initiator.h

/*
 * This file is part of libqbox
 * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All Rights Reserved.
 * Author: GreenSocs 2021
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
 
#ifndef _LIBQBOX_PORTS_INITIATOR_H
#define _LIBQBOX_PORTS_INITIATOR_H
 
#include <functional>
#include <limits>
#include <cassert>
#include <cinttypes>
 
#include <tlm>
 
#include <libqemu-cxx/libqemu-cxx.h>
 
#include <libgssync.h>
 
#include <scp/report.h>
 
#include <qemu-instance.h>
#include <tlm-extensions/qemu-mr-hint.h>
#include <tlm-extensions/exclusive-access.h>
#include <tlm-extensions/shmem_extension.h>
#include <tlm-extensions/underlying-dmi.h>
#include <tlm_sockets_buswidth.h>
 
/*
 * Define this as 1 if you want to enable the cache debug mechanism below.
 */
#define DEBUG_CACHE 0
 
class QemuInitiatorIface
{
public:
    using TlmPayload = tlm::tlm_generic_payload;
 
    virtual void initiator_customize_tlm_payload(TlmPayload& payload) = 0;
    virtual void initiator_tidy_tlm_payload(TlmPayload& payload) = 0;
    virtual sc_core::sc_time initiator_get_local_time() = 0;
    virtual void initiator_set_local_time(const sc_core::sc_time&) = 0;
    virtual void initiator_async_run(qemu::Cpu::AsyncJobFn job) = 0;
};
 
template <unsigned int BUSWIDTH = DEFAULT_TLM_BUSWIDTH>
class QemuInitiatorSocket
    : public tlm::tlm_initiator_socket<BUSWIDTH, tlm::tlm_base_protocol_types, 1, sc_core::SC_ZERO_OR_MORE_BOUND>,
      public tlm::tlm_bw_transport_if<>
{
private:
    std::mutex m_mutex;
    std::vector<std::pair<sc_dt::uint64, sc_dt::uint64>> m_ranges;
 
public:
    SCP_LOGGER(());
 
    using TlmInitiatorSocket = tlm::tlm_initiator_socket<BUSWIDTH, tlm::tlm_base_protocol_types, 1,
                                                         sc_core::SC_ZERO_OR_MORE_BOUND>;
    using TlmPayload = tlm::tlm_generic_payload;
    using MemTxResult = qemu::MemoryRegionOps::MemTxResult;
    using MemTxAttrs = qemu::MemoryRegionOps::MemTxAttrs;
    using DmiRegion = QemuInstanceDmiManager::DmiRegion;
    using DmiRegionAlias = QemuInstanceDmiManager::DmiRegionAlias;
 
    using DmiRegionAliasKey = uint64_t;
 
protected:
    QemuInstance& m_inst;
    QemuInitiatorIface& m_initiator;
    qemu::Device m_dev;
    gs::runonsysc m_on_sysc;
    int reentrancy = 0;
 
    bool m_finished = false;
 
    std::shared_ptr<qemu::AddressSpace> m_as;
    std::shared_ptr<qemu::MemoryListener> m_listener;
    std::map<uint64_t, std::shared_ptr<qemu::IOMMUMemoryRegion>> m_mmio_mrs;
 
    class m_mem_obj
    {
    public:
        std::shared_ptr<qemu::MemoryRegion> m_root;
        m_mem_obj(qemu::LibQemu& inst) { m_root.reset(new qemu::MemoryRegion(inst.object_new<qemu::MemoryRegion>())); }
        m_mem_obj(std::shared_ptr<qemu::MemoryRegion> memory): m_root(std::move(memory)) {}
    };
    m_mem_obj* m_r = nullptr;
 
