// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2024 Ventana Micro Systems Inc.
 */

#include <linux/kvm_host.h>
#include <linux/wordpart.h>

#include <asm/kvm_vcpu_sbi.h>
#include <asm/sbi.h>

static int kvm_sbi_ext_susp_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
                                    struct kvm_vcpu_sbi_return *retdata)
{
        struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
        unsigned long funcid = cp->a6;
        unsigned long hva, i;
        struct kvm_vcpu *tmp;

        switch (funcid) {
        case SBI_EXT_SUSP_SYSTEM_SUSPEND:
                if (lower_32_bits(cp->a0) != SBI_SUSP_SLEEP_TYPE_SUSPEND_TO_RAM) {
                        retdata->err_val = SBI_ERR_INVALID_PARAM;
                        return 0;
                }

                if (!(cp->sstatus & SR_SPP)) {
                        retdata->err_val = SBI_ERR_FAILURE;
                        return 0;
                }

                hva = kvm_vcpu_gfn_to_hva_prot(vcpu, cp->a1 >> PAGE_SHIFT, NULL);
                if (kvm_is_error_hva(hva)) {
                        retdata->err_val = SBI_ERR_INVALID_ADDRESS;
                        return 0;
                }

                kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
                        if (tmp == vcpu)
                                continue;
                        if (!kvm_riscv_vcpu_stopped(tmp)) {
                                retdata->err_val = SBI_ERR_DENIED;
                                return 0;
                        }
                }

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

                /* userspace provides the suspend implementation */
                return kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
        default:
                retdata->err_val = SBI_ERR_NOT_SUPPORTED;
                break;
        }

        return 0;
}

const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_susp = {
        .extid_start = SBI_EXT_SUSP,
        .extid_end = SBI_EXT_SUSP,
        .default_disabled = true,
        .handler = kvm_sbi_ext_susp_handler,
};