package vexiiriscv.memory

import spinal.core
import spinal.core._
import spinal.lib._
import spinal.lib.fsm._
import spinal.lib.misc.plugin.FiberPlugin
import spinal.lib.misc.pipeline._
import vexiiriscv._
import Global._
import spinal.lib.misc.pipeline.{NodeBaseApi, Payload}
import vexiiriscv.execute.{CsrAccessPlugin, CsrListFilter, CsrRamService}
import vexiiriscv.memory.AddressTranslationPortUsage.{FETCH, LOAD_STORE}
import vexiiriscv.misc.{PerformanceCounterService, PipelineBuilderPlugin, PrivilegedPlugin, TrapReason}
import vexiiriscv.riscv.{CSR, PrivilegeMode}
import vexiiriscv.riscv.Riscv._

import scala.collection.mutable.ArrayBuffer

case class MmuStorageLevel(id : Int,
                           ways : Int,
                           sets : Int){
  assert(isPow2(sets))
}

case class MmuStorageParameter(levels : Seq[MmuStorageLevel],
                               priority : Int)

case class MmuPortParameter(var readAt : Int,
                            var hitsAt : Int,
                            var ctrlAt : Int,
                            var rspAt : Int){

}

case class MmuStorageSpec(p: MmuStorageParameter, pmuEventId : Int) extends Nameable

case class MmuSpec(levels : Seq[MmuLevel],
                   entryBytes : Int,
                   virtualWidth : Int,
                   physicalWidth : Int,
                   satpMode : Int,
                   pteReserved : BigInt)

case class MmuLevel(virtualWidth : Int,
                    physicalWidth : Int,
                    virtualOffset : Int,
                    physicalOffset : Int,
                    entryOffset : Int){
  def vpn(address : UInt) : UInt = address(virtualRange)

  val virtualRange  = virtualOffset  + virtualWidth  -1 downto virtualOffset
  val entryRange    = entryOffset    + physicalWidth -1 downto entryOffset
  val physicalRange = physicalOffset + physicalWidth -1 downto physicalOffset
}

object MmuSpec{
  val sv32 = MmuSpec(
    levels     = List(
      MmuLevel(virtualWidth = 10, physicalWidth = 10, virtualOffset =  12, physicalOffset = 12, entryOffset =  10),
      MmuLevel(virtualWidth = 10, physicalWidth = 10, virtualOffset =  22, physicalOffset = 22, entryOffset =  20) //Avoid 34 bits physical address
    ),
    entryBytes = 4,
    virtualWidth   = 32,
    physicalWidth  = 32,
    satpMode   = 1,
    pteReserved = 0
  )
  val sv39 = MmuSpec(
    levels     = List(
      MmuLevel(virtualWidth = 9, physicalWidth = 9 , virtualOffset =  12, physicalOffset = 12, entryOffset =  10),
      MmuLevel(virtualWidth = 9, physicalWidth = 9 , virtualOffset =  21, physicalOffset = 21, entryOffset =  19),
      MmuLevel(virtualWidth = 9, physicalWidth = 26, virtualOffset =  30, physicalOffset = 30, entryOffset =  28)
    ),
    entryBytes = 8,
    virtualWidth   = 39,
    physicalWidth  = 56,
    satpMode   = 8,
    pteReserved = BigInt("FFC0000000000000", 16)
  )
}

case class MmuTlbStorageEntryParam(
  checkUser: Boolean,
  checkGuest: Boolean
)

class MmuTlbStorageEntry(
  spec : MmuSpec,
  physicalWidth : Int,
  p : MmuTlbStorageEntryParam,
  levelId : Int,
  depth : Int
) extends Bundle {
  def vw = spec.levels.drop(levelId).map(_.virtualWidth).sum
  def pw = spec.levels.drop(levelId).map(_.physicalWidth).sum-(spec.physicalWidth-physicalWidth)

  val valid = Bool()
  val virtualAddress  = UInt(vw-log2Up(depth) bits)
  val physicalAddress = UInt(pw bits)
  val allowRead, allowWrite, allowExecute = Bool()
  val allowUser = p.checkUser generate Bool()
  val guest = p.checkGuest generate Bool()

  def hit(address : UInt) = /*valid && */virtualAddress === address(spec.levels(levelId).virtualOffset + log2Up(depth), vw - log2Up(depth) bits)
  def physicalAddressFrom(address : UInt) = physicalAddress @@ address(0, spec.levels(levelId).physicalOffset bits)
}