    // we use an ordered map to find and combine elements
    std::map<DmiRegionAliasKey, DmiRegionAlias::Ptr> m_dmi_aliases;
    using AliasesIterator = std::map<DmiRegionAliasKey, DmiRegionAlias::Ptr>::iterator;
 
    void init_payload(TlmPayload& trans, tlm::tlm_command command, uint64_t addr, uint64_t* val, unsigned int size)
    {
        trans.set_command(command);
        trans.set_address(addr);
        trans.set_data_ptr(reinterpret_cast<unsigned char*>(val));
        trans.set_data_length(size);
        trans.set_streaming_width(size);
        trans.set_byte_enable_length(0);
        trans.set_dmi_allowed(false);
        trans.set_response_status(tlm::TLM_INCOMPLETE_RESPONSE);
 
        m_initiator.initiator_customize_tlm_payload(trans);
    }
 
    void add_dmi_mr_alias(DmiRegionAlias::Ptr alias)
    {
        SCP_INFO(()) << "Adding " << *alias;
        qemu::MemoryRegion alias_mr = alias->get_alias_mr();
        m_r->m_root->add_subregion(alias_mr, alias->get_start());
        alias->set_installed();
    }
 
    void del_dmi_mr_alias(const DmiRegionAlias::Ptr alias)
    {
        if (!alias->is_installed()) {
            return;
        }
        SCP_INFO(()) << "Removing " << *alias;
        m_r->m_root->del_subregion(alias->get_alias_mr());
    }
 
    void dmi_translate(qemu::IOMMUMemoryRegion::IOMMUTLBEntry* te, std::shared_ptr<qemu::IOMMUMemoryRegion> iommumr,
                       uint64_t base_addr, uint64_t addr, qemu::IOMMUMemoryRegion::IOMMUAccessFlags flags, int idx)
    {
        TlmPayload ltrans;
        uint64_t tmp;
#if DEBUG_CACHE
        bool incache = false;
        qemu::IOMMUMemoryRegion::IOMMUTLBEntry tmpte;
#endif // DEBUG_CACHE
 
        /*
         * Fast path : check to see if the TE is already cached, if so return it straight away.
         */
        {
            // Really wish we didn't need the lock here
            std::lock_guard<std::mutex> lock(m_mutex);
 
            auto m = iommumr->m_mapped_te.find(addr >> iommumr->min_page_sz);
            if (m != iommumr->m_mapped_te.end()) {
                *te = m->second;
                SCP_TRACE(())
                ("FAST (unord) translate for 0x{:x} :  0x{:x}->0x{:x} (mask 0x{:x}) perm={}", addr, te->iova,
                 te->translated_addr, te->addr_mask, te->perm);
                return;
            }
        }
 
        /*
         * Slow path, use DMI to investigate the memory, and see what sort of TE we can set up
         *
         * There are 3 options
         * 1/ a real IOMMU region that should be mapped into the IOMMU address space
         * 2/ a 'dmi-able' region which is not an IOMMU (e.g. local memory)
         * 3/ a 'non-dmi-able' object (e.g. an MMIO device) - a minimum page size will be used for this.
         *
         * Enable DEBUG_CACHE to see if the fast path should have been used.
         */
 
        // construct maximal mask.
        uint64_t start_msk = (base_addr ^ (base_addr - 1)) >> 1;
 
        SCP_DEBUG(())("Doing Translate for {:x} (Absolute 0x{:x})", addr, addr + base_addr);
 
        gs::UnderlyingDMITlmExtension lu_dmi;
        init_payload(ltrans, tlm::TLM_IGNORE_COMMAND, base_addr + addr, &tmp, 0);
        ltrans.set_extension(&lu_dmi);
        tlm::tlm_dmi ldmi_data;
 
        if ((*this)->get_direct_mem_ptr(ltrans, ldmi_data)) {
            if (lu_dmi.has_dmi(gs::tlm_dmi_ex::dmi_iommu)) {
                // Add te to 'special' IOMMU address space
                tlm::tlm_dmi lu_dmi_data = lu_dmi.get_last(gs::tlm_dmi_ex::dmi_iommu);
                if (0 == iommumr->m_dmi_aliases_te.count(lu_dmi_data.get_start_address())) {
                    qemu::RcuReadLock l_rcu_read_lock = m_inst.get().rcu_read_lock_new();
                    // take our own memory here, dont use an alias as
                    // we may have different sizes for the underlying DMI
 
