/*
 * RISC-V Control and Status Registers.
 *
 * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
 * Copyright (c) 2017-2018 SiFive, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2 or later, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "qemu/osdep.h"
#include "qemu/log.h"
#include "qemu/timer.h"
#include "cpu.h"
#include "pmu.h"
#include "time_helper.h"
#include "qemu/main-loop.h"
#include "exec/exec-all.h"
#include "exec/tb-flush.h"
#include "sysemu/cpu-timers.h"
#include "qemu/guest-random.h"
#include "qapi/error.h"

/* CSR function table public API */
void riscv_get_csr_ops(int csrno, riscv_csr_operations *ops)
{
    *ops = csr_ops[csrno & (CSR_TABLE_SIZE - 1)];
}

void riscv_set_csr_ops(int csrno, riscv_csr_operations *ops)
{
    csr_ops[csrno & (CSR_TABLE_SIZE - 1)] = *ops;
}

/* Predicates */
#if !defined(CONFIG_USER_ONLY)
static RISCVException smstateen_acc_ok(CPURISCVState *env, int index,
                                       uint64_t bit)
{
    bool virt = riscv_cpu_virt_enabled(env);

    if (env->priv == PRV_M || !riscv_cpu_cfg(env)->ext_smstateen) {
        return RISCV_EXCP_NONE;
    }

    if (!(env->mstateen[index] & bit)) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    if (virt) {
        if (!(env->hstateen[index] & bit)) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        }

        if (env->priv == PRV_U && !(env->sstateen[index] & bit)) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        }
    }

    if (env->priv == PRV_U && riscv_has_ext(env, RVS)) {
        if (!(env->sstateen[index] & bit)) {
            return RISCV_EXCP_ILLEGAL_INST;
        }
    }

    return RISCV_EXCP_NONE;
}
#endif

static RISCVException fs(CPURISCVState *env, int csrno)
{
#if !defined(CONFIG_USER_ONLY)
    if (!env->debugger && !riscv_cpu_fp_enabled(env) &&
        !riscv_cpu_cfg(env)->ext_zfinx) {
        return RISCV_EXCP_ILLEGAL_INST;
    }
#endif
    return RISCV_EXCP_NONE;
}

static RISCVException vs(CPURISCVState *env, int csrno)
{
    RISCVCPU *cpu = env_archcpu(env);

    if (cpu->cfg.ext_zve32f) {
#if !defined(CONFIG_USER_ONLY)
        if (!env->debugger && !riscv_cpu_vector_enabled(env)) {
            return RISCV_EXCP_ILLEGAL_INST;
        }
#endif
        return RISCV_EXCP_NONE;
    }
    return RISCV_EXCP_ILLEGAL_INST;
}

static RISCVException ctr(CPURISCVState *env, int csrno)
{
#if !defined(CONFIG_USER_ONLY)
    RISCVCPU *cpu = env_archcpu(env);
    int ctr_index;
    target_ulong ctr_mask;
    int base_csrno = CSR_CYCLE;
    bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;

    if (rv32 && csrno >= CSR_CYCLEH) {
        /* Offset for RV32 hpmcounternh counters */
        base_csrno += 0x80;
    }
    ctr_index = csrno - base_csrno;
    ctr_mask = BIT(ctr_index);

    if ((csrno >= CSR_CYCLE && csrno <= CSR_INSTRET) ||
        (csrno >= CSR_CYCLEH && csrno <= CSR_INSTRETH)) {
        goto skip_ext_pmu_check;
    }

    if (!(cpu->pmu_avail_ctrs & ctr_mask)) {
        /* No counter is enabled in PMU or the counter is out of range */
        return RISCV_EXCP_ILLEGAL_INST;
    }

skip_ext_pmu_check:

    if (env->debugger) {
        return RISCV_EXCP_NONE;
    }

    if (env->priv < PRV_M && !get_field(env->mcounteren, ctr_mask)) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    if (riscv_cpu_virt_enabled(env)) {
        if (!get_field(env->hcounteren, ctr_mask) ||
            (env->priv == PRV_U && !get_field(env->scounteren, ctr_mask))) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        }
    }

    if (riscv_has_ext(env, RVS) && env->priv == PRV_U &&
        !get_field(env->scounteren, ctr_mask)) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

#endif
    return RISCV_EXCP_NONE;
}

static RISCVException ctr32(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_mxl(env) != MXL_RV32) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return ctr(env, csrno);
}

#if !defined(CONFIG_USER_ONLY)
static RISCVException mctr(CPURISCVState *env, int csrno)
{
    int pmu_num = riscv_cpu_cfg(env)->pmu_num;
    int ctr_index;
    int base_csrno = CSR_MHPMCOUNTER3;

    if ((riscv_cpu_mxl(env) == MXL_RV32) && csrno >= CSR_MCYCLEH) {
        /* Offset for RV32 mhpmcounternh counters */
        base_csrno += 0x80;
    }
    ctr_index = csrno - base_csrno;
    if (!pmu_num || ctr_index >= pmu_num) {
        /* The PMU is not enabled or counter is out of range*/
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return RISCV_EXCP_NONE;
}

static RISCVException mctr32(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_mxl(env) != MXL_RV32) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return mctr(env, csrno);
}

static RISCVException sscofpmf(CPURISCVState *env, int csrno)
{
    RISCVCPU *cpu = env_archcpu(env);

    if (!cpu->cfg.ext_sscofpmf) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return RISCV_EXCP_NONE;
}

static RISCVException any(CPURISCVState *env, int csrno)
{
    return RISCV_EXCP_NONE;
}

static RISCVException any32(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_mxl(env) != MXL_RV32) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return any(env, csrno);

}

static int aia_any(CPURISCVState *env, int csrno)
{
    if (!riscv_cpu_cfg(env)->ext_smaia) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return any(env, csrno);
}

static int aia_any32(CPURISCVState *env, int csrno)
{
    if (!riscv_cpu_cfg(env)->ext_smaia) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return any32(env, csrno);
}

static RISCVException smode(CPURISCVState *env, int csrno)
{
    if (riscv_has_ext(env, RVS)) {
        return RISCV_EXCP_NONE;
    }

    return RISCV_EXCP_ILLEGAL_INST;
}

static int smode32(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_mxl(env) != MXL_RV32) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return smode(env, csrno);
}

static int aia_smode(CPURISCVState *env, int csrno)
{
    if (!riscv_cpu_cfg(env)->ext_ssaia) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return smode(env, csrno);
}

static int aia_smode32(CPURISCVState *env, int csrno)
{
    if (!riscv_cpu_cfg(env)->ext_ssaia) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return smode32(env, csrno);
}

static RISCVException hmode(CPURISCVState *env, int csrno)
{
    if (riscv_has_ext(env, RVH)) {
        return RISCV_EXCP_NONE;
    }

    return RISCV_EXCP_ILLEGAL_INST;
}

static RISCVException hmode32(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_mxl(env) != MXL_RV32) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return hmode(env, csrno);

}

static RISCVException umode(CPURISCVState *env, int csrno)
{
    if (riscv_has_ext(env, RVU)) {
        return RISCV_EXCP_NONE;
    }

    return RISCV_EXCP_ILLEGAL_INST;
}

static RISCVException umode32(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_mxl(env) != MXL_RV32) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return umode(env, csrno);
}

static RISCVException mstateen(CPURISCVState *env, int csrno)
{
    RISCVCPU *cpu = env_archcpu(env);

    if (!cpu->cfg.ext_smstateen) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return any(env, csrno);
}

static RISCVException hstateen_pred(CPURISCVState *env, int csrno, int base)
{
    RISCVCPU *cpu = env_archcpu(env);

    if (!cpu->cfg.ext_smstateen) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    RISCVException ret = hmode(env, csrno);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    if (env->debugger) {
        return RISCV_EXCP_NONE;
    }

    if (env->priv < PRV_M) {
        if (!(env->mstateen[csrno - base] & SMSTATEEN_STATEEN)) {
            return RISCV_EXCP_ILLEGAL_INST;
        }
    }

    return RISCV_EXCP_NONE;
}

static RISCVException hstateen(CPURISCVState *env, int csrno)
{
    return hstateen_pred(env, csrno, CSR_HSTATEEN0);
}

static RISCVException hstateenh(CPURISCVState *env, int csrno)
{
    return hstateen_pred(env, csrno, CSR_HSTATEEN0H);
}

static RISCVException sstateen(CPURISCVState *env, int csrno)
{
    bool virt = riscv_cpu_virt_enabled(env);
    int index = csrno - CSR_SSTATEEN0;

    if (!riscv_cpu_cfg(env)->ext_smstateen) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    RISCVException ret = smode(env, csrno);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    if (env->debugger) {
        return RISCV_EXCP_NONE;
    }

    if (env->priv < PRV_M) {
        if (!(env->mstateen[index] & SMSTATEEN_STATEEN)) {
            return RISCV_EXCP_ILLEGAL_INST;
        }

        if (virt) {
            if (!(env->hstateen[index] & SMSTATEEN_STATEEN)) {
                return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
            }
        }
    }

    return RISCV_EXCP_NONE;
}

static RISCVException sstc(CPURISCVState *env, int csrno)
{
    RISCVCPU *cpu = env_archcpu(env);
    bool hmode_check = false;

    if (!cpu->cfg.ext_sstc || !env->rdtime_fn) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    if ((csrno == CSR_VSTIMECMP) || (csrno == CSR_VSTIMECMPH)) {
        hmode_check = true;
    }

    RISCVException ret = hmode_check ? hmode(env, csrno) : smode(env, csrno);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    if (env->debugger) {
        return RISCV_EXCP_NONE;
    }

    if (env->priv == PRV_M) {
        return RISCV_EXCP_NONE;
    }

    /*
     * No need of separate function for rv32 as menvcfg stores both menvcfg
     * menvcfgh for RV32.
     */
    if (!(get_field(env->mcounteren, COUNTEREN_TM) &&
          get_field(env->menvcfg, MENVCFG_STCE))) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    if (riscv_cpu_virt_enabled(env)) {
        if (!(get_field(env->hcounteren, COUNTEREN_TM) &&
              get_field(env->henvcfg, HENVCFG_STCE))) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        }
    }

    return RISCV_EXCP_NONE;
}

static RISCVException sstc_32(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_mxl(env) != MXL_RV32) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return sstc(env, csrno);
}