class MmuTlbStorage(
  spec : MmuSpec,
  physicalWidth : Int,
  tsp : MmuTlbStorageEntryParam,
  ss : MmuStorageSpec
) extends Composite(ss, "logic", false) {
  def newTlbEntry(level: Int, depth: Int) = new MmuTlbStorageEntry(spec, physicalWidth, tsp, level, depth)

  val sl = for(e <- ss.p.levels) yield new Area{
    val slp = e
    val level = spec.levels(slp.id)
    def newEntry() = newTlbEntry(slp.id, slp.sets)
    val ways = List.fill(slp.ways)(Mem.fill(slp.sets)(newEntry()))
    val lineRange = level.virtualRange.low + log2Up(slp.sets) -1 downto level.virtualRange.low

    val write = new Area{
      val mask    = Bits(slp.ways bits)
      val address = UInt(log2Up(slp.sets) bits)
      val data    = newEntry()

      mask := 0
      address.assignDontCare()
      data.assignDontCare()

      for((way, sel) <- (ways, mask.asBools).zipped){
        way.write(address, data, sel)
      }
    }
    val allocId = Counter(slp.ways)

    val keys = new Area {
      // setName(s"MMU_L${e.id}")
      val ENTRIES = Payload(Vec.fill(slp.ways)(newEntry()))
      val HITS_PRE_VALID = Payload(Bits(slp.ways bits))
      val HITS = Payload(Bits(slp.ways bits))
    }
  }
}

trait GenericMmuPlugin extends AddressTranslationService {
  override def mayNeedRedo: Boolean = true

  case class PortSpec(stages: Seq[NodeBaseApi],
                      req: AddressTranslationReq,
                      usage : AddressTranslationPortUsage,
                      pp: MmuPortParameter,
                      ss : MmuStorageSpec,
                      rsp : AddressTranslationRsp){
    val readStage = stages(pp.readAt)
    val hitsStage = stages(pp.hitsAt)
    val ctrlStage = stages(pp.ctrlAt)
    val rspStage  = stages(pp.ctrlAt)
  }
  val portSpecs = ArrayBuffer[PortSpec]()

  val storageSpecs = ArrayBuffer[MmuStorageSpec]()

  override def newStorage(pAny: Any, pmuEventId : Int) : Any = {
    val p = pAny.asInstanceOf[MmuStorageParameter]
    storageSpecs.addRet(MmuStorageSpec(p, pmuEventId))
  }

  override def getStorageId(s: Any): Int = storageSpecs.indexOf(s)
  override def getStorageIdWidth(): Int = {
    storageLock.await()
    log2Up(storageSpecs.size)
  }

  override def newTranslationPort(stages: Seq[NodeBaseApi],
                                  req: AddressTranslationReq,
                                  usage : AddressTranslationPortUsage,
                                  portSpec: Any,
                                  storageSpec: Any) = {
    val pp = portSpec.asInstanceOf[MmuPortParameter]
    val ss = storageSpec.asInstanceOf[MmuStorageSpec]
    portSpecs.addRet(
      new PortSpec(
        stages      = stages,
        req         = req,
        usage       = usage,
        pp          = pp,
        ss          = ss,
        rsp         = new AddressTranslationRsp(this /*, stages(pp.rspAt)*/, ss.p.levels.map(_.ways).sum)
      )
    ).rsp
  }
}

/**
 * Implement the RISC-V MMU using a N-way set associative TLB storage. This fit very well with FPGA which have distributed memories.
 * For FPGA that do not have that, the MmuPortParameter can be configured to have a low number of sets or use 1 cycle delay to be inferable as block ram.
 *
 * Plugins which uses the MmuPlugin can request TLB storage, then they can require the MmuPlugin to bind a new port on a existing pipeline using that TLB storage.
 * A given TLB storage can be used by multiple MMU ports.
 *
 * MMU miss will not by itself trigger a TLB refill. This is instead triggered by the TrapPlugin.
 */
class MmuPlugin(var spec : MmuSpec,
                var physicalWidth : Int,
                var asidWidth : Int) extends FiberPlugin with GenericMmuPlugin{
  override def isShadowMmu : Boolean = false

  val api = during build new Area{
    val fetchTranslationEnable = Bool()
    val lsuTranslationEnable = Bool()
  }