                    DmiRegion region = DmiRegion(lu_dmi_data, 0, m_inst.get());
                    SCP_DEBUG(())
                    ("Adding IOMMU DMI Region  start 0x{:x} - 0x{:x}", lu_dmi_data.get_start_address(),
                     lu_dmi_data.get_start_address() + region.get_size());
                    iommumr->m_root_te.add_subregion(region.get_mut_mr(), lu_dmi_data.get_start_address());
                    iommumr->m_dmi_aliases_te[lu_dmi_data.get_start_address()] = std::make_shared<DmiRegion>(region);
                }
 
                te->target_as = iommumr->m_as_te->get_ptr();
                te->addr_mask = ldmi_data.get_end_address() - ldmi_data.get_start_address();
                te->iova = addr;
                te->translated_addr = (lu_dmi_data.get_start_address() +
                                       (ldmi_data.get_dmi_ptr() - lu_dmi_data.get_dmi_ptr()));
                te->perm = (qemu::IOMMUMemoryRegion::IOMMUAccessFlags)ldmi_data.get_granted_access();
 
                SCP_DEBUG(())
                ("Translate IOMMU 0x{:x}->0x{:x} (mask 0x{:x})", te->iova, te->translated_addr, te->addr_mask);
 
            } else {
                // no underlying DMI, add a 1-1 passthrough to normal address space
                if (0 == iommumr->m_dmi_aliases_io.count(ldmi_data.get_start_address())) {
                    qemu::RcuReadLock l_rcu_read_lock = m_inst.get().rcu_read_lock_new();
                    DmiRegionAlias::Ptr alias = m_inst.get_dmi_manager().get_new_region_alias(ldmi_data);
                    SCP_DEBUG(()) << "Adding DMI Region alias " << *alias;
                    qemu::MemoryRegion alias_mr = alias->get_alias_mr();
                    iommumr->m_root.add_subregion(alias_mr, alias->get_start());
                    alias->set_installed();
                    iommumr->m_dmi_aliases_io[alias->get_start()] = alias;
                }
 
                te->target_as = iommumr->m_as->get_ptr();
                te->addr_mask = start_msk;
                te->iova = addr & ~start_msk;
                te->translated_addr = (addr & ~start_msk) + base_addr;
                te->perm = (qemu::IOMMUMemoryRegion::IOMMUAccessFlags)ldmi_data.get_granted_access();
 
                SCP_DEBUG(())
                ("Translate 1-1 passthrough 0x{:x}->0x{:x} (mask 0x{:x})", te->iova, te->translated_addr,
                 te->addr_mask);
            }
#if DEBUG_CACHE
            if (incache) {
                SCP_WARN(())("Could have used the cache! {:x}\n", addr);
                assert(te->iova == tmpte.iova);
                assert(te->target_as == tmpte.target_as);
                assert(te->addr_mask == tmpte.addr_mask);
                assert(te->translated_addr == tmpte.translated_addr);
                assert(te->perm == tmpte.perm);
            }
#endif // DEBUG_CACHE
            std::lock_guard<std::mutex> lock(m_mutex);
            iommumr->m_mapped_te[(addr & ~te->addr_mask) >> iommumr->min_page_sz] = *te;
            SCP_DEBUG(())
            ("Caching TE at addr 0x{:x} (mask {:x})", addr & ~te->addr_mask, te->addr_mask);
 
        } else {
            // No DMI at all, either an MMIO, or a DMI failure, setup for a 1-1 translation for the minimal page
            // in the normal address space
 
            te->target_as = iommumr->m_as->get_ptr();
            te->addr_mask = (1 << iommumr->min_page_sz) - 1;
            te->iova = addr & ~te->addr_mask;
            te->translated_addr = (addr & ~te->addr_mask) + base_addr;
            te->perm = qemu::IOMMUMemoryRegion::IOMMU_RW;
 
            SCP_DEBUG(())
            ("Translate 1-1 limited passthrough  0x{:x}->0x{:x} (mask 0x{:x})", te->iova, te->translated_addr,
             te->addr_mask);
        }
        ltrans.clear_extension(&lu_dmi);
    }
 
    tlm::tlm_dmi check_dmi_hint_locked(TlmPayload& trans)
    {
        assert(trans.is_dmi_allowed());
        tlm::tlm_dmi dmi_data;
        int shm_fd = -1;
 
        SCP_INFO(()) << "DMI request for address 0x" << std::hex << trans.get_address();
 
