xref: /openbmc/linux/arch/arm64/kvm/sys_regs.c (revision afb46f79)
1 /*
2  * Copyright (C) 2012,2013 - ARM Ltd
3  * Author: Marc Zyngier <marc.zyngier@arm.com>
4  *
5  * Derived from arch/arm/kvm/coproc.c:
6  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
7  * Authors: Rusty Russell <rusty@rustcorp.com.au>
8  *          Christoffer Dall <c.dall@virtualopensystems.com>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License, version 2, as
12  * published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
21  */
22 
23 #include <linux/mm.h>
24 #include <linux/kvm_host.h>
25 #include <linux/uaccess.h>
26 #include <asm/kvm_arm.h>
27 #include <asm/kvm_host.h>
28 #include <asm/kvm_emulate.h>
29 #include <asm/kvm_coproc.h>
30 #include <asm/kvm_mmu.h>
31 #include <asm/cacheflush.h>
32 #include <asm/cputype.h>
33 #include <trace/events/kvm.h>
34 
35 #include "sys_regs.h"
36 
37 /*
38  * All of this file is extremly similar to the ARM coproc.c, but the
39  * types are different. My gut feeling is that it should be pretty
40  * easy to merge, but that would be an ABI breakage -- again. VFP
41  * would also need to be abstracted.
42  *
43  * For AArch32, we only take care of what is being trapped. Anything
44  * that has to do with init and userspace access has to go via the
45  * 64bit interface.
46  */
47 
48 /* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
49 static u32 cache_levels;
50 
51 /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
52 #define CSSELR_MAX 12
53 
54 /* Which cache CCSIDR represents depends on CSSELR value. */
55 static u32 get_ccsidr(u32 csselr)
56 {
57 	u32 ccsidr;
58 
59 	/* Make sure noone else changes CSSELR during this! */
60 	local_irq_disable();
61 	/* Put value into CSSELR */
62 	asm volatile("msr csselr_el1, %x0" : : "r" (csselr));
63 	isb();
64 	/* Read result out of CCSIDR */
65 	asm volatile("mrs %0, ccsidr_el1" : "=r" (ccsidr));
66 	local_irq_enable();
67 
68 	return ccsidr;
69 }
70 
71 static void do_dc_cisw(u32 val)
72 {
73 	asm volatile("dc cisw, %x0" : : "r" (val));
74 	dsb();
75 }
76 
77 static void do_dc_csw(u32 val)
78 {
79 	asm volatile("dc csw, %x0" : : "r" (val));
80 	dsb();
81 }
82 
83 /* See note at ARM ARM B1.14.4 */
84 static bool access_dcsw(struct kvm_vcpu *vcpu,
85 			const struct sys_reg_params *p,
86 			const struct sys_reg_desc *r)
87 {
88 	unsigned long val;
89 	int cpu;
90 
91 	if (!p->is_write)
92 		return read_from_write_only(vcpu, p);
93 
94 	cpu = get_cpu();
95 
96 	cpumask_setall(&vcpu->arch.require_dcache_flush);
97 	cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);
98 
99 	/* If we were already preempted, take the long way around */
100 	if (cpu != vcpu->arch.last_pcpu) {
101 		flush_cache_all();
102 		goto done;
103 	}
104 
105 	val = *vcpu_reg(vcpu, p->Rt);
106 
107 	switch (p->CRm) {
108 	case 6:			/* Upgrade DCISW to DCCISW, as per HCR.SWIO */
109 	case 14:		/* DCCISW */
110 		do_dc_cisw(val);
111 		break;
112 
113 	case 10:		/* DCCSW */
114 		do_dc_csw(val);
115 		break;
116 	}
117 
118 done:
119 	put_cpu();
120 
121 	return true;
122 }
123 
124 /*
125  * Generic accessor for VM registers. Only called as long as HCR_TVM
126  * is set.
127  */
128 static bool access_vm_reg(struct kvm_vcpu *vcpu,
129 			  const struct sys_reg_params *p,
130 			  const struct sys_reg_desc *r)
131 {
132 	unsigned long val;
133 
134 	BUG_ON(!p->is_write);
135 
136 	val = *vcpu_reg(vcpu, p->Rt);
137 	if (!p->is_aarch32) {
138 		vcpu_sys_reg(vcpu, r->reg) = val;
139 	} else {
140 		vcpu_cp15(vcpu, r->reg) = val & 0xffffffffUL;
141 		if (!p->is_32bit)
142 			vcpu_cp15(vcpu, r->reg + 1) = val >> 32;
143 	}
144 	return true;
145 }
146 
147 /*
148  * SCTLR_EL1 accessor. Only called as long as HCR_TVM is set.  If the
149  * guest enables the MMU, we stop trapping the VM sys_regs and leave
150  * it in complete control of the caches.
151  */
152 static bool access_sctlr(struct kvm_vcpu *vcpu,
153 			 const struct sys_reg_params *p,
154 			 const struct sys_reg_desc *r)
155 {
156 	access_vm_reg(vcpu, p, r);
157 
158 	if (vcpu_has_cache_enabled(vcpu)) {	/* MMU+Caches enabled? */
159 		vcpu->arch.hcr_el2 &= ~HCR_TVM;
160 		stage2_flush_vm(vcpu->kvm);
161 	}
162 
163 	return true;
164 }
165 
166 /*
167  * We could trap ID_DFR0 and tell the guest we don't support performance
168  * monitoring.  Unfortunately the patch to make the kernel check ID_DFR0 was
169  * NAKed, so it will read the PMCR anyway.
