xref: /openbmc/linux/arch/powerpc/kernel/kvm_emul.S (revision a20eefae)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 *
4 * Copyright SUSE Linux Products GmbH 2010
5 * Copyright 2010-2011 Freescale Semiconductor, Inc.
6 *
7 * Authors: Alexander Graf <agraf@suse.de>
8 */
9
10#include <asm/ppc_asm.h>
11#include <asm/kvm_asm.h>
12#include <asm/reg.h>
13#include <asm/page.h>
14#include <asm/asm-offsets.h>
15#include <asm/asm-compat.h>
16
17#define KVM_MAGIC_PAGE		(-4096)
18
19#ifdef CONFIG_64BIT
20#define LL64(reg, offs, reg2)	ld	reg, (offs)(reg2)
21#define STL64(reg, offs, reg2)	std	reg, (offs)(reg2)
22#else
23#define LL64(reg, offs, reg2)	lwz	reg, (offs + 4)(reg2)
24#define STL64(reg, offs, reg2)	stw	reg, (offs + 4)(reg2)
25#endif
26
27#define SCRATCH_SAVE							\
28	/* Enable critical section. We are critical if			\
29	   shared->critical == r1 */					\
30	STL64(r1, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0);		\
31									\
32	/* Save state */						\
33	PPC_STL	r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH1)(0);		\
34	PPC_STL	r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH2)(0);		\
35	mfcr	r31;							\
36	stw	r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH3)(0);
37
38#define SCRATCH_RESTORE							\
39	/* Restore state */						\
40	PPC_LL	r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH1)(0);		\
41	lwz	r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH3)(0);		\
42	mtcr	r30;							\
43	PPC_LL	r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH2)(0);		\
44									\
45	/* Disable critical section. We are critical if			\
46	   shared->critical == r1 and r2 is always != r1 */		\
47	STL64(r2, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0);
48
49.global kvm_template_start
50kvm_template_start:
51
52.global kvm_emulate_mtmsrd
53kvm_emulate_mtmsrd:
54
55	SCRATCH_SAVE
56
57	/* Put MSR & ~(MSR_EE|MSR_RI) in r31 */
58	LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
59	lis	r30, (~(MSR_EE | MSR_RI))@h
60	ori	r30, r30, (~(MSR_EE | MSR_RI))@l
61	and	r31, r31, r30
62
63	/* OR the register's (MSR_EE|MSR_RI) on MSR */
64kvm_emulate_mtmsrd_reg:
65	ori	r30, r0, 0
66	andi.	r30, r30, (MSR_EE|MSR_RI)
67	or	r31, r31, r30
68
69	/* Put MSR back into magic page */
70	STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
71
72	/* Check if we have to fetch an interrupt */
73	lwz	r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
74	cmpwi	r31, 0
75	beq+	no_check
76
77	/* Check if we may trigger an interrupt */
78	andi.	r30, r30, MSR_EE
79	beq	no_check
80
81	SCRATCH_RESTORE
82
83	/* Nag hypervisor */
84kvm_emulate_mtmsrd_orig_ins:
85	tlbsync
86
87	b	kvm_emulate_mtmsrd_branch
88
89no_check:
90
91	SCRATCH_RESTORE
92
93	/* Go back to caller */
94kvm_emulate_mtmsrd_branch:
95	b	.