        // It is 'safer' from the SystemC perspective to  m_on_sysc.run_on_sysc([this,
        // &trans]{...}).
        gs::UnderlyingDMITlmExtension u_dmi;
 
        trans.set_extension(&u_dmi);
        bool dmi_valid = (*this)->get_direct_mem_ptr(trans, dmi_data);
        trans.clear_extension(&u_dmi);
        if (!dmi_valid) {
            SCP_INFO(())("No DMI available for {:x}", trans.get_address());
            /* this is used by the map function below
             * - a better plan may be to tag memories to be mapped so we dont need this
             */
            if (u_dmi.has_dmi(gs::tlm_dmi_ex::dmi_mapped)) {
                tlm::tlm_dmi first_map = u_dmi.get_first(gs::tlm_dmi_ex::dmi_mapped);
                return first_map;
            }
            if (u_dmi.has_dmi(gs::tlm_dmi_ex::dmi_nomap)) {
                tlm::tlm_dmi first_nomap = u_dmi.get_first(gs::tlm_dmi_ex::dmi_nomap);
                return first_nomap;
            }
            return dmi_data;
        }
 
        /*
         * This is the 'special' case of IOMMU's which require an IOMMU memory region setup
         * The IOMMU will be constructed here, but not populated - that will happen in the callback
         * There will be a 'pair' of new regions, one to hold non iommu regions within this space,
         * the other to hold iommu regions themselves.
         *
         * In extreme circumstances, if the IOMMU DMI to this region previously failed, we may have
         * ended up with a normal DMI region here, which needs removing. We do that here, and then simply
         * return and wait for a new access to sort things out.
         */
        if (u_dmi.has_dmi(gs::tlm_dmi_ex::dmi_iommu)) {
            /* We have an IOMMU request setup an IOMMU region */
            SCP_INFO(())("IOMMU DMI available for {:x}", trans.get_address());
 
            /* The first mapped DMI will be the scope of the IOMMU region from our perspective */
            tlm::tlm_dmi first_map = u_dmi.get_first(gs::tlm_dmi_ex::dmi_mapped);
 
            uint64_t start = first_map.get_start_address();
            uint64_t size = first_map.get_end_address() - first_map.get_start_address();
 
            auto itr = m_mmio_mrs.find(start);
            if (itr == m_mmio_mrs.end()) {
                // Better check for overlapping iommu's - they must be banned     !!
 
                qemu::RcuReadLock rcu_read_lock = m_inst.get().rcu_read_lock_new();
 
                /* invalidate any 'old' regions we happen to have mapped previously */
                invalidate_single_range(start, start + size);
 
                SCP_INFO(())
                ("Adding IOMMU for VA 0x{:x} [0x{:x} - 0x{:x}]", trans.get_address(), start, start + size);
 
                using namespace std::placeholders;
                qemu::MemoryRegionOpsPtr ops;
                ops = m_inst.get().memory_region_ops_new();
                ops->set_read_callback(std::bind(&QemuInitiatorSocket::qemu_io_read, this, _1, _2, _3, _4));
                ops->set_write_callback(std::bind(&QemuInitiatorSocket::qemu_io_write, this, _1, _2, _3, _4));
                ops->set_max_access_size(8);
 
                auto iommumr = std::make_shared<qemu::IOMMUMemoryRegion>(
                    m_inst.get().template object_new_unparented<qemu::IOMMUMemoryRegion>());
 
                iommumr->init(*iommumr, "dmi-manager-iommu", size, ops,
                              [=](qemu::IOMMUMemoryRegion::IOMMUTLBEntry* te, uint64_t addr,
                                  qemu::IOMMUMemoryRegion::IOMMUAccessFlags flags,
                                  int idx) { dmi_translate(te, iommumr, start, addr, flags, idx); });
                {
                    std::lock_guard<std::mutex> lock(m_mutex);
                    m_mmio_mrs[start] = iommumr;
                }
                m_r->m_root->add_subregion(*iommumr, start);
 
