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/arch/powerpc/kvm/emulate.c

http://github.com/mirrors/linux
C | 307 lines | 225 code | 46 blank | 36 comment | 29 complexity | 3b00f2372f026a4fa9e0b92185785bc0 MD5 | raw file
  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_run *run, 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			run->exit_reason = KVM_EXIT_DEBUG;
274			run->debug.arch.status = 0;
275			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(run, 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}
307EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);