/* Checks if PointerMasking registers could be accessed */
static RISCVException pointer_masking(CPURISCVState *env, int csrno)
{
    /* Check if j-ext is present */
    if (riscv_has_ext(env, RVJ)) {
        return RISCV_EXCP_NONE;
    }
    return RISCV_EXCP_ILLEGAL_INST;
}

static int aia_hmode(CPURISCVState *env, int csrno)
{
    if (!riscv_cpu_cfg(env)->ext_ssaia) {
        return RISCV_EXCP_ILLEGAL_INST;
     }

     return hmode(env, csrno);
}

static int aia_hmode32(CPURISCVState *env, int csrno)
{
    if (!riscv_cpu_cfg(env)->ext_ssaia) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return hmode32(env, csrno);
}

static RISCVException pmp(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_cfg(env)->pmp) {
        if (csrno <= CSR_PMPCFG3) {
            uint32_t reg_index = csrno - CSR_PMPCFG0;

            /* TODO: RV128 restriction check */
            if ((reg_index & 1) && (riscv_cpu_mxl(env) == MXL_RV64)) {
                return RISCV_EXCP_ILLEGAL_INST;
            }
        }

        return RISCV_EXCP_NONE;
    }

    return RISCV_EXCP_ILLEGAL_INST;
}

static RISCVException epmp(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_cfg(env)->epmp) {
        return RISCV_EXCP_NONE;
    }

    return RISCV_EXCP_ILLEGAL_INST;
}

static RISCVException debug(CPURISCVState *env, int csrno)
{
    if (riscv_cpu_cfg(env)->debug) {
        return RISCV_EXCP_NONE;
    }

    return RISCV_EXCP_ILLEGAL_INST;
}
#endif

static RISCVException seed(CPURISCVState *env, int csrno)
{
    if (!riscv_cpu_cfg(env)->ext_zkr) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

#if !defined(CONFIG_USER_ONLY)
    if (env->debugger) {
        return RISCV_EXCP_NONE;
    }

    /*
     * With a CSR read-write instruction:
     * 1) The seed CSR is always available in machine mode as normal.
     * 2) Attempted access to seed from virtual modes VS and VU always raises
     * an exception(virtual instruction exception only if mseccfg.sseed=1).
     * 3) Without the corresponding access control bit set to 1, any attempted
     * access to seed from U, S or HS modes will raise an illegal instruction
     * exception.
     */
    if (env->priv == PRV_M) {
        return RISCV_EXCP_NONE;
    } else if (riscv_cpu_virt_enabled(env)) {
        if (env->mseccfg & MSECCFG_SSEED) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        } else {
            return RISCV_EXCP_ILLEGAL_INST;
        }
    } else {
        if (env->priv == PRV_S && (env->mseccfg & MSECCFG_SSEED)) {
            return RISCV_EXCP_NONE;
        } else if (env->priv == PRV_U && (env->mseccfg & MSECCFG_USEED)) {
            return RISCV_EXCP_NONE;
        } else {
            return RISCV_EXCP_ILLEGAL_INST;
        }
    }
#else
    return RISCV_EXCP_NONE;
#endif
}

/* User Floating-Point CSRs */
static RISCVException read_fflags(CPURISCVState *env, int csrno,
                                  target_ulong *val)
{
    *val = riscv_cpu_get_fflags(env);
    return RISCV_EXCP_NONE;
}

static RISCVException write_fflags(CPURISCVState *env, int csrno,
                                   target_ulong val)
{
#if !defined(CONFIG_USER_ONLY)
    if (riscv_has_ext(env, RVF)) {
        env->mstatus |= MSTATUS_FS;
    }
#endif
    riscv_cpu_set_fflags(env, val & (FSR_AEXC >> FSR_AEXC_SHIFT));
    return RISCV_EXCP_NONE;
}

static RISCVException read_frm(CPURISCVState *env, int csrno,
                               target_ulong *val)
{
    *val = env->frm;
    return RISCV_EXCP_NONE;
}

static RISCVException write_frm(CPURISCVState *env, int csrno,
                                target_ulong val)
{
#if !defined(CONFIG_USER_ONLY)
    if (riscv_has_ext(env, RVF)) {
        env->mstatus |= MSTATUS_FS;
    }
#endif
    env->frm = val & (FSR_RD >> FSR_RD_SHIFT);
    return RISCV_EXCP_NONE;
}

static RISCVException read_fcsr(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    *val = (riscv_cpu_get_fflags(env) << FSR_AEXC_SHIFT)
        | (env->frm << FSR_RD_SHIFT);
    return RISCV_EXCP_NONE;
}

static RISCVException write_fcsr(CPURISCVState *env, int csrno,
                                 target_ulong val)
{
#if !defined(CONFIG_USER_ONLY)
    if (riscv_has_ext(env, RVF)) {
        env->mstatus |= MSTATUS_FS;
    }
#endif
    env->frm = (val & FSR_RD) >> FSR_RD_SHIFT;
    riscv_cpu_set_fflags(env, (val & FSR_AEXC) >> FSR_AEXC_SHIFT);
    return RISCV_EXCP_NONE;
}

static RISCVException read_vtype(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    uint64_t vill;
    switch (env->xl) {
    case MXL_RV32:
        vill = (uint32_t)env->vill << 31;
        break;
    case MXL_RV64:
        vill = (uint64_t)env->vill << 63;
        break;
    default:
        g_assert_not_reached();
    }
    *val = (target_ulong)vill | env->vtype;
    return RISCV_EXCP_NONE;
}

static RISCVException read_vl(CPURISCVState *env, int csrno,
                              target_ulong *val)
{
    *val = env->vl;
    return RISCV_EXCP_NONE;
}

static int read_vlenb(CPURISCVState *env, int csrno, target_ulong *val)
{
    *val = riscv_cpu_cfg(env)->vlen >> 3;
    return RISCV_EXCP_NONE;
}

static RISCVException read_vxrm(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    *val = env->vxrm;
    return RISCV_EXCP_NONE;
}

static RISCVException write_vxrm(CPURISCVState *env, int csrno,
                                 target_ulong val)
{
#if !defined(CONFIG_USER_ONLY)
    env->mstatus |= MSTATUS_VS;
#endif
    env->vxrm = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_vxsat(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    *val = env->vxsat;
    return RISCV_EXCP_NONE;
}

static RISCVException write_vxsat(CPURISCVState *env, int csrno,
                                  target_ulong val)
{
#if !defined(CONFIG_USER_ONLY)
    env->mstatus |= MSTATUS_VS;
#endif
    env->vxsat = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_vstart(CPURISCVState *env, int csrno,
                                  target_ulong *val)
{
    *val = env->vstart;
    return RISCV_EXCP_NONE;
}

static RISCVException write_vstart(CPURISCVState *env, int csrno,
                                   target_ulong val)
{
#if !defined(CONFIG_USER_ONLY)
    env->mstatus |= MSTATUS_VS;
#endif
    /*
     * The vstart CSR is defined to have only enough writable bits
     * to hold the largest element index, i.e. lg2(VLEN) bits.
     */
    env->vstart = val & ~(~0ULL << ctzl(riscv_cpu_cfg(env)->vlen));
    return RISCV_EXCP_NONE;
}

static int read_vcsr(CPURISCVState *env, int csrno, target_ulong *val)
{
    *val = (env->vxrm << VCSR_VXRM_SHIFT) | (env->vxsat << VCSR_VXSAT_SHIFT);
    return RISCV_EXCP_NONE;
}

static int write_vcsr(CPURISCVState *env, int csrno, target_ulong val)
{
#if !defined(CONFIG_USER_ONLY)
    env->mstatus |= MSTATUS_VS;
#endif
    env->vxrm = (val & VCSR_VXRM) >> VCSR_VXRM_SHIFT;
    env->vxsat = (val & VCSR_VXSAT) >> VCSR_VXSAT_SHIFT;
    return RISCV_EXCP_NONE;
}

/* User Timers and Counters */
static target_ulong get_ticks(bool shift)
{
    int64_t val;
    target_ulong result;

#if !defined(CONFIG_USER_ONLY)
    if (icount_enabled()) {
        val = icount_get();
    } else {
        val = cpu_get_host_ticks();
    }
#else
    val = cpu_get_host_ticks();
#endif

    if (shift) {
        result = val >> 32;
    } else {
        result = val;
    }

    return result;
}

#if defined(CONFIG_USER_ONLY)
static RISCVException read_time(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    *val = cpu_get_host_ticks();
    return RISCV_EXCP_NONE;
}

static RISCVException read_timeh(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    *val = cpu_get_host_ticks() >> 32;
    return RISCV_EXCP_NONE;
}

static int read_hpmcounter(CPURISCVState *env, int csrno, target_ulong *val)
{
    *val = get_ticks(false);
    return RISCV_EXCP_NONE;
}

static int read_hpmcounterh(CPURISCVState *env, int csrno, target_ulong *val)
{
    *val = get_ticks(true);
    return RISCV_EXCP_NONE;
}

#else /* CONFIG_USER_ONLY */

static int read_mhpmevent(CPURISCVState *env, int csrno, target_ulong *val)
{
    int evt_index = csrno - CSR_MCOUNTINHIBIT;

    *val = env->mhpmevent_val[evt_index];

    return RISCV_EXCP_NONE;
}

static int write_mhpmevent(CPURISCVState *env, int csrno, target_ulong val)
{
    int evt_index = csrno - CSR_MCOUNTINHIBIT;
    uint64_t mhpmevt_val = val;

    env->mhpmevent_val[evt_index] = val;

    if (riscv_cpu_mxl(env) == MXL_RV32) {
        mhpmevt_val = mhpmevt_val |
                      ((uint64_t)env->mhpmeventh_val[evt_index] << 32);
    }
    riscv_pmu_update_event_map(env, mhpmevt_val, evt_index);

    return RISCV_EXCP_NONE;
}

static int read_mhpmeventh(CPURISCVState *env, int csrno, target_ulong *val)
{
    int evt_index = csrno - CSR_MHPMEVENT3H + 3;

