// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2021 Western Digital Corporation or its affiliates.
 *
 * Authors:
 *     Atish Patra <atish.patra@wdc.com>
 */

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/version.h>
#include <asm/sbi.h>
#include <asm/kvm_vcpu_sbi.h>

static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
                                    struct kvm_vcpu_sbi_return *retdata)
{
        struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
        const struct kvm_vcpu_sbi_extension *sbi_ext;
        unsigned long *out_val = &retdata->out_val;

        switch (cp->a6) {
        case SBI_EXT_BASE_GET_SPEC_VERSION:
                *out_val = (KVM_SBI_VERSION_MAJOR <<
                            SBI_SPEC_VERSION_MAJOR_SHIFT) |
                            KVM_SBI_VERSION_MINOR;
                break;
        case SBI_EXT_BASE_GET_IMP_ID:
                *out_val = KVM_SBI_IMPID;
                break;
        case SBI_EXT_BASE_GET_IMP_VERSION:
                *out_val = LINUX_VERSION_CODE;
                break;
        case SBI_EXT_BASE_PROBE_EXT:
                if ((cp->a0 >= SBI_EXT_EXPERIMENTAL_START &&
                     cp->a0 <= SBI_EXT_EXPERIMENTAL_END) ||
                    (cp->a0 >= SBI_EXT_VENDOR_START &&
                     cp->a0 <= SBI_EXT_VENDOR_END)) {
                        /*
                         * For experimental/vendor extensions
                         * forward it to the userspace
                         */
                        return kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
                } else {
                        sbi_ext = kvm_vcpu_sbi_find_ext(vcpu, cp->a0);
                        *out_val = sbi_ext && sbi_ext->probe ?
                                           sbi_ext->probe(vcpu) : !!sbi_ext;
                }
                break;
        case SBI_EXT_BASE_GET_MVENDORID:
                *out_val = vcpu->arch.mvendorid;
                break;
        case SBI_EXT_BASE_GET_MARCHID:
                *out_val = vcpu->arch.marchid;
                break;
        case SBI_EXT_BASE_GET_MIMPID:
                *out_val = vcpu->arch.mimpid;
                break;
        default:
                retdata->err_val = SBI_ERR_NOT_SUPPORTED;
                break;
        }

        return 0;
}

const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base = {
        .extid_start = SBI_EXT_BASE,
        .extid_end = SBI_EXT_BASE,
        .handler = kvm_sbi_ext_base_handler,
};