170  *
171  * Therefore we tell the guest we have 0 counters.  Unfortunately, we
172  * must always support PMCCNTR (the cycle counter): we just RAZ/WI for
173  * all PM registers, which doesn't crash the guest kernel at least.
174  */
175 static bool pm_fake(struct kvm_vcpu *vcpu,
176 		    const struct sys_reg_params *p,
177 		    const struct sys_reg_desc *r)
178 {
179 	if (p->is_write)
180 		return ignore_write(vcpu, p);
181 	else
182 		return read_zero(vcpu, p);
183 }
184 
185 static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
186 {
187 	u64 amair;
188 
189 	asm volatile("mrs %0, amair_el1\n" : "=r" (amair));
190 	vcpu_sys_reg(vcpu, AMAIR_EL1) = amair;
191 }
192 
193 static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
194 {
195 	/*
196 	 * Simply map the vcpu_id into the Aff0 field of the MPIDR.
197 	 */
198 	vcpu_sys_reg(vcpu, MPIDR_EL1) = (1UL << 31) | (vcpu->vcpu_id & 0xff);
199 }
200 
201 /*
202  * Architected system registers.
203  * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
204  */
205 static const struct sys_reg_desc sys_reg_descs[] = {
206 	/* DC ISW */
207 	{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b0110), Op2(0b010),
208 	  access_dcsw },
209 	/* DC CSW */
210 	{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b1010), Op2(0b010),
211 	  access_dcsw },
212 	/* DC CISW */
213 	{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b1110), Op2(0b010),
214 	  access_dcsw },
215 
216 	/* TEECR32_EL1 */
217 	{ Op0(0b10), Op1(0b010), CRn(0b0000), CRm(0b0000), Op2(0b000),
218 	  NULL, reset_val, TEECR32_EL1, 0 },
219 	/* TEEHBR32_EL1 */
220 	{ Op0(0b10), Op1(0b010), CRn(0b0001), CRm(0b0000), Op2(0b000),
221 	  NULL, reset_val, TEEHBR32_EL1, 0 },
222 	/* DBGVCR32_EL2 */
223 	{ Op0(0b10), Op1(0b100), CRn(0b0000), CRm(0b0111), Op2(0b000),
224 	  NULL, reset_val, DBGVCR32_EL2, 0 },
225 
226 	/* MPIDR_EL1 */
227 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b101),
228 	  NULL, reset_mpidr, MPIDR_EL1 },
229 	/* SCTLR_EL1 */
230 	{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b000),
231 	  access_sctlr, reset_val, SCTLR_EL1, 0x00C50078 },
232 	/* CPACR_EL1 */
233 	{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b010),
234 	  NULL, reset_val, CPACR_EL1, 0 },
235 	/* TTBR0_EL1 */
236 	{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b000),
237 	  access_vm_reg, reset_unknown, TTBR0_EL1 },
238 	/* TTBR1_EL1 */
239 	{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b001),
240 	  access_vm_reg, reset_unknown, TTBR1_EL1 },
241 	/* TCR_EL1 */
242 	{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b010),
243 	  access_vm_reg, reset_val, TCR_EL1, 0 },
244 
245 	/* AFSR0_EL1 */
246 	{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b000),
247 	  access_vm_reg, reset_unknown, AFSR0_EL1 },
248 	/* AFSR1_EL1 */
249 	{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b001),
250 	  access_vm_reg, reset_unknown, AFSR1_EL1 },
251 	/* ESR_EL1 */
252 	{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0010), Op2(0b000),
253 	  access_vm_reg, reset_unknown, ESR_EL1 },
254 	/* FAR_EL1 */
255 	{ Op0(0b11), Op1(0b000), CRn(0b0110), CRm(0b0000), Op2(0b000),
256 	  access_vm_reg, reset_unknown, FAR_EL1 },
257 	/* PAR_EL1 */
258 	{ Op0(0b11), Op1(0b000), CRn(0b0111), CRm(0b0100), Op2(0b000),
259 	  NULL, reset_unknown, PAR_EL1 },
260 
261 	/* PMINTENSET_EL1 */
262 	{ Op0(0b11), Op1(0b000), CRn(0b1001), CRm(0b1110), Op2(0b001),
263 	  pm_fake },
264 	/* PMINTENCLR_EL1 */
265 	{ Op0(0b11), Op1(0b000), CRn(0b1001), CRm(0b1110), Op2(0b010),
266 	  pm_fake },
267 
268 	/* MAIR_EL1 */
269 	{ Op0(0b11), Op1(0b000), CRn(0b1010), CRm(0b0010), Op2(0b000),
270 	  access_vm_reg, reset_unknown, MAIR_EL1 },
271 	/* AMAIR_EL1 */
272 	{ Op0(0b11), Op1(0b000), CRn(0b1010), CRm(0b0011), Op2(0b000),
273 	  access_vm_reg, reset_amair_el1, AMAIR_EL1 },
274 
275 	/* VBAR_EL1 */
276 	{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b0000), Op2(0b000),
277 	  NULL, reset_val, VBAR_EL1, 0 },
278 	/* CONTEXTIDR_EL1 */
279 	{ Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b001),
280 	  access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 },
281 	/* TPIDR_EL1 */
282 	{ Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b100),