    *val = env->mhpmeventh_val[evt_index];

    return RISCV_EXCP_NONE;
}

static int write_mhpmeventh(CPURISCVState *env, int csrno, target_ulong val)
{
    int evt_index = csrno - CSR_MHPMEVENT3H + 3;
    uint64_t mhpmevth_val = val;
    uint64_t mhpmevt_val = env->mhpmevent_val[evt_index];

    mhpmevt_val = mhpmevt_val | (mhpmevth_val << 32);
    env->mhpmeventh_val[evt_index] = val;

    riscv_pmu_update_event_map(env, mhpmevt_val, evt_index);

    return RISCV_EXCP_NONE;
}

static int write_mhpmcounter(CPURISCVState *env, int csrno, target_ulong val)
{
    int ctr_idx = csrno - CSR_MCYCLE;
    PMUCTRState *counter = &env->pmu_ctrs[ctr_idx];
    uint64_t mhpmctr_val = val;

    counter->mhpmcounter_val = val;
    if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
        riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
        counter->mhpmcounter_prev = get_ticks(false);
        if (ctr_idx > 2) {
            if (riscv_cpu_mxl(env) == MXL_RV32) {
                mhpmctr_val = mhpmctr_val |
                              ((uint64_t)counter->mhpmcounterh_val << 32);
            }
            riscv_pmu_setup_timer(env, mhpmctr_val, ctr_idx);
        }
     } else {
        /* Other counters can keep incrementing from the given value */
        counter->mhpmcounter_prev = val;
    }

    return RISCV_EXCP_NONE;
}

static int write_mhpmcounterh(CPURISCVState *env, int csrno, target_ulong val)
{
    int ctr_idx = csrno - CSR_MCYCLEH;
    PMUCTRState *counter = &env->pmu_ctrs[ctr_idx];
    uint64_t mhpmctr_val = counter->mhpmcounter_val;
    uint64_t mhpmctrh_val = val;

    counter->mhpmcounterh_val = val;
    mhpmctr_val = mhpmctr_val | (mhpmctrh_val << 32);
    if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
        riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
        counter->mhpmcounterh_prev = get_ticks(true);
        if (ctr_idx > 2) {
            riscv_pmu_setup_timer(env, mhpmctr_val, ctr_idx);
        }
    } else {
        counter->mhpmcounterh_prev = val;
    }

    return RISCV_EXCP_NONE;
}

static RISCVException riscv_pmu_read_ctr(CPURISCVState *env, target_ulong *val,
                                         bool upper_half, uint32_t ctr_idx)
{
    PMUCTRState counter = env->pmu_ctrs[ctr_idx];
    target_ulong ctr_prev = upper_half ? counter.mhpmcounterh_prev :
                                         counter.mhpmcounter_prev;
    target_ulong ctr_val = upper_half ? counter.mhpmcounterh_val :
                                        counter.mhpmcounter_val;

    if (get_field(env->mcountinhibit, BIT(ctr_idx))) {
        /**
         * Counter should not increment if inhibit bit is set. We can't really
         * stop the icount counting. Just return the counter value written by
         * the supervisor to indicate that counter was not incremented.
         */
        if (!counter.started) {
            *val = ctr_val;
            return RISCV_EXCP_NONE;
        } else {
            /* Mark that the counter has been stopped */
            counter.started = false;
        }
    }

    /**
     * The kernel computes the perf delta by subtracting the current value from
     * the value it initialized previously (ctr_val).
     */
    if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
        riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
        *val = get_ticks(upper_half) - ctr_prev + ctr_val;
    } else {
        *val = ctr_val;
    }

    return RISCV_EXCP_NONE;
}

static int read_hpmcounter(CPURISCVState *env, int csrno, target_ulong *val)
{
    uint16_t ctr_index;

    if (csrno >= CSR_MCYCLE && csrno <= CSR_MHPMCOUNTER31) {
        ctr_index = csrno - CSR_MCYCLE;
    } else if (csrno >= CSR_CYCLE && csrno <= CSR_HPMCOUNTER31) {
        ctr_index = csrno - CSR_CYCLE;
    } else {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return riscv_pmu_read_ctr(env, val, false, ctr_index);
}

static int read_hpmcounterh(CPURISCVState *env, int csrno, target_ulong *val)
{
    uint16_t ctr_index;

    if (csrno >= CSR_MCYCLEH && csrno <= CSR_MHPMCOUNTER31H) {
        ctr_index = csrno - CSR_MCYCLEH;
    } else if (csrno >= CSR_CYCLEH && csrno <= CSR_HPMCOUNTER31H) {
        ctr_index = csrno - CSR_CYCLEH;
    } else {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    return riscv_pmu_read_ctr(env, val, true, ctr_index);
}

static int read_scountovf(CPURISCVState *env, int csrno, target_ulong *val)
{
    int mhpmevt_start = CSR_MHPMEVENT3 - CSR_MCOUNTINHIBIT;
    int i;
    *val = 0;
    target_ulong *mhpm_evt_val;
    uint64_t of_bit_mask;

    if (riscv_cpu_mxl(env) == MXL_RV32) {
        mhpm_evt_val = env->mhpmeventh_val;
        of_bit_mask = MHPMEVENTH_BIT_OF;
    } else {
        mhpm_evt_val = env->mhpmevent_val;
        of_bit_mask = MHPMEVENT_BIT_OF;
    }

    for (i = mhpmevt_start; i < RV_MAX_MHPMEVENTS; i++) {
        if ((get_field(env->mcounteren, BIT(i))) &&
            (mhpm_evt_val[i] & of_bit_mask)) {
                    *val |= BIT(i);
            }
    }

    return RISCV_EXCP_NONE;
}

static RISCVException read_time(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    uint64_t delta = riscv_cpu_virt_enabled(env) ? env->htimedelta : 0;

    if (!env->rdtime_fn) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    *val = env->rdtime_fn(env->rdtime_fn_arg) + delta;
    return RISCV_EXCP_NONE;
}

static RISCVException read_timeh(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    uint64_t delta = riscv_cpu_virt_enabled(env) ? env->htimedelta : 0;

    if (!env->rdtime_fn) {
        return RISCV_EXCP_ILLEGAL_INST;
    }

    *val = (env->rdtime_fn(env->rdtime_fn_arg) + delta) >> 32;
    return RISCV_EXCP_NONE;
}

static RISCVException read_vstimecmp(CPURISCVState *env, int csrno,
                                     target_ulong *val)
{
    *val = env->vstimecmp;

    return RISCV_EXCP_NONE;
}

static RISCVException read_vstimecmph(CPURISCVState *env, int csrno,
                                      target_ulong *val)
{
    *val = env->vstimecmp >> 32;

    return RISCV_EXCP_NONE;
}

static RISCVException write_vstimecmp(CPURISCVState *env, int csrno,

                                      target_ulong val)
{
    RISCVCPU *cpu = env_archcpu(env);

    if (riscv_cpu_mxl(env) == MXL_RV32) {
        env->vstimecmp = deposit64(env->vstimecmp, 0, 32, (uint64_t)val);
    } else {
        env->vstimecmp = val;
    }

    riscv_timer_write_timecmp(cpu, env->vstimer, env->vstimecmp,
                              env->htimedelta, MIP_VSTIP);

    return RISCV_EXCP_NONE;
}

static RISCVException write_vstimecmph(CPURISCVState *env, int csrno,
                                       target_ulong val)
{
    RISCVCPU *cpu = env_archcpu(env);

    env->vstimecmp = deposit64(env->vstimecmp, 32, 32, (uint64_t)val);
    riscv_timer_write_timecmp(cpu, env->vstimer, env->vstimecmp,
                              env->htimedelta, MIP_VSTIP);

    return RISCV_EXCP_NONE;
}

static RISCVException read_stimecmp(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    if (riscv_cpu_virt_enabled(env)) {
        *val = env->vstimecmp;
    } else {
        *val = env->stimecmp;
    }

    return RISCV_EXCP_NONE;
}

static RISCVException read_stimecmph(CPURISCVState *env, int csrno,
                                     target_ulong *val)
{
    if (riscv_cpu_virt_enabled(env)) {
        *val = env->vstimecmp >> 32;
    } else {
        *val = env->stimecmp >> 32;
    }

    return RISCV_EXCP_NONE;
}

static RISCVException write_stimecmp(CPURISCVState *env, int csrno,
                                     target_ulong val)
{
    RISCVCPU *cpu = env_archcpu(env);

    if (riscv_cpu_virt_enabled(env)) {
        if (env->hvictl & HVICTL_VTI) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        }
        return write_vstimecmp(env, csrno, val);
    }

    if (riscv_cpu_mxl(env) == MXL_RV32) {
        env->stimecmp = deposit64(env->stimecmp, 0, 32, (uint64_t)val);
    } else {
        env->stimecmp = val;
    }

    riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);

    return RISCV_EXCP_NONE;
}

static RISCVException write_stimecmph(CPURISCVState *env, int csrno,
                                      target_ulong val)
{
    RISCVCPU *cpu = env_archcpu(env);

    if (riscv_cpu_virt_enabled(env)) {
        if (env->hvictl & HVICTL_VTI) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        }
        return write_vstimecmph(env, csrno, val);
    }

    env->stimecmp = deposit64(env->stimecmp, 32, 32, (uint64_t)val);
    riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);

    return RISCV_EXCP_NONE;
}

/* Machine constants */

#define M_MODE_INTERRUPTS  ((uint64_t)(MIP_MSIP | MIP_MTIP | MIP_MEIP))
#define S_MODE_INTERRUPTS  ((uint64_t)(MIP_SSIP | MIP_STIP | MIP_SEIP | \
                                      MIP_LCOFIP))
#define VS_MODE_INTERRUPTS ((uint64_t)(MIP_VSSIP | MIP_VSTIP | MIP_VSEIP))
#define HS_MODE_INTERRUPTS ((uint64_t)(MIP_SGEIP | VS_MODE_INTERRUPTS))