  override def getSignExtension(kind: AddressTranslationPortUsage, rawAddress: UInt): Bool = {
    val translationEnable = kind match {
      case AddressTranslationPortUsage.FETCH => api.fetchTranslationEnable
      case AddressTranslationPortUsage.LOAD_STORE => api.lsuTranslationEnable
    }
    translationEnable.mux(rawAddress(MIXED_WIDTH-1), False)
  }

  val logic = during setup new Area{
    val priv = host[PrivilegedPlugin]
    val csr = host[CsrAccessPlugin]
    val access = host[TranslatedDBusAccessService]
    val ram = host[CsrRamService]
    val pcs = host.get[PerformanceCounterService]

    val csrLock = retains(csr.csrLock, ram.csrLock)
    val accessLock = retains(access.accessRetainer)
    val buildBefore = retains(List(host[PipelineBuilderPlugin].elaborationLock) ++ pcs.map(_.elaborationLock))


    awaitBuild()

    PHYSICAL_WIDTH.set(physicalWidth)
    VIRTUAL_WIDTH.set(spec.virtualWidth)
    MIXED_WIDTH.set(VIRTUAL_WIDTH.get)
    PC_WIDTH.set(MIXED_WIDTH)
    TVAL_WIDTH.set(MIXED_WIDTH)
    assert(VIRTUAL_WIDTH.get == XLEN.get || XLEN.get > VIRTUAL_WIDTH.get && VIRTUAL_WIDTH.get > physicalWidth)

    val accessBus = access.newDBusAccess(priv.implementHypervisor)

    accessLock.release()

    def physCap(range : Range) = (range.high min physicalWidth-1) downto range.low

    assert(HART_COUNT.get == 1)
    val satp = new Area {
      val (modeOffset, modeWidth, ppnWidth, asidOffset, asidWidthMax) = XLEN.get match {
        case 32 => (31, 1, 20, 22, 9) //20 instead of 22 to avoid 34 physical bits
        case 64 => (60, 4, 44, 44, 16)
      }
      assert(asidWidth <= asidWidthMax, "asidWidth is too big")
      val mode = Reg(Bits(modeWidth bits)) init(0)
      val asid = Reg(Bits(asidWidth bits)) init(0)
      val ppn =  Reg(UInt(ppnWidth bits))  init(0)
    }
    val status = new Area{
      val mxr  = RegInit(False)
      val sum  = RegInit(False)
    }

    val vsatp = priv.implementHypervisor generate new Area {
      val mode = Reg(Bits(satp.modeWidth bits)) init(0)
      val asid = Reg(Bits(asidWidth bits)) init(0)
      val ppn =  Reg(UInt(satp.ppnWidth bits))  init(0)
    }
    val vsstatus = priv.implementHypervisor generate new Area{
      val mxr  = RegInit(False)
      val sum  = RegInit(False)
    }

    for(offset <- List(CSR.MSTATUS, CSR.SSTATUS)) csr.readWrite(offset, 19 -> status.mxr, 18 -> status.sum)

    csr.readWrite(CSR.SATP, satp.modeOffset -> satp.mode, satp.asidOffset -> satp.asid, 0 -> satp.ppn)
    val satpModeWrite = csr.bus.write.bits(satp.modeOffset, satp.modeWidth bits)
    csr.writeCancel(CSR.SATP, satpModeWrite =/= 0 && satpModeWrite =/= spec.satpMode)

    csr.allowCsr(CSR.SATP, !priv.logic.harts(0).m.status.tvm || priv.isMachine(0))
    csr.onDecode(CSR.SATP) {
      when (csr.bus.decode.write) {
        csr.bus.decode.doTrap(TrapReason.SFENCE_VMA)
      }
    }

    if (priv.implementHypervisor) {
      csr.readWrite(CSR.VSSTATUS, 19 -> vsstatus.mxr, 18 -> vsstatus.sum)

      csr.readWrite(CSR.VSATP, satp.modeOffset -> vsatp.mode, satp.asidOffset -> vsatp.asid, 0 -> vsatp.ppn)
      val vsatpModeWrite = csr.bus.write.bits(satp.modeOffset, satp.modeWidth bits)
      csr.writeCancel(CSR.VSATP, vsatpModeWrite =/= 0 && vsatpModeWrite =/= spec.satpMode)

