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
15static 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 SBI_ERR_INVALID_PARAM;
25	if (!target_vcpu->arch.power_off)
26		return SBI_ERR_ALREADY_AVAILABLE;
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
42static int kvm_sbi_hsm_vcpu_stop(struct kvm_vcpu *vcpu)
43{
44	if (vcpu->arch.power_off)
45		return SBI_ERR_FAILURE;
46
47	kvm_riscv_vcpu_power_off(vcpu);
48
49	return 0;
50}
51
52static 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 SBI_ERR_INVALID_PARAM;
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
69static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
70				   struct kvm_vcpu_sbi_return *retdata)
71{
72	int ret = 0;
73	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
74	struct kvm *kvm = vcpu->kvm;
75	unsigned long funcid = cp->a6;
76
77	switch (funcid) {
78	case SBI_EXT_HSM_HART_START:
79		mutex_lock(&kvm->lock);
80		ret = kvm_sbi_hsm_vcpu_start(vcpu);
81		mutex_unlock(&kvm->lock);
82		break;
83	case SBI_EXT_HSM_HART_STOP:
84		ret = kvm_sbi_hsm_vcpu_stop(vcpu);
85		break;
86	case SBI_EXT_HSM_HART_STATUS:
87		ret = kvm_sbi_hsm_vcpu_get_status(vcpu);
88		if (ret >= 0) {
89			retdata->out_val = ret;
90			retdata->err_val = 0;
91		}
92		return 0;
93	case SBI_EXT_HSM_HART_SUSPEND:
94		switch (cp->a0) {
95		case SBI_HSM_SUSPEND_RET_DEFAULT:
96			kvm_riscv_vcpu_wfi(vcpu);
97			break;
98		case SBI_HSM_SUSPEND_NON_RET_DEFAULT:
99			ret = SBI_ERR_NOT_SUPPORTED;
100			break;
101		default:
102			ret = SBI_ERR_INVALID_PARAM;
103		}
104		break;
105	default:
106		ret = SBI_ERR_NOT_SUPPORTED;
107	}
108
109	retdata->err_val = ret;
110
111	return 0;
112}
113
114const 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