xref: /openbmc/linux/arch/riscv/kvm/vcpu_sbi_hsm.c (revision a13144e2)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2021 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 static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu)
16 {
17 	struct kvm_cpu_context *reset_cntx;
18 	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
19 	struct kvm_vcpu *target_vcpu;
20 	unsigned long target_vcpuid = cp->a0;
21 
22 	target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
23 	if (!target_vcpu)
24 		return -EINVAL;
25 	if (!target_vcpu->arch.power_off)
26 		return -EALREADY;
27 
28 	reset_cntx = &target_vcpu->arch.guest_reset_context;
29 	/* start address */
30 	reset_cntx->sepc = cp->a1;
31 	/* target vcpu id to start */
32 	reset_cntx->a0 = target_vcpuid;
33 	/* private data passed from kernel */
34 	reset_cntx->a1 = cp->a2;
35 	kvm_make_request(KVM_REQ_VCPU_RESET, target_vcpu);
36 
37 	kvm_riscv_vcpu_power_on(target_vcpu);
38 
39 	return 0;
40 }
41 
42 static int kvm_sbi_hsm_vcpu_stop(struct kvm_vcpu *vcpu)
43 {
44 	if (vcpu->arch.power_off)
45 		return -EINVAL;
46 
47 	kvm_riscv_vcpu_power_off(vcpu);
48 
49 	return 0;
50 }
51 
52 static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu)
53 {
54 	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
55 	unsigned long target_vcpuid = cp->a0;
56 	struct kvm_vcpu *target_vcpu;
57 
58 	target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
59 	if (!target_vcpu)
60 		return -EINVAL;
61 	if (!target_vcpu->arch.power_off)
62 		return SBI_HSM_STATE_STARTED;
63 	else if (vcpu->stat.generic.blocking)
64 		return SBI_HSM_STATE_SUSPENDED;
65 	else
66 		return SBI_HSM_STATE_STOPPED;
67 }
68 
69 static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
70 				   unsigned long *out_val,
71 				   struct kvm_cpu_trap *utrap,
72 				   bool *exit)
73 {
74 	int ret = 0;
75 	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
76 	struct kvm *kvm = vcpu->kvm;
77 	unsigned long funcid = cp->a6;
78 
79 	switch (funcid) {
80 	case SBI_EXT_HSM_HART_START:
81 		mutex_lock(&kvm->lock);
82 		ret = kvm_sbi_hsm_vcpu_start(vcpu);
83 		mutex_unlock(&kvm->lock);
84 		break;
85 	case SBI_EXT_HSM_HART_STOP:
86 		ret = kvm_sbi_hsm_vcpu_stop(vcpu);
87 		break;
88 	case SBI_EXT_HSM_HART_STATUS:
89 		ret = kvm_sbi_hsm_vcpu_get_status(vcpu);
90 		if (ret >= 0) {
91 			*out_val = ret;
92 			ret = 0;
93 		}
94 		break;
95 	case SBI_EXT_HSM_HART_SUSPEND:
96 		switch (cp->a0) {
97 		case SBI_HSM_SUSPEND_RET_DEFAULT:
98 			kvm_riscv_vcpu_wfi(vcpu);
99 			break;
100 		case SBI_HSM_SUSPEND_NON_RET_DEFAULT:
101 			ret = -EOPNOTSUPP;
102 			break;
103 		default:
104 			ret = -EINVAL;
105 		}
106 		break;
107 	default:
108 		ret = -EOPNOTSUPP;
109 	}
110 
111 	return ret;
112 }
113 
114 const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm = {
115 	.extid_start = SBI_EXT_HSM,
116 	.extid_end = SBI_EXT_HSM,
117 	.handler = kvm_sbi_ext_hsm_handler,
118 };
119