      csr.remapWhen(CSR.SATP, CSR.VSATP, PrivilegeMode.isGuest(priv.getPrivilege(0)))

      csr.allowCsr(CSR.VSATP, !priv.logic.harts(0).h.status.vtvm || priv.getPrivilege(0) =/= PrivilegeMode.VS)
      csr.onDecode(CSR.VSATP) {
        when (csr.bus.decode.write) {
          csr.bus.decode.doTrap(TrapReason.SFENCE_VMA)
        }
      }
    }

    csrLock.release()
    portsLock.await()

    assert(storageSpecs.map(_.p.priority).distinct.size == storageSpecs.size, "MMU storages needs different priorities")
    // Implement the hardware for all the TLB storages
    val tlbGenerateParam = MmuTlbStorageEntryParam(
      checkUser   = true,
      checkGuest  = priv.implementHypervisor
    )
    val storages = for(ss <- storageSpecs) yield new MmuTlbStorage(spec, physicalWidth, tlbGenerateParam, ss)

    assert(HART_COUNT.get == 1)
    val isMachine = priv.getPrivilege(0) === PrivilegeMode.M
    val isGuest = PrivilegeMode.isGuest(priv.getPrivilege(0))
    def mprv = priv.logic.harts(0).m.status.mprv
    def mpp = priv.logic.harts(0).m.status.mpp
    val effectiveGuest = isGuest || (mprv && priv.logic.harts(0).m.status.mpv)

    val satpValid = satp.mode === spec.satpMode
    val vsatpValid = priv.implementHypervisor.mux(vsatp.mode === spec.satpMode, False)

    api.fetchTranslationEnable := Mux(isGuest, vsatpValid, satpValid)
    api.fetchTranslationEnable clearWhen(isMachine)

    api.lsuTranslationEnable := Mux(effectiveGuest, vsatpValid, satpValid)
    when(isMachine) {
      api.lsuTranslationEnable clearWhen (!mprv || priv.logic.harts(0).m.status.mpp === PrivilegeMode.M)
    }


    // Implement the hardware of very MMU ports on their respective pipelines / storages
    val portSpecsSorted = portSpecs.sortBy(_.ss.p.priority).reverse
    val ports = for(ps <- portSpecsSorted) yield new Composite(ps.rsp, "logic", false){
      import ps._

      val storage = storages.find(_.self == ps.ss).get
      val read = for (sl <- storage.sl) yield new Area {
        val readAddress = readStage(ps.req.PRE_ADDRESS)(sl.lineRange)
        val forceGuest = ctrlStage(ps.req.FORCE_GUEST) || effectiveGuest
        for ((way, wayId) <- sl.ways.zipWithIndex) {
          readStage(sl.keys.ENTRIES)(wayId) := way.readAsync(readAddress)
          hitsStage(sl.keys.HITS_PRE_VALID)(wayId) := hitsStage(sl.keys.ENTRIES)(wayId).hit(hitsStage(ps.req.PRE_ADDRESS))
          ctrlStage(sl.keys.HITS)(wayId) := ctrlStage(sl.keys.HITS_PRE_VALID)(wayId) &&
            ctrlStage(sl.keys.ENTRIES)(wayId).valid &&
            priv.implementHypervisor.mux(ctrlStage(sl.keys.ENTRIES)(wayId).guest === forceGuest, True)
        }
      }


      val ctrl = new Area{
        import ctrlStage._

        val isGuestAccess = effectiveGuest || ps.req.FORCE_GUEST
        val effectivePrivilege = ps.usage match {
          case LOAD_STORE => mprv.mux(mpp, priv.getPrivilege(0).asUInt.resize(2))
          case FETCH => priv.getPrivilege(0).asUInt.resize(2)
        }
        val isSupervisor = effectivePrivilege === PrivilegeMode.S
        val isUser = effectivePrivilege === PrivilegeMode.U
        val nominalSupervisor = priv.implementHypervisor.mux(ps.req.FORCE_GUEST.mux(priv.logic.harts(0).h.status.spvp, isSupervisor), isSupervisor)
        val nominalUser = priv.implementHypervisor.mux(ps.req.FORCE_GUEST.mux(!priv.logic.harts(0).h.status.spvp, isUser), isUser)
        val hits = Cat(storage.sl.map(s => ctrlStage(s.keys.HITS)))
        val entries = storage.sl.flatMap(s => ctrlStage(s.keys.ENTRIES))
        val hit = hits.orR
        val oh = OHMasking.firstV2(hits)

