->hdsisr = swab64(hr->hdsisr);
83 	hr->heir = swab64(hr->heir);
84 	hr->asdr = swab64(hr->asdr);
85 	hr->srr0 = swab64(hr->srr0);
86 	hr->srr1 = swab64(hr->srr1);
87 	hr->sprg[0] = swab64(hr->sprg[0]);
88 	hr->sprg[1] = swab64(hr->sprg[1]);
89 	hr->sprg[2] = swab64(hr->sprg[2]);
90 	hr->sprg[3] = swab64(hr->sprg[3]);
91 	hr->pidr = swab64(hr->pidr);
92 	hr->cfar = swab64(hr->cfar);
93 	hr->ppr = swab64(hr->ppr);
94 }
95 
96 static void save_hv_return_state(struct kvm_vcpu *vcpu, int trap,
97 				 struct hv_guest_state *hr)
98 {
99 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
100 
101 	hr->dpdes = vc->dpdes;
102 	hr->hfscr = vcpu->arch.hfscr;
103 	hr->purr = vcpu->arch.purr;
104 	hr->spurr = vcpu->arch.spurr;
105 	hr->ic = vcpu->arch.ic;
106 	hr->vtb = vc->vtb;
107 	hr->srr0 = vcpu->arch.shregs.srr0;
108 	hr->srr1 = vcpu->arch.shregs.srr1;
109 	hr->sprg[0] = vcpu->arch.shregs.sprg0;
110 	hr->sprg[1] = vcpu->arch.shregs.sprg1;
111 	hr->sprg[2] = vcpu->arch.shregs.sprg2;
112 	hr->sprg[3] = vcpu->arch.shregs.sprg3;
113 	hr->pidr = vcpu->arch.pid;
114 	hr->cfar = vcpu->arch.cfar;
115 	hr->ppr = vcpu->arch.ppr;
116 	switch (trap) {
117 	case BOOK3S_INTERRUPT_H_DATA_STORAGE:
118 		hr->hdar = vcpu->arch.fault_dar;
119 		hr->hdsisr = vcpu->arch.fault_dsisr;
120 		hr->asdr = vcpu->arch.fault_gpa;
121 		break;
122 	case BOOK3S_INTERRUPT_H_INST_STORAGE:
123 		hr->asdr = vcpu->arch.fault_gpa;
124 		break;
125 	case BOOK3S_INTERRUPT_H_EMUL_ASSIST:
126 		hr->heir = vcpu->arch.emul_inst;
127 		break;
128 	}
129 }
130 
131 static void sanitise_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
132 {
133 	/*
134 	 * Don't let L1 enable features for L2 which we've disabled for L1,
135 	 * but preserve the interrupt cause field.
136 	 */
137 	hr->hfscr &= (HFSCR_INTR_CAUSE | vcpu->arch.hfscr);
138 
139 	/* Don't let data address watchpoint match in hypervisor state */
140 	hr->dawrx0 &= ~DAWRX_HYP;
141 
142 	/* Don't let completed instruction address breakpt match in HV state */
143 	if ((hr->ciabr & CIABR_PRIV) == CIABR_PRIV_HYPER)
144 		hr->ciabr &= ~CIABR_PRIV;
145 }
146 
147 static void restore_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
148 {
149 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
150 
151 	vc->pcr = hr->pcr;
152 	vc->dpdes = hr->dpdes;
153 	vcpu->arch.hfscr = hr->hfscr;
154 	vcpu->arch.dawr = hr->dawr0;
155 	vcpu->arch.dawrx = hr->dawrx0;
156 	vcpu->arch.ciabr = hr->ciabr;
157 	vcpu->arch.purr = hr->purr;
158 	vcpu->arch.spurr = hr->spurr;
159 	vcpu->arch.ic = hr->ic;
160 	vc->vtb = hr->vtb;
161 	vcpu->arch.shregs.srr0 = hr->srr0;
162 	vcpu->arch.shregs.srr1 = hr->srr1;
163 	vcpu->arch.shregs.sprg0 = hr->sprg[0];
164 	vcpu->arch.shregs.sprg1 = hr->sprg[1];
165 	vcpu->arch.shregs.sprg2 = hr->sprg[2];
166 	vcpu->arch.shregs.sprg3 = hr->sprg[3];
167 	vcpu->arch.pid = hr->pidr;
168 	vcpu->arch.cfar = hr->cfar;
169 	vcpu->arch.ppr = hr->ppr;
170 }
171 
172 void kvmhv_restore_hv_return_state(struct kvm_vcpu *vcpu,
173 				   struct hv_guest_state *hr)
174 {
175 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
176 
177 	vc->dpdes = hr->dpdes;
178 	vcpu->arch.hfscr = hr->hfscr;
179 	vcpu->arch.purr = hr->purr;
180 	vcpu->arch.spurr = hr->spurr;
181 	vcpu->arch.ic = hr->ic;
182 	vc->vtb = hr->vtb;
183 	vcpu->arch.fault_dar = hr->hdar;
184 	vcpu->arch.fault_dsisr = hr->hdsisr;
185 	vcpu->arch.fault_gpa = hr->asdr;
186 	vcpu->arch.emul_inst = hr->heir;
187 	vcpu->arch.shregs.srr0 = hr->srr0;
188 	vcpu->arch.shregs.srr1 = hr->srr1;
189 	vcpu->arch.shregs.sprg0 = hr->sprg[0];
190 	vcpu->arch.shregs.sprg1 = hr->sprg[1];
191 	vcpu->arch.shregs.sprg2 = hr->sprg[2];
192 	vcpu->arch.shregs.sprg3 = hr->sprg[3];
193 	vcpu->arch.pid = hr->pidr;
194 	vcpu->arch.cfar = hr->cfar;
195 	vcpu->arch.ppr = hr->ppr;
196 }
197 
198 static void kvmhv_nested_mmio_needed(struct kvm_vcpu *vcpu, u64 regs_ptr)
199 {
200 	/* No need to reflect the page fault to L1, we've handled it */
201 	vcpu->arch.trap = 0;
202 
203 	/*
204 	 * Since the L2 gprs have already been written back into L1 memory when
205 	 * we complete the mmio, store the L1 memory location of the L2 gpr
206 	 * being loaded into by the mmio so that the loaded value can be
207 	 * written there in kvmppc_complete_mmio_load()
208 	 */
209 	if (((vcpu->arch.io_gpr & KVM_MMIO_REG_EXT_MASK) == KVM_MMIO_REG_GPR)
210 	    && (vcpu->mmio_is_write == 0)) {
211 		vcpu->arch.nested_io_gpr = (gpa_t) regs_ptr +
212 					   offsetof(struct pt_regs,
213 						    gpr[vcpu->arch.io_gpr]);
214 		vcpu->arch.io_gpr = KVM_MMIO_REG_NESTED_GPR;
215 	}
216 }
217 
218 long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
219 {
220 	long int err, r;
221 	struct kvm_nested_guest *l2;
222 	struct pt_regs l2_regs, saved_l1_regs;
223 	struct hv_guest_state l2_hv, saved_l1_hv;
224 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
225 	u64 hv_ptr, regs_ptr;
226 	u64 hdec_exp;