283 	  NULL, reset_unknown, TPIDR_EL1 },
284 
285 	/* CNTKCTL_EL1 */
286 	{ Op0(0b11), Op1(0b000), CRn(0b1110), CRm(0b0001), Op2(0b000),
287 	  NULL, reset_val, CNTKCTL_EL1, 0},
288 
289 	/* CSSELR_EL1 */
290 	{ Op0(0b11), Op1(0b010), CRn(0b0000), CRm(0b0000), Op2(0b000),
291 	  NULL, reset_unknown, CSSELR_EL1 },
292 
293 	/* PMCR_EL0 */
294 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b000),
295 	  pm_fake },
296 	/* PMCNTENSET_EL0 */
297 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b001),
298 	  pm_fake },
299 	/* PMCNTENCLR_EL0 */
300 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b010),
301 	  pm_fake },
302 	/* PMOVSCLR_EL0 */
303 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b011),
304 	  pm_fake },
305 	/* PMSWINC_EL0 */
306 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b100),
307 	  pm_fake },
308 	/* PMSELR_EL0 */
309 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b101),
310 	  pm_fake },
311 	/* PMCEID0_EL0 */
312 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b110),
313 	  pm_fake },
314 	/* PMCEID1_EL0 */
315 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b111),
316 	  pm_fake },
317 	/* PMCCNTR_EL0 */
318 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b000),
319 	  pm_fake },
320 	/* PMXEVTYPER_EL0 */
321 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b001),
322 	  pm_fake },
323 	/* PMXEVCNTR_EL0 */
324 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b010),
325 	  pm_fake },
326 	/* PMUSERENR_EL0 */
327 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b000),
328 	  pm_fake },
329 	/* PMOVSSET_EL0 */
330 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b011),
331 	  pm_fake },
332 
333 	/* TPIDR_EL0 */
334 	{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b010),
335 	  NULL, reset_unknown, TPIDR_EL0 },
336 	/* TPIDRRO_EL0 */
337 	{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b011),
338 	  NULL, reset_unknown, TPIDRRO_EL0 },
339 
340 	/* DACR32_EL2 */
341 	{ Op0(0b11), Op1(0b100), CRn(0b0011), CRm(0b0000), Op2(0b000),
342 	  NULL, reset_unknown, DACR32_EL2 },
343 	/* IFSR32_EL2 */
344 	{ Op0(0b11), Op1(0b100), CRn(0b0101), CRm(0b0000), Op2(0b001),
345 	  NULL, reset_unknown, IFSR32_EL2 },
346 	/* FPEXC32_EL2 */
347 	{ Op0(0b11), Op1(0b100), CRn(0b0101), CRm(0b0011), Op2(0b000),
348 	  NULL, reset_val, FPEXC32_EL2, 0x70 },
349 };
350 
351 /*
352  * Trapped cp15 registers. TTBR0/TTBR1 get a double encoding,
353  * depending on the way they are accessed (as a 32bit or a 64bit
354  * register).
355  */
356 static const struct sys_reg_desc cp15_regs[] = {
357 	{ Op1( 0), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, c2_TTBR0 },
358 	{ Op1( 0), CRn( 1), CRm( 0), Op2( 0), access_sctlr, NULL, c1_SCTLR },
359 	{ Op1( 0), CRn( 2), CRm( 0), Op2( 0), access_vm_reg, NULL, c2_TTBR0 },
360 	{ Op1( 0), CRn( 2), CRm( 0), Op2( 1), access_vm_reg, NULL, c2_TTBR1 },
361 	{ Op1( 0), CRn( 2), CRm( 0), Op2( 2), access_vm_reg, NULL, c2_TTBCR },
362 	{ Op1( 0), CRn( 3), CRm( 0), Op2( 0), access_vm_reg, NULL, c3_DACR },
363 	{ Op1( 0), CRn( 5), CRm( 0), Op2( 0), access_vm_reg, NULL, c5_DFSR },
364 	{ Op1( 0), CRn( 5), CRm( 0), Op2( 1), access_vm_reg, NULL, c5_IFSR },
365 	{ Op1( 0), CRn( 5), CRm( 1), Op2( 0), access_vm_reg, NULL, c5_ADFSR },
366 	{ Op1( 0), CRn( 5), CRm( 1), Op2( 1), access_vm_reg, NULL, c5_AIFSR },
367 	{ Op1( 0), CRn( 6), CRm( 0), Op2( 0), access_vm_reg, NULL, c6_DFAR },
368 	{ Op1( 0), CRn( 6), CRm( 0), Op2( 2), access_vm_reg, NULL, c6_IFAR },
369 
370 	/*
371 	 * DC{C,I,CI}SW operations:
372 	 */
373 	{ Op1( 0), CRn( 7), CRm( 6), Op2( 2), access_dcsw },
374 	{ Op1( 0), CRn( 7), CRm(10), Op2( 2), access_dcsw },
375 	{ Op1( 0), CRn( 7), CRm(14), Op2( 2), access_dcsw },
376 
377 	{ Op1( 0), CRn( 9), CRm(12), Op2( 0), pm_fake },
378 	{ Op1( 0), CRn( 9), CRm(12), Op2( 1), pm_fake },
379 	{ Op1( 0), CRn( 9), CRm(12), Op2( 2), pm_fake },
380 	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), pm_fake },
381 	{ Op1( 0), CRn( 9), CRm(12), Op2( 5), pm_fake },
382 	{ Op1( 0), CRn( 9), CRm(12), Op2( 6), pm_fake },
383 	{ Op1( 0), CRn( 9), CRm(12), Op2( 7), pm_fake },
384 	{ Op1( 0), CRn( 9), CRm(13), Op2( 0), pm_fake },
385 	{ Op1( 0), CRn( 9), CRm(13), Op2( 1), pm_fake },
