1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2019 Western Digital Corporation or its affiliates.
4 *
5 * Authors:
6 * Atish Patra <atish.patra@wdc.com>
7 */
8
9 #include <linux/errno.h>
10 #include <linux/err.h>
11 #include <linux/kvm_host.h>
12 #include <asm/sbi.h>
13 #include <asm/kvm_vcpu_sbi.h>
14
15 #ifndef CONFIG_RISCV_SBI_V01
16 static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
17 .extid_start = -1UL,
18 .extid_end = -1UL,
19 .handler = NULL,
20 };
21 #endif
22
23 #ifdef CONFIG_RISCV_PMU_SBI
24 extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu;
25 #else
26 static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
27 .extid_start = -1UL,
28 .extid_end = -1UL,
29 .handler = NULL,
30 };
31 #endif
32
33 static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
34 &vcpu_sbi_ext_v01,
35 &vcpu_sbi_ext_base,
36 &vcpu_sbi_ext_time,
37 &vcpu_sbi_ext_ipi,
38 &vcpu_sbi_ext_rfence,
39 &vcpu_sbi_ext_srst,
40 &vcpu_sbi_ext_hsm,
41 &vcpu_sbi_ext_pmu,
42 &vcpu_sbi_ext_experimental,
43 &vcpu_sbi_ext_vendor,
44 };
45
kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu * vcpu,struct kvm_run * run)46 void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
47 {
48 struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
49
50 vcpu->arch.sbi_context.return_handled = 0;
51 vcpu->stat.ecall_exit_stat++;
52 run->exit_reason = KVM_EXIT_RISCV_SBI;
53 run->riscv_sbi.extension_id = cp->a7;
54 run->riscv_sbi.function_id = cp->a6;
55 run->riscv_sbi.args[0] = cp->a0;
56 run->riscv_sbi.args[1] = cp->a1;
57 run->riscv_sbi.args[2] = cp->a2;
58 run->riscv_sbi.args[3] = cp->a3;
59 run->riscv_sbi.args[4] = cp->a4;
60 run->riscv_sbi.args[5] = cp->a5;
61 run->riscv_sbi.ret[0] = cp->a0;
62 run->riscv_sbi.ret[1] = cp->a1;
63 }
64
kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu * vcpu,struct kvm_run * run,u32 type,u64 reason)65 void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
66 struct kvm_run *run,
67 u32 type, u64 reason)
68 {
69 unsigned long i;
70 struct kvm_vcpu *tmp;
71
72 kvm_for_each_vcpu(i, tmp, vcpu->kvm)
73 tmp->arch.power_off = true;
74 kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
75
76 memset(&run->system_event, 0, sizeof(run->system_event));
77 run->system_event.type = type;
78 run->system_event.ndata = 1;
79 run->system_event.data[0] = reason;
80 run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
81 }
82
kvm_riscv_vcpu_sbi_return(struct kvm_vcpu * vcpu,struct kvm_run * run)83 int kvm_riscv_vcpu_sbi_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
84 {
85 struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
86
87 /* Handle SBI return only once */
88 if (vcpu->arch.sbi_context.return_handled)
89 return 0;
90 vcpu->arch.sbi_context.return_handled = 1;
91
92 /* Update return values */
93 cp->a0 = run->riscv_sbi.ret[0];
94 cp->a1 = run->riscv_sbi.ret[1];
95
96 /* Move to next instruction */
97 vcpu->arch.guest_context.sepc += 4;
98
99 return 0;
100 }
101
kvm_vcpu_sbi_find_ext(unsigned long extid)102 const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(unsigned long extid)
103 {
104 int i = 0;
105
106 for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
107 if (sbi_ext[i]->extid_start <= extid &&
108 sbi_ext[i]->extid_end >= extid)
109 return sbi_ext[i];
110 }
111
112 return NULL;
113 }
114
kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu * vcpu,struct kvm_run * run)115 int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
116 {
117 int ret = 1;
118 bool next_sepc = true;
119 struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
120 const struct kvm_vcpu_sbi_extension *sbi_ext;
121 struct kvm_cpu_trap utrap = {0};
122 struct kvm_vcpu_sbi_return sbi_ret = {
123 .out_val = 0,
124 .err_val = 0,
125 .utrap = &utrap,
126 };
127 bool ext_is_v01 = false;
128
129 sbi_ext = kvm_vcpu_sbi_find_ext(cp->a7);
130 if (sbi_ext && sbi_ext->handler) {
131 #ifdef CONFIG_RISCV_SBI_V01
132 if (cp->a7 >= SBI_EXT_0_1_SET_TIMER &&
133 cp->a7 <= SBI_EXT_0_1_SHUTDOWN)
134 ext_is_v01 = true;
135 #endif
136 ret = sbi_ext->handler(vcpu, run, &sbi_ret);
137 } else {
138 /* Return error for unsupported SBI calls */
139 cp->a0 = SBI_ERR_NOT_SUPPORTED;
140 goto ecall_done;
141 }
142
143 /*
144 * When the SBI extension returns a Linux error code, it exits the ioctl
145 * loop and forwards the error to userspace.
146 */
147 if (ret < 0) {
148 next_sepc = false;
149 goto ecall_done;
150 }
151
152 /* Handle special error cases i.e trap, exit or userspace forward */
153 if (sbi_ret.utrap->scause) {
154 /* No need to increment sepc or exit ioctl loop */
155 ret = 1;
156 sbi_ret.utrap->sepc = cp->sepc;
157 kvm_riscv_vcpu_trap_redirect(vcpu, sbi_ret.utrap);
158 next_sepc = false;
159 goto ecall_done;
160 }
161
162 /* Exit ioctl loop or Propagate the error code the guest */
163 if (sbi_ret.uexit) {
164 next_sepc = false;
165 ret = 0;
166 } else {
167 cp->a0 = sbi_ret.err_val;
168 ret = 1;
169 }
170 ecall_done:
171 if (next_sepc)
172 cp->sepc += 4;
173 /* a1 should only be updated when we continue the ioctl loop */
174 if (!ext_is_v01 && ret == 1)
175 cp->a1 = sbi_ret.out_val;
176
177 return ret;
178 }
179