227 	s64 delta_purr, delta_spurr, delta_ic, delta_vtb;
228 	u64 mask;
229 	unsigned long lpcr;
230 
231 	if (vcpu->kvm->arch.l1_ptcr == 0)
232 		return H_NOT_AVAILABLE;
233 
234 	/* copy parameters in */
235 	hv_ptr = kvmppc_get_gpr(vcpu, 4);
236 	err = kvm_vcpu_read_guest(vcpu, hv_ptr, &l2_hv,
237 				  sizeof(struct hv_guest_state));
238 	if (err)
239 		return H_PARAMETER;
240 	if (kvmppc_need_byteswap(vcpu))
241 		byteswap_hv_regs(&l2_hv);
242 	if (l2_hv.version != HV_GUEST_STATE_VERSION)
243 		return H_P2;
244 
245 	regs_ptr = kvmppc_get_gpr(vcpu, 5);
246 	err = kvm_vcpu_read_guest(vcpu, regs_ptr, &l2_regs,
247 				  sizeof(struct pt_regs));
248 	if (err)
249 		return H_PARAMETER;
250 	if (kvmppc_need_byteswap(vcpu))
251 		byteswap_pt_regs(&l2_regs);
252 	if (l2_hv.vcpu_token >= NR_CPUS)
253 		return H_PARAMETER;
254 
255 	/* translate lpid */
256 	l2 = kvmhv_get_nested(vcpu->kvm, l2_hv.lpid, true);
257 	if (!l2)
258 		return H_PARAMETER;
259 	if (!l2->l1_gr_to_hr) {
260 		mutex_lock(&l2->tlb_lock);
261 		kvmhv_update_ptbl_cache(l2);
262 		mutex_unlock(&l2->tlb_lock);
263 	}
264 
265 	/* save l1 values of things */
266 	vcpu->arch.regs.msr = vcpu->arch.shregs.msr;
267 	saved_l1_regs = vcpu->arch.regs;
268 	kvmhv_save_hv_regs(vcpu, &saved_l1_hv);
269 
270 	/* convert TB values/offsets to host (L0) values */
271 	hdec_exp = l2_hv.hdec_expiry - vc->tb_offset;
272 	vc->tb_offset += l2_hv.tb_offset;
273 
274 	/* set L1 state to L2 state */
275 	vcpu->arch.nested = l2;
276 	vcpu->arch.nested_vcpu_id = l2_hv.vcpu_token;
277 	vcpu->arch.regs = l2_regs;
278 	vcpu->arch.shregs.msr = vcpu->arch.regs.msr;
279 	mask = LPCR_DPFD | LPCR_ILE | LPCR_TC | LPCR_AIL | LPCR_LD |
280 		LPCR_LPES | LPCR_MER;
281 	lpcr = (vc->lpcr & ~mask) | (l2_hv.lpcr & mask);
282 	sanitise_hv_regs(vcpu, &l2_hv);
283 	restore_hv_regs(vcpu, &l2_hv);
284 
285 	vcpu->arch.ret = RESUME_GUEST;
286 	vcpu->arch.trap = 0;
287 	do {
288 		if (mftb() >= hdec_exp) {
289 			vcpu->arch.trap = BOOK3S_INTERRUPT_HV_DECREMENTER;
290 			r = RESUME_HOST;
291 			break;
292 		}
293 		r = kvmhv_run_single_vcpu(vcpu->arch.kvm_run, vcpu, hdec_exp,
294 					  lpcr);
295 	} while (is_kvmppc_resume_guest(r));
296 
297 	/* save L2 state for return */
298 	l2_regs = vcpu->arch.regs;
299 	l2_regs.msr = vcpu->arch.shregs.msr;
300 	delta_purr = vcpu->arch.purr - l2_hv.purr;
301 	delta_spurr = vcpu->arch.spurr - l2_hv.spurr;
302 	delta_ic = vcpu->arch.ic - l2_hv.ic;
303 	delta_vtb = vc->vtb - l2_hv.vtb;
304 	save_hv_return_state(vcpu, vcpu->arch.trap, &l2_hv);
305 
306 	/* restore L1 state */
307 	vcpu->arch.nested = NULL;
308 	vcpu->arch.regs = saved_l1_regs;
309 	vcpu->arch.shregs.msr = saved_l1_regs.msr & ~MSR_TS_MASK;
310 	/* set L1 MSR TS field according to L2 transaction state */
311 	if (l2_regs.msr & MSR_TS_MASK)
312 		vcpu->arch.shregs.msr |= MSR_TS_S;
313 	vc->tb_offset = saved_l1_hv.tb_offset;
314 	restore_hv_regs(vcpu, &saved_l1_hv);
315 	vcpu->arch.purr += delta_purr;
316 	vcpu->arch.spurr += delta_spurr;
317 	vcpu->arch.ic += delta_ic;
318 	vc->vtb += delta_vtb;
319 
320 	kvmhv_put_nested(l2);
321 
322 	/* copy l2_hv_state and regs back to guest */
323 	if (kvmppc_need_byteswap(vcpu)) {
324 		byteswap_hv_regs(&l2_hv);
325 		byteswap_pt_regs(&l2_regs);
326 	}
327 	err = kvm_vcpu_write_guest(vcpu, hv_ptr, &l2_hv,
328 				   sizeof(struct hv_guest_state));
329 	if (err)
330 		return H_AUTHORITY;
331 	err = kvm_vcpu_write_guest(vcpu, regs_ptr, &l2_regs,
332 				   sizeof(struct pt_regs));
333 	if (err)
334 		return H_AUTHORITY;
335 
336 	if (r == -EINTR)
337 		return H_INTERRUPT;
338 
339 	if (vcpu->mmio_needed) {
340 		kvmhv_nested_mmio_needed(vcpu, regs_ptr);
341 		return H_TOO_HARD;
342 	}
343 
344 	return vcpu->arch.trap;
345 }
346 
347 long kvmhv_nested_init(void)
348 {
349 	long int ptb_order;
350 	unsigned long ptcr;
351 	long rc;
352 
353 	if (!kvmhv_on_pseries())
354 		return 0;
355 	if (!radix_enabled())
356 		return -ENODEV;
357 
358 	/* find log base 2 of KVMPPC_NR_LPIDS, rounding up */
359 	ptb_order = __ilog2(KVMPPC_NR_LPIDS - 1) + 1;
360 	if (ptb_order < 8)
361 		ptb_order = 8;
362 	pseries_partition_tb = kmalloc(sizeof(struct patb_entry) << ptb_order,
363 				       GFP_KERNEL);
364 	if (!pseries_partition_tb) {
365 		pr_err("kvm-hv: failed to allocated nested partition table\n");
366 		return -ENOMEM;
367 	}
368 
369 	ptcr = __pa(pseries_partition_tb) | (ptb_order - 8);
370 	rc = plpar_hcall_norets(H_SET_PARTITION_TABLE, ptcr);
371 	if (rc != H_SUCCESS) {
372 		pr_err("kvm-hv: Parent hypervisor does not support nesting (rc=%ld)\n",
373 		       rc);
374 		kfree(pseries_partition_tb);
375 		pseries_partition_tb = NULL;
376 		return -ENODEV;
377 	}
378 
379 	return 0;
380 }
381 
382 void kvmhv_nested_exit(void)
383 {
384 	/*
385 	 * N.B. the kvmhv_on_pseries() test is there because it enables
386 	 * the compiler to remove the call to plpar_hcall_norets()
387 	 * when CONFIG_PPC_PSERIES=n.