386 	{ Op1( 0), CRn( 9), CRm(13), Op2( 2), pm_fake },
387 	{ Op1( 0), CRn( 9), CRm(14), Op2( 0), pm_fake },
388 	{ Op1( 0), CRn( 9), CRm(14), Op2( 1), pm_fake },
389 	{ Op1( 0), CRn( 9), CRm(14), Op2( 2), pm_fake },
390 
391 	{ Op1( 0), CRn(10), CRm( 2), Op2( 0), access_vm_reg, NULL, c10_PRRR },
392 	{ Op1( 0), CRn(10), CRm( 2), Op2( 1), access_vm_reg, NULL, c10_NMRR },
393 	{ Op1( 0), CRn(10), CRm( 3), Op2( 0), access_vm_reg, NULL, c10_AMAIR0 },
394 	{ Op1( 0), CRn(10), CRm( 3), Op2( 1), access_vm_reg, NULL, c10_AMAIR1 },
395 	{ Op1( 0), CRn(13), CRm( 0), Op2( 1), access_vm_reg, NULL, c13_CID },
396 
397 	{ Op1( 1), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, c2_TTBR1 },
398 };
399 
400 /* Target specific emulation tables */
401 static struct kvm_sys_reg_target_table *target_tables[KVM_ARM_NUM_TARGETS];
402 
403 void kvm_register_target_sys_reg_table(unsigned int target,
404 				       struct kvm_sys_reg_target_table *table)
405 {
406 	target_tables[target] = table;
407 }
408 
409 /* Get specific register table for this target. */
410 static const struct sys_reg_desc *get_target_table(unsigned target,
411 						   bool mode_is_64,
412 						   size_t *num)
413 {
414 	struct kvm_sys_reg_target_table *table;
415 
416 	table = target_tables[target];
417 	if (mode_is_64) {
418 		*num = table->table64.num;
419 		return table->table64.table;
420 	} else {
421 		*num = table->table32.num;
422 		return table->table32.table;
423 	}
424 }
425 
426 static const struct sys_reg_desc *find_reg(const struct sys_reg_params *params,
427 					 const struct sys_reg_desc table[],
428 					 unsigned int num)
429 {
430 	unsigned int i;
431 
432 	for (i = 0; i < num; i++) {
433 		const struct sys_reg_desc *r = &table[i];
434 
435 		if (params->Op0 != r->Op0)
436 			continue;
437 		if (params->Op1 != r->Op1)
438 			continue;
439 		if (params->CRn != r->CRn)
440 			continue;
441 		if (params->CRm != r->CRm)
442 			continue;
443 		if (params->Op2 != r->Op2)
444 			continue;
445 
446 		return r;
447 	}
448 	return NULL;
449 }
450 
451 int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu, struct kvm_run *run)
452 {
453 	kvm_inject_undefined(vcpu);
454 	return 1;
455 }
456 
457 int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct kvm_run *run)
458 {
459 	kvm_inject_undefined(vcpu);
460 	return 1;
461 }
462 
463 static void emulate_cp15(struct kvm_vcpu *vcpu,
464 			 const struct sys_reg_params *params)
465 {
466 	size_t num;
467 	const struct sys_reg_desc *table, *r;
468 
469 	table = get_target_table(vcpu->arch.target, false, &num);
470 
471 	/* Search target-specific then generic table. */
472 	r = find_reg(params, table, num);
473 	if (!r)
474 		r = find_reg(params, cp15_regs, ARRAY_SIZE(cp15_regs));
475 
476 	if (likely(r)) {
477 		/*
478 		 * Not having an accessor means that we have
479 		 * configured a trap that we don't know how to
480 		 * handle. This certainly qualifies as a gross bug
481 		 * that should be fixed right away.
482 		 */
483 		BUG_ON(!r->access);
484 
485 		if (likely(r->access(vcpu, params, r))) {
486 			/* Skip instruction, since it was emulated */
487 			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
488 			return;
489 		}
490 		/* If access function fails, it should complain. */
491 	}
492 
493 	kvm_err("Unsupported guest CP15 access at: %08lx\n", *vcpu_pc(vcpu));
494 	print_sys_reg_instr(params);
495 	kvm_inject_undefined(vcpu);
496 }
497 
498 /**
499  * kvm_handle_cp15_64 -- handles a mrrc/mcrr trap on a guest CP15 access
500  * @vcpu: The VCPU pointer
501  * @run:  The kvm_run struct
502  */
503 int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
504 {
505 	struct sys_reg_params params;
506 	u32 hsr = kvm_vcpu_get_hsr(vcpu);
507 	int Rt2 = (hsr >> 10) & 0xf;
508 
509 	params.is_aarch32 = true;
510 	params.is_32bit = false;
511 	params.CRm = (hsr >> 1) & 0xf;
512 	params.Rt = (hsr >> 5) & 0xf;
513 	params.is_write = ((hsr & 1) == 0);
514 
515 	params.Op0 = 0;
516 	params.Op1 = (hsr >> 16) & 0xf;
517 	params.Op2 = 0;
518 	params.CRn = 0;
519 
520 	/*
521 	 * Massive hack here. Store Rt2 in the top 32bits so we only
522 	 * have one register to deal with. As we use the same trap
523 	 * backends between AArch32 and AArch64, we get away with it.
