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
26void 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
63u32 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
75static 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
128static 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. */
194int kvmppc_emulate_instruction(struct kvm_vcpu *vcpu)
195{
196	u32 inst;
197	ppc_inst_t pinst;
198	int rs, rt, sprn;
199	enum emulation_result emulated;
200	int advance = 1;
201
202	/* this default type might be overwritten by subcategories */
203	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
204
205	emulated = kvmppc_get_last_inst(vcpu, INST_GENERIC, &pinst);
206	inst = ppc_inst_val(pinst);
207	if (emulated != EMULATE_DONE)
208		return emulated;
209
210	pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
211
212	rs = get_rs(inst);
213	rt = get_rt(inst);
214	sprn = get_sprn(inst);
215
216	switch (get_op(inst)) {
217	case OP_TRAP:
218#ifdef CONFIG_PPC_BOOK3S
219	case OP_TRAP_64:
220		kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
221#else
222		kvmppc_core_queue_program(vcpu,
223					  vcpu->arch.shared->esr | ESR_PTR);
224#endif
225		advance = 0;
226		break;
227
228	case 31:
229		switch (get_xop(inst)) {
230
231		case OP_31_XOP_TRAP:
232#ifdef CONFIG_64BIT
233		case OP_31_XOP_TRAP_64:
234#endif
235#ifdef CONFIG_PPC_BOOK3S
236			kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
237#else
238			kvmppc_core_queue_program(vcpu,
239					vcpu->arch.shared->esr | ESR_PTR);
240#endif
241			advance = 0;
242			break;
243
244		case OP_31_XOP_MFSPR:
245			emulated = kvmppc_emulate_mfspr(vcpu, sprn, rt);
246			if (emulated == EMULATE_AGAIN) {
247				emulated = EMULATE_DONE;
248				advance = 0;
249			}
250			break;
251
252		case OP_31_XOP_MTSPR:
253			emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
254			if (emulated == EMULATE_AGAIN) {
255				emulated = EMULATE_DONE;
256				advance = 0;
257			}
258			break;
259
260		case OP_31_XOP_TLBSYNC:
261			break;
262
263		default:
264			/* Attempt core-specific emulation below. */
265			emulated = EMULATE_FAIL;
266		}
267		break;
268
269	case 0:
270		/*
271		 * Instruction with primary opcode 0. Based on PowerISA
272		 * these are illegal instructions.
273		 */
274		if (inst == KVMPPC_INST_SW_BREAKPOINT) {
275			vcpu->run->exit_reason = KVM_EXIT_DEBUG;
276			vcpu->run->debug.arch.status = 0;
277			vcpu->run->debug.arch.address = kvmppc_get_pc(vcpu);
278			emulated = EMULATE_EXIT_USER;
279			advance = 0;
280		} else
281			emulated = EMULATE_FAIL;
282
283		break;
284
285	default:
286		emulated = EMULATE_FAIL;
287	}
288
289	if (emulated == EMULATE_FAIL) {
290		emulated = vcpu->kvm->arch.kvm_ops->emulate_op(vcpu, inst,
291							       &advance);
292		if (emulated == EMULATE_AGAIN) {
293			advance = 0;
294		} else if (emulated == EMULATE_FAIL) {
295			advance = 0;
296			printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
297			       "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
298		}
299	}
300
301	trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
302
303	/* Advance past emulated instruction. */
304	/*
305	 * If this ever handles prefixed instructions, the 4
306	 * will need to become ppc_inst_len(pinst) instead.
307	 */
308	if (advance)
309		kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
310
311	return emulated;
312}
313EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);
314