388 	 */
389 	if (kvmhv_on_pseries() && pseries_partition_tb) {
390 		plpar_hcall_norets(H_SET_PARTITION_TABLE, 0);
391 		kfree(pseries_partition_tb);
392 		pseries_partition_tb = NULL;
393 	}
394 }
395 
396 static void kvmhv_flush_lpid(unsigned int lpid)
397 {
398 	long rc;
399 
400 	if (!kvmhv_on_pseries()) {
401 		radix__flush_tlb_lpid(lpid);
402 		return;
403 	}
404 
405 	rc = plpar_hcall_norets(H_TLB_INVALIDATE, H_TLBIE_P1_ENC(2, 0, 1),
406 				lpid, TLBIEL_INVAL_SET_LPID);
407 	if (rc)
408 		pr_err("KVM: TLB LPID invalidation hcall failed, rc=%ld\n", rc);
409 }
410 
411 void kvmhv_set_ptbl_entry(unsigned int lpid, u64 dw0, u64 dw1)
412 {
413 	if (!kvmhv_on_pseries()) {
414 		mmu_partition_table_set_entry(lpid, dw0, dw1);
415 		return;
416 	}
417 
418 	pseries_partition_tb[lpid].patb0 = cpu_to_be64(dw0);
419 	pseries_partition_tb[lpid].patb1 = cpu_to_be64(dw1);
420 	/* L0 will do the necessary barriers */
421 	kvmhv_flush_lpid(lpid);
422 }
423 
424 static void kvmhv_set_nested_ptbl(struct kvm_nested_guest *gp)
425 {
426 	unsigned long dw0;
427 
428 	dw0 = PATB_HR | radix__get_tree_size() |
429 		__pa(gp->shadow_pgtable) | RADIX_PGD_INDEX_SIZE;
430 	kvmhv_set_ptbl_entry(gp->shadow_lpid, dw0, gp->process_table);
431 }
432 
433 void kvmhv_vm_nested_init(struct kvm *kvm)
434 {
435 	kvm->arch.max_nested_lpid = -1;
436 }
437 
438 /*
439  * Handle the H_SET_PARTITION_TABLE hcall.
440  * r4 = guest real address of partition table + log_2(size) - 12
441  * (formatted as for the PTCR).
442  */
443 long kvmhv_set_partition_table(struct kvm_vcpu *vcpu)
444 {
445 	struct kvm *kvm = vcpu->kvm;
446 	unsigned long ptcr = kvmppc_get_gpr(vcpu, 4);
447 	int srcu_idx;
448 	long ret = H_SUCCESS;
449 
450 	srcu_idx = srcu_read_lock(&kvm->srcu);
451 	/*
452 	 * Limit the partition table to 4096 entries (because that's what
453 	 * hardware supports), and check the base address.
454 	 */
455 	if ((ptcr & PRTS_MASK) > 12 - 8 ||
456 	    !kvm_is_visible_gfn(vcpu->kvm, (ptcr & PRTB_MASK) >> PAGE_SHIFT))
457 		ret = H_PARAMETER;
458 	srcu_read_unlock(&kvm->srcu, srcu_idx);
459 	if (ret == H_SUCCESS)
460 		kvm->arch.l1_ptcr = ptcr;
461 	return ret;
462 }
463 
464 /*
465  * Handle the H_COPY_TOFROM_GUEST hcall.
466  * r4 = L1 lpid of nested guest
467  * r5 = pid
468  * r6 = eaddr to access
469  * r7 = to buffer (L1 gpa)
470  * r8 = from buffer (L1 gpa)
471  * r9 = n bytes to copy
472  */
473 long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu)
474 {
475 	struct kvm_nested_guest *gp;
476 	int l1_lpid = kvmppc_get_gpr(vcpu, 4);
477 	int pid = kvmppc_get_gpr(vcpu, 5);
478 	gva_t eaddr = kvmppc_get_gpr(vcpu, 6);
479 	gpa_t gp_to = (gpa_t) kvmppc_get_gpr(vcpu, 7);
480 	gpa_t gp_from = (gpa_t) kvmppc_get_gpr(vcpu, 8);
481 	void *buf;
482 	unsigned long n = kvmppc_get_gpr(vcpu, 9);
483 	bool is_load = !!gp_to;
484 	long rc;
485 
486 	if (gp_to && gp_from) /* One must be NULL to determine the direction */
487 		return H_PARAMETER;
488 
489 	if (eaddr & (0xFFFUL << 52))
490 		return H_PARAMETER;
491 
492 	buf = kzalloc(n, GFP_KERNEL);
493 	if (!buf)
494 		return H_NO_MEM;
495 
496 	gp = kvmhv_get_nested(vcpu->kvm, l1_lpid, false);
497 	if (!gp) {
498 		rc = H_PARAMETER;
499 		goto out_free;
500 	}
501 
502 	mutex_lock(&gp->tlb_lock);
503 
504 	if (is_load) {
505 		/* Load from the nested guest into our buffer */
506 		rc = __kvmhv_copy_tofrom_guest_radix(gp->shadow_lpid, pid,
507 						     eaddr, buf, NULL, n);
508 		if (rc)
509 			goto not_found;
510 
511 		/* Write what was loaded into our buffer back to the L1 guest */
512 		rc = kvm_vcpu_write_guest(vcpu, gp_to, buf, n);
513 		if (rc)
514 			goto not_found;
515 	} else {
516 		/* Load the data to be stored from the L1 guest into our buf */
517 		rc = kvm_vcpu_read_guest(vcpu, gp_from, buf, n);
518 		if (rc)
519 			goto not_found;
520 
521 		/* Store from our buffer into the nested guest */
522 		rc = __kvmhv_copy_tofrom_guest_radix(gp->shadow_lpid, pid,
523 						     eaddr, NULL, buf, n);
524 		if (rc)
525 			goto not_found;
526 	}
527 
528 out_unlock:
529 	mutex_unlock(&gp->tlb_lock);
530 	kvmhv_put_nested(gp);
531 out_free:
532 	kfree(buf);
533 	return rc;
534 not_found:
535 	rc = H_NOT_FOUND;
536 	goto out_unlock;
537 }
538 
539 /*
540  * Reload the partition table entry for a guest.
541  * Caller must hold gp->tlb_lock.
542  */
543 static void kvmhv_update_ptbl_cache(struct kvm_nested_guest *gp)
544 {
545 	int ret;
546 	struct patb_entry ptbl_entry;
547 	unsigned long ptbl_addr;
548 	struct kvm *kvm = gp->l1_host;
549 
550 	ret = -EFAULT;
551 	ptbl_addr = (kvm->arch.l1_ptcr & PRTB_MASK) + (gp->l1_lpid << 4);
552 	if (gp->l1_lpid < (1ul << ((kvm->arch.l1_ptcr & PRTS_MASK) + 8)))
553 		ret = kvm_read_guest(kvm, ptbl_addr,
554 				     &ptbl_entry, sizeof(ptbl_entry));
555 	if (ret) {
556 		gp->l1_gr_to_hr = 0;
557 		gp->process_table = 0;
558 	} else {
559 		gp->l1_gr_to_hr = be64_to_cpu(ptbl_entry.patb0);
560 		gp->process_table = be64_to_cpu(ptbl_entry.patb1);
561 	}
562 	kvmhv_set_nested_ptbl(gp);
563 }
564 
565 struct kvm_nested_guest *kvmhv_alloc_nested(struct kvm *kvm, unsigned int lpid)
566 {
567 	struct kvm_nested_guest *gp;
568 	long shadow_lpid;
569 
570 	gp = kzalloc(sizeof(*gp), GFP_KERNEL);
571 	if (!gp)
572 		return NULL;
573 	gp->l1_host = kvm;
574 	gp->l1_lpid = lpid;
575 	mutex_init(&gp->tlb_lock);
576 	gp->shadow_pgtable = pgd_alloc(kvm->mm);
577 	if (!gp->shadow_pgtable)
578 		goto out_free;
579 	shadow_lpid = kvmppc_alloc_lpid();
580 	if (shadow_lpid < 0)
581 		goto out_free2;
582 	gp->shadow_lpid = shadow_lpid;
583 	gp->radix = 1;
584 
585 	memset(gp->prev_cpu, -1, sizeof(gp->prev_cpu));
586 
587 	return gp;
588 
589  out_free2:
590 	pgd_free(kvm->mm, gp->shadow_pgtable);
591  out_free:
592 	kfree(gp);
593 	return NULL;
594 }
595 
596 /*
597  * Free up any resources allocated for a nested guest.