524 	 */
525 	if (params.is_write) {
526 		u64 val = *vcpu_reg(vcpu, params.Rt);
527 		val &= 0xffffffff;
528 		val |= *vcpu_reg(vcpu, Rt2) << 32;
529 		*vcpu_reg(vcpu, params.Rt) = val;
530 	}
531 
532 	emulate_cp15(vcpu, &params);
533 
534 	/* Do the opposite hack for the read side */
535 	if (!params.is_write) {
536 		u64 val = *vcpu_reg(vcpu, params.Rt);
537 		val >>= 32;
538 		*vcpu_reg(vcpu, Rt2) = val;
539 	}
540 
541 	return 1;
542 }
543 
544 /**
545  * kvm_handle_cp15_32 -- handles a mrc/mcr trap on a guest CP15 access
546  * @vcpu: The VCPU pointer
547  * @run:  The kvm_run struct
548  */
549 int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
550 {
551 	struct sys_reg_params params;
552 	u32 hsr = kvm_vcpu_get_hsr(vcpu);
553 
554 	params.is_aarch32 = true;
555 	params.is_32bit = true;
556 	params.CRm = (hsr >> 1) & 0xf;
557 	params.Rt  = (hsr >> 5) & 0xf;
558 	params.is_write = ((hsr & 1) == 0);
559 	params.CRn = (hsr >> 10) & 0xf;
560 	params.Op0 = 0;
561 	params.Op1 = (hsr >> 14) & 0x7;
562 	params.Op2 = (hsr >> 17) & 0x7;
563 
564 	emulate_cp15(vcpu, &params);
565 	return 1;
566 }
567 
568 static int emulate_sys_reg(struct kvm_vcpu *vcpu,
569 			   const struct sys_reg_params *params)
570 {
571 	size_t num;
572 	const struct sys_reg_desc *table, *r;
573 
574 	table = get_target_table(vcpu->arch.target, true, &num);
575 
576 	/* Search target-specific then generic table. */
577 	r = find_reg(params, table, num);
578 	if (!r)
579 		r = find_reg(params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
580 
581 	if (likely(r)) {
582 		/*
583 		 * Not having an accessor means that we have
584 		 * configured a trap that we don't know how to
585 		 * handle. This certainly qualifies as a gross bug
586 		 * that should be fixed right away.
587 		 */
588 		BUG_ON(!r->access);
589 
590 		if (likely(r->access(vcpu, params, r))) {
591 			/* Skip instruction, since it was emulated */
592 			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
593 			return 1;
594 		}
595 		/* If access function fails, it should complain. */
596 	} else {
597 		kvm_err("Unsupported guest sys_reg access at: %lx\n",
598 			*vcpu_pc(vcpu));
599 		print_sys_reg_instr(params);
600 	}
601 	kvm_inject_undefined(vcpu);
602 	return 1;
603 }
604 
605 static void reset_sys_reg_descs(struct kvm_vcpu *vcpu,
606 			      const struct sys_reg_desc *table, size_t num)
607 {
608 	unsigned long i;
609 
610 	for (i = 0; i < num; i++)
611 		if (table[i].reset)
612 			table[i].reset(vcpu, &table[i]);
613 }
614 
615 /**
616  * kvm_handle_sys_reg -- handles a mrs/msr trap on a guest sys_reg access
617  * @vcpu: The VCPU pointer
618  * @run:  The kvm_run struct
619  */
620 int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run)
621 {
622 	struct sys_reg_params params;
623 	unsigned long esr = kvm_vcpu_get_hsr(vcpu);
624 
625 	params.is_aarch32 = false;
626 	params.is_32bit = false;
627 	params.Op0 = (esr >> 20) & 3;
628 	params.Op1 = (esr >> 14) & 0x7;
629 	params.CRn = (esr >> 10) & 0xf;
630 	params.CRm = (esr >> 1) & 0xf;
631 	params.Op2 = (esr >> 17) & 0x7;
632 	params.Rt = (esr >> 5) & 0x1f;
633 	params.is_write = !(esr & 1);
634 
635 	return emulate_sys_reg(vcpu, &params);
636 }
637 
638 /******************************************************************************
639  * Userspace API
640  *****************************************************************************/
641 
642 static bool index_to_params(u64 id, struct sys_reg_params *params)
643 {
644 	switch (id & KVM_REG_SIZE_MASK) {
645 	case KVM_REG_SIZE_U64:
646 		/* Any unused index bits means it's not valid. */
647 		if (id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK
648 			      | KVM_REG_ARM_COPROC_MASK
649 			      | KVM_REG_ARM64_SYSREG_OP0_MASK
650 			      | KVM_REG_ARM64_SYSREG_OP1_MASK
651 			      | KVM_REG_ARM64_SYSREG_CRN_MASK
652 			      | KVM_REG_ARM64_SYSREG_CRM_MASK
653 			      | KVM_REG_ARM64_SYSREG_OP2_MASK))
654 			return false;
655 		params->Op0 = ((id & KVM_REG_ARM64_SYSREG_OP0_MASK)
656 			       >> KVM_REG_ARM64_SYSREG_OP0_SHIFT);
657 		params->Op1 = ((id & KVM_REG_ARM64_SYSREG_OP1_MASK)
658 			       >> KVM_REG_ARM64_SYSREG_OP1_SHIFT);
659 		params->CRn = ((id & KVM_REG_ARM64_SYSREG_CRN_MASK)
660 			       >> KVM_REG_ARM64_SYSREG_CRN_SHIFT);
661 		params->CRm = ((id & KVM_REG_ARM64_SYSREG_CRM_MASK)
662 			       >> KVM_REG_ARM64_SYSREG_CRM_SHIFT);
663 		params->Op2 = ((id & KVM_REG_ARM64_SYSREG_OP2_MASK)
664 			       >> KVM_REG_ARM64_SYSREG_OP2_SHIFT);
665 		return true;
666 	default:
667 		return false;
668 	}
669 }
670 
671 /* Decode an index value, and find the sys_reg_desc entry. */
672 static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
673 						    u64 id)
674 {
675 	size_t num;
676 	const struct sys_reg_desc *table, *r;
677 	struct sys_reg_params params;
678 
679 	/* We only do sys_reg for now. */
680 	if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
681 		return NULL;
682 
683 	if (!index_to_params(id, &params))
684 		return NULL;
685 
686 	table = get_target_table(vcpu->arch.target, true, &num);
687 	r = find_reg(&params, table, num);
688 	if (!r)
689 		r = find_reg(&params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
690 
691 	/* Not saved in the sys_reg array? */
692 	if (r && !r->reg)
693 		r = NULL;
694 
695 	return r;
696 }
697 
698 /*
699  * These are the invariant sys_reg registers: we let the guest see the
700  * host versions of these, so they're part of the guest state.