        def entriesMux[T <: Data](f : MmuTlbStorageEntry => T) : T = OhMux.or(oh, entries.map(f))
        val lineAllowExecute = entriesMux(_.allowExecute)
        val lineAllowRead    = entriesMux(_.allowRead)
        val lineAllowWrite   = entriesMux(_.allowWrite)
        val lineAllowUser    = entriesMux(_.allowUser)
        val lineTranslated   = entriesMux(_.physicalAddressFrom(ps.req.PRE_ADDRESS))

        val requireMmuLockup  = CombInit(ps.usage match {
          case LOAD_STORE => ps.req.FORCE_GUEST.mux(vsatpValid, api.lsuTranslationEnable)
          case FETCH => api.fetchTranslationEnable
        })
        requireMmuLockup clearWhen(ps.req.FORCE_PHYSICAL)

        import ps.rsp.keys._
        when(requireMmuLockup) {
          val allow_mxr     = priv.implementHypervisor.mux(isGuestAccess.mux(vsstatus.mxr, False), False) || status.mxr
          val allow_sum     = priv.implementHypervisor.mux(isGuestAccess.mux(vsstatus.sum, status.sum), status.sum)
          val allow_execute = lineAllowExecute && !(lineAllowUser && nominalSupervisor)
          val allow_read    = lineAllowRead || allow_mxr && lineAllowExecute
          val allow_write   = lineAllowWrite

          val privCheck     = (lineAllowUser && nominalSupervisor && !allow_sum) ||
                              (!lineAllowUser && nominalUser)
          val readCheck     = ps.req.LOAD && !allow_read
          val writeCheck    = ps.req.STORE && !allow_write
          val executeCheck  = ps.req.EXECUTE && !allow_execute
          val page_fault    = privCheck || readCheck || writeCheck || executeCheck

          HAZARD        := False
          REFILL        := !hit
          TRANSLATED    := lineTranslated
          PAGE_FAULT    := page_fault
          ACCESS_FAULT  := False
        } otherwise {
          HAZARD        := False
          REFILL        := False
          TRANSLATED    := ps.req.PRE_ADDRESS.resized
          PAGE_FAULT    := False
          ACCESS_FAULT  := ps.req.PRE_ADDRESS.drop(physicalWidth) =/= 0
        }


        ADDRESS_EXTENSION := requireMmuLockup.mux(ps.req.PRE_ADDRESS(MIXED_WIDTH-1), False)
        BYPASS_TRANSLATION := !requireMmuLockup
        WAYS_OH       := oh
        (WAYS_PHYSICAL, entries.map(_.physicalAddressFrom(ps.req.PRE_ADDRESS))).zipped.foreach(_ := _)
      }
    }

    // Implement the TLB storage refill FSM
    val refill = new StateMachine{
      val IDLE = new State
      val CMD, RSP, REFILL, DONE = List.fill(spec.levels.size)(new State)

      val busy = !isActive(IDLE)
      val virtual = Reg(UInt(MIXED_WIDTH bits))

      setEntry(IDLE)

      val arbiter = StreamArbiterFactory().roundRobin.transactionLock.buildOn(refillPorts.map(_.cmd))
      val portOhReg = Reg(Bits(refillPorts.size bits))
      val storageOhReg = Reg(Bits(storages.size bits))
      val storageEnable = Reg(Bool())
      val isTwoStage = Reg(Bool())

      arbiter.io.output.ready := False
      IDLE whenIsActive {
        when(arbiter.io.output.valid) {
          val ppn = priv.implementHypervisor.mux(
            Mux(arbiter.io.output.indirect, vsatp.ppn, satp.ppn),
            satp.ppn
          )
          portOhReg := arbiter.io.chosenOH
          storageOhReg := UIntToOh(arbiter.io.output.storageId)
          storageEnable := arbiter.io.output.storageEnable
          virtual := arbiter.io.output.address
          load.address := (ppn @@ spec.levels.last.vpn(arbiter.io.output.address) @@ U(0, log2Up(spec.entryBytes) bits)).resized
          isTwoStage := arbiter.io.output.indirect
          arbiter.io.output.ready := True
          goto(CMD(spec.levels.size - 1))
        }
      }