598  */
599 static void kvmhv_release_nested(struct kvm_nested_guest *gp)
600 {
601 	struct kvm *kvm = gp->l1_host;
602 
603 	if (gp->shadow_pgtable) {
604 		/*
605 		 * No vcpu is using this struct and no call to
606 		 * kvmhv_get_nested can find this struct,
607 		 * so we don't need to hold kvm->mmu_lock.
608 		 */
609 		kvmppc_free_pgtable_radix(kvm, gp->shadow_pgtable,
610 					  gp->shadow_lpid);
611 		pgd_free(kvm->mm, gp->shadow_pgtable);
612 	}
613 	kvmhv_set_ptbl_entry(gp->shadow_lpid, 0, 0);
614 	kvmppc_free_lpid(gp->shadow_lpid);
615 	kfree(gp);
616 }
617 
618 static void kvmhv_remove_nested(struct kvm_nested_guest *gp)
619 {
620 	struct kvm *kvm = gp->l1_host;
621 	int lpid = gp->l1_lpid;
622 	long ref;
623 
624 	spin_lock(&kvm->mmu_lock);
625 	if (gp == kvm->arch.nested_guests[lpid]) {
626 		kvm->arch.nested_guests[lpid] = NULL;
627 		if (lpid == kvm->arch.max_nested_lpid) {
628 			while (--lpid >= 0 && !kvm->arch.nested_guests[lpid])
629 				;
630 			kvm->arch.max_nested_lpid = lpid;
631 		}
632 		--gp->refcnt;
633 	}
634 	ref = gp->refcnt;
635 	spin_unlock(&kvm->mmu_lock);
636 	if (ref == 0)
637 		kvmhv_release_nested(gp);
638 }
639 
640 /*
641  * Free up all nested resources allocated for this guest.
642  * This is called with no vcpus of the guest running, when
643  * switching the guest to HPT mode or when destroying the
644  * guest.
645  */
646 void kvmhv_release_all_nested(struct kvm *kvm)
647 {
648 	int i;
649 	struct kvm_nested_guest *gp;
650 	struct kvm_nested_guest *freelist = NULL;
651 	struct kvm_memory_slot *memslot;
652 	int srcu_idx;
653 
654 	spin_lock(&kvm->mmu_lock);
655 	for (i = 0; i <= kvm->arch.max_nested_lpid; i++) {
656 		gp = kvm->arch.nested_guests[i];
657 		if (!gp)
658 			continue;
659 		kvm->arch.nested_guests[i] = NULL;
660 		if (--gp->refcnt == 0) {
661 			gp->next = freelist;
662 			freelist = gp;
663 		}
664 	}
665 	kvm->arch.max_nested_lpid = -1;
666 	spin_unlock(&kvm->mmu_lock);
667 	while ((gp = freelist) != NULL) {
668 		freelist = gp->next;
669 		kvmhv_release_nested(gp);
670 	}
671 
672 	srcu_idx = srcu_read_lock(&kvm->srcu);
673 	kvm_for_each_memslot(memslot, kvm_memslots(kvm))
674 		kvmhv_free_memslot_nest_rmap(memslot);
675 	srcu_read_unlock(&kvm->srcu, srcu_idx);
676 }
677 
678 /* caller must hold gp->tlb_lock */
679 static void kvmhv_flush_nested(struct kvm_nested_guest *gp)
680 {
681 	struct kvm *kvm = gp->l1_host;
682 
683 	spin_lock(&kvm->mmu_lock);
684 	kvmppc_free_pgtable_radix(kvm, gp->shadow_pgtable, gp->shadow_lpid);
685 	spin_unlock(&kvm->mmu_lock);
686 	kvmhv_flush_lpid(gp->shadow_lpid);
687 	kvmhv_update_ptbl_cache(gp);
688 	if (gp->l1_gr_to_hr == 0)
689 		kvmhv_remove_nested(gp);
690 }
691 
692 struct kvm_nested_guest *kvmhv_get_nested(struct kvm *kvm, int l1_lpid,
693 					  bool create)
694 {
695 	struct kvm_nested_guest *gp, *newgp;
696 
697 	if (l1_lpid >= KVM_MAX_NESTED_GUESTS ||
698 	    l1_lpid >= (1ul << ((kvm->arch.l1_ptcr & PRTS_MASK) + 12 - 4)))
699 		return NULL;
700 
701 	spin_lock(&kvm->mmu_lock);
702 	gp = kvm->arch.nested_guests[l1_lpid];
703 	if (gp)
704 		++gp->refcnt;
705 	spin_unlock(&kvm->mmu_lock);
706 
707 	if (gp || !create)
708 		return gp;
709 
710 	newgp = kvmhv_alloc_nested(kvm, l1_lpid);
711 	if (!newgp)
712 		return NULL;
713 	spin_lock(&kvm->mmu_lock);
714 	if (kvm->arch.nested_guests[l1_lpid]) {
715 		/* someone else beat us to it */
716 		gp = kvm->arch.nested_guests[l1_lpid];
717 	} else {
718 		kvm->arch.nested_guests[l1_lpid] = newgp;
719 		++newgp->refcnt;
720 		gp = newgp;
721 		newgp = NULL;
722 		if (l1_lpid > kvm->arch.max_nested_lpid)
723 			kvm->arch.max_nested_lpid = l1_lpid;
724 	}
725 	++gp->refcnt;
726 	spin_unlock(&kvm->mmu_lock);
727 
728 	if (newgp)
729 		kvmhv_release_nested(newgp);
730 
731 	return gp;
732 }
733 
734 void kvmhv_put_nested(struct kvm_nested_guest *gp)
735 {
736 	struct kvm *kvm = gp->l1_host;
737 	long ref;
738 
739 	spin_lock(&kvm->mmu_lock);
740 	ref = --gp->refcnt;
741 	spin_unlock(&kvm->mmu_lock);
742 	if (ref == 0)
743 		kvmhv_release_nested(gp);
744 }
745 
746 static struct kvm_nested_guest *kvmhv_find_nested(struct kvm *kvm, int lpid)
747 {
748 	if (lpid > kvm->arch.max_nested_lpid)
749 		return NULL;
750 	return kvm->arch.nested_guests[lpid];
751 }
752 
753 static inline bool kvmhv_n_rmap_is_equal(u64 rmap_1, u64 rmap_2)
754 {
755 	return !((rmap_1 ^ rmap_2) & (RMAP_NESTED_LPID_MASK |
756 				       RMAP_NESTED_GPA_MASK));
757 }
758 
759 void kvmhv_insert_nest_rmap(struct kvm *kvm, unsigned long *rmapp,
760 			    struct rmap_nested **n_rmap)
761 {
762 	struct llist_node *entry = ((struct llist_head *) rmapp)->first;
763 	struct rmap_nested *cursor;
764 	u64 rmap, new_rmap = (*n_rmap)->rmap;
765 
766 	/* Are there any existing entries? */
767 	if (!(*rmapp)) {
768 		/* No -> use the rmap as a single entry */
769 		*rmapp = new_rmap | RMAP_NESTED_IS_SINGLE_ENTRY;
770 		return;
771 	}
772 
773 	/* Do any entries match what we're trying to insert? */
774 	for_each_nest_rmap_safe(cursor, entry, &rmap) {