701  *
702  * A future CPU may provide a mechanism to present different values to
703  * the guest, or a future kvm may trap them.
704  */
705 
706 #define FUNCTION_INVARIANT(reg)						\
707 	static void get_##reg(struct kvm_vcpu *v,			\
708 			      const struct sys_reg_desc *r)		\
709 	{								\
710 		u64 val;						\
711 									\
712 		asm volatile("mrs %0, " __stringify(reg) "\n"		\
713 			     : "=r" (val));				\
714 		((struct sys_reg_desc *)r)->val = val;			\
715 	}
716 
717 FUNCTION_INVARIANT(midr_el1)
718 FUNCTION_INVARIANT(ctr_el0)
719 FUNCTION_INVARIANT(revidr_el1)
720 FUNCTION_INVARIANT(id_pfr0_el1)
721 FUNCTION_INVARIANT(id_pfr1_el1)
722 FUNCTION_INVARIANT(id_dfr0_el1)
723 FUNCTION_INVARIANT(id_afr0_el1)
724 FUNCTION_INVARIANT(id_mmfr0_el1)
725 FUNCTION_INVARIANT(id_mmfr1_el1)
726 FUNCTION_INVARIANT(id_mmfr2_el1)
727 FUNCTION_INVARIANT(id_mmfr3_el1)
728 FUNCTION_INVARIANT(id_isar0_el1)
729 FUNCTION_INVARIANT(id_isar1_el1)
730 FUNCTION_INVARIANT(id_isar2_el1)
731 FUNCTION_INVARIANT(id_isar3_el1)
732 FUNCTION_INVARIANT(id_isar4_el1)
733 FUNCTION_INVARIANT(id_isar5_el1)
734 FUNCTION_INVARIANT(clidr_el1)
735 FUNCTION_INVARIANT(aidr_el1)
736 
737 /* ->val is filled in by kvm_sys_reg_table_init() */
738 static struct sys_reg_desc invariant_sys_regs[] = {
739 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b000),
740 	  NULL, get_midr_el1 },
741 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b110),
742 	  NULL, get_revidr_el1 },
743 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b000),
744 	  NULL, get_id_pfr0_el1 },
745 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b001),
746 	  NULL, get_id_pfr1_el1 },
747 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b010),
748 	  NULL, get_id_dfr0_el1 },
749 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b011),
750 	  NULL, get_id_afr0_el1 },
751 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b100),
752 	  NULL, get_id_mmfr0_el1 },
753 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b101),
754 	  NULL, get_id_mmfr1_el1 },
755 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b110),
756 	  NULL, get_id_mmfr2_el1 },
757 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b111),
758 	  NULL, get_id_mmfr3_el1 },
759 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b000),
760 	  NULL, get_id_isar0_el1 },
761 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b001),
762 	  NULL, get_id_isar1_el1 },
763 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b010),
764 	  NULL, get_id_isar2_el1 },
765 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b011),
766 	  NULL, get_id_isar3_el1 },
767 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b100),
768 	  NULL, get_id_isar4_el1 },
769 	{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b101),
770 	  NULL, get_id_isar5_el1 },
771 	{ Op0(0b11), Op1(0b001), CRn(0b0000), CRm(0b0000), Op2(0b001),
772 	  NULL, get_clidr_el1 },
773 	{ Op0(0b11), Op1(0b001), CRn(0b0000), CRm(0b0000), Op2(0b111),
774 	  NULL, get_aidr_el1 },
775 	{ Op0(0b11), Op1(0b011), CRn(0b0000), CRm(0b0000), Op2(0b001),
776 	  NULL, get_ctr_el0 },
777 };
778 
779 static int reg_from_user(void *val, const void __user *uaddr, u64 id)
780 {
781 	/* This Just Works because we are little endian. */
782 	if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
783 		return -EFAULT;
784 	return 0;
785 }
786 
787 static int reg_to_user(void __user *uaddr, const void *val, u64 id)
788 {
789 	/* This Just Works because we are little endian. */
790 	if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
791 		return -EFAULT;
792 	return 0;
793 }
794 
795 static int get_invariant_sys_reg(u64 id, void __user *uaddr)
796 {
797 	struct sys_reg_params params;
798 	const struct sys_reg_desc *r;
799 
800 	if (!index_to_params(id, &params))
801 		return -ENOENT;
802 
803 	r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
804 	if (!r)
805 		return -ENOENT;
806 
807 	return reg_to_user(uaddr, &r->val, id);
808 }
809 
810 static int set_invariant_sys_reg(u64 id, void __user *uaddr)
811 {
812 	struct sys_reg_params params;
813 	const struct sys_reg_desc *r;
814 	int err;
815 	u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
816 
817 	if (!index_to_params(id, &params))
818 		return -ENOENT;
819 	r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
820 	if (!r)
821 		return -ENOENT;
822 
823 	err = reg_from_user(&val, uaddr, id);
824 	if (err)
825 		return err;
826 
827 	/* This is what we mean by invariant: you can't change it. */
