xref: /openbmc/linux/arch/riscv/kvm/vcpu_switch.S (revision 9f701326)
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2019 Western Digital Corporation or its affiliates.
4 *
5 * Authors:
6 *     Anup Patel <anup.patel@wdc.com>
7 */
8
9#include <linux/linkage.h>
10#include <asm/asm.h>
11#include <asm/asm-offsets.h>
12#include <asm/csr.h>
13
14	.text
15	.altmacro
16	.option norelax
17
18ENTRY(__kvm_riscv_switch_to)
19	/* Save Host GPRs (except A0 and T0-T6) */
20	REG_S	ra, (KVM_ARCH_HOST_RA)(a0)
21	REG_S	sp, (KVM_ARCH_HOST_SP)(a0)
22	REG_S	gp, (KVM_ARCH_HOST_GP)(a0)
23	REG_S	tp, (KVM_ARCH_HOST_TP)(a0)
24	REG_S	s0, (KVM_ARCH_HOST_S0)(a0)
25	REG_S	s1, (KVM_ARCH_HOST_S1)(a0)
26	REG_S	a1, (KVM_ARCH_HOST_A1)(a0)
27	REG_S	a2, (KVM_ARCH_HOST_A2)(a0)
28	REG_S	a3, (KVM_ARCH_HOST_A3)(a0)
29	REG_S	a4, (KVM_ARCH_HOST_A4)(a0)
30	REG_S	a5, (KVM_ARCH_HOST_A5)(a0)
31	REG_S	a6, (KVM_ARCH_HOST_A6)(a0)
32	REG_S	a7, (KVM_ARCH_HOST_A7)(a0)
33	REG_S	s2, (KVM_ARCH_HOST_S2)(a0)
34	REG_S	s3, (KVM_ARCH_HOST_S3)(a0)
35	REG_S	s4, (KVM_ARCH_HOST_S4)(a0)
36	REG_S	s5, (KVM_ARCH_HOST_S5)(a0)
37	REG_S	s6, (KVM_ARCH_HOST_S6)(a0)
38	REG_S	s7, (KVM_ARCH_HOST_S7)(a0)
39	REG_S	s8, (KVM_ARCH_HOST_S8)(a0)
40	REG_S	s9, (KVM_ARCH_HOST_S9)(a0)
41	REG_S	s10, (KVM_ARCH_HOST_S10)(a0)
42	REG_S	s11, (KVM_ARCH_HOST_S11)(a0)
43
44	/* Save Host and Restore Guest SSTATUS */
45	REG_L	t0, (KVM_ARCH_GUEST_SSTATUS)(a0)
46	csrrw	t0, CSR_SSTATUS, t0
47	REG_S	t0, (KVM_ARCH_HOST_SSTATUS)(a0)
48
49	/* Save Host and Restore Guest HSTATUS */
50	REG_L	t1, (KVM_ARCH_GUEST_HSTATUS)(a0)
51	csrrw	t1, CSR_HSTATUS, t1
52	REG_S	t1, (KVM_ARCH_HOST_HSTATUS)(a0)
53
54	/* Save Host and Restore Guest SCOUNTEREN */
55	REG_L	t2, (KVM_ARCH_GUEST_SCOUNTEREN)(a0)
56	csrrw	t2, CSR_SCOUNTEREN, t2
57	REG_S	t2, (KVM_ARCH_HOST_SCOUNTEREN)(a0)
58
59	/* Save Host SSCRATCH and change it to struct kvm_vcpu_arch pointer */
60	csrrw	t3, CSR_SSCRATCH, a0
61	REG_S	t3, (KVM_ARCH_HOST_SSCRATCH)(a0)
62
63	/* Save Host STVEC and change it to return path */
64	la	t4, __kvm_switch_return
65	csrrw	t4, CSR_STVEC, t4
66	REG_S	t4, (KVM_ARCH_HOST_STVEC)(a0)
67
68	/* Restore Guest SEPC */
69	REG_L	t0, (KVM_ARCH_GUEST_SEPC)(a0)
70	csrw	CSR_SEPC, t0
71
72	/* Restore Guest GPRs (except A0) */
73	REG_L	ra, (KVM_ARCH_GUEST_RA)(a0)
74	REG_L	sp, (KVM_ARCH_GUEST_SP)(a0)
75	REG_L	gp, (KVM_ARCH_GUEST_GP)(a0)
76	REG_L	tp, (KVM_ARCH_GUEST_TP)(a0)
77	REG_L	t0, (KVM_ARCH_GUEST_T0)(a0)
78	REG_L	t1, (KVM_ARCH_GUEST_T1)(a0)
