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 
kvm_linux_err_map_sbi(int err)15 static int kvm_linux_err_map_sbi(int err)
16 {
17 	switch (err) {
18 	case 0:
19 		return SBI_SUCCESS;
20 	case -EPERM:
21 		return SBI_ERR_DENIED;
22 	case -EINVAL:
23 		return SBI_ERR_INVALID_PARAM;
24 	case -EFAULT:
25 		return SBI_ERR_INVALID_ADDRESS;
26 	case -EOPNOTSUPP:
27 		return SBI_ERR_NOT_SUPPORTED;
28 	case -EALREADY:
29 		return SBI_ERR_ALREADY_AVAILABLE;
30 	default:
31 		return SBI_ERR_FAILURE;
32 	};
33 }
34 
35 #ifndef CONFIG_RISCV_SBI_V01
36 static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
37 	.extid_start = -1UL,
38 	.extid_end = -1UL,
39 	.handler = NULL,
40 };
41 #endif
42 
43 static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
44 	&vcpu_sbi_ext_v01,
45 	&vcpu_sbi_ext_base,
46 	&vcpu_sbi_ext_time,
47 	&vcpu_sbi_ext_ipi,
48 	&vcpu_sbi_ext_rfence,
49 	&vcpu_sbi_ext_srst,
50 	&vcpu_sbi_ext_hsm,
51 	&vcpu_sbi_ext_experimental,
52 	&vcpu_sbi_ext_vendor,
53 };
54 
kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu * vcpu,struct kvm_run * run)55 void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
56 {
57 	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
58 
59 	vcpu->arch.sbi_context.return_handled = 0;
60 	vcpu->stat.ecall_exit_stat++;
61 	run->exit_reason = KVM_EXIT_RISCV_SBI;
62 	run->riscv_sbi.extension_id = cp->a7;
63 	run->riscv_sbi.function_id = cp->a6;
64 	run->riscv_sbi.args[0] = cp->a0;
65 	run->riscv_sbi.args[1] = cp->a1;
66 	run->riscv_sbi.args[2] = cp->a2;
67 	run->riscv_sbi.args[3] = cp->a3;
68 	run->riscv_sbi.args[4] = cp->a4;
69 	run->riscv_sbi.args[5] = cp->a5;
70 	run->riscv_sbi.ret[0] = cp->a0;
71 	run->riscv_sbi.ret[1] = cp->a1;
72 }
73 
kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu * vcpu,struct kvm_run * run,u32 type,u64 reason)74 void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
75 				     struct kvm_run *run,
76 				     u32 type, u64 reason)
77 {
78 	unsigned long i;
79 	struct kvm_vcpu *tmp;
80 
81 	kvm_for_each_vcpu(i, tmp, vcpu->kvm)
82 		tmp->arch.power_off = true;
83 	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
84 
85 	memset(&run->system_event, 0, sizeof(run->system_event));
86 	run->system_event.type = type;
87 	run->system_event.ndata = 1;
88 	run->system_event.data[0] = reason;
89 	run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
90 }
91 
kvm_riscv_vcpu_sbi_return(struct kvm_vcpu * vcpu,struct kvm_run * run)92 int kvm_riscv_vcpu_sbi_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
93 {
94 	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
95 
96 	/* Handle SBI return only once */
97 	if (vcpu->arch.sbi_context.return_handled)
98 		return 0;
99 	vcpu->arch.sbi_context.return_handled = 1;
100 
101 	/* Update return values */
102 	cp->a0 = run->riscv_sbi.ret[0];
103 	cp->a1 = run->riscv_sbi.ret[1];
104 
105 	/* Move to next instruction */
106 	vcpu->arch.guest_context.sepc += 4;
107 
108 	return 0;
109 }
110 
kvm_vcpu_sbi_find_ext(unsigned long extid)111 const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(unsigned long extid)
112 {
113 	int i = 0;
114 
115 	for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
116 		if (sbi_ext[i]->extid_start <= extid &&
117 		    sbi_ext[i]->extid_end >= extid)
118 			return sbi_ext[i];
119 	}
120 
121 	return NULL;
122 }
123 
kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu * vcpu,struct kvm_run * run)124 int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
125 {
126 	int ret = 1;
127 	bool next_sepc = true;
128 	bool userspace_exit = false;
129 	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
130 	const struct kvm_vcpu_sbi_extension *sbi_ext;
131 	struct kvm_cpu_trap utrap = { 0 };
132 	unsigned long out_val = 0;
133 	bool ext_is_v01 = false;
134 
135 	sbi_ext = kvm_vcpu_sbi_find_ext(cp->a7);
136 	if (sbi_ext && sbi_ext->handler) {
137 #ifdef CONFIG_RISCV_SBI_V01
138 		if (cp->a7 >= SBI_EXT_0_1_SET_TIMER &&
139 		    cp->a7 <= SBI_EXT_0_1_SHUTDOWN)
140 			ext_is_v01 = true;
141 #endif
142 		ret = sbi_ext->handler(vcpu, run, &out_val, &utrap, &userspace_exit);
143 	} else {
144 		/* Return error for unsupported SBI calls */
145 		cp->a0 = SBI_ERR_NOT_SUPPORTED;
146 		goto ecall_done;
147 	}
148 
149 	/* Handle special error cases i.e trap, exit or userspace forward */
150 	if (utrap.scause) {
151 		/* No need to increment sepc or exit ioctl loop */
152 		ret = 1;
153 		utrap.sepc = cp->sepc;
154 		kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
155 		next_sepc = false;
156 		goto ecall_done;
157 	}
158 
159 	/* Exit ioctl loop or Propagate the error code the guest */
160 	if (userspace_exit) {
161 		next_sepc = false;
162 		ret = 0;
163 	} else {
164 		/**
165 		 * SBI extension handler always returns an Linux error code. Convert
166 		 * it to the SBI specific error code that can be propagated the SBI
167 		 * caller.
168 		 */
169 		ret = kvm_linux_err_map_sbi(ret);
170 		cp->a0 = ret;
171 		ret = 1;
172 	}
173 ecall_done:
174 	if (next_sepc)
175 		cp->sepc += 4;
176 	if (!ext_is_v01)
177 		cp->a1 = out_val;
178 
179 	return ret;
180 }
181