1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  * Copyright IBM Corp. 2007
5  * Copyright 2011 Freescale Semiconductor, Inc.
6  *
7  * Authors: Hollis Blanchard <hollisb@us.ibm.com>
8  */
9 
10 #include <linux/jiffies.h>
11 #include <linux/hrtimer.h>
12 #include <linux/types.h>
13 #include <linux/string.h>
14 #include <linux/kvm_host.h>
15 #include <linux/clockchips.h>
16 
17 #include <asm/reg.h>
18 #include <asm/time.h>
19 #include <asm/byteorder.h>
20 #include <asm/kvm_ppc.h>
21 #include <asm/disassemble.h>
22 #include <asm/ppc-opcode.h>
23 #include "timing.h"
24 #include "trace.h"
25 
kvmppc_emulate_dec(struct kvm_vcpu * vcpu)26 void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
27 {
28 	unsigned long dec_nsec;
29 	unsigned long long dec_time;
30 
31 	pr_debug("mtDEC: %lx\n", vcpu->arch.dec);
32 	hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
33 
34 #ifdef CONFIG_PPC_BOOK3S
35 	/* mtdec lowers the interrupt line when positive. */
36 	kvmppc_core_dequeue_dec(vcpu);
37 #endif
38 
39 #ifdef CONFIG_BOOKE
40 	/* On BOOKE, DEC = 0 is as good as decrementer not enabled */
41 	if (vcpu->arch.dec == 0)
42 		return;
43 #endif
44 
45 	/*
46 	 * The decrementer ticks at the same rate as the timebase, so
47 	 * that's how we convert the guest DEC value to the number of
48 	 * host ticks.
49 	 */
50 
51 	dec_time = vcpu->arch.dec;
52 	/*
53 	 * Guest timebase ticks at the same frequency as host timebase.
54 	 * So use the host timebase calculations for decrementer emulation.
55 	 */
56 	dec_time = tb_to_ns(dec_time);
57 	dec_nsec = do_div(dec_time, NSEC_PER_SEC);
58 	hrtimer_start(&vcpu->arch.dec_timer,
59 		ktime_set(dec_time, dec_nsec), HRTIMER_MODE_REL);
60 	vcpu->arch.dec_jiffies = get_tb();
61 }
62 
kvmppc_get_dec(struct kvm_vcpu * vcpu,u64 tb)63 u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb)
64 {
65 	u64 jd = tb - vcpu->arch.dec_jiffies;
66 
67 #ifdef CONFIG_BOOKE
68 	if (vcpu->arch.dec < jd)
69 		return 0;
70 #endif
71 
72 	return vcpu->arch.dec - jd;
73 }
74 
kvmppc_emulate_mtspr(struct kvm_vcpu * vcpu,int sprn,int rs)75 static int kvmppc_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
76 {
77 	enum emulation_result emulated = EMULATE_DONE;
78 	ulong spr_val = kvmppc_get_gpr(vcpu, rs);
79 
80 	switch (sprn) {
81 	case SPRN_SRR0:
82 		kvmppc_set_srr0(vcpu, spr_val);
83 		break;
84 	case SPRN_SRR1:
85 		kvmppc_set_srr1(vcpu, spr_val);
86 		break;
87 
88 	/* XXX We need to context-switch the timebase for
89 	 * watchdog and FIT. */
90 	case SPRN_TBWL: break;
91 	case SPRN_TBWU: break;
92 
93 	case SPRN_DEC:
94 		vcpu->arch.dec = (u32) spr_val;
95 		kvmppc_emulate_dec(vcpu);
96 		break;
97 
98 	case SPRN_SPRG0:
99 		kvmppc_set_sprg0(vcpu, spr_val);
100 		break;
101 	case SPRN_SPRG1:
102 		kvmppc_set_sprg1(vcpu, spr_val);
103 		break;
104 	case SPRN_SPRG2:
105 		kvmppc_set_sprg2(vcpu, spr_val);
106 		break;
107 	case SPRN_SPRG3:
108 		kvmppc_set_sprg3(vcpu, spr_val);
109 		break;
110 
111 	/* PIR can legally be written, but we ignore it */
112 	case SPRN_PIR: break;
113 
114 	default:
115 		emulated = vcpu->kvm->arch.kvm_ops->emulate_mtspr(vcpu, sprn,
116 								  spr_val);
117 		if (emulated == EMULATE_FAIL)
118 			printk(KERN_INFO "mtspr: unknown spr "
119 				"0x%x\n", sprn);
120 		break;
121 	}
122 
123 	kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
124 
125 	return emulated;
126 }
127 
kvmppc_emulate_mfspr(struct kvm_vcpu * vcpu,int sprn,int rt)128 static int kvmppc_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt)
129 {
130 	enum emulation_result emulated = EMULATE_DONE;
131 	ulong spr_val = 0;
132 
133 	switch (sprn) {
134 	case SPRN_SRR0:
135 		spr_val = kvmppc_get_srr0(vcpu);
136 		break;
137 	case SPRN_SRR1:
138 		spr_val = kvmppc_get_srr1(vcpu);
139 		break;
140 	case SPRN_PVR:
141 		spr_val = vcpu->arch.pvr;
142 		break;
143 	case SPRN_PIR:
144 		spr_val = vcpu->vcpu_id;
145 		break;
146 
147 	/* Note: mftb and TBRL/TBWL are user-accessible, so
148 	 * the guest can always access the real TB anyways.