            } else {
                // Previously when looking up a TE, we failed to get the lock, so the DMI failed, we ended up in a
                // limited passthrough. Which causes us to re-arrive here.... but, with a DMI hint. Hopefully next time
                // the TE is looked up, we'll get the lock and re-establish the translation. In any case we should do
                // nothing and simply return
                // Moving to a cached TE will improve speed and prevent this from happening?
                SCP_DEBUG(())
                ("Memory request should be directed via MMIO interface {:x} {:x}", start, trans.get_address());
 
                //                std::lock_guard<std::mutex> lock(m_mutex);
 
                uint64_t start_range = itr->first;
                uint64_t end_range = itr->first + itr->second->get_size();
 
                invalidate_direct_mem_ptr(start_range, end_range);
            }
            return dmi_data;
        }
 
        gs::ShmemIDExtension* shm_ext = trans.get_extension<gs::ShmemIDExtension>();
        // it's ok that ShmemIDExtension is not added to trans as this should only happen when
        // memory is a shared memory type.
        if (shm_ext) {
            shm_fd = shm_ext->m_fd;
        }
 
        SCP_INFO(()) << "DMI Adding for address 0x" << std::hex << trans.get_address();
 
        // The upper limit is set within QEMU by the TBU
        // e.g. 1k small pages for ARM.
        // setting to 1/2 the size of the ARM TARGET_PAGE_SIZE,
        // Comment from QEMU code:
        /* The physical section number is ORed with a page-aligned
         * pointer to produce the iotlb entries.  Thus it should
         * never overflow into the page-aligned value.
         */
#define MAX_MAP 250
 
        // Current function may be called by the MMIO thread which does not hold
        // any RCU read lock. This is required in case of a memory transaction
        // commit on a TCG accelerated Qemu instance
        qemu::RcuReadLock rcu_read_lock = m_inst.get().rcu_read_lock_new();
 
        if (m_dmi_aliases.size() > MAX_MAP) {
            SCP_FATAL(())("Too many DMI regions requested, consider using an IOMMU");
        }
        uint64_t start = dmi_data.get_start_address();
        uint64_t end = dmi_data.get_end_address();
 
        if (0 == m_dmi_aliases.count(start)) {
            SCP_INFO(()) << "Adding DMI for range [0x" << std::hex << dmi_data.get_start_address() << "-0x" << std::hex
                         << dmi_data.get_end_address() << "]";
 
            DmiRegionAlias::Ptr alias = m_inst.get_dmi_manager().get_new_region_alias(dmi_data, shm_fd);
 
            m_dmi_aliases[start] = alias;
            add_dmi_mr_alias(m_dmi_aliases[start]);
        } else {
            SCP_INFO(())("Already have DMI for 0x{:x}", start);
        }
        return dmi_data;
    }
 
    void check_qemu_mr_hint(TlmPayload& trans)
    {
        QemuMrHintTlmExtension* ext = nullptr;
        uint64_t mapping_addr;
 
        trans.get_extension(ext);
 
        if (ext == nullptr) {
            return;
        }
 
        qemu::MemoryRegion target_mr(ext->get_mr());
 
        if (target_mr.get_inst_id() != m_dev.get_inst_id()) {
            return;
        }
 
        mapping_addr = trans.get_address() - ext->get_offset();
 
        qemu::MemoryRegion mr(m_inst.get().template object_new<qemu::MemoryRegion>());
 
        mr.init_alias(m_dev, "mr-alias", target_mr, 0, target_mr.get_size());
        m_r->m_root->add_subregion(mr, mapping_addr);
    }
 
    void do_regular_access(TlmPayload& trans)
    {
        using sc_core::sc_time;
 
        uint64_t addr = trans.get_address();
        sc_time now = m_initiator.initiator_get_local_time();
 
        m_inst.get().unlock_iothread();
        m_on_sysc.run_on_sysc([this, &trans, &now] { (*this)->b_transport(trans, now); });
        m_inst.get().lock_iothread();
        /*
         * Reset transaction address before dmi check (could be altered by
         * b_transport).
         */
        trans.set_address(addr);
        check_qemu_mr_hint(trans);
        if (trans.is_dmi_allowed()) {
            check_dmi_hint_locked(trans);
        }
 
        m_initiator.initiator_set_local_time(now);
    }
 
    void do_debug_access(TlmPayload& trans)
    {
        m_inst.get().unlock_iothread();
        m_on_sysc.run_on_sysc([this, &trans] { (*this)->transport_dbg(trans); });
        m_inst.get().lock_iothread();
    }
 
    void do_direct_access(TlmPayload& trans)
    {
        sc_core::sc_time now = m_initiator.initiator_get_local_time();
        (*this)->b_transport(trans, now);
    }
 