#define VSTOPI_NUM_SRCS 5

static const uint64_t delegable_ints = S_MODE_INTERRUPTS |
                                           VS_MODE_INTERRUPTS;
static const uint64_t vs_delegable_ints = VS_MODE_INTERRUPTS;
static const uint64_t all_ints = M_MODE_INTERRUPTS | S_MODE_INTERRUPTS |
                                     HS_MODE_INTERRUPTS;
#define DELEGABLE_EXCPS ((1ULL << (RISCV_EXCP_INST_ADDR_MIS)) | \
                         (1ULL << (RISCV_EXCP_INST_ACCESS_FAULT)) | \
                         (1ULL << (RISCV_EXCP_ILLEGAL_INST)) | \
                         (1ULL << (RISCV_EXCP_BREAKPOINT)) | \
                         (1ULL << (RISCV_EXCP_LOAD_ADDR_MIS)) | \
                         (1ULL << (RISCV_EXCP_LOAD_ACCESS_FAULT)) | \
                         (1ULL << (RISCV_EXCP_STORE_AMO_ADDR_MIS)) | \
                         (1ULL << (RISCV_EXCP_STORE_AMO_ACCESS_FAULT)) | \
                         (1ULL << (RISCV_EXCP_U_ECALL)) | \
                         (1ULL << (RISCV_EXCP_S_ECALL)) | \
                         (1ULL << (RISCV_EXCP_VS_ECALL)) | \
                         (1ULL << (RISCV_EXCP_M_ECALL)) | \
                         (1ULL << (RISCV_EXCP_INST_PAGE_FAULT)) | \
                         (1ULL << (RISCV_EXCP_LOAD_PAGE_FAULT)) | \
                         (1ULL << (RISCV_EXCP_STORE_PAGE_FAULT)) | \
                         (1ULL << (RISCV_EXCP_INST_GUEST_PAGE_FAULT)) | \
                         (1ULL << (RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT)) | \
                         (1ULL << (RISCV_EXCP_VIRT_INSTRUCTION_FAULT)) | \
                         (1ULL << (RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT)))
static const target_ulong vs_delegable_excps = DELEGABLE_EXCPS &
    ~((1ULL << (RISCV_EXCP_S_ECALL)) |
      (1ULL << (RISCV_EXCP_VS_ECALL)) |
      (1ULL << (RISCV_EXCP_M_ECALL)) |
      (1ULL << (RISCV_EXCP_INST_GUEST_PAGE_FAULT)) |
      (1ULL << (RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT)) |
      (1ULL << (RISCV_EXCP_VIRT_INSTRUCTION_FAULT)) |
      (1ULL << (RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT)));
static const target_ulong sstatus_v1_10_mask = SSTATUS_SIE | SSTATUS_SPIE |
    SSTATUS_UIE | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS |
    SSTATUS_SUM | SSTATUS_MXR | SSTATUS_VS;
static const target_ulong sip_writable_mask = SIP_SSIP | MIP_USIP | MIP_UEIP |
                                              SIP_LCOFIP;
static const target_ulong hip_writable_mask = MIP_VSSIP;
static const target_ulong hvip_writable_mask = MIP_VSSIP | MIP_VSTIP | MIP_VSEIP;
static const target_ulong vsip_writable_mask = MIP_VSSIP;

const bool valid_vm_1_10_32[16] = {
    [VM_1_10_MBARE] = true,
    [VM_1_10_SV32] = true
};

const bool valid_vm_1_10_64[16] = {
    [VM_1_10_MBARE] = true,
    [VM_1_10_SV39] = true,
    [VM_1_10_SV48] = true,
    [VM_1_10_SV57] = true
};

/* Machine Information Registers */
static RISCVException read_zero(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    *val = 0;
    return RISCV_EXCP_NONE;
}

static RISCVException write_ignore(CPURISCVState *env, int csrno,
                                   target_ulong val)
{
    return RISCV_EXCP_NONE;
}

static RISCVException read_mvendorid(CPURISCVState *env, int csrno,
                                     target_ulong *val)
{
    RISCVCPU *cpu = env_archcpu(env);

    *val = cpu->cfg.mvendorid;
    return RISCV_EXCP_NONE;
}

static RISCVException read_marchid(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    RISCVCPU *cpu = env_archcpu(env);

    *val = cpu->cfg.marchid;
    return RISCV_EXCP_NONE;
}

static RISCVException read_mimpid(CPURISCVState *env, int csrno,
                                  target_ulong *val)
{
    RISCVCPU *cpu = env_archcpu(env);

    *val = cpu->cfg.mimpid;
    return RISCV_EXCP_NONE;
}

static RISCVException read_mhartid(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    *val = env->mhartid;
    return RISCV_EXCP_NONE;
}

/* Machine Trap Setup */

/* We do not store SD explicitly, only compute it on demand. */
static uint64_t add_status_sd(RISCVMXL xl, uint64_t status)
{
    if ((status & MSTATUS_FS) == MSTATUS_FS ||
        (status & MSTATUS_VS) == MSTATUS_VS ||
        (status & MSTATUS_XS) == MSTATUS_XS) {
        switch (xl) {
        case MXL_RV32:
            return status | MSTATUS32_SD;
        case MXL_RV64:
            return status | MSTATUS64_SD;
        case MXL_RV128:
            return MSTATUSH128_SD;
        default:
            g_assert_not_reached();
        }
    }
    return status;
}

static RISCVException read_mstatus(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    *val = add_status_sd(riscv_cpu_mxl(env), env->mstatus);
    return RISCV_EXCP_NONE;
}

static bool validate_vm(CPURISCVState *env, target_ulong vm)
{
    RISCVCPU *cpu = RISCV_CPU(env_cpu(env));

    return (vm & 0xf) <= satp_mode_max_from_map(cpu->cfg.satp_mode.map);
}

static RISCVException write_mstatus(CPURISCVState *env, int csrno,
                                    target_ulong val)
{
    uint64_t mstatus = env->mstatus;
    uint64_t mask = 0;
    RISCVMXL xl = riscv_cpu_mxl(env);

    /* flush tlb on mstatus fields that affect VM */
    if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP | MSTATUS_MPV |
            MSTATUS_MPRV | MSTATUS_SUM)) {
        tlb_flush(env_cpu(env));
    }
    mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
        MSTATUS_SPP | MSTATUS_MPRV | MSTATUS_SUM |
        MSTATUS_MPP | MSTATUS_MXR | MSTATUS_TVM | MSTATUS_TSR |
        MSTATUS_TW | MSTATUS_VS;

    if (riscv_has_ext(env, RVF)) {
        mask |= MSTATUS_FS;
    }

    if (xl != MXL_RV32 || env->debugger) {
        /*
         * RV32: MPV and GVA are not in mstatus. The current plan is to
         * add them to mstatush. For now, we just don't support it.
         */
        mask |= MSTATUS_MPV | MSTATUS_GVA;
        if ((val & MSTATUS64_UXL) != 0) {
            mask |= MSTATUS64_UXL;
        }
    }

    mstatus = (mstatus & ~mask) | (val & mask);

    if (xl > MXL_RV32) {
        /* SXL field is for now read only */
        mstatus = set_field(mstatus, MSTATUS64_SXL, xl);
    }
    env->mstatus = mstatus;
    env->xl = cpu_recompute_xl(env);

    return RISCV_EXCP_NONE;
}

static RISCVException read_mstatush(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    *val = env->mstatus >> 32;
    return RISCV_EXCP_NONE;
}

static RISCVException write_mstatush(CPURISCVState *env, int csrno,
                                     target_ulong val)
{
    uint64_t valh = (uint64_t)val << 32;
    uint64_t mask = MSTATUS_MPV | MSTATUS_GVA;

    if ((valh ^ env->mstatus) & (MSTATUS_MPV)) {
        tlb_flush(env_cpu(env));
    }

    env->mstatus = (env->mstatus & ~mask) | (valh & mask);

    return RISCV_EXCP_NONE;
}

static RISCVException read_mstatus_i128(CPURISCVState *env, int csrno,
                                        Int128 *val)
{
    *val = int128_make128(env->mstatus, add_status_sd(MXL_RV128, env->mstatus));
    return RISCV_EXCP_NONE;
}

static RISCVException read_misa_i128(CPURISCVState *env, int csrno,
                                     Int128 *val)
{
    *val = int128_make128(env->misa_ext, (uint64_t)MXL_RV128 << 62);
    return RISCV_EXCP_NONE;
}

static RISCVException read_misa(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    target_ulong misa;

    switch (env->misa_mxl) {
    case MXL_RV32:
        misa = (target_ulong)MXL_RV32 << 30;
        break;
#ifdef TARGET_RISCV64
    case MXL_RV64:
        misa = (target_ulong)MXL_RV64 << 62;
        break;
#endif
    default:
        g_assert_not_reached();
    }

    *val = misa | env->misa_ext;
    return RISCV_EXCP_NONE;
}

static RISCVException write_misa(CPURISCVState *env, int csrno,
                                 target_ulong val)
{
    if (!riscv_cpu_cfg(env)->misa_w) {
        /* drop write to misa */
        return RISCV_EXCP_NONE;
    }

    /* 'I' or 'E' must be present */
    if (!(val & (RVI | RVE))) {
        /* It is not, drop write to misa */
        return RISCV_EXCP_NONE;
    }

    /* 'E' excludes all other extensions */
    if (val & RVE) {
        /*
         * when we support 'E' we can do "val = RVE;" however
         * for now we just drop writes if 'E' is present.
         */
        return RISCV_EXCP_NONE;
    }

    /*
     * misa.MXL writes are not supported by QEMU.
     * Drop writes to those bits.
     */

    /* Mask extensions that are not supported by this hart */
    val &= env->misa_ext_mask;

    /* 'D' depends on 'F', so clear 'D' if 'F' is not present */
    if ((val & RVD) && !(val & RVF)) {
        val &= ~RVD;
    }

    /*
     * Suppress 'C' if next instruction is not aligned
     * TODO: this should check next_pc
     */
    if ((val & RVC) && (GETPC() & ~3) != 0) {
        val &= ~RVC;
    }

