vcpu_sbi_hsm.c

  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 <linux/wordpart.h>
 13#include <asm/sbi.h>
 14#include <asm/kvm_vcpu_sbi.h>
 15
 16static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu)
 17{
 18	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 19	struct kvm_vcpu *target_vcpu;
 20	unsigned long target_vcpuid = cp->a0;
 21	int ret = 0;
 22
 23	target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
 24	if (!target_vcpu)
 25		return SBI_ERR_INVALID_PARAM;
 26
 27	spin_lock(&target_vcpu->arch.mp_state_lock);
 28
 29	if (!kvm_riscv_vcpu_stopped(target_vcpu)) {
 30		ret = SBI_ERR_ALREADY_AVAILABLE;
 31		goto out;
 32	}
 33
 34	kvm_riscv_vcpu_sbi_request_reset(target_vcpu, cp->a1, cp->a2);
 35
 36	__kvm_riscv_vcpu_power_on(target_vcpu);
 37
 38out:
 39	spin_unlock(&target_vcpu->arch.mp_state_lock);
 40
 41	return ret;
 42}
 43
 44static int kvm_sbi_hsm_vcpu_stop(struct kvm_vcpu *vcpu)
 45{
 46	int ret = 0;
 47
 48	spin_lock(&vcpu->arch.mp_state_lock);
 49
 50	if (kvm_riscv_vcpu_stopped(vcpu)) {
 51		ret = SBI_ERR_FAILURE;
 52		goto out;
 53	}
 54
 55	__kvm_riscv_vcpu_power_off(vcpu);
 56
 57out:
 58	spin_unlock(&vcpu->arch.mp_state_lock);
 59
 60	return ret;
 61}
 62
 63static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu)
 64{
 65	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 66	unsigned long target_vcpuid = cp->a0;
 67	struct kvm_vcpu *target_vcpu;
 68
 69	target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
 70	if (!target_vcpu)
 71		return SBI_ERR_INVALID_PARAM;
 72	if (kvm_riscv_vcpu_stopped(target_vcpu))
 73		return SBI_HSM_STATE_STOPPED;
 74	else if (target_vcpu->stat.generic.blocking)
 75		return SBI_HSM_STATE_SUSPENDED;
 76	else
 77		return SBI_HSM_STATE_STARTED;
 78}
 79
 80static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
 81				   struct kvm_vcpu_sbi_return *retdata)
 82{
 83	int ret = 0;
 84	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 85	unsigned long funcid = cp->a6;
 86
 87	switch (funcid) {
 88	case SBI_EXT_HSM_HART_START:
 89		ret = kvm_sbi_hsm_vcpu_start(vcpu);
 90		break;
 91	case SBI_EXT_HSM_HART_STOP:
 92		ret = kvm_sbi_hsm_vcpu_stop(vcpu);
 93		break;
 94	case SBI_EXT_HSM_HART_STATUS:
 95		ret = kvm_sbi_hsm_vcpu_get_status(vcpu);
 96		if (ret >= 0) {
 97			retdata->out_val = ret;
 98			retdata->err_val = 0;
 99		}
100		return 0;
101	case SBI_EXT_HSM_HART_SUSPEND:
102		switch (lower_32_bits(cp->a0)) {
103		case SBI_HSM_SUSPEND_RET_DEFAULT:
104			kvm_riscv_vcpu_wfi(vcpu);
105			break;
106		case SBI_HSM_SUSPEND_NON_RET_DEFAULT:
107			ret = SBI_ERR_NOT_SUPPORTED;
108			break;
109		default:
110			ret = SBI_ERR_INVALID_PARAM;
111		}
112		break;
113	default:
114		ret = SBI_ERR_NOT_SUPPORTED;
115	}
116
117	retdata->err_val = ret;
118
119	return 0;
120}
121
122const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm = {
123	.extid_start = SBI_EXT_HSM,
124	.extid_end = SBI_EXT_HSM,
125	.handler = kvm_sbi_ext_hsm_handler,
126};