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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/riscv/kvm/vcpu_sbi_hsm.c
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// SPDX-License-Identifier: GPL-2.0

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/*

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 * Copyright (c) 2021 Western Digital Corporation or its affiliates.

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 *

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 * Authors:

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 *     Atish Patra <[email protected]>

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 */

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#include <linux/errno.h>

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#include <linux/err.h>

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#include <linux/kvm_host.h>

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#include <linux/wordpart.h>

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#include <asm/sbi.h>

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#include <asm/kvm_vcpu_sbi.h>

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static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu)

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{

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	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;

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	struct kvm_vcpu *target_vcpu;

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	unsigned long target_vcpuid = cp->a0;

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	int ret = 0;

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	target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);

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	if (!target_vcpu)

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		return SBI_ERR_INVALID_PARAM;

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	spin_lock(&target_vcpu->arch.mp_state_lock);

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	if (!kvm_riscv_vcpu_stopped(target_vcpu)) {

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		ret = SBI_ERR_ALREADY_AVAILABLE;

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		goto out;

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	}

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	kvm_riscv_vcpu_sbi_request_reset(target_vcpu, cp->a1, cp->a2);

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	__kvm_riscv_vcpu_power_on(target_vcpu);

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out:

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	spin_unlock(&target_vcpu->arch.mp_state_lock);

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	return ret;

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}

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static int kvm_sbi_hsm_vcpu_stop(struct kvm_vcpu *vcpu)

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{

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	int ret = 0;

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	spin_lock(&vcpu->arch.mp_state_lock);

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	if (kvm_riscv_vcpu_stopped(vcpu)) {

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		ret = SBI_ERR_FAILURE;

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		goto out;

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	}

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	__kvm_riscv_vcpu_power_off(vcpu);

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out:

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	spin_unlock(&vcpu->arch.mp_state_lock);

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	return ret;

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}

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static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu)

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{

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	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;

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	unsigned long target_vcpuid = cp->a0;

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	struct kvm_vcpu *target_vcpu;

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	target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);

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	if (!target_vcpu)

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		return SBI_ERR_INVALID_PARAM;

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	if (kvm_riscv_vcpu_stopped(target_vcpu))

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		return SBI_HSM_STATE_STOPPED;

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	else if (target_vcpu->stat.generic.blocking)

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		return SBI_HSM_STATE_SUSPENDED;

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	else

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		return SBI_HSM_STATE_STARTED;

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}

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static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,

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				   struct kvm_vcpu_sbi_return *retdata)

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{

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	int ret = 0;

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	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;

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	unsigned long funcid = cp->a6;

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	switch (funcid) {

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	case SBI_EXT_HSM_HART_START:

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		ret = kvm_sbi_hsm_vcpu_start(vcpu);

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		break;

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	case SBI_EXT_HSM_HART_STOP:

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		ret = kvm_sbi_hsm_vcpu_stop(vcpu);

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		break;

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	case SBI_EXT_HSM_HART_STATUS:

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		ret = kvm_sbi_hsm_vcpu_get_status(vcpu);

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		if (ret >= 0) {

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			retdata->out_val = ret;

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			retdata->err_val = 0;

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		}

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		return 0;

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	case SBI_EXT_HSM_HART_SUSPEND:

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		switch (lower_32_bits(cp->a0)) {

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		case SBI_HSM_SUSPEND_RET_DEFAULT:

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			kvm_riscv_vcpu_wfi(vcpu);

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			break;

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		case SBI_HSM_SUSPEND_NON_RET_DEFAULT:

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			ret = SBI_ERR_NOT_SUPPORTED;

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			break;

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		default:

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			ret = SBI_ERR_INVALID_PARAM;

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		}

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		break;

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	default:

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		ret = SBI_ERR_NOT_SUPPORTED;

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	}

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	retdata->err_val = ret;

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	return 0;

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}

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const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm = {

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	.extid_start = SBI_EXT_HSM,

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	.extid_end = SBI_EXT_HSM,

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	.handler = kvm_sbi_ext_hsm_handler,

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};

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