// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2023 Rivos Inc
 *
 * Authors:
 *     Atish Patra <atishp@rivosinc.com>
 */

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

static int kvm_sbi_ext_pmu_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
                                   struct kvm_vcpu_sbi_return *retdata)
{
        int ret = 0;
        struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
        struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
        unsigned long funcid = cp->a6;
        u64 temp;

        if (!kvpmu->init_done) {
                retdata->err_val = SBI_ERR_NOT_SUPPORTED;
                return 0;
        }

        switch (funcid) {
        case SBI_EXT_PMU_NUM_COUNTERS:
                ret = kvm_riscv_vcpu_pmu_num_ctrs(vcpu, retdata);
                break;
        case SBI_EXT_PMU_COUNTER_GET_INFO:
                ret = kvm_riscv_vcpu_pmu_ctr_info(vcpu, cp->a0, retdata);
                break;
        case SBI_EXT_PMU_COUNTER_CFG_MATCH:
#if defined(CONFIG_32BIT)
                temp = ((uint64_t)cp->a5 << 32) | cp->a4;
#else
                temp = cp->a4;
#endif
                /*
                 * This can fail if perf core framework fails to create an event.
                 * No need to forward the error to userspace and exit the guest.
                 * The operation can continue without profiling. Forward the
                 * appropriate SBI error to the guest.
                 */
                ret = kvm_riscv_vcpu_pmu_ctr_cfg_match(vcpu, cp->a0, cp->a1,
                                                       cp->a2, cp->a3, temp, retdata);
                break;
        case SBI_EXT_PMU_COUNTER_START:
#if defined(CONFIG_32BIT)
                temp = ((uint64_t)cp->a4 << 32) | cp->a3;
#else
                temp = cp->a3;
#endif
                ret = kvm_riscv_vcpu_pmu_ctr_start(vcpu, cp->a0, cp->a1, cp->a2,
                                                   temp, retdata);
                break;
        case SBI_EXT_PMU_COUNTER_STOP:
                ret = kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, retdata);
                break;
        case SBI_EXT_PMU_COUNTER_FW_READ:
                ret = kvm_riscv_vcpu_pmu_fw_ctr_read(vcpu, cp->a0, retdata);
                break;
        case SBI_EXT_PMU_COUNTER_FW_READ_HI:
                if (IS_ENABLED(CONFIG_32BIT))
                        ret = kvm_riscv_vcpu_pmu_fw_ctr_read_hi(vcpu, cp->a0, retdata);
                else
                        retdata->out_val = 0;
                break;
        case SBI_EXT_PMU_SNAPSHOT_SET_SHMEM:
                ret = kvm_riscv_vcpu_pmu_snapshot_set_shmem(vcpu, cp->a0, cp->a1, cp->a2, retdata);
                break;
        case SBI_EXT_PMU_EVENT_GET_INFO:
                ret = kvm_riscv_vcpu_pmu_event_info(vcpu, cp->a0, cp->a1, cp->a2, cp->a3, retdata);
                break;
        default:
                retdata->err_val = SBI_ERR_NOT_SUPPORTED;
        }

        return ret;
}

static unsigned long kvm_sbi_ext_pmu_probe(struct kvm_vcpu *vcpu)
{
        struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);

        return kvpmu->init_done;
}

const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
        .extid_start = SBI_EXT_PMU,
        .extid_end = SBI_EXT_PMU,
        .handler = kvm_sbi_ext_pmu_handler,
        .probe = kvm_sbi_ext_pmu_probe,
};