    /* If nothing changed, do nothing. */
    if (val == env->misa_ext) {
        return RISCV_EXCP_NONE;
    }

    if (!(val & RVF)) {
        env->mstatus &= ~MSTATUS_FS;
    }

    /* flush translation cache */
    tb_flush(env_cpu(env));
    env->misa_ext = val;
    env->xl = riscv_cpu_mxl(env);
    return RISCV_EXCP_NONE;
}

static RISCVException read_medeleg(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    *val = env->medeleg;
    return RISCV_EXCP_NONE;
}

static RISCVException write_medeleg(CPURISCVState *env, int csrno,
                                    target_ulong val)
{
    env->medeleg = (env->medeleg & ~DELEGABLE_EXCPS) | (val & DELEGABLE_EXCPS);
    return RISCV_EXCP_NONE;
}

static RISCVException rmw_mideleg64(CPURISCVState *env, int csrno,
                                    uint64_t *ret_val,
                                    uint64_t new_val, uint64_t wr_mask)
{
    uint64_t mask = wr_mask & delegable_ints;

    if (ret_val) {
        *ret_val = env->mideleg;
    }

    env->mideleg = (env->mideleg & ~mask) | (new_val & mask);

    if (riscv_has_ext(env, RVH)) {
        env->mideleg |= HS_MODE_INTERRUPTS;
    }

    return RISCV_EXCP_NONE;
}

static RISCVException rmw_mideleg(CPURISCVState *env, int csrno,
                                  target_ulong *ret_val,
                                  target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_mideleg64(env, csrno, &rval, new_val, wr_mask);
    if (ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_midelegh(CPURISCVState *env, int csrno,
                                   target_ulong *ret_val,
                                   target_ulong new_val,
                                   target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_mideleg64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

static RISCVException rmw_mie64(CPURISCVState *env, int csrno,
                                uint64_t *ret_val,
                                uint64_t new_val, uint64_t wr_mask)
{
    uint64_t mask = wr_mask & all_ints;

    if (ret_val) {
        *ret_val = env->mie;
    }

    env->mie = (env->mie & ~mask) | (new_val & mask);

    if (!riscv_has_ext(env, RVH)) {
        env->mie &= ~((uint64_t)MIP_SGEIP);
    }

    return RISCV_EXCP_NONE;
}

static RISCVException rmw_mie(CPURISCVState *env, int csrno,
                              target_ulong *ret_val,
                              target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_mie64(env, csrno, &rval, new_val, wr_mask);
    if (ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_mieh(CPURISCVState *env, int csrno,
                               target_ulong *ret_val,
                               target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_mie64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

static int read_mtopi(CPURISCVState *env, int csrno, target_ulong *val)
{
    int irq;
    uint8_t iprio;

    irq = riscv_cpu_mirq_pending(env);
    if (irq <= 0 || irq > 63) {
        *val = 0;
    } else {
        iprio = env->miprio[irq];
        if (!iprio) {
            if (riscv_cpu_default_priority(irq) > IPRIO_DEFAULT_M) {
                iprio = IPRIO_MMAXIPRIO;
            }
        }
        *val = (irq & TOPI_IID_MASK) << TOPI_IID_SHIFT;
        *val |= iprio;
    }

    return RISCV_EXCP_NONE;
}

static int aia_xlate_vs_csrno(CPURISCVState *env, int csrno)
{
    if (!riscv_cpu_virt_enabled(env)) {
        return csrno;
    }

    switch (csrno) {
    case CSR_SISELECT:
        return CSR_VSISELECT;
    case CSR_SIREG:
        return CSR_VSIREG;
    case CSR_STOPEI:
        return CSR_VSTOPEI;
    default:
        return csrno;
    };
}

static int rmw_xiselect(CPURISCVState *env, int csrno, target_ulong *val,
                        target_ulong new_val, target_ulong wr_mask)
{
    target_ulong *iselect;

    /* Translate CSR number for VS-mode */
    csrno = aia_xlate_vs_csrno(env, csrno);

    /* Find the iselect CSR based on CSR number */
    switch (csrno) {
    case CSR_MISELECT:
        iselect = &env->miselect;
        break;
    case CSR_SISELECT:
        iselect = &env->siselect;
        break;
    case CSR_VSISELECT:
        iselect = &env->vsiselect;
        break;
    default:
         return RISCV_EXCP_ILLEGAL_INST;
    };

    if (val) {
        *val = *iselect;
    }

    wr_mask &= ISELECT_MASK;
    if (wr_mask) {
        *iselect = (*iselect & ~wr_mask) | (new_val & wr_mask);
    }

    return RISCV_EXCP_NONE;
}

static int rmw_iprio(target_ulong xlen,
                     target_ulong iselect, uint8_t *iprio,
                     target_ulong *val, target_ulong new_val,
                     target_ulong wr_mask, int ext_irq_no)
{
    int i, firq, nirqs;
    target_ulong old_val;

    if (iselect < ISELECT_IPRIO0 || ISELECT_IPRIO15 < iselect) {
        return -EINVAL;
    }
    if (xlen != 32 && iselect & 0x1) {
        return -EINVAL;
    }

    nirqs = 4 * (xlen / 32);
    firq = ((iselect - ISELECT_IPRIO0) / (xlen / 32)) * (nirqs);

    old_val = 0;
    for (i = 0; i < nirqs; i++) {
        old_val |= ((target_ulong)iprio[firq + i]) << (IPRIO_IRQ_BITS * i);
    }

    if (val) {
        *val = old_val;
    }

    if (wr_mask) {
        new_val = (old_val & ~wr_mask) | (new_val & wr_mask);
        for (i = 0; i < nirqs; i++) {
            /*
             * M-level and S-level external IRQ priority always read-only
             * zero. This means default priority order is always preferred
             * for M-level and S-level external IRQs.
             */
            if ((firq + i) == ext_irq_no) {
                continue;
            }
            iprio[firq + i] = (new_val >> (IPRIO_IRQ_BITS * i)) & 0xff;
        }
    }

    return 0;
}

static int rmw_xireg(CPURISCVState *env, int csrno, target_ulong *val,
                     target_ulong new_val, target_ulong wr_mask)
{
    bool virt;
    uint8_t *iprio;
    int ret = -EINVAL;
    target_ulong priv, isel, vgein;

    /* Translate CSR number for VS-mode */
    csrno = aia_xlate_vs_csrno(env, csrno);

    /* Decode register details from CSR number */
    virt = false;
    switch (csrno) {
    case CSR_MIREG:
        iprio = env->miprio;
        isel = env->miselect;
        priv = PRV_M;
        break;
    case CSR_SIREG:
        iprio = env->siprio;
        isel = env->siselect;
        priv = PRV_S;
        break;
    case CSR_VSIREG:
        iprio = env->hviprio;
        isel = env->vsiselect;
        priv = PRV_S;
        virt = true;
        break;
    default:
         goto done;
    };

    /* Find the selected guest interrupt file */
    vgein = (virt) ? get_field(env->hstatus, HSTATUS_VGEIN) : 0;

    if (ISELECT_IPRIO0 <= isel && isel <= ISELECT_IPRIO15) {
        /* Local interrupt priority registers not available for VS-mode */
        if (!virt) {
            ret = rmw_iprio(riscv_cpu_mxl_bits(env),
                            isel, iprio, val, new_val, wr_mask,
                            (priv == PRV_M) ? IRQ_M_EXT : IRQ_S_EXT);
        }
    } else if (ISELECT_IMSIC_FIRST <= isel && isel <= ISELECT_IMSIC_LAST) {
        /* IMSIC registers only available when machine implements it. */
        if (env->aia_ireg_rmw_fn[priv]) {
            /* Selected guest interrupt file should not be zero */
            if (virt && (!vgein || env->geilen < vgein)) {
                goto done;
            }
            /* Call machine specific IMSIC register emulation */
            ret = env->aia_ireg_rmw_fn[priv](env->aia_ireg_rmw_fn_arg[priv],
                                    AIA_MAKE_IREG(isel, priv, virt, vgein,
                                                  riscv_cpu_mxl_bits(env)),
                                    val, new_val, wr_mask);
        }
    }

done:
    if (ret) {
        return (riscv_cpu_virt_enabled(env) && virt) ?
               RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
    }
    return RISCV_EXCP_NONE;
}

static int rmw_xtopei(CPURISCVState *env, int csrno, target_ulong *val,
                      target_ulong new_val, target_ulong wr_mask)
{
    bool virt;
    int ret = -EINVAL;
    target_ulong priv, vgein;

    /* Translate CSR number for VS-mode */
    csrno = aia_xlate_vs_csrno(env, csrno);

    /* Decode register details from CSR number */
    virt = false;
    switch (csrno) {
    case CSR_MTOPEI:
        priv = PRV_M;
        break;
    case CSR_STOPEI:
        priv = PRV_S;
        break;
    case CSR_VSTOPEI:
        priv = PRV_S;
        virt = true;
        break;
    default:
        goto done;
    };

    /* IMSIC CSRs only available when machine implements IMSIC. */
    if (!env->aia_ireg_rmw_fn[priv]) {
        goto done;
    }

    /* Find the selected guest interrupt file */
    vgein = (virt) ? get_field(env->hstatus, HSTATUS_VGEIN) : 0;

    /* Selected guest interrupt file should be valid */
    if (virt && (!vgein || env->geilen < vgein)) {
        goto done;
    }

    /* Call machine specific IMSIC register emulation for TOPEI */
    ret = env->aia_ireg_rmw_fn[priv](env->aia_ireg_rmw_fn_arg[priv],
                    AIA_MAKE_IREG(ISELECT_IMSIC_TOPEI, priv, virt, vgein,
                                  riscv_cpu_mxl_bits(env)),
                    val, new_val, wr_mask);

done:
    if (ret) {
        return (riscv_cpu_virt_enabled(env) && virt) ?
               RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
    }
    return RISCV_EXCP_NONE;
}

static RISCVException read_mtvec(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    *val = env->mtvec;
    return RISCV_EXCP_NONE;
}

static RISCVException write_mtvec(CPURISCVState *env, int csrno,
                                  target_ulong val)
{
    /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
    if ((val & 3) < 2) {
        env->mtvec = val;
    } else {
        qemu_log_mask(LOG_UNIMP, "CSR_MTVEC: reserved mode not supported\n");
    }
    return RISCV_EXCP_NONE;
}

static RISCVException read_mcountinhibit(CPURISCVState *env, int csrno,
                                         target_ulong *val)
{
    *val = env->mcountinhibit;
    return RISCV_EXCP_NONE;
}

static RISCVException write_mcountinhibit(CPURISCVState *env, int csrno,
                                          target_ulong val)
{
    int cidx;
    PMUCTRState *counter;

    env->mcountinhibit = val;

    /* Check if any other counter is also monitoring cycles/instructions */
    for (cidx = 0; cidx < RV_MAX_MHPMCOUNTERS; cidx++) {
        if (!get_field(env->mcountinhibit, BIT(cidx))) {
            counter = &env->pmu_ctrs[cidx];
            counter->started = true;
        }
    }

    return RISCV_EXCP_NONE;
}

static RISCVException read_mcounteren(CPURISCVState *env, int csrno,
                                      target_ulong *val)
{
    *val = env->mcounteren;
    return RISCV_EXCP_NONE;
}

static RISCVException write_mcounteren(CPURISCVState *env, int csrno,
                                       target_ulong val)
{
    env->mcounteren = val;
    return RISCV_EXCP_NONE;
}