775 		if (kvmhv_n_rmap_is_equal(rmap, new_rmap))
776 			return;
777 	}
778 
779 	/* Do we need to create a list or just add the new entry? */
780 	rmap = *rmapp;
781 	if (rmap & RMAP_NESTED_IS_SINGLE_ENTRY) /* Not previously a list */
782 		*rmapp = 0UL;
783 	llist_add(&((*n_rmap)->list), (struct llist_head *) rmapp);
784 	if (rmap & RMAP_NESTED_IS_SINGLE_ENTRY) /* Not previously a list */
785 		(*n_rmap)->list.next = (struct llist_node *) rmap;
786 
787 	/* Set NULL so not freed by caller */
788 	*n_rmap = NULL;
789 }
790 
791 static void kvmhv_update_nest_rmap_rc(struct kvm *kvm, u64 n_rmap,
792 				      unsigned long clr, unsigned long set,
793 				      unsigned long hpa, unsigned long mask)
794 {
795 	struct kvm_nested_guest *gp;
796 	unsigned long gpa;
797 	unsigned int shift, lpid;
798 	pte_t *ptep;
799 
800 	gpa = n_rmap & RMAP_NESTED_GPA_MASK;
801 	lpid = (n_rmap & RMAP_NESTED_LPID_MASK) >> RMAP_NESTED_LPID_SHIFT;
802 	gp = kvmhv_find_nested(kvm, lpid);
803 	if (!gp)
804 		return;
805 
806 	/* Find the pte */
807 	ptep = __find_linux_pte(gp->shadow_pgtable, gpa, NULL, &shift);
808 	/*
809 	 * If the pte is present and the pfn is still the same, update the pte.
810 	 * If the pfn has changed then this is a stale rmap entry, the nested
811 	 * gpa actually points somewhere else now, and there is nothing to do.
812 	 * XXX A future optimisation would be to remove the rmap entry here.
813 	 */
814 	if (ptep && pte_present(*ptep) && ((pte_val(*ptep) & mask) == hpa)) {
815 		__radix_pte_update(ptep, clr, set);
816 		kvmppc_radix_tlbie_page(kvm, gpa, shift, lpid);
817 	}
818 }
819 
820 /*
821  * For a given list of rmap entries, update the rc bits in all ptes in shadow
822  * page tables for nested guests which are referenced by the rmap list.
823  */
824 void kvmhv_update_nest_rmap_rc_list(struct kvm *kvm, unsigned long *rmapp,
825 				    unsigned long clr, unsigned long set,
826 				    unsigned long hpa, unsigned long nbytes)
827 {
828 	struct llist_node *entry = ((struct llist_head *) rmapp)->first;
829 	struct rmap_nested *cursor;
830 	unsigned long rmap, mask;
831 
832 	if ((clr | set) & ~(_PAGE_DIRTY | _PAGE_ACCESSED))
833 		return;
834 
835 	mask = PTE_RPN_MASK & ~(nbytes - 1);
836 	hpa &= mask;
837 
838 	for_each_nest_rmap_safe(cursor, entry, &rmap)
839 		kvmhv_update_nest_rmap_rc(kvm, rmap, clr, set, hpa, mask);
840 }
841 
842 static void kvmhv_remove_nest_rmap(struct kvm *kvm, u64 n_rmap,
843 				   unsigned long hpa, unsigned long mask)
844 {
845 	struct kvm_nested_guest *gp;
846 	unsigned long gpa;
847 	unsigned int shift, lpid;
848 	pte_t *ptep;
849 
850 	gpa = n_rmap & RMAP_NESTED_GPA_MASK;
851 	lpid = (n_rmap & RMAP_NESTED_LPID_MASK) >> RMAP_NESTED_LPID_SHIFT;
852 	gp = kvmhv_find_nested(kvm, lpid);
853 	if (!gp)
854 		return;
855 
856 	/* Find and invalidate the pte */
857 	ptep = __find_linux_pte(gp->shadow_pgtable, gpa, NULL, &shift);
858 	/* Don't spuriously invalidate ptes if the pfn has changed */
859 	if (ptep && pte_present(*ptep) && ((pte_val(*ptep) & mask) == hpa))
860 		kvmppc_unmap_pte(kvm, ptep, gpa, shift, NULL, gp->shadow_lpid);
861 }
862 
863 static void kvmhv_remove_nest_rmap_list(struct kvm *kvm, unsigned long *rmapp,
864 					unsigned long hpa, unsigned long mask)
865 {
866 	struct llist_node *entry = llist_del_all((struct llist_head *) rmapp);
867 	struct rmap_nested *cursor;
868 	unsigned long rmap;
869 
870 	for_each_nest_rmap_safe(cursor, entry, &rmap) {
871 		kvmhv_remove_nest_rmap(kvm, rmap, hpa, mask);
872 		kfree(cursor);
873 	}
874 }
875 
876 /* called with kvm->mmu_lock held */
877 void kvmhv_remove_nest_rmap_range(struct kvm *kvm,
878 				  const struct kvm_memory_slot *memslot,
879 				  unsigned long gpa, unsigned long hpa,
880 				  unsigned long nbytes)
881 {
882 	unsigned long gfn, end_gfn;
883 	unsigned long addr_mask;
884 
885 	if (!memslot)
886 		return;
887 	gfn = (gpa >> PAGE_SHIFT) - memslot->base_gfn;
888 	end_gfn = gfn + (nbytes >> PAGE_SHIFT);
889 
890 	addr_mask = PTE_RPN_MASK & ~(nbytes - 1);
891 	hpa &= addr_mask;
892 
893 	for (; gfn < end_gfn; gfn++) {
894 		unsigned long *rmap = &memslot->arch.rmap[gfn];
895 		kvmhv_remove_nest_rmap_list(kvm, rmap, hpa, addr_mask);
896 	}
897 }
898 
899 static void kvmhv_free_memslot_nest_rmap(struct kvm_memory_slot *free)
900 {
901 	unsigned long page;
902 
903 	for (page = 0; page < free->npages; page++) {
904 		unsigned long rmap, *rmapp = &free->arch.rmap[page];
905 		struct rmap_nested *cursor;
906 		struct llist_node *entry;
907 
908 		entry = llist_del_all((struct llist_head *) rmapp);
909 		for_each_nest_rmap_safe(cursor, entry, &rmap)
910 			kfree(cursor);
911 	}
912 }
913 
914 static bool kvmhv_invalidate_shadow_pte(struct kvm_vcpu *vcpu,
915 					struct kvm_nested_guest *gp,
916 					long gpa, int *shift_ret)
917 {
918 	struct kvm *kvm = vcpu->kvm;
919 	bool ret = false;
920 	pte_t *ptep;
921 	int shift;
922 
923 	spin_lock(&kvm->mmu_lock);
924 	ptep = __find_linux_pte(gp->shadow_pgtable, gpa, NULL, &shift);
925 	if (!shift)