828 	if (r->val != val)
829 		return -EINVAL;
830 
831 	return 0;
832 }
833 
834 static bool is_valid_cache(u32 val)
835 {
836 	u32 level, ctype;
837 
838 	if (val >= CSSELR_MAX)
839 		return -ENOENT;
840 
841 	/* Bottom bit is Instruction or Data bit.  Next 3 bits are level. */
842 	level = (val >> 1);
843 	ctype = (cache_levels >> (level * 3)) & 7;
844 
845 	switch (ctype) {
846 	case 0: /* No cache */
847 		return false;
848 	case 1: /* Instruction cache only */
849 		return (val & 1);
850 	case 2: /* Data cache only */
851 	case 4: /* Unified cache */
852 		return !(val & 1);
853 	case 3: /* Separate instruction and data caches */
854 		return true;
855 	default: /* Reserved: we can't know instruction or data. */
856 		return false;
857 	}
858 }
859 
860 static int demux_c15_get(u64 id, void __user *uaddr)
861 {
862 	u32 val;
863 	u32 __user *uval = uaddr;
864 
865 	/* Fail if we have unknown bits set. */
866 	if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
867 		   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
868 		return -ENOENT;
869 
870 	switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
871 	case KVM_REG_ARM_DEMUX_ID_CCSIDR:
872 		if (KVM_REG_SIZE(id) != 4)
873 			return -ENOENT;
874 		val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
875 			>> KVM_REG_ARM_DEMUX_VAL_SHIFT;
876 		if (!is_valid_cache(val))
877 			return -ENOENT;
878 
879 		return put_user(get_ccsidr(val), uval);
880 	default:
881 		return -ENOENT;
882 	}
883 }
884 
885 static int demux_c15_set(u64 id, void __user *uaddr)
886 {
887 	u32 val, newval;
888 	u32 __user *uval = uaddr;
889 
890 	/* Fail if we have unknown bits set. */
891 	if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
892 		   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
893 		return -ENOENT;
894 
895 	switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
896 	case KVM_REG_ARM_DEMUX_ID_CCSIDR:
897 		if (KVM_REG_SIZE(id) != 4)
898 			return -ENOENT;
899 		val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
900 			>> KVM_REG_ARM_DEMUX_VAL_SHIFT;
901 		if (!is_valid_cache(val))
902 			return -ENOENT;
903 
904 		if (get_user(newval, uval))
905 			return -EFAULT;
906 
907 		/* This is also invariant: you can't change it. */
908 		if (newval != get_ccsidr(val))
909 			return -EINVAL;
910 		return 0;
911 	default:
912 		return -ENOENT;
913 	}
914 }
915 
916 int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
917 {
918 	const struct sys_reg_desc *r;
919 	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
920 
921 	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
922 		return demux_c15_get(reg->id, uaddr);
923 
924 	if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
925 		return -ENOENT;
926 
927 	r = index_to_sys_reg_desc(vcpu, reg->id);
928 	if (!r)
929 		return get_invariant_sys_reg(reg->id, uaddr);
930 
931 	return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
932 }
933 
934 int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
935 {
936 	const struct sys_reg_desc *r;
937 	void __user *uaddr = (void __user *)(unsigned long)reg->addr;
938 
939 	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
940 		return demux_c15_set(reg->id, uaddr);
941 
942 	if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
943 		return -ENOENT;
944 
945 	r = index_to_sys_reg_desc(vcpu, reg->id);
946 	if (!r)
947 		return set_invariant_sys_reg(reg->id, uaddr);
948 
949 	return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
950 }
951 
952 static unsigned int num_demux_regs(void)
953 {
954 	unsigned int i, count = 0;
955 
956 	for (i = 0; i < CSSELR_MAX; i++)
957 		if (is_valid_cache(i))
958 			count++;
959 
960 	return count;
961 }
962 
963 static int write_demux_regids(u64 __user *uindices)
964 {
965 	u64 val = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_DEMUX;
966 	unsigned int i;
967 
968 	val |= KVM_REG_ARM_DEMUX_ID_CCSIDR;
969 	for (i = 0; i < CSSELR_MAX; i++) {
970 		if (!is_valid_cache(i))
971 			continue;
972 		if (put_user(val | i, uindices))
973 			return -EFAULT;
974 		uindices++;
975 	}
976 	return 0;
977 }
978 
979 static u64 sys_reg_to_index(const struct sys_reg_desc *reg)
980 {
981 	return (KVM_REG_ARM64 | KVM_REG_SIZE_U64 |
982 		KVM_REG_ARM64_SYSREG |
983 		(reg->Op0 << KVM_REG_ARM64_SYSREG_OP0_SHIFT) |
984 		(reg->Op1 << KVM_REG_ARM64_SYSREG_OP1_SHIFT) |
985 		(reg->CRn << KVM_REG_ARM64_SYSREG_CRN_SHIFT) |
986 		(reg->CRm << KVM_REG_ARM64_SYSREG_CRM_SHIFT) |
987 		(reg->Op2 << KVM_REG_ARM64_SYSREG_OP2_SHIFT));
988 }
989 