/* Machine Trap Handling */
static RISCVException read_mscratch_i128(CPURISCVState *env, int csrno,
                                         Int128 *val)
{
    *val = int128_make128(env->mscratch, env->mscratchh);
    return RISCV_EXCP_NONE;
}

static RISCVException write_mscratch_i128(CPURISCVState *env, int csrno,
                                          Int128 val)
{
    env->mscratch = int128_getlo(val);
    env->mscratchh = int128_gethi(val);
    return RISCV_EXCP_NONE;
}

static RISCVException read_mscratch(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    *val = env->mscratch;
    return RISCV_EXCP_NONE;
}

static RISCVException write_mscratch(CPURISCVState *env, int csrno,
                                     target_ulong val)
{
    env->mscratch = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_mepc(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    *val = env->mepc;
    return RISCV_EXCP_NONE;
}

static RISCVException write_mepc(CPURISCVState *env, int csrno,
                                 target_ulong val)
{
    env->mepc = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_mcause(CPURISCVState *env, int csrno,
                                  target_ulong *val)
{
    *val = env->mcause;
    return RISCV_EXCP_NONE;
}

static RISCVException write_mcause(CPURISCVState *env, int csrno,
                                   target_ulong val)
{
    env->mcause = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_mtval(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    *val = env->mtval;
    return RISCV_EXCP_NONE;
}

static RISCVException write_mtval(CPURISCVState *env, int csrno,
                                  target_ulong val)
{
    env->mtval = val;
    return RISCV_EXCP_NONE;
}

/* Execution environment configuration setup */
static RISCVException read_menvcfg(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    *val = env->menvcfg;
    return RISCV_EXCP_NONE;
}

static RISCVException write_menvcfg(CPURISCVState *env, int csrno,
                                    target_ulong val)
{
    RISCVCPUConfig *cfg = &env_archcpu(env)->cfg;
    uint64_t mask = MENVCFG_FIOM | MENVCFG_CBIE | MENVCFG_CBCFE | MENVCFG_CBZE;

    if (riscv_cpu_mxl(env) == MXL_RV64) {
        mask |= (cfg->ext_svpbmt ? MENVCFG_PBMTE : 0) |
                (cfg->ext_sstc ? MENVCFG_STCE : 0) |
                (cfg->ext_svadu ? MENVCFG_HADE : 0);
    }
    env->menvcfg = (env->menvcfg & ~mask) | (val & mask);

    return RISCV_EXCP_NONE;
}

static RISCVException read_menvcfgh(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    *val = env->menvcfg >> 32;
    return RISCV_EXCP_NONE;
}

static RISCVException write_menvcfgh(CPURISCVState *env, int csrno,
                                     target_ulong val)
{
    RISCVCPUConfig *cfg = &env_archcpu(env)->cfg;
    uint64_t mask = (cfg->ext_svpbmt ? MENVCFG_PBMTE : 0) |
                    (cfg->ext_sstc ? MENVCFG_STCE : 0) |
                    (cfg->ext_svadu ? MENVCFG_HADE : 0);
    uint64_t valh = (uint64_t)val << 32;

    env->menvcfg = (env->menvcfg & ~mask) | (valh & mask);

    return RISCV_EXCP_NONE;
}

static RISCVException read_senvcfg(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    RISCVException ret;

    ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSENVCFG);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    *val = env->senvcfg;
    return RISCV_EXCP_NONE;
}

static RISCVException write_senvcfg(CPURISCVState *env, int csrno,
                                    target_ulong val)
{
    uint64_t mask = SENVCFG_FIOM | SENVCFG_CBIE | SENVCFG_CBCFE | SENVCFG_CBZE;
    RISCVException ret;

    ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSENVCFG);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    env->senvcfg = (env->senvcfg & ~mask) | (val & mask);
    return RISCV_EXCP_NONE;
}

static RISCVException read_henvcfg(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    RISCVException ret;

    ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSENVCFG);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    /*
     * henvcfg.pbmte is read_only 0 when menvcfg.pbmte = 0
     * henvcfg.stce is read_only 0 when menvcfg.stce = 0
     * henvcfg.hade is read_only 0 when menvcfg.hade = 0
     */
    *val = env->henvcfg & (~(HENVCFG_PBMTE | HENVCFG_STCE | HENVCFG_HADE) |
                           env->menvcfg);
    return RISCV_EXCP_NONE;
}

static RISCVException write_henvcfg(CPURISCVState *env, int csrno,
                                    target_ulong val)
{
    uint64_t mask = HENVCFG_FIOM | HENVCFG_CBIE | HENVCFG_CBCFE | HENVCFG_CBZE;
    RISCVException ret;

    ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSENVCFG);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    if (riscv_cpu_mxl(env) == MXL_RV64) {
        mask |= env->menvcfg & (HENVCFG_PBMTE | HENVCFG_STCE | HENVCFG_HADE);
    }

    env->henvcfg = (env->henvcfg & ~mask) | (val & mask);

    return RISCV_EXCP_NONE;
}

static RISCVException read_henvcfgh(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    RISCVException ret;

    ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSENVCFG);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    *val = (env->henvcfg & (~(HENVCFG_PBMTE | HENVCFG_STCE | HENVCFG_HADE) |
                            env->menvcfg)) >> 32;
    return RISCV_EXCP_NONE;
}

static RISCVException write_henvcfgh(CPURISCVState *env, int csrno,
                                     target_ulong val)
{
    uint64_t mask = env->menvcfg & (HENVCFG_PBMTE | HENVCFG_STCE |
                                    HENVCFG_HADE);
    uint64_t valh = (uint64_t)val << 32;
    RISCVException ret;

    ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSENVCFG);
    if (ret != RISCV_EXCP_NONE) {
        return ret;
    }

    env->henvcfg = (env->henvcfg & ~mask) | (valh & mask);
    return RISCV_EXCP_NONE;
}

static RISCVException read_mstateen(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    *val = env->mstateen[csrno - CSR_MSTATEEN0];

    return RISCV_EXCP_NONE;
}

static RISCVException write_mstateen(CPURISCVState *env, int csrno,
                                     uint64_t wr_mask, target_ulong new_val)
{
    uint64_t *reg;

    reg = &env->mstateen[csrno - CSR_MSTATEEN0];
    *reg = (*reg & ~wr_mask) | (new_val & wr_mask);

    return RISCV_EXCP_NONE;
}

static RISCVException write_mstateen0(CPURISCVState *env, int csrno,
                                      target_ulong new_val)
{
    uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;

    return write_mstateen(env, csrno, wr_mask, new_val);
}

static RISCVException write_mstateen_1_3(CPURISCVState *env, int csrno,
                                         target_ulong new_val)
{
    return write_mstateen(env, csrno, SMSTATEEN_STATEEN, new_val);
}

static RISCVException read_mstateenh(CPURISCVState *env, int csrno,
                                     target_ulong *val)
{
    *val = env->mstateen[csrno - CSR_MSTATEEN0H] >> 32;

    return RISCV_EXCP_NONE;
}

static RISCVException write_mstateenh(CPURISCVState *env, int csrno,
                                      uint64_t wr_mask, target_ulong new_val)
{
    uint64_t *reg, val;

    reg = &env->mstateen[csrno - CSR_MSTATEEN0H];
    val = (uint64_t)new_val << 32;
    val |= *reg & 0xFFFFFFFF;
    *reg = (*reg & ~wr_mask) | (val & wr_mask);

    return RISCV_EXCP_NONE;
}

static RISCVException write_mstateen0h(CPURISCVState *env, int csrno,
                                       target_ulong new_val)
{
    uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;

    return write_mstateenh(env, csrno, wr_mask, new_val);
}

static RISCVException write_mstateenh_1_3(CPURISCVState *env, int csrno,
                                          target_ulong new_val)
{
    return write_mstateenh(env, csrno, SMSTATEEN_STATEEN, new_val);
}

static RISCVException read_hstateen(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    int index = csrno - CSR_HSTATEEN0;

    *val = env->hstateen[index] & env->mstateen[index];

    return RISCV_EXCP_NONE;
}

static RISCVException write_hstateen(CPURISCVState *env, int csrno,
                                     uint64_t mask, target_ulong new_val)
{
    int index = csrno - CSR_HSTATEEN0;
    uint64_t *reg, wr_mask;

    reg = &env->hstateen[index];
    wr_mask = env->mstateen[index] & mask;
    *reg = (*reg & ~wr_mask) | (new_val & wr_mask);

    return RISCV_EXCP_NONE;
}

static RISCVException write_hstateen0(CPURISCVState *env, int csrno,
                                      target_ulong new_val)
{
    uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;

    return write_hstateen(env, csrno, wr_mask, new_val);
}

static RISCVException write_hstateen_1_3(CPURISCVState *env, int csrno,
                                         target_ulong new_val)
{
    return write_hstateen(env, csrno, SMSTATEEN_STATEEN, new_val);
}

static RISCVException read_hstateenh(CPURISCVState *env, int csrno,
                                     target_ulong *val)
{
    int index = csrno - CSR_HSTATEEN0H;

    *val = (env->hstateen[index] >> 32) & (env->mstateen[index] >> 32);

    return RISCV_EXCP_NONE;
}

static RISCVException write_hstateenh(CPURISCVState *env, int csrno,
                                      uint64_t mask, target_ulong new_val)
{
    int index = csrno - CSR_HSTATEEN0H;
    uint64_t *reg, wr_mask, val;

    reg = &env->hstateen[index];
    val = (uint64_t)new_val << 32;
    val |= *reg & 0xFFFFFFFF;
    wr_mask = env->mstateen[index] & mask;
    *reg = (*reg & ~wr_mask) | (val & wr_mask);

    return RISCV_EXCP_NONE;
}

static RISCVException write_hstateen0h(CPURISCVState *env, int csrno,
                                       target_ulong new_val)
{
    uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;

    return write_hstateenh(env, csrno, wr_mask, new_val);
}

static RISCVException write_hstateenh_1_3(CPURISCVState *env, int csrno,
                                          target_ulong new_val)
{
    return write_hstateenh(env, csrno, SMSTATEEN_STATEEN, new_val);
}

static RISCVException read_sstateen(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    bool virt = riscv_cpu_virt_enabled(env);
    int index = csrno - CSR_SSTATEEN0;