      val events = pcs map (pcs => new Area {
        val onStorage = for((storage, sel) <- storageSpecs zip storageOhReg.asBools) yield new Area {
          val waiting = pcs.createEventPort(storage.pmuEventId, busy && sel)
        }
      })

      val load = new Area{
        val address = Reg(UInt(PHYSICAL_WIDTH bits))

        def cmd = accessBus.cmd
        val rspUnbuffered = accessBus.rsp
        val rsp = rspUnbuffered.toStream.stage()
        rsp.ready := False
        val readed = rsp.data.subdivideIn(spec.entryBytes*8 bits).read((address >> log2Up(spec.entryBytes)).resized)

        cmd.valid             := False
        cmd.address           := address.resized
        cmd.size              := U(log2Up(spec.entryBytes))
        if (priv.implementHypervisor) cmd.guest := isTwoStage

        val flags = readed.resized.as(MmuEntryFlags())
        val leaf = flags.R || flags.X
        val reservedFault = (readed & spec.pteReserved).orR
        val exception = !flags.V || (!flags.R && flags.W) || rsp.error.orR ||
                        (!leaf && (flags.D | flags.A | flags.U)) ||
                        (leaf && !flags.A) ||
                        reservedFault
        val levelToPhysicalAddress = List.fill(spec.levels.size)(UInt(spec.physicalWidth bits))
        val levelException = List.fill(spec.levels.size)(False)
        val nextLevelBase = U(0, PHYSICAL_WIDTH bits)
        for((level, id) <- spec.levels.zipWithIndex) {
          nextLevelBase(physCap(level.physicalRange)) := readed(level.entryRange).asUInt.resized
          levelToPhysicalAddress(id) := 0
          for((e, eId) <- spec.levels.zipWithIndex){
            if(eId < id) {
              levelException(id) setWhen(readed(e.entryRange) =/= 0)
              levelToPhysicalAddress(id)(e.physicalRange) := e.vpn(virtual)
            } else {
              levelToPhysicalAddress(id)(e.physicalRange) := readed(e.entryRange).asUInt
            }
          }
        }
      }

      for (port <- refillPorts; rsp = port.rsp) {
        rsp.valid := False
        rsp.pageFault.assignDontCare()
        rsp.accessFault.assignDontCare()
        rsp.guestFault.assignDontCare()
        rsp.bypass.assignDontCare()
        rsp.pf.assignDontCare()
        rsp.ae_ptw.assignDontCare()
        rsp.ae_final.assignDontCare()
        rsp.level.assignDontCare()
        rsp.address.assignDontCare()
      }

//      for((storage, sid) <- storages.zipWithIndex) {
//        for(storageLevel <- storage.sl) {
//          storageLevel.write.address := virtual(storageLevel.lineRange)
//          storageLevel.write.data.valid := True
//          storageLevel.write.data.allowRead := load.flags.R
//          storageLevel.write.data.allowWrite := load.flags.W && load.flags.D
//          storageLevel.write.data.allowExecute := load.flags.X
//          storageLevel.write.data.allowUser := load.flags.U
//        }
//      }
    refillPorts.map(_.rsp).foreach{o =>
      o.gf  := False
      o.hr  := False
      o.hw  := False
      o.hx  := False

      o.pte.flags := load.flags
      o.pte.ppn := U(load.readed.dropLow(10)).resized
    }

      val fetch = for((level, levelId) <- spec.levels.zipWithIndex) yield new Area{
        val pteFault = (load.exception || load.levelException(levelId)) || (levelId == 0).mux(!load.leaf, False)
        val pteReadError = load.rsp.error(0)
        val shadowReadError = load.rsp.error(1)
        val leafAccessFault = load.levelToPhysicalAddress(levelId).drop(physicalWidth) =/= 0 //levelToPhysicalAddress is used to emit fault when the final translated address it outside the range of the physical addresses
        val pageFault = !shadowReadError && !pteReadError && pteFault
        val accessFault = pteReadError || (!pteFault && leafAccessFault)
        val guestFault = shadowReadError && !pteReadError
        val translationFault = pteFault || leafAccessFault

        def doneLogic() : Unit = {
          val translatedAddress = load.levelToPhysicalAddress(levelId)
          translatedAddress(0, level.virtualOffset bits) := virtual.resize(level.virtualOffset)