79	REG_L	t2, (KVM_ARCH_GUEST_T2)(a0)
80	REG_L	s0, (KVM_ARCH_GUEST_S0)(a0)
81	REG_L	s1, (KVM_ARCH_GUEST_S1)(a0)
82	REG_L	a1, (KVM_ARCH_GUEST_A1)(a0)
83	REG_L	a2, (KVM_ARCH_GUEST_A2)(a0)
84	REG_L	a3, (KVM_ARCH_GUEST_A3)(a0)
85	REG_L	a4, (KVM_ARCH_GUEST_A4)(a0)
86	REG_L	a5, (KVM_ARCH_GUEST_A5)(a0)
87	REG_L	a6, (KVM_ARCH_GUEST_A6)(a0)
88	REG_L	a7, (KVM_ARCH_GUEST_A7)(a0)
89	REG_L	s2, (KVM_ARCH_GUEST_S2)(a0)
90	REG_L	s3, (KVM_ARCH_GUEST_S3)(a0)
91	REG_L	s4, (KVM_ARCH_GUEST_S4)(a0)
92	REG_L	s5, (KVM_ARCH_GUEST_S5)(a0)
93	REG_L	s6, (KVM_ARCH_GUEST_S6)(a0)
94	REG_L	s7, (KVM_ARCH_GUEST_S7)(a0)
95	REG_L	s8, (KVM_ARCH_GUEST_S8)(a0)
96	REG_L	s9, (KVM_ARCH_GUEST_S9)(a0)
97	REG_L	s10, (KVM_ARCH_GUEST_S10)(a0)
98	REG_L	s11, (KVM_ARCH_GUEST_S11)(a0)
99	REG_L	t3, (KVM_ARCH_GUEST_T3)(a0)
100	REG_L	t4, (KVM_ARCH_GUEST_T4)(a0)
101	REG_L	t5, (KVM_ARCH_GUEST_T5)(a0)
102	REG_L	t6, (KVM_ARCH_GUEST_T6)(a0)
103
104	/* Restore Guest A0 */
105	REG_L	a0, (KVM_ARCH_GUEST_A0)(a0)
106
107	/* Resume Guest */
108	sret
109
110	/* Back to Host */
111	.align 2
112__kvm_switch_return:
113	/* Swap Guest A0 with SSCRATCH */
114	csrrw	a0, CSR_SSCRATCH, a0
115
116	/* Save Guest GPRs (except A0) */
117	REG_S	ra, (KVM_ARCH_GUEST_RA)(a0)
118	REG_S	sp, (KVM_ARCH_GUEST_SP)(a0)
119	REG_S	gp, (KVM_ARCH_GUEST_GP)(a0)
120	REG_S	tp, (KVM_ARCH_GUEST_TP)(a0)
121	REG_S	t0, (KVM_ARCH_GUEST_T0)(a0)
122	REG_S	t1, (KVM_ARCH_GUEST_T1)(a0)
123	REG_S	t2, (KVM_ARCH_GUEST_T2)(a0)
124	REG_S	s0, (KVM_ARCH_GUEST_S0)(a0)
125	REG_S	s1, (KVM_ARCH_GUEST_S1)(a0)
126	REG_S	a1, (KVM_ARCH_GUEST_A1)(a0)
127	REG_S	a2, (KVM_ARCH_GUEST_A2)(a0)
128	REG_S	a3, (KVM_ARCH_GUEST_A3)(a0)
129	REG_S	a4, (KVM_ARCH_GUEST_A4)(a0)
130	REG_S	a5, (KVM_ARCH_GUEST_A5)(a0)
131	REG_S	a6, (KVM_ARCH_GUEST_A6)(a0)
132	REG_S	a7, (KVM_ARCH_GUEST_A7)(a0)
133	REG_S	s2, (KVM_ARCH_GUEST_S2)(a0)
134	REG_S	s3, (KVM_ARCH_GUEST_S3)(a0)
135	REG_S	s4, (KVM_ARCH_GUEST_S4)(a0)
136	REG_S	s5, (KVM_ARCH_GUEST_S5)(a0)
137	REG_S	s6, (KVM_ARCH_GUEST_S6)(a0)
138	REG_S	s7, (KVM_ARCH_GUEST_S7)(a0)
139	REG_S	s8, (KVM_ARCH_GUEST_S8)(a0)
140	REG_S	s9, (KVM_ARCH_GUEST_S9)(a0)
141	REG_S	s10, (KVM_ARCH_GUEST_S10)(a0)
142	REG_S	s11, (KVM_ARCH_GUEST_S11)(a0)
143	REG_S	t3, (KVM_ARCH_GUEST_T3)(a0)
144	REG_S	t4, (KVM_ARCH_GUEST_T4)(a0)
145	REG_S	t5, (KVM_ARCH_GUEST_T5)(a0)
146	REG_S	t6, (KVM_ARCH_GUEST_T6)(a0)
147
148	/* Save Guest SEPC */
149	csrr	t0, CSR_SEPC
150	REG_S	t0, (KVM_ARCH_GUEST_SEPC)(a0)
151