149 	 * In fact, we probably will never see these traps. */
150 	case SPRN_TBWL:
151 		spr_val = get_tb() >> 32;
152 		break;
153 	case SPRN_TBWU:
154 		spr_val = get_tb();
155 		break;
156 
157 	case SPRN_SPRG0:
158 		spr_val = kvmppc_get_sprg0(vcpu);
159 		break;
160 	case SPRN_SPRG1:
161 		spr_val = kvmppc_get_sprg1(vcpu);
162 		break;
163 	case SPRN_SPRG2:
164 		spr_val = kvmppc_get_sprg2(vcpu);
165 		break;
166 	case SPRN_SPRG3:
167 		spr_val = kvmppc_get_sprg3(vcpu);
168 		break;
169 	/* Note: SPRG4-7 are user-readable, so we don't get
170 	 * a trap. */
171 
172 	case SPRN_DEC:
173 		spr_val = kvmppc_get_dec(vcpu, get_tb());
174 		break;
175 	default:
176 		emulated = vcpu->kvm->arch.kvm_ops->emulate_mfspr(vcpu, sprn,
177 								  &spr_val);
178 		if (unlikely(emulated == EMULATE_FAIL)) {
179 			printk(KERN_INFO "mfspr: unknown spr "
180 				"0x%x\n", sprn);
181 		}
182 		break;
183 	}
184 
185 	if (emulated == EMULATE_DONE)
186 		kvmppc_set_gpr(vcpu, rt, spr_val);
187 	kvmppc_set_exit_type(vcpu, EMULATED_MFSPR_EXITS);
188 
189 	return emulated;
190 }
191 
192 /* XXX Should probably auto-generate instruction decoding for a particular core
193  * from opcode tables in the future. */
kvmppc_emulate_instruction(struct kvm_vcpu * vcpu)194 int kvmppc_emulate_instruction(struct kvm_vcpu *vcpu)
195 {
196 	u32 inst;
197 	int rs, rt, sprn;
198 	enum emulation_result emulated;
199 	int advance = 1;
200 
201 	/* this default type might be overwritten by subcategories */
202 	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
203 
204 	emulated = kvmppc_get_last_inst(vcpu, INST_GENERIC, &inst);
205 	if (emulated != EMULATE_DONE)
206 		return emulated;
207 
208 	pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
209 
210 	rs = get_rs(inst);
211 	rt = get_rt(inst);
212 	sprn = get_sprn(inst);
213 
214 	switch (get_op(inst)) {
215 	case OP_TRAP:
216 #ifdef CONFIG_PPC_BOOK3S
217 	case OP_TRAP_64:
218 		kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
219 #else
220 		kvmppc_core_queue_program(vcpu,
221 					  vcpu->arch.shared->esr | ESR_PTR);
222 #endif
223 		advance = 0;
224 		break;
225 
226 	case 31:
227 		switch (get_xop(inst)) {
228 
229 		case OP_31_XOP_TRAP:
230 #ifdef CONFIG_64BIT
231 		case OP_31_XOP_TRAP_64:
232 #endif
233 #ifdef CONFIG_PPC_BOOK3S
234 			kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
235 #else
236 			kvmppc_core_queue_program(vcpu,
237 					vcpu->arch.shared->esr | ESR_PTR);
238 #endif
239 			advance = 0;
240 			break;
241 
242 		case OP_31_XOP_MFSPR:
243 			emulated = kvmppc_emulate_mfspr(vcpu, sprn, rt);
244 			if (emulated == EMULATE_AGAIN) {
245 				emulated = EMULATE_DONE;
246 				advance = 0;
247 			}
248 			break;
249 
250 		case OP_31_XOP_MTSPR:
251 			emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
252 			if (emulated == EMULATE_AGAIN) {
253 				emulated = EMULATE_DONE;
254 				advance = 0;
255 			}
256 			break;
257 
258 		case OP_31_XOP_TLBSYNC:
259 			break;
260 
261 		default:
262 			/* Attempt core-specific emulation below. */
263 			emulated = EMULATE_FAIL;
264 		}
265 		break;
266 
267 	case 0:
268 		/*
269 		 * Instruction with primary opcode 0. Based on PowerISA
270 		 * these are illegal instructions.
271 		 */
272 		if (inst == KVMPPC_INST_SW_BREAKPOINT) {
273 			vcpu->run->exit_reason = KVM_EXIT_DEBUG;
274 			vcpu->run->debug.arch.status = 0;
275 			vcpu->run->debug.arch.address = kvmppc_get_pc(vcpu);
276 			emulated = EMULATE_EXIT_USER;
277 			advance = 0;
278 		} else
279 			emulated = EMULATE_FAIL;
280 
281 		break;
282 
283 	default:
284 		emulated = EMULATE_FAIL;
285 	}
286 
287 	if (emulated == EMULATE_FAIL) {
288 		emulated = vcpu->kvm->arch.kvm_ops->emulate_op(vcpu, inst,
289 							       &advance);
290 		if (emulated == EMULATE_AGAIN) {
291 			advance = 0;
292 		} else if (emulated == EMULATE_FAIL) {
293 			advance = 0;
294 			printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
295 			       "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
296 		}
297 	}
298 
299 	trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
300 
301 	/* Advance past emulated instruction. */
302 	if (advance)
303 		kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
304 
305 	return emulated;
306 }
307 EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);
308