96kvm_emulate_mtmsrd_end:
97
98.global kvm_emulate_mtmsrd_branch_offs
99kvm_emulate_mtmsrd_branch_offs:
100	.long (kvm_emulate_mtmsrd_branch - kvm_emulate_mtmsrd) / 4
101
102.global kvm_emulate_mtmsrd_reg_offs
103kvm_emulate_mtmsrd_reg_offs:
104	.long (kvm_emulate_mtmsrd_reg - kvm_emulate_mtmsrd) / 4
105
106.global kvm_emulate_mtmsrd_orig_ins_offs
107kvm_emulate_mtmsrd_orig_ins_offs:
108	.long (kvm_emulate_mtmsrd_orig_ins - kvm_emulate_mtmsrd) / 4
109
110.global kvm_emulate_mtmsrd_len
111kvm_emulate_mtmsrd_len:
112	.long (kvm_emulate_mtmsrd_end - kvm_emulate_mtmsrd) / 4
113
114
115#define MSR_SAFE_BITS (MSR_EE | MSR_RI)
116#define MSR_CRITICAL_BITS ~MSR_SAFE_BITS
117
118.global kvm_emulate_mtmsr
119kvm_emulate_mtmsr:
120
121	SCRATCH_SAVE
122
123	/* Fetch old MSR in r31 */
124	LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
125
126	/* Find the changed bits between old and new MSR */
127kvm_emulate_mtmsr_reg1:
128	ori	r30, r0, 0
129	xor	r31, r30, r31
130
131	/* Check if we need to really do mtmsr */
132	LOAD_REG_IMMEDIATE(r30, MSR_CRITICAL_BITS)
133	and.	r31, r31, r30
134
135	/* No critical bits changed? Maybe we can stay in the guest. */
136	beq	maybe_stay_in_guest
137
138do_mtmsr:
139
140	SCRATCH_RESTORE
141
142	/* Just fire off the mtmsr if it's critical */
143kvm_emulate_mtmsr_orig_ins:
144	mtmsr	r0
145
146	b	kvm_emulate_mtmsr_branch
147
148maybe_stay_in_guest:
149
150	/* Get the target register in r30 */
151kvm_emulate_mtmsr_reg2:
152	ori	r30, r0, 0
153
154	/* Put MSR into magic page because we don't call mtmsr */
155	STL64(r30, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
156
157	/* Check if we have to fetch an interrupt */
158	lwz	r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
159	cmpwi	r31, 0
160	beq+	no_mtmsr
161
162	/* Check if we may trigger an interrupt */
163	andi.	r31, r30, MSR_EE
164	bne	do_mtmsr
165
166no_mtmsr:
167
168	SCRATCH_RESTORE
169
170	/* Go back to caller */
171kvm_emulate_mtmsr_branch:
172	b	.
173kvm_emulate_mtmsr_end:
174
175.global kvm_emulate_mtmsr_branch_offs
176kvm_emulate_mtmsr_branch_offs:
177	.long (kvm_emulate_mtmsr_branch - kvm_emulate_mtmsr) / 4
178
179.global kvm_emulate_mtmsr_reg1_offs
180kvm_emulate_mtmsr_reg1_offs:
181	.long (kvm_emulate_mtmsr_reg1 - kvm_emulate_mtmsr) / 4
182
183.global kvm_emulate_mtmsr_reg2_offs
184kvm_emulate_mtmsr_reg2_offs:
185	.long (kvm_emulate_mtmsr_reg2 - kvm_emulate_mtmsr) / 4
186
187.global kvm_emulate_mtmsr_orig_ins_offs
188kvm_emulate_mtmsr_orig_ins_offs:
189	.long (kvm_emulate_mtmsr_orig_ins - kvm_emulate_mtmsr) / 4
190
191.global kvm_emulate_mtmsr_len
192kvm_emulate_mtmsr_len:
193	.long (kvm_emulate_mtmsr_end - kvm_emulate_mtmsr) / 4
194
195/* also used for wrteei 1 */
196.global kvm_emulate_wrtee
197kvm_emulate_wrtee:
198
199	SCRATCH_SAVE
200
201	/* Fetch old MSR in r31 */
202	LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
203
204	/* Insert new MSR[EE] */
205kvm_emulate_wrtee_reg:
206	ori	r30, r0, 0
207	rlwimi	r31, r30, 0, MSR_EE
208
209	/*
210	 * If MSR[EE] is now set, check for a pending interrupt.
211	 * We could skip this if MSR[EE] was already on, but that
212	 * should be rare, so don't bother.
213	 */
214	andi.	r30, r30, MSR_EE
215
216	/* Put MSR into magic page because we don't call wrtee */
217	STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
218
219	beq	no_wrtee
220
221	/* Check if we have to fetch an interrupt */
222	lwz	r30, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
223	cmpwi	r30, 0
224	bne	do_wrtee
225
226no_wrtee:
227	SCRATCH_RESTORE
228
229	/* Go back to caller */
230kvm_emulate_wrtee_branch:
231	b	.