    *val = env->sstateen[index] & env->mstateen[index];
    if (virt) {
        *val &= env->hstateen[index];
    }

    return RISCV_EXCP_NONE;
}

static RISCVException write_sstateen(CPURISCVState *env, int csrno,
                                     uint64_t mask, target_ulong new_val)
{
    bool virt = riscv_cpu_virt_enabled(env);
    int index = csrno - CSR_SSTATEEN0;
    uint64_t wr_mask;
    uint64_t *reg;

    wr_mask = env->mstateen[index] & mask;
    if (virt) {
        wr_mask &= env->hstateen[index];
    }

    reg = &env->sstateen[index];
    *reg = (*reg & ~wr_mask) | (new_val & wr_mask);

    return RISCV_EXCP_NONE;
}

static RISCVException write_sstateen0(CPURISCVState *env, int csrno,
                                      target_ulong new_val)
{
    uint64_t wr_mask = SMSTATEEN_STATEEN | SMSTATEEN0_HSENVCFG;

    return write_sstateen(env, csrno, wr_mask, new_val);
}

static RISCVException write_sstateen_1_3(CPURISCVState *env, int csrno,
                                      target_ulong new_val)
{
    return write_sstateen(env, csrno, SMSTATEEN_STATEEN, new_val);
}

static RISCVException rmw_mip64(CPURISCVState *env, int csrno,
                                uint64_t *ret_val,
                                uint64_t new_val, uint64_t wr_mask)
{
    RISCVCPU *cpu = env_archcpu(env);
    uint64_t old_mip, mask = wr_mask & delegable_ints;
    uint32_t gin;

    if (mask & MIP_SEIP) {
        env->software_seip = new_val & MIP_SEIP;
        new_val |= env->external_seip * MIP_SEIP;
    }

    if (cpu->cfg.ext_sstc && (env->priv == PRV_M) &&
        get_field(env->menvcfg, MENVCFG_STCE)) {
        /* sstc extension forbids STIP & VSTIP to be writeable in mip */
        mask = mask & ~(MIP_STIP | MIP_VSTIP);
    }

    if (mask) {
        old_mip = riscv_cpu_update_mip(cpu, mask, (new_val & mask));
    } else {
        old_mip = env->mip;
    }

    if (csrno != CSR_HVIP) {
        gin = get_field(env->hstatus, HSTATUS_VGEIN);
        old_mip |= (env->hgeip & ((target_ulong)1 << gin)) ? MIP_VSEIP : 0;
        old_mip |= env->vstime_irq ? MIP_VSTIP : 0;
    }

    if (ret_val) {
        *ret_val = old_mip;
    }

    return RISCV_EXCP_NONE;
}

static RISCVException rmw_mip(CPURISCVState *env, int csrno,
                              target_ulong *ret_val,
                              target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_mip64(env, csrno, &rval, new_val, wr_mask);
    if (ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_miph(CPURISCVState *env, int csrno,
                               target_ulong *ret_val,
                               target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_mip64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

/* Supervisor Trap Setup */
static RISCVException read_sstatus_i128(CPURISCVState *env, int csrno,
                                        Int128 *val)
{
    uint64_t mask = sstatus_v1_10_mask;
    uint64_t sstatus = env->mstatus & mask;
    if (env->xl != MXL_RV32 || env->debugger) {
        mask |= SSTATUS64_UXL;
    }

    *val = int128_make128(sstatus, add_status_sd(MXL_RV128, sstatus));
    return RISCV_EXCP_NONE;
}

static RISCVException read_sstatus(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    target_ulong mask = (sstatus_v1_10_mask);
    if (env->xl != MXL_RV32 || env->debugger) {
        mask |= SSTATUS64_UXL;
    }
    /* TODO: Use SXL not MXL. */
    *val = add_status_sd(riscv_cpu_mxl(env), env->mstatus & mask);
    return RISCV_EXCP_NONE;
}

static RISCVException write_sstatus(CPURISCVState *env, int csrno,
                                    target_ulong val)
{
    target_ulong mask = (sstatus_v1_10_mask);

    if (env->xl != MXL_RV32 || env->debugger) {
        if ((val & SSTATUS64_UXL) != 0) {
            mask |= SSTATUS64_UXL;
        }
    }
    target_ulong newval = (env->mstatus & ~mask) | (val & mask);
    return write_mstatus(env, CSR_MSTATUS, newval);
}

static RISCVException rmw_vsie64(CPURISCVState *env, int csrno,
                                 uint64_t *ret_val,
                                 uint64_t new_val, uint64_t wr_mask)
{
    RISCVException ret;
    uint64_t rval, mask = env->hideleg & VS_MODE_INTERRUPTS;

    /* Bring VS-level bits to correct position */
    new_val = (new_val & (VS_MODE_INTERRUPTS >> 1)) << 1;
    wr_mask = (wr_mask & (VS_MODE_INTERRUPTS >> 1)) << 1;

    ret = rmw_mie64(env, csrno, &rval, new_val, wr_mask & mask);
    if (ret_val) {
        *ret_val = (rval & mask) >> 1;
    }

    return ret;
}

static RISCVException rmw_vsie(CPURISCVState *env, int csrno,
                               target_ulong *ret_val,
                               target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_vsie64(env, csrno, &rval, new_val, wr_mask);
    if (ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_vsieh(CPURISCVState *env, int csrno,
                                target_ulong *ret_val,
                                target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_vsie64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

static RISCVException rmw_sie64(CPURISCVState *env, int csrno,
                                uint64_t *ret_val,
                                uint64_t new_val, uint64_t wr_mask)
{
    RISCVException ret;
    uint64_t mask = env->mideleg & S_MODE_INTERRUPTS;

    if (riscv_cpu_virt_enabled(env)) {
        if (env->hvictl & HVICTL_VTI) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        }
        ret = rmw_vsie64(env, CSR_VSIE, ret_val, new_val, wr_mask);
    } else {
        ret = rmw_mie64(env, csrno, ret_val, new_val, wr_mask & mask);
    }

    if (ret_val) {
        *ret_val &= mask;
    }

    return ret;
}

static RISCVException rmw_sie(CPURISCVState *env, int csrno,
                              target_ulong *ret_val,
                              target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_sie64(env, csrno, &rval, new_val, wr_mask);
    if (ret == RISCV_EXCP_NONE && ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_sieh(CPURISCVState *env, int csrno,
                               target_ulong *ret_val,
                               target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_sie64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

static RISCVException read_stvec(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    *val = env->stvec;
    return RISCV_EXCP_NONE;
}

static RISCVException write_stvec(CPURISCVState *env, int csrno,
                                  target_ulong val)
{
    /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
    if ((val & 3) < 2) {
        env->stvec = val;
    } else {
        qemu_log_mask(LOG_UNIMP, "CSR_STVEC: reserved mode not supported\n");
    }
    return RISCV_EXCP_NONE;
}

static RISCVException read_scounteren(CPURISCVState *env, int csrno,
                                      target_ulong *val)
{
    *val = env->scounteren;
    return RISCV_EXCP_NONE;
}

static RISCVException write_scounteren(CPURISCVState *env, int csrno,
                                       target_ulong val)
{
    env->scounteren = val;
    return RISCV_EXCP_NONE;
}

/* Supervisor Trap Handling */
static RISCVException read_sscratch_i128(CPURISCVState *env, int csrno,
                                         Int128 *val)
{
    *val = int128_make128(env->sscratch, env->sscratchh);
    return RISCV_EXCP_NONE;
}

static RISCVException write_sscratch_i128(CPURISCVState *env, int csrno,
                                          Int128 val)
{
    env->sscratch = int128_getlo(val);
    env->sscratchh = int128_gethi(val);
    return RISCV_EXCP_NONE;
}

static RISCVException read_sscratch(CPURISCVState *env, int csrno,
                                    target_ulong *val)
{
    *val = env->sscratch;
    return RISCV_EXCP_NONE;
}

static RISCVException write_sscratch(CPURISCVState *env, int csrno,
                                     target_ulong val)
{
    env->sscratch = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_sepc(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    *val = env->sepc;
    return RISCV_EXCP_NONE;
}

static RISCVException write_sepc(CPURISCVState *env, int csrno,
                                 target_ulong val)
{
    env->sepc = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_scause(CPURISCVState *env, int csrno,
                                  target_ulong *val)
{
    *val = env->scause;
    return RISCV_EXCP_NONE;
}

static RISCVException write_scause(CPURISCVState *env, int csrno,
                                   target_ulong val)
{
    env->scause = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_stval(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    *val = env->stval;
    return RISCV_EXCP_NONE;
}

static RISCVException write_stval(CPURISCVState *env, int csrno,
                                  target_ulong val)
{
    env->stval = val;
    return RISCV_EXCP_NONE;
}

static RISCVException rmw_vsip64(CPURISCVState *env, int csrno,
                                 uint64_t *ret_val,
                                 uint64_t new_val, uint64_t wr_mask)
{
    RISCVException ret;
    uint64_t rval, mask = env->hideleg & VS_MODE_INTERRUPTS;

    /* Bring VS-level bits to correct position */
    new_val = (new_val & (VS_MODE_INTERRUPTS >> 1)) << 1;
    wr_mask = (wr_mask & (VS_MODE_INTERRUPTS >> 1)) << 1;

    ret = rmw_mip64(env, csrno, &rval, new_val,
                    wr_mask & mask & vsip_writable_mask);
    if (ret_val) {
        *ret_val = (rval & mask) >> 1;
    }

    return ret;
}

static RISCVException rmw_vsip(CPURISCVState *env, int csrno,
                               target_ulong *ret_val,
                               target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_vsip64(env, csrno, &rval, new_val, wr_mask);
    if (ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_vsiph(CPURISCVState *env, int csrno,
                                target_ulong *ret_val,
                                target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_vsip64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

static RISCVException rmw_sip64(CPURISCVState *env, int csrno,
                                uint64_t *ret_val,
                                uint64_t new_val, uint64_t wr_mask)
{
    RISCVException ret;
    uint64_t mask = env->mideleg & sip_writable_mask;

    if (riscv_cpu_virt_enabled(env)) {
        if (env->hvictl & HVICTL_VTI) {
            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
        }
        ret = rmw_vsip64(env, CSR_VSIP, ret_val, new_val, wr_mask);
    } else {
        ret = rmw_mip64(env, csrno, ret_val, new_val, wr_mask & mask);
    }

    if (ret_val) {
        *ret_val &= env->mideleg & S_MODE_INTERRUPTS;
    }

    return ret;
}

static RISCVException rmw_sip(CPURISCVState *env, int csrno,
                              target_ulong *ret_val,
                              target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_sip64(env, csrno, &rval, new_val, wr_mask);
    if (ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_siph(CPURISCVState *env, int csrno,
                               target_ulong *ret_val,
                               target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_sip64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