926 		shift = PAGE_SHIFT;
927 	if (ptep && pte_present(*ptep)) {
928 		kvmppc_unmap_pte(kvm, ptep, gpa, shift, NULL, gp->shadow_lpid);
929 		ret = true;
930 	}
931 	spin_unlock(&kvm->mmu_lock);
932 
933 	if (shift_ret)
934 		*shift_ret = shift;
935 	return ret;
936 }
937 
938 static inline int get_ric(unsigned int instr)
939 {
940 	return (instr >> 18) & 0x3;
941 }
942 
943 static inline int get_prs(unsigned int instr)
944 {
945 	return (instr >> 17) & 0x1;
946 }
947 
948 static inline int get_r(unsigned int instr)
949 {
950 	return (instr >> 16) & 0x1;
951 }
952 
953 static inline int get_lpid(unsigned long r_val)
954 {
955 	return r_val & 0xffffffff;
956 }
957 
958 static inline int get_is(unsigned long r_val)
959 {
960 	return (r_val >> 10) & 0x3;
961 }
962 
963 static inline int get_ap(unsigned long r_val)
964 {
965 	return (r_val >> 5) & 0x7;
966 }
967 
968 static inline long get_epn(unsigned long r_val)
969 {
970 	return r_val >> 12;
971 }
972 
973 static int kvmhv_emulate_tlbie_tlb_addr(struct kvm_vcpu *vcpu, int lpid,
974 					int ap, long epn)
975 {
976 	struct kvm *kvm = vcpu->kvm;
977 	struct kvm_nested_guest *gp;
978 	long npages;
979 	int shift, shadow_shift;
980 	unsigned long addr;
981 
982 	shift = ap_to_shift(ap);
983 	addr = epn << 12;
984 	if (shift < 0)
985 		/* Invalid ap encoding */
986 		return -EINVAL;
987 
988 	addr &= ~((1UL << shift) - 1);
989 	npages = 1UL << (shift - PAGE_SHIFT);
990 
991 	gp = kvmhv_get_nested(kvm, lpid, false);
992 	if (!gp) /* No such guest -> nothing to do */
993 		return 0;
994 	mutex_lock(&gp->tlb_lock);
995 
996 	/* There may be more than one host page backing this single guest pte */
997 	do {
998 		kvmhv_invalidate_shadow_pte(vcpu, gp, addr, &shadow_shift);
999 
1000 		npages -= 1UL << (shadow_shift - PAGE_SHIFT);
1001 		addr += 1UL << shadow_shift;
1002 	} while (npages > 0);
1003 
1004 	mutex_unlock(&gp->tlb_lock);
1005 	kvmhv_put_nested(gp);
1006 	return 0;
1007 }
1008 
1009 static void kvmhv_emulate_tlbie_lpid(struct kvm_vcpu *vcpu,
1010 				     struct kvm_nested_guest *gp, int ric)
1011 {
1012 	struct kvm *kvm = vcpu->kvm;
1013 
1014 	mutex_lock(&gp->tlb_lock);
1015 	switch (ric) {
1016 	case 0:
1017 		/* Invalidate TLB */
1018 		spin_lock(&kvm->mmu_lock);
1019 		kvmppc_free_pgtable_radix(kvm, gp->shadow_pgtable,
1020 					  gp->shadow_lpid);
1021 		kvmhv_flush_lpid(gp->shadow_lpid);
1022 		spin_unlock(&kvm->mmu_lock);
1023 		break;
1024 	case 1:
1025 		/*
1026 		 * Invalidate PWC
1027 		 * We don't cache this -> nothing to do
1028 		 */
1029 		break;
1030 	case 2:
1031 		/* Invalidate TLB, PWC and caching of partition table entries */
1032 		kvmhv_flush_nested(gp);
1033 		break;
1034 	default:
1035 		break;
1036 	}
1037 	mutex_unlock(&gp->tlb_lock);
1038 }
1039 
1040 static void kvmhv_emulate_tlbie_all_lpid(struct kvm_vcpu *vcpu, int ric)
1041 {
1042 	struct kvm *kvm = vcpu->kvm;
1043 	struct kvm_nested_guest *gp;
1044 	int i;
1045 
1046 	spin_lock(&kvm->mmu_lock);
1047 	for (i = 0; i <= kvm->arch.max_nested_lpid; i++) {
1048 		gp = kvm->arch.nested_guests[i];
1049 		if (gp) {
1050 			spin_unlock(&kvm->mmu_lock);
1051 			kvmhv_emulate_tlbie_lpid(vcpu, gp, ric);
1052 			spin_lock(&kvm->mmu_lock);
1053 		}
1054 	}
1055 	spin_unlock(&kvm->mmu_lock);
1056 }
1057 
1058 static int kvmhv_emulate_priv_tlbie(struct kvm_vcpu *vcpu, unsigned int instr,
1059 				    unsigned long rsval, unsigned long rbval)
1060 {
1061 	struct kvm *kvm = vcpu->kvm;
1062 	struct kvm_nested_guest *gp;
1063 	int r, ric, prs, is, ap;
1064 	int lpid;
1065 	long epn;
1066 	int ret = 0;
1067 
1068 	ric = get_ric(instr);
1069 	prs = get_prs(instr);
1070 	r = get_r(instr);
1071 	lpid = get_lpid(rsval);
1072 	is = get_is(rbval);
1073 
1074 	/*
1075 	 * These cases are invalid and are not handled:
1076 	 * r   != 1 -> Only radix supported
1077 	 * prs == 1 -> Not HV privileged
1078 	 * ric == 3 -> No cluster bombs for radix
1079 	 * is  == 1 -> Partition scoped translations not associated with pid
1080 	 * (!is) && (ric == 1 || ric == 2) -> Not supported by ISA
1081 	 */
1082 	if ((!r) || (prs) || (ric == 3) || (is == 1) ||
1083 	    ((!is) && (ric == 1 || ric == 2)))
1084 		return -EINVAL;
1085 
1086 	switch (is) {
1087 	case 0:
1088 		/*
1089 		 * We know ric == 0
1090 		 * Invalidate TLB for a given target address
1091 		 */
1092 		epn = get_epn(rbval);
1093 		ap = get_ap(rbval);
1094 		ret = kvmhv_emulate_tlbie_tlb_addr(vcpu, lpid, ap, epn);
1095 		break;
1096 	case 2:
1097 		/* Invalidate matching LPID */
1098 		gp = kvmhv_get_nested(kvm, lpid, false);
1099 		if (gp) {
1100 			kvmhv_emulate_tlbie_lpid(vcpu, gp, ric);
1101 			kvmhv_put_nested(gp);
1102 		}
1103 		break;
1104 	case 3:
1105 		/* Invalidate ALL LPIDs */
1106 		kvmhv_emulate_tlbie_all_lpid(vcpu, ric);
1107 		break;
1108 	default:
1109 		ret = -EINVAL;
1110 		break;
1111 	}
1112 
1113 	return ret;
1114 }
1115 
1116 /*
1117  * This handles the H_TLB_INVALIDATE hcall.
1118  * Parameters are (r4) tlbie instruction code, (r5) rS contents,
1119  * (r6) rB contents.