    MemTxResult qemu_io_access(tlm::tlm_command command, uint64_t addr, uint64_t* val, unsigned int size,
                               MemTxAttrs attrs)
    {
        TlmPayload trans;
        if (m_finished) return qemu::MemoryRegionOps::MemTxError;
 
        init_payload(trans, command, addr, val, size);
 
        if (trans.get_extension<ExclusiveAccessTlmExtension>()) {
            /* in the case of an exclusive access keep the iolock (and assume NO side-effects)
             * clearly dangerous, but exclusives are not guaranteed to work on IO space anyway
             */
            do_direct_access(trans);
        } else {
            if (!m_inst.g_rec_qemu_io_lock.try_lock()) {
                /* Allow only a single access, but handle re-entrant code,
                 * while allowing side-effects in SystemC (e.g. calling wait)
                 * [NB re-entrant code caused via memory listeners to
                 * creation of memory regions (due to DMI) in some models]
                 */
                m_inst.get().unlock_iothread();
                m_inst.g_rec_qemu_io_lock.lock();
                m_inst.get().lock_iothread();
            }
            reentrancy++;
 
            /* Force re-entrant code to use a direct access (safe for reentrancy with no side effects) */
            if (reentrancy > 1) {
                do_direct_access(trans);
            } else if (attrs.debug) {
                do_debug_access(trans);
            } else {
                do_regular_access(trans);
            }
 
            reentrancy--;
            m_inst.g_rec_qemu_io_lock.unlock();
        }
        m_initiator.initiator_tidy_tlm_payload(trans);
 
        switch (trans.get_response_status()) {
        case tlm::TLM_OK_RESPONSE:
            return qemu::MemoryRegionOps::MemTxOK;
 
        case tlm::TLM_ADDRESS_ERROR_RESPONSE:
            return qemu::MemoryRegionOps::MemTxDecodeError;
 
        default:
            return qemu::MemoryRegionOps::MemTxError;
        }
    }
 
public:
    MemTxResult qemu_io_read(uint64_t addr, uint64_t* val, unsigned int size, MemTxAttrs attrs)
    {
        return qemu_io_access(tlm::TLM_READ_COMMAND, addr, val, size, attrs);
    }
 
    MemTxResult qemu_io_write(uint64_t addr, uint64_t val, unsigned int size, MemTxAttrs attrs)
    {
        return qemu_io_access(tlm::TLM_WRITE_COMMAND, addr, &val, size, attrs);
    }
 
    QemuInitiatorSocket(const char* name, QemuInitiatorIface& initiator, QemuInstance& inst)
        : TlmInitiatorSocket(name)
        , m_inst(inst)
        , m_initiator(initiator)
        , m_on_sysc(sc_core::sc_gen_unique_name("initiator_run_on_sysc"))
    {
        SCP_DEBUG(()) << "QemuInitiatorSocket constructor";
        TlmInitiatorSocket::bind(*static_cast<tlm::tlm_bw_transport_if<>*>(this));
    }
 
    void init(qemu::Device& dev, const char* prop)
    {
        using namespace std::placeholders;
 
        qemu::LibQemu& inst = m_inst.get();
        qemu::MemoryRegionOpsPtr ops;
 
        m_r = new m_mem_obj(inst); // oot = inst.object_new<qemu::MemoryRegion>();
        ops = inst.memory_region_ops_new();
 
        ops->set_read_callback(std::bind(&QemuInitiatorSocket::qemu_io_read, this, _1, _2, _3, _4));
        ops->set_write_callback(std::bind(&QemuInitiatorSocket::qemu_io_write, this, _1, _2, _3, _4));
        ops->set_max_access_size(8);
 
        m_r->m_root->init_io(dev, TlmInitiatorSocket::name(), std::numeric_limits<uint64_t>::max(), ops);
        dev.set_prop_link(prop, *m_r->m_root);
 
        m_dev = dev;
    }
 
    void end_of_simulation()
    {
        m_finished = true;
        cancel_all();
    }
 