/* Supervisor Protection and Translation */
static RISCVException read_satp(CPURISCVState *env, int csrno,
                                target_ulong *val)
{
    if (!riscv_cpu_cfg(env)->mmu) {
        *val = 0;
        return RISCV_EXCP_NONE;
    }

    if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
        return RISCV_EXCP_ILLEGAL_INST;
    } else {
        *val = env->satp;
    }

    return RISCV_EXCP_NONE;
}

static RISCVException write_satp(CPURISCVState *env, int csrno,
                                 target_ulong val)
{
    target_ulong mask;
    bool vm;

    if (!riscv_cpu_cfg(env)->mmu) {
        return RISCV_EXCP_NONE;
    }

    if (riscv_cpu_mxl(env) == MXL_RV32) {
        vm = validate_vm(env, get_field(val, SATP32_MODE));
        mask = (val ^ env->satp) & (SATP32_MODE | SATP32_ASID | SATP32_PPN);
    } else {
        vm = validate_vm(env, get_field(val, SATP64_MODE));
        mask = (val ^ env->satp) & (SATP64_MODE | SATP64_ASID | SATP64_PPN);
    }

    if (vm && mask) {
        if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
            return RISCV_EXCP_ILLEGAL_INST;
        } else {
            /*
             * The ISA defines SATP.MODE=Bare as "no translation", but we still
             * pass these through QEMU's TLB emulation as it improves
             * performance.  Flushing the TLB on SATP writes with paging
             * enabled avoids leaking those invalid cached mappings.
             */
            tlb_flush(env_cpu(env));
            env->satp = val;
        }
    }
    return RISCV_EXCP_NONE;
}

static int read_vstopi(CPURISCVState *env, int csrno, target_ulong *val)
{
    int irq, ret;
    target_ulong topei;
    uint64_t vseip, vsgein;
    uint32_t iid, iprio, hviid, hviprio, gein;
    uint32_t s, scount = 0, siid[VSTOPI_NUM_SRCS], siprio[VSTOPI_NUM_SRCS];

    gein = get_field(env->hstatus, HSTATUS_VGEIN);
    hviid = get_field(env->hvictl, HVICTL_IID);
    hviprio = get_field(env->hvictl, HVICTL_IPRIO);

    if (gein) {
        vsgein = (env->hgeip & (1ULL << gein)) ? MIP_VSEIP : 0;
        vseip = env->mie & (env->mip | vsgein) & MIP_VSEIP;
        if (gein <= env->geilen && vseip) {
            siid[scount] = IRQ_S_EXT;
            siprio[scount] = IPRIO_MMAXIPRIO + 1;
            if (env->aia_ireg_rmw_fn[PRV_S]) {
                /*
                 * Call machine specific IMSIC register emulation for
                 * reading TOPEI.
                 */
                ret = env->aia_ireg_rmw_fn[PRV_S](
                        env->aia_ireg_rmw_fn_arg[PRV_S],
                        AIA_MAKE_IREG(ISELECT_IMSIC_TOPEI, PRV_S, true, gein,
                                      riscv_cpu_mxl_bits(env)),
                        &topei, 0, 0);
                if (!ret && topei) {
                    siprio[scount] = topei & IMSIC_TOPEI_IPRIO_MASK;
                }
            }
            scount++;
        }
    } else {
        if (hviid == IRQ_S_EXT && hviprio) {
            siid[scount] = IRQ_S_EXT;
            siprio[scount] = hviprio;
            scount++;
        }
    }

    if (env->hvictl & HVICTL_VTI) {
        if (hviid != IRQ_S_EXT) {
            siid[scount] = hviid;
            siprio[scount] = hviprio;
            scount++;
        }
    } else {
        irq = riscv_cpu_vsirq_pending(env);
        if (irq != IRQ_S_EXT && 0 < irq && irq <= 63) {
            siid[scount] = irq;
            siprio[scount] = env->hviprio[irq];
            scount++;
        }
    }

    iid = 0;
    iprio = UINT_MAX;
    for (s = 0; s < scount; s++) {
        if (siprio[s] < iprio) {
            iid = siid[s];
            iprio = siprio[s];
        }
    }

    if (iid) {
        if (env->hvictl & HVICTL_IPRIOM) {
            if (iprio > IPRIO_MMAXIPRIO) {
                iprio = IPRIO_MMAXIPRIO;
            }
            if (!iprio) {
                if (riscv_cpu_default_priority(iid) > IPRIO_DEFAULT_S) {
                    iprio = IPRIO_MMAXIPRIO;
                }
            }
        } else {
            iprio = 1;
        }
    } else {
        iprio = 0;
    }

    *val = (iid & TOPI_IID_MASK) << TOPI_IID_SHIFT;
    *val |= iprio;
    return RISCV_EXCP_NONE;
}

static int read_stopi(CPURISCVState *env, int csrno, target_ulong *val)
{
    int irq;
    uint8_t iprio;

    if (riscv_cpu_virt_enabled(env)) {
        return read_vstopi(env, CSR_VSTOPI, val);
    }

    irq = riscv_cpu_sirq_pending(env);
    if (irq <= 0 || irq > 63) {
        *val = 0;
    } else {
        iprio = env->siprio[irq];
        if (!iprio) {
            if (riscv_cpu_default_priority(irq) > IPRIO_DEFAULT_S) {
                iprio = IPRIO_MMAXIPRIO;
           }
        }
        *val = (irq & TOPI_IID_MASK) << TOPI_IID_SHIFT;
        *val |= iprio;
    }

    return RISCV_EXCP_NONE;
}

/* Hypervisor Extensions */
static RISCVException read_hstatus(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    *val = env->hstatus;
    if (riscv_cpu_mxl(env) != MXL_RV32) {
        /* We only support 64-bit VSXL */
        *val = set_field(*val, HSTATUS_VSXL, 2);
    }
    /* We only support little endian */
    *val = set_field(*val, HSTATUS_VSBE, 0);
    return RISCV_EXCP_NONE;
}

static RISCVException write_hstatus(CPURISCVState *env, int csrno,
                                    target_ulong val)
{
    env->hstatus = val;
    if (riscv_cpu_mxl(env) != MXL_RV32 && get_field(val, HSTATUS_VSXL) != 2) {
        qemu_log_mask(LOG_UNIMP, "QEMU does not support mixed HSXLEN options.");
    }
    if (get_field(val, HSTATUS_VSBE) != 0) {
        qemu_log_mask(LOG_UNIMP, "QEMU does not support big endian guests.");
    }
    return RISCV_EXCP_NONE;
}

static RISCVException read_hedeleg(CPURISCVState *env, int csrno,
                                   target_ulong *val)
{
    *val = env->hedeleg;
    return RISCV_EXCP_NONE;
}

static RISCVException write_hedeleg(CPURISCVState *env, int csrno,
                                    target_ulong val)
{
    env->hedeleg = val & vs_delegable_excps;
    return RISCV_EXCP_NONE;
}

static RISCVException rmw_hideleg64(CPURISCVState *env, int csrno,
                                    uint64_t *ret_val,
                                    uint64_t new_val, uint64_t wr_mask)
{
    uint64_t mask = wr_mask & vs_delegable_ints;

    if (ret_val) {
        *ret_val = env->hideleg & vs_delegable_ints;
    }

    env->hideleg = (env->hideleg & ~mask) | (new_val & mask);
    return RISCV_EXCP_NONE;
}

static RISCVException rmw_hideleg(CPURISCVState *env, int csrno,
                                  target_ulong *ret_val,
                                  target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_hideleg64(env, csrno, &rval, new_val, wr_mask);
    if (ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_hidelegh(CPURISCVState *env, int csrno,
                                   target_ulong *ret_val,
                                   target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_hideleg64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

static RISCVException rmw_hvip64(CPURISCVState *env, int csrno,
                                 uint64_t *ret_val,
                                 uint64_t new_val, uint64_t wr_mask)
{
    RISCVException ret;

    ret = rmw_mip64(env, csrno, ret_val, new_val,
                    wr_mask & hvip_writable_mask);
    if (ret_val) {
        *ret_val &= VS_MODE_INTERRUPTS;
    }

    return ret;
}

static RISCVException rmw_hvip(CPURISCVState *env, int csrno,
                               target_ulong *ret_val,
                               target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_hvip64(env, csrno, &rval, new_val, wr_mask);
    if (ret_val) {
        *ret_val = rval;
    }

    return ret;
}

static RISCVException rmw_hviph(CPURISCVState *env, int csrno,
                                target_ulong *ret_val,
                                target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_hvip64(env, csrno, &rval,
        ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
    if (ret_val) {
        *ret_val = rval >> 32;
    }

    return ret;
}

static RISCVException rmw_hip(CPURISCVState *env, int csrno,
                              target_ulong *ret_value,
                              target_ulong new_value, target_ulong write_mask)
{
    int ret = rmw_mip(env, csrno, ret_value, new_value,
                      write_mask & hip_writable_mask);

    if (ret_value) {
        *ret_value &= HS_MODE_INTERRUPTS;
    }
    return ret;
}

static RISCVException rmw_hie(CPURISCVState *env, int csrno,
                              target_ulong *ret_val,
                              target_ulong new_val, target_ulong wr_mask)
{
    uint64_t rval;
    RISCVException ret;

    ret = rmw_mie64(env, csrno, &rval, new_val, wr_mask & HS_MODE_INTERRUPTS);
    if (ret_val) {
        *ret_val = rval & HS_MODE_INTERRUPTS;
    }

    return ret;
}

static RISCVException read_hcounteren(CPURISCVState *env, int csrno,
                                      target_ulong *val)
{
    *val = env->hcounteren;
    return RISCV_EXCP_NONE;
}

static RISCVException write_hcounteren(CPURISCVState *env, int csrno,
                                       target_ulong val)
{
    env->hcounteren = val;
    return RISCV_EXCP_NONE;
}

static RISCVException read_hgeie(CPURISCVState *env, int csrno,
                                 target_ulong *val)
{
    if (val) {
        *val = env->hgeie;
    }
    return RISCV_EXCP_NONE;
}

static RISCVException write_hgeie(CPURISCVState *env, int csrno,