          refillPorts.onMask(portOhReg){port =>
            port.rsp.valid := True
            load.rsp.ready := port.rsp.ready

            when(port.rsp.ready) {
              goto(IDLE)
            }
          }

          refillPorts.map(_.rsp).foreach { o =>
            o.bypass := False
            o.pageFault := pageFault
            o.accessFault := accessFault
            o.guestFault := shadowReadError
            o.pf  := pageFault
            o.ae_ptw    := accessFault && !load.leaf
            o.ae_final  := accessFault && load.leaf //Note so sure
            o.level := spec.levels.size - 1 - levelId
            o.address := Mux(translationFault,
              Mux(shadowReadError, load.readed.asUInt, U(0)),
              translatedAddress
            ).resized
          }
        }

        def rspCheck(): Unit = {
          when(!storageEnable || translationFault) {
            goto(DONE(levelId))
          } otherwise {
            goto(REFILL(levelId))
          }
        }

        CMD(levelId) whenIsActive{
          load.cmd.valid := True
          when(load.cmd.ready) {
            goto(RSP(levelId))
          }
        }

        RSP(levelId) whenIsActive{
          if(levelId == 0) load.exception setWhen(!load.leaf)
          when(load.rsp.valid){
            levelId match {
              case 0 => rspCheck
              case _ => {
                when(load.exception) {
                  goto(DONE(levelId))
                } elsewhen(load.leaf) {
                  rspCheck
                } otherwise {
                  val targetLevelId = levelId - 1
                  val targetLevel = spec.levels(targetLevelId)
                  load.address := load.nextLevelBase
                  load.address(log2Up(spec.entryBytes), targetLevel.physicalWidth bits) := targetLevel.vpn(virtual)
                  load.rsp.ready := True
                  goto(CMD(targetLevelId))
                }
              }
            }
          }
        }

        REFILL(levelId) whenIsActive {
          for((storage, sid) <- storages.zipWithIndex){
            val storageLevelId = storage.self.p.levels.filter(_.id <= levelId).map(_.id).max
            val storageLevel = storage.sl.find(_.slp.id == storageLevelId).get
            val specLevel = storageLevel.level

            val sel = storageOhReg(sid)
            storageLevel.write.mask                 := UIntToOh(storageLevel.allocId).andMask(sel).resized
            storageLevel.write.address              := virtual(storageLevel.lineRange)
            storageLevel.write.data.valid           := True
            storageLevel.write.data.virtualAddress  := virtual(specLevel.virtualOffset + log2Up(storageLevel.slp.sets), widthOf(storageLevel.write.data.virtualAddress) bits)
            storageLevel.write.data.physicalAddress := (load.levelToPhysicalAddress(levelId) >> specLevel.virtualOffset).resized
            storageLevel.write.data.allowRead       := load.flags.R
            storageLevel.write.data.allowWrite      := load.flags.W && load.flags.D
            storageLevel.write.data.allowExecute    := load.flags.X
            storageLevel.write.data.allowUser       := load.flags.U
            if (priv.implementHypervisor) storageLevel.write.data.guest := isTwoStage

            storageLevel.allocId.increment()
          }
          goto(DONE(levelId))
        }

        DONE(levelId) whenIsActive{
          doneLogic
        }
      }
    }

    //Assume no mmu access are done to the given hart while being invalidated
    val invalidate = new Area{
      val arbiter = StreamArbiterFactory().roundRobin.transactionLock.buildOn(invalidationPorts.map(_.cmd))
      val depthMax = storageSpecs.map(_.p.levels.map(_.sets).max).max
      val counter = Reg(UInt(log2Up(depthMax) bits))
      val busy = RegInit(False)

      arbiter.io.output.ready := False
      when(!busy){
        counter := 0
        when (arbiter.io.output.valid) {
          busy := True
        }
      } otherwise {
        assert(HART_COUNT.get == 1)
        for (storage <- storages;
             sl <- storage.sl) {
          sl.write.mask := (default -> true)
          sl.write.address := counter.resized
          sl.write.data.valid := False
        }
        counter := counter + 1
        when(counter.andR){
          busy := False
          arbiter.io.output.ready := True
        }
      }
    }
//    fetch.release()

//    core.fiber.hardFork(refill.build())

    buildBefore.release()
  }
}


case class MmuEntryFlags() extends Bundle{
  val V, R, W ,X, U, G, A, D = Bool()
}