152	/* Restore Host STVEC */
153	REG_L	t1, (KVM_ARCH_HOST_STVEC)(a0)
154	csrw	CSR_STVEC, t1
155
156	/* Save Guest A0 and Restore Host SSCRATCH */
157	REG_L	t2, (KVM_ARCH_HOST_SSCRATCH)(a0)
158	csrrw	t2, CSR_SSCRATCH, t2
159	REG_S	t2, (KVM_ARCH_GUEST_A0)(a0)
160
161	/* Save Guest and Restore Host SCOUNTEREN */
162	REG_L	t3, (KVM_ARCH_HOST_SCOUNTEREN)(a0)
163	csrrw	t3, CSR_SCOUNTEREN, t3
164	REG_S	t3, (KVM_ARCH_GUEST_SCOUNTEREN)(a0)
165
166	/* Save Guest and Restore Host HSTATUS */
167	REG_L	t4, (KVM_ARCH_HOST_HSTATUS)(a0)
168	csrrw	t4, CSR_HSTATUS, t4
169	REG_S	t4, (KVM_ARCH_GUEST_HSTATUS)(a0)
170
171	/* Save Guest and Restore Host SSTATUS */
172	REG_L	t5, (KVM_ARCH_HOST_SSTATUS)(a0)
173	csrrw	t5, CSR_SSTATUS, t5
174	REG_S	t5, (KVM_ARCH_GUEST_SSTATUS)(a0)
175
176	/* Restore Host GPRs (except A0 and T0-T6) */
177	REG_L	ra, (KVM_ARCH_HOST_RA)(a0)
178	REG_L	sp, (KVM_ARCH_HOST_SP)(a0)
179	REG_L	gp, (KVM_ARCH_HOST_GP)(a0)
180	REG_L	tp, (KVM_ARCH_HOST_TP)(a0)
181	REG_L	s0, (KVM_ARCH_HOST_S0)(a0)
182	REG_L	s1, (KVM_ARCH_HOST_S1)(a0)
183	REG_L	a1, (KVM_ARCH_HOST_A1)(a0)
184	REG_L	a2, (KVM_ARCH_HOST_A2)(a0)
185	REG_L	a3, (KVM_ARCH_HOST_A3)(a0)
186	REG_L	a4, (KVM_ARCH_HOST_A4)(a0)
187	REG_L	a5, (KVM_ARCH_HOST_A5)(a0)
188	REG_L	a6, (KVM_ARCH_HOST_A6)(a0)
189	REG_L	a7, (KVM_ARCH_HOST_A7)(a0)
190	REG_L	s2, (KVM_ARCH_HOST_S2)(a0)
191	REG_L	s3, (KVM_ARCH_HOST_S3)(a0)
192	REG_L	s4, (KVM_ARCH_HOST_S4)(a0)
193	REG_L	s5, (KVM_ARCH_HOST_S5)(a0)
194	REG_L	s6, (KVM_ARCH_HOST_S6)(a0)
195	REG_L	s7, (KVM_ARCH_HOST_S7)(a0)
196	REG_L	s8, (KVM_ARCH_HOST_S8)(a0)
197	REG_L	s9, (KVM_ARCH_HOST_S9)(a0)
198	REG_L	s10, (KVM_ARCH_HOST_S10)(a0)
199	REG_L	s11, (KVM_ARCH_HOST_S11)(a0)
200
201	/* Return to C code */
202	ret
203ENDPROC(__kvm_riscv_switch_to)
204
205ENTRY(__kvm_riscv_unpriv_trap)
206	/*
207	 * We assume that faulting unpriv load/store instruction is
208	 * 4-byte long and blindly increment SEPC by 4.
209	 *
210	 * The trap details will be saved at address pointed by 'A0'
211	 * register and we use 'A1' register as temporary.
212	 */
213	csrr	a1, CSR_SEPC
214	REG_S	a1, (KVM_ARCH_TRAP_SEPC)(a0)
215	addi	a1, a1, 4
216	csrw	CSR_SEPC, a1
217	csrr	a1, CSR_SCAUSE
218	REG_S	a1, (KVM_ARCH_TRAP_SCAUSE)(a0)
219	csrr	a1, CSR_STVAL
220	REG_S	a1, (KVM_ARCH_TRAP_STVAL)(a0)
221	csrr	a1, CSR_HTVAL
222	REG_S	a1, (KVM_ARCH_TRAP_HTVAL)(a0)
223	csrr	a1, CSR_HTINST
224	REG_S	a1, (KVM_ARCH_TRAP_HTINST)(a0)
225	sret
226ENDPROC(__kvm_riscv_unpriv_trap)
227