232
233do_wrtee:
234	SCRATCH_RESTORE
235
236	/* Just fire off the wrtee if it's critical */
237kvm_emulate_wrtee_orig_ins:
238	wrtee	r0
239
240	b	kvm_emulate_wrtee_branch
241
242kvm_emulate_wrtee_end:
243
244.global kvm_emulate_wrtee_branch_offs
245kvm_emulate_wrtee_branch_offs:
246	.long (kvm_emulate_wrtee_branch - kvm_emulate_wrtee) / 4
247
248.global kvm_emulate_wrtee_reg_offs
249kvm_emulate_wrtee_reg_offs:
250	.long (kvm_emulate_wrtee_reg - kvm_emulate_wrtee) / 4
251
252.global kvm_emulate_wrtee_orig_ins_offs
253kvm_emulate_wrtee_orig_ins_offs:
254	.long (kvm_emulate_wrtee_orig_ins - kvm_emulate_wrtee) / 4
255
256.global kvm_emulate_wrtee_len
257kvm_emulate_wrtee_len:
258	.long (kvm_emulate_wrtee_end - kvm_emulate_wrtee) / 4
259
260.global kvm_emulate_wrteei_0
261kvm_emulate_wrteei_0:
262	SCRATCH_SAVE
263
264	/* Fetch old MSR in r31 */
265	LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
266
267	/* Remove MSR_EE from old MSR */
268	rlwinm	r31, r31, 0, ~MSR_EE
269
270	/* Write new MSR value back */
271	STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
272
273	SCRATCH_RESTORE
274
275	/* Go back to caller */
276kvm_emulate_wrteei_0_branch:
277	b	.
278kvm_emulate_wrteei_0_end:
279
280.global kvm_emulate_wrteei_0_branch_offs
281kvm_emulate_wrteei_0_branch_offs:
282	.long (kvm_emulate_wrteei_0_branch - kvm_emulate_wrteei_0) / 4
283
284.global kvm_emulate_wrteei_0_len
285kvm_emulate_wrteei_0_len:
286	.long (kvm_emulate_wrteei_0_end - kvm_emulate_wrteei_0) / 4
287
288.global kvm_emulate_mtsrin
289kvm_emulate_mtsrin:
290
291	SCRATCH_SAVE
292
293	LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
294	andi.	r31, r31, MSR_DR | MSR_IR
295	beq	kvm_emulate_mtsrin_reg1
296
297	SCRATCH_RESTORE
298
299kvm_emulate_mtsrin_orig_ins:
300	nop
301	b	kvm_emulate_mtsrin_branch
302
303kvm_emulate_mtsrin_reg1:
304	/* rX >> 26 */
305	rlwinm  r30,r0,6,26,29
306
307kvm_emulate_mtsrin_reg2:
308	stw	r0, (KVM_MAGIC_PAGE + KVM_MAGIC_SR)(r30)
309
310	SCRATCH_RESTORE
311
312	/* Go back to caller */
313kvm_emulate_mtsrin_branch:
314	b	.
315kvm_emulate_mtsrin_end:
316
317.global kvm_emulate_mtsrin_branch_offs
318kvm_emulate_mtsrin_branch_offs:
319	.long (kvm_emulate_mtsrin_branch - kvm_emulate_mtsrin) / 4
320
321.global kvm_emulate_mtsrin_reg1_offs
322kvm_emulate_mtsrin_reg1_offs:
323	.long (kvm_emulate_mtsrin_reg1 - kvm_emulate_mtsrin) / 4
324
325.global kvm_emulate_mtsrin_reg2_offs
326kvm_emulate_mtsrin_reg2_offs:
327	.long (kvm_emulate_mtsrin_reg2 - kvm_emulate_mtsrin) / 4
328
329.global kvm_emulate_mtsrin_orig_ins_offs
330kvm_emulate_mtsrin_orig_ins_offs:
331	.long (kvm_emulate_mtsrin_orig_ins - kvm_emulate_mtsrin) / 4
332
333.global kvm_emulate_mtsrin_len
334kvm_emulate_mtsrin_len:
335	.long (kvm_emulate_mtsrin_end - kvm_emulate_mtsrin) / 4
336
337.global kvm_template_end
338kvm_template_end:
339