990 static bool copy_reg_to_user(const struct sys_reg_desc *reg, u64 __user **uind)
991 {
992 	if (!*uind)
993 		return true;
994 
995 	if (put_user(sys_reg_to_index(reg), *uind))
996 		return false;
997 
998 	(*uind)++;
999 	return true;
1000 }
1001 
1002 /* Assumed ordered tables, see kvm_sys_reg_table_init. */
1003 static int walk_sys_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
1004 {
1005 	const struct sys_reg_desc *i1, *i2, *end1, *end2;
1006 	unsigned int total = 0;
1007 	size_t num;
1008 
1009 	/* We check for duplicates here, to allow arch-specific overrides. */
1010 	i1 = get_target_table(vcpu->arch.target, true, &num);
1011 	end1 = i1 + num;
1012 	i2 = sys_reg_descs;
1013 	end2 = sys_reg_descs + ARRAY_SIZE(sys_reg_descs);
1014 
1015 	BUG_ON(i1 == end1 || i2 == end2);
1016 
1017 	/* Walk carefully, as both tables may refer to the same register. */
1018 	while (i1 || i2) {
1019 		int cmp = cmp_sys_reg(i1, i2);
1020 		/* target-specific overrides generic entry. */
1021 		if (cmp <= 0) {
1022 			/* Ignore registers we trap but don't save. */
1023 			if (i1->reg) {
1024 				if (!copy_reg_to_user(i1, &uind))
1025 					return -EFAULT;
1026 				total++;
1027 			}
1028 		} else {
1029 			/* Ignore registers we trap but don't save. */
1030 			if (i2->reg) {
1031 				if (!copy_reg_to_user(i2, &uind))
1032 					return -EFAULT;
1033 				total++;
1034 			}
1035 		}
1036 
1037 		if (cmp <= 0 && ++i1 == end1)
1038 			i1 = NULL;
1039 		if (cmp >= 0 && ++i2 == end2)
1040 			i2 = NULL;
1041 	}
1042 	return total;
1043 }
1044 
1045 unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu)
1046 {
1047 	return ARRAY_SIZE(invariant_sys_regs)
1048 		+ num_demux_regs()
1049 		+ walk_sys_regs(vcpu, (u64 __user *)NULL);
1050 }
1051 
1052 int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
1053 {
1054 	unsigned int i;
1055 	int err;
1056 
1057 	/* Then give them all the invariant registers' indices. */
1058 	for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++) {
1059 		if (put_user(sys_reg_to_index(&invariant_sys_regs[i]), uindices))
1060 			return -EFAULT;
1061 		uindices++;
1062 	}
1063 
1064 	err = walk_sys_regs(vcpu, uindices);
1065 	if (err < 0)
1066 		return err;
1067 	uindices += err;
1068 
1069 	return write_demux_regids(uindices);
1070 }
1071 
1072 void kvm_sys_reg_table_init(void)
1073 {
1074 	unsigned int i;
1075 	struct sys_reg_desc clidr;
1076 
1077 	/* Make sure tables are unique and in order. */
1078 	for (i = 1; i < ARRAY_SIZE(sys_reg_descs); i++)
1079 		BUG_ON(cmp_sys_reg(&sys_reg_descs[i-1], &sys_reg_descs[i]) >= 0);
1080 
1081 	/* We abuse the reset function to overwrite the table itself. */
1082 	for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++)
1083 		invariant_sys_regs[i].reset(NULL, &invariant_sys_regs[i]);
1084 
1085 	/*
1086 	 * CLIDR format is awkward, so clean it up.  See ARM B4.1.20:
1087 	 *
1088 	 *   If software reads the Cache Type fields from Ctype1
1089 	 *   upwards, once it has seen a value of 0b000, no caches
1090 	 *   exist at further-out levels of the hierarchy. So, for
1091 	 *   example, if Ctype3 is the first Cache Type field with a
1092 	 *   value of 0b000, the values of Ctype4 to Ctype7 must be
1093 	 *   ignored.
1094 	 */
1095 	get_clidr_el1(NULL, &clidr); /* Ugly... */
1096 	cache_levels = clidr.val;
1097 	for (i = 0; i < 7; i++)
1098 		if (((cache_levels >> (i*3)) & 7) == 0)
1099 			break;
1100 	/* Clear all higher bits. */
1101 	cache_levels &= (1 << (i*3))-1;
1102 }
1103 
1104 /**
1105  * kvm_reset_sys_regs - sets system registers to reset value
1106  * @vcpu: The VCPU pointer
1107  *
1108  * This function finds the right table above and sets the registers on the
1109  * virtual CPU struct to their architecturally defined reset values.
1110  */
1111 void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
1112 {
1113 	size_t num;
1114 	const struct sys_reg_desc *table;
1115 
1116 	/* Catch someone adding a register without putting in reset entry. */
1117 	memset(&vcpu->arch.ctxt.sys_regs, 0x42, sizeof(vcpu->arch.ctxt.sys_regs));
1118 
1119 	/* Generic chip reset first (so target could override). */
1120 	reset_sys_reg_descs(vcpu, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
1121 
1122 	table = get_target_table(vcpu->arch.target, true, &num);
1123 	reset_sys_reg_descs(vcpu, table, num);
1124 
1125 	for (num = 1; num < NR_SYS_REGS; num++)
1126 		if (vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
1127 			panic("Didn't reset vcpu_sys_reg(%zi)", num);
1128 }
1129