    // This could happen during void end_of_simulation() but there is a race with other units trying
    // to pull down their DMI's
    ~QemuInitiatorSocket()
    {
        cancel_all();
        if (m_r) {
            if (m_r->m_root) {
                m_r->m_root->removeSubRegions();
            }
            delete m_r;
            m_r = nullptr;
        }
        //        dmimgr_unlock();
    }
 
    void qemu_map(qemu::MemoryListener& listener, uint64_t addr, uint64_t len)
    {
        // this function is relatively expensive, and called a lot, it should be done a different way and removed.
        if (m_finished) return;
 
        SCP_DEBUG(()) << "Mapping request for address [0x" << std::hex << addr << "-0x" << addr + len << "]";
 
        TlmPayload trans;
        uint64_t current_addr = addr;
        uint64_t temp;
        init_payload(trans, tlm::TLM_IGNORE_COMMAND, current_addr, &temp, 0);
        trans.set_dmi_allowed(true);
 
        while (current_addr < addr + len) {
            tlm::tlm_dmi dmi_data = check_dmi_hint_locked(trans);
 
            // Current addr is an absolute address while the dmi range might be relative
            // hence not necesseraly current_addr falls withing dmi_range address boundaries
            // TODO: is there a way to retrieve the dmi range block offset?
            SCP_INFO(()) << "0x" << std::hex << current_addr << " mapped [0x" << dmi_data.get_start_address() << "-0x"
                         << dmi_data.get_end_address() << "]";
 
            // The allocated range may not span the whole length required for mapping
            assert(dmi_data.get_end_address() > current_addr);
            current_addr = dmi_data.get_end_address();
            if (current_addr >= addr + len) break; // Catch potential loop-rounds
            current_addr += 1;
            trans.set_address(current_addr);
        }
 
        m_initiator.initiator_tidy_tlm_payload(trans);
    }
 
    void init_global(qemu::Device& dev)
    {
        using namespace std::placeholders;
 
        qemu::LibQemu& inst = m_inst.get();
        qemu::MemoryRegionOpsPtr ops;
        ops = inst.memory_region_ops_new();
 
        ops->set_read_callback(std::bind(&QemuInitiatorSocket::qemu_io_read, this, _1, _2, _3, _4));
        ops->set_write_callback(std::bind(&QemuInitiatorSocket::qemu_io_write, this, _1, _2, _3, _4));
        ops->set_max_access_size(8);
 
        auto system_memory = inst.get_system_memory();
        system_memory->init_io(dev, TlmInitiatorSocket::name(), std::numeric_limits<uint64_t>::max() - 1, ops);
        m_r = new m_mem_obj(std::move(system_memory));
 
        m_as = inst.address_space_get_system_memory();
        // System memory has been changed from container to "io", this is relevant
        // for flatview, and to reflect that we can just update the topology
        m_as->update_topology();
 
        m_listener = inst.memory_listener_new();
        m_listener->set_map_callback(std::bind(&QemuInitiatorSocket::qemu_map, this, _1, _2, _3));
        m_listener->register_as(m_as);
 
        m_dev = dev;
    }
 
    void cancel_all() { m_on_sysc.cancel_all(); }
 
    /* tlm::tlm_bw_transport_if<> */
    virtual tlm::tlm_sync_enum nb_transport_bw(tlm::tlm_generic_payload& trans, tlm::tlm_phase& phase,
                                               sc_core::sc_time& t)
    {
        /* Should not be reached */
        assert(false);
        return tlm::TLM_COMPLETED;
    }
 
    virtual AliasesIterator remove_alias(AliasesIterator it)
    {
        DmiRegionAlias::Ptr r = it->second; /*
                                             * Invalidate this region. Do not bother with
                                             * partial invalidation as it's really not worth
                                             * it. Better let the target model returns sub-DMI
                                             * regions during future accesses.
                                             */
 