1120  */
1121 long kvmhv_do_nested_tlbie(struct kvm_vcpu *vcpu)
1122 {
1123 	int ret;
1124 
1125 	ret = kvmhv_emulate_priv_tlbie(vcpu, kvmppc_get_gpr(vcpu, 4),
1126 			kvmppc_get_gpr(vcpu, 5), kvmppc_get_gpr(vcpu, 6));
1127 	if (ret)
1128 		return H_PARAMETER;
1129 	return H_SUCCESS;
1130 }
1131 
1132 /* Used to convert a nested guest real address to a L1 guest real address */
1133 static int kvmhv_translate_addr_nested(struct kvm_vcpu *vcpu,
1134 				       struct kvm_nested_guest *gp,
1135 				       unsigned long n_gpa, unsigned long dsisr,
1136 				       struct kvmppc_pte *gpte_p)
1137 {
1138 	u64 fault_addr, flags = dsisr & DSISR_ISSTORE;
1139 	int ret;
1140 
1141 	ret = kvmppc_mmu_walk_radix_tree(vcpu, n_gpa, gpte_p, gp->l1_gr_to_hr,
1142 					 &fault_addr);
1143 
1144 	if (ret) {
1145 		/* We didn't find a pte */
1146 		if (ret == -EINVAL) {
1147 			/* Unsupported mmu config */
1148 			flags |= DSISR_UNSUPP_MMU;
1149 		} else if (ret == -ENOENT) {
1150 			/* No translation found */
1151 			flags |= DSISR_NOHPTE;
1152 		} else if (ret == -EFAULT) {
1153 			/* Couldn't access L1 real address */
1154 			flags |= DSISR_PRTABLE_FAULT;
1155 			vcpu->arch.fault_gpa = fault_addr;
1156 		} else {
1157 			/* Unknown error */
1158 			return ret;
1159 		}
1160 		goto forward_to_l1;
1161 	} else {
1162 		/* We found a pte -> check permissions */
1163 		if (dsisr & DSISR_ISSTORE) {
1164 			/* Can we write? */
1165 			if (!gpte_p->may_write) {
1166 				flags |= DSISR_PROTFAULT;
1167 				goto forward_to_l1;
1168 			}
1169 		} else if (vcpu->arch.trap == BOOK3S_INTERRUPT_H_INST_STORAGE) {
1170 			/* Can we execute? */
1171 			if (!gpte_p->may_execute) {
1172 				flags |= SRR1_ISI_N_OR_G;
1173 				goto forward_to_l1;
1174 			}
1175 		} else {
1176 			/* Can we read? */
1177 			if (!gpte_p->may_read && !gpte_p->may_write) {
1178 				flags |= DSISR_PROTFAULT;
1179 				goto forward_to_l1;
1180 			}
1181 		}
1182 	}
1183 
1184 	return 0;
1185 
1186 forward_to_l1:
1187 	vcpu->arch.fault_dsisr = flags;
1188 	if (vcpu->arch.trap == BOOK3S_INTERRUPT_H_INST_STORAGE) {
1189 		vcpu->arch.shregs.msr &= ~0x783f0000ul;
1190 		vcpu->arch.shregs.msr |= flags;
1191 	}
1192 	return RESUME_HOST;
1193 }
1194 
1195 static long kvmhv_handle_nested_set_rc(struct kvm_vcpu *vcpu,
1196 				       struct kvm_nested_guest *gp,
1197 				       unsigned long n_gpa,
1198 				       struct kvmppc_pte gpte,
1199 				       unsigned long dsisr)
1200 {
1201 	struct kvm *kvm = vcpu->kvm;
1202 	bool writing = !!(dsisr & DSISR_ISSTORE);
1203 	u64 pgflags;
1204 	long ret;
1205 
1206 	/* Are the rc bits set in the L1 partition scoped pte? */
1207 	pgflags = _PAGE_ACCESSED;
1208 	if (writing)
1209 		pgflags |= _PAGE_DIRTY;
1210 	if (pgflags & ~gpte.rc)
1211 		return RESUME_HOST;
1212 
1213 	spin_lock(&kvm->mmu_lock);
1214 	/* Set the rc bit in the pte of our (L0) pgtable for the L1 guest */
1215 	ret = kvmppc_hv_handle_set_rc(kvm, kvm->arch.pgtable, writing,
1216 				     gpte.raddr, kvm->arch.lpid);
1217 	if (!ret) {
1218 		ret = -EINVAL;
1219 		goto out_unlock;
1220 	}
1221 
1222 	/* Set the rc bit in the pte of the shadow_pgtable for the nest guest */
1223 	ret = kvmppc_hv_handle_set_rc(kvm, gp->shadow_pgtable, writing, n_gpa,
1224 				      gp->shadow_lpid);
1225 	if (!ret)
1226 		ret = -EINVAL;
1227 	else
1228 		ret = 0;
1229 
1230 out_unlock:
1231 	spin_unlock(&kvm->mmu_lock);
1232 	return ret;
1233 }
1234 
1235 static inline int kvmppc_radix_level_to_shift(int level)
1236 {
1237 	switch (level) {
1238 	case 2:
1239 		return PUD_SHIFT;
1240 	case 1:
1241 		return PMD_SHIFT;
1242 	default:
1243 		return PAGE_SHIFT;
1244 	}
1245 }
1246 
1247 static inline int kvmppc_radix_shift_to_level(int shift)
1248 {
1249 	if (shift == PUD_SHIFT)
1250 		return 2;
1251 	if (shift == PMD_SHIFT)
1252 		return 1;
1253 	if (shift == PAGE_SHIFT)
1254 		return 0;
1255 	WARN_ON_ONCE(1);
1256 	return 0;
1257 }
1258 
1259 /* called with gp->tlb_lock held */
1260 static long int __kvmhv_nested_page_fault(struct kvm_run *run,
1261 					  struct kvm_vcpu *vcpu,
1262 					  struct kvm_nested_guest *gp)
1263 {
1264 	struct kvm *kvm = vcpu->kvm;
1265 	struct kvm_memory_slot *memslot;
1266 	struct rmap_nested *n_rmap;
1267 	struct kvmppc_pte gpte;
1268 	pte_t pte, *pte_p;
1269 	unsigned long mmu_seq;
1270 	unsigned long dsisr = vcpu->arch.fault_dsisr;
1271 	unsigned long ea = vcpu->arch.fault_dar;
1272 	unsigned long *rmapp;
1273 	unsigned long n_gpa, gpa, gfn, perm = 0UL;
1274 	unsigned int shift, l1_shift, level;
1275 	bool writing = !!(dsisr & DSISR_ISSTORE);
1276 	bool kvm_ro = false;
1277 	long int ret;
1278 
1279 	if (!gp->l1_gr_to_hr) {
1280 		kvmhv_update_ptbl_cache(gp);
1281 		if (!gp->l1_gr_to_hr)
1282 			return RESUME_HOST;
1283 	}
1284 
1285 	/* Convert the nested guest real address into a L1 guest real address */
1286 
1287 	n_gpa = vcpu->arch.fault_gpa & ~0xF000000000000FFFULL;
1288 	if (!(dsisr & DSISR_PRTABLE_FAULT))
1289 		n_gpa |= ea & 0xFFF;
1290 	ret = kvmhv_translate_addr_nested(vcpu, gp, n_gpa, dsisr, &gpte);
1291 
1292 	/*
1293 	 * If the hardware found a translation but we don't now have a usable
1294 	 * translation in the l1 partition-scoped tree, remove the shadow pte
1295 	 * and let the guest retry.
