#include "vmtrace/vmtrace.hpp"

#include <WinHvPlatform.h>

#include <array>
#include <cstring>
#include <iomanip>
#include <memory>
#include <optional>
#include <sstream>
#include <stdexcept>
#include <unordered_map>

namespace vmtrace
{
    namespace
    {
        constexpr UINT32 vp_index = 0;
        constexpr std::uint64_t page_table_entry_present = 1ull << 0;
        constexpr std::uint64_t page_table_entry_writable = 1ull << 1;
        constexpr std::uint64_t page_table_