        /*
         * Mark the whole region this alias maps to as invalid. This has
         * the effect of marking all the other aliases mapping to the same
         * region as invalid too. If a DMI request for the same region is
         * already in progress, it will have a chance to detect it is now
         * invalid before mapping it on the QEMU root MR (see
         * check_dmi_hint comment).
         */
        // r->invalidate_region();
 
        assert(r->is_installed());
        //        if (!r->is_installed()) {
        /*
         * The alias is not mapped onto the QEMU root MR yet. Simply
         * skip it. It will be removed from m_dmi_aliases by
         * check_dmi_hint.
         */
        //            return it++;
        //        }
 
        /*
         * Remove the alias from the root MR. This is enough to perform
         * required invalidations on QEMU's side in a thread-safe manner.
         */
        del_dmi_mr_alias(r);
 
        /*
         * Remove the alias from the collection. The DmiRegionAlias object
         * is then destructed, leading to the destruction of the DmiRegion
         * shared pointer it contains. When no more alias reference this
         * region, it is in turn destructed, effectively destroying the
         * corresponding memory region in QEMU.
         */
        return m_dmi_aliases.erase(it);
    }
 
private:
    void invalidate_single_range(sc_dt::uint64 start_range, sc_dt::uint64 end_range)
    {
        auto it = m_dmi_aliases.upper_bound(start_range);
 
        if (it != m_dmi_aliases.begin()) {
            /*
             * Start with the preceding region, as it may already cross the
             * range we must invalidate.
             */
            it--;
        }
        while (it != m_dmi_aliases.end()) {
            DmiRegionAlias::Ptr r = it->second;
 
            if (r->get_start() > end_range) {
                /* We've got out of the invalidation range */
                break;
            }
 
            if (r->get_end() < start_range) {
                /* We are not in yet */
                it++;
                continue;
            }
 
            it = remove_alias(it);
 
            SCP_DEBUG(()) << "Invalidated region [0x" << std::hex << r->get_start() << ", 0x" << std::hex
                          << r->get_end() << "]";
        }
    }
 
    void invalidate_ranges_safe_cb()
    {
        std::lock_guard<std::mutex> lock(m_mutex);
 
        SCP_DEBUG(()) << "Invalidating " << m_ranges.size() << " ranges";
        auto rit = m_ranges.begin();
        while (rit != m_ranges.end()) {
            invalidate_single_range(rit->first, rit->second);
            rit = m_ranges.erase(rit);
        }
    }
 
public:
    virtual void invalidate_direct_mem_ptr(sc_dt::uint64 start_range, sc_dt::uint64 end_range)
    {
        if (m_finished) return;
        SCP_DEBUG(()) << "DMI invalidate [0x" << std::hex << start_range << ", 0x" << std::hex << end_range << "]";
 
        {
            std::lock_guard<std::mutex> lock(m_mutex);
 
            for (auto m : m_mmio_mrs) {
                auto mr_start = m.first;
                auto mr_end = m.first + m.second->get_size();
                if ((mr_start >= start_range && mr_start <= end_range) ||
                    (mr_end >= start_range && mr_end <= end_range) || (mr_start < start_range && mr_end > end_range)) {
                    for (auto it = m.second->m_mapped_te.begin(); it != m.second->m_mapped_te.end();) {
                        if ((it->first << m.second->min_page_sz) + mr_start >= start_range &&
                            (it->first << m.second->min_page_sz) + mr_start < end_range) {
                            m.second->iommu_unmap(&(it->second));
                            it = m.second->m_mapped_te.erase(it);
                        } else
                            it++;
                    }
                    return; // If we found this, then we're done. Overlapping IOMMU's are not allowed.
                }
            }
        }
        {
            std::lock_guard<std::mutex> lock(m_mutex);
            m_ranges.push_back(std::make_pair(start_range, end_range));
        }
 
        m_initiator.initiator_async_run([&]() { invalidate_ranges_safe_cb(); });
 
        /* For 7.2 this may need to be safe aync work ???????? */
    }
 
    virtual void reset()
    {
        std::lock_guard<std::mutex> lock(m_mutex);
 
        for (auto m : m_mmio_mrs) {
            m.second->m_mapped_te.clear();
            auto it = m_dmi_aliases.begin();
            while (it != m_dmi_aliases.end()) {
                DmiRegionAlias::Ptr r = it->second;
                it = remove_alias(it);
            }
        }
    }
};
 
#endif