1296 	 */
1297 	if (ret == RESUME_HOST &&
1298 	    (dsisr & (DSISR_PROTFAULT | DSISR_BADACCESS | DSISR_NOEXEC_OR_G |
1299 		      DSISR_BAD_COPYPASTE)))
1300 		goto inval;
1301 	if (ret)
1302 		return ret;
1303 
1304 	/* Failed to set the reference/change bits */
1305 	if (dsisr & DSISR_SET_RC) {
1306 		ret = kvmhv_handle_nested_set_rc(vcpu, gp, n_gpa, gpte, dsisr);
1307 		if (ret == RESUME_HOST)
1308 			return ret;
1309 		if (ret)
1310 			goto inval;
1311 		dsisr &= ~DSISR_SET_RC;
1312 		if (!(dsisr & (DSISR_BAD_FAULT_64S | DSISR_NOHPTE |
1313 			       DSISR_PROTFAULT)))
1314 			return RESUME_GUEST;
1315 	}
1316 
1317 	/*
1318 	 * We took an HISI or HDSI while we were running a nested guest which
1319 	 * means we have no partition scoped translation for that. This means
1320 	 * we need to insert a pte for the mapping into our shadow_pgtable.
1321 	 */
1322 
1323 	l1_shift = gpte.page_shift;
1324 	if (l1_shift < PAGE_SHIFT) {
1325 		/* We don't support l1 using a page size smaller than our own */
1326 		pr_err("KVM: L1 guest page shift (%d) less than our own (%d)\n",
1327 			l1_shift, PAGE_SHIFT);
1328 		return -EINVAL;
1329 	}
1330 	gpa = gpte.raddr;
1331 	gfn = gpa >> PAGE_SHIFT;
1332 
1333 	/* 1. Get the corresponding host memslot */
1334 
1335 	memslot = gfn_to_memslot(kvm, gfn);
1336 	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {
1337 		if (dsisr & (DSISR_PRTABLE_FAULT | DSISR_BADACCESS)) {
1338 			/* unusual error -> reflect to the guest as a DSI */
1339 			kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
1340 			return RESUME_GUEST;
1341 		}
1342 
1343 		/* passthrough of emulated MMIO case */
1344 		return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea, writing);
1345 	}
1346 	if (memslot->flags & KVM_MEM_READONLY) {
1347 		if (writing) {
1348 			/* Give the guest a DSI */
1349 			kvmppc_core_queue_data_storage(vcpu, ea,
1350 					DSISR_ISSTORE | DSISR_PROTFAULT);
1351 			return RESUME_GUEST;
1352 		}
1353 		kvm_ro = true;
1354 	}
1355 
1356 	/* 2. Find the host pte for this L1 guest real address */
1357 
1358 	/* Used to check for invalidations in progress */
1359 	mmu_seq = kvm->mmu_notifier_seq;
1360 	smp_rmb();
1361 
1362 	/* See if can find translation in our partition scoped tables for L1 */
1363 	pte = __pte(0);
1364 	spin_lock(&kvm->mmu_lock);
1365 	pte_p = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
1366 	if (!shift)
1367 		shift = PAGE_SHIFT;
1368 	if (pte_p)
1369 		pte = *pte_p;
1370 	spin_unlock(&kvm->mmu_lock);
1371 
1372 	if (!pte_present(pte) || (writing && !(pte_val(pte) & _PAGE_WRITE))) {
1373 		/* No suitable pte found -> try to insert a mapping */
1374 		ret = kvmppc_book3s_instantiate_page(vcpu, gpa, memslot,
1375 					writing, kvm_ro, &pte, &level);
1376 		if (ret == -EAGAIN)
1377 			return RESUME_GUEST;
1378 		else if (ret)
1379 			return ret;
1380 		shift = kvmppc_radix_level_to_shift(level);
1381 	}
1382 	/* Align gfn to the start of the page */
1383 	gfn = (gpa & ~((1UL << shift) - 1)) >> PAGE_SHIFT;
1384 
1385 	/* 3. Compute the pte we need to insert for nest_gpa -> host r_addr */
1386 
1387 	/* The permissions is the combination of the host and l1 guest ptes */
1388 	perm |= gpte.may_read ? 0UL : _PAGE_READ;
1389 	perm |= gpte.may_write ? 0UL : _PAGE_WRITE;
1390 	perm |= gpte.may_execute ? 0UL : _PAGE_EXEC;
1391 	/* Only set accessed/dirty (rc) bits if set in host and l1 guest ptes */
1392 	perm |= (gpte.rc & _PAGE_ACCESSED) ? 0UL : _PAGE_ACCESSED;
1393 	perm |= ((gpte.rc & _PAGE_DIRTY) && writing) ? 0UL : _PAGE_DIRTY;
1394 	pte = __pte(pte_val(pte) & ~perm);
1395 
1396 	/* What size pte can we insert? */
1397 	if (shift > l1_shift) {
1398 		u64 mask;
1399 		unsigned int actual_shift = PAGE_SHIFT;
1400 		if (PMD_SHIFT < l1_shift)
1401 			actual_shift = PMD_SHIFT;
1402 		mask = (1UL << shift) - (1UL << actual_shift);
1403 		pte = __pte(pte_val(pte) | (gpa & mask));
1404 		shift = actual_shift;
1405 	}
1406 	level = kvmppc_radix_shift_to_level(shift);
1407 	n_gpa &= ~((1UL << shift) - 1);
1408 
1409 	/* 4. Insert the pte into our shadow_pgtable */
1410 
1411 	n_rmap = kzalloc(sizeof(*n_rmap), GFP_KERNEL);
1412 	if (!n_rmap)
1413 		return RESUME_GUEST; /* Let the guest try again */
1414 	n_rmap->rmap = (n_gpa & RMAP_NESTED_GPA_MASK) |
1415 		(((unsigned long) gp->l1_lpid) << RMAP_NESTED_LPID_SHIFT);
1416 	rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];
1417 	ret = kvmppc_create_pte(kvm, gp->shadow_pgtable, pte, n_gpa, level,
1418 				mmu_seq, gp->shadow_lpid, rmapp, &n_rmap);
1419 	if (n_rmap)
1420 		kfree(n_rmap);
1421 	if (ret == -EAGAIN)
1422 		ret = RESUME_GUEST;	/* Let the guest try again */
1423 
1424 	return ret;
1425 
1426  inval:
1427 	kvmhv_invalidate_shadow_pte(vcpu, gp, n_gpa, NULL);
1428 	return RESUME_GUEST;
1429 }
1430 
1431 long int kvmhv_nested_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu)
1432 {
1433 	struct kvm_nested_guest *gp = vcpu->arch.nested;
1434 	long int ret;
1435 
1436 	mutex_lock(&gp->tlb_lock);
1437 	ret = __kvmhv_nested_page_fault(run, vcpu, gp);
1438 	mutex_unlock(&gp->tlb_lock);
1439 	return ret;
1440 }
1441 
1442 int kvmhv_nested_next_lpid(struct kvm *kvm, int lpid)
1443 {
1444 	int ret = -1;
1445 
1446 	spin_lock(&kvm->mmu_lock);
1447 	while (++lpid <= kvm->arch.max_nested_lpid) {
1448 		if (kvm->arch.nested_guests[lpid]) {
1449 			ret = lpid;
1450 			break;
1451 		}
1452 	}
1453 	spin_unlock(&kvm->mmu_lock);
1454 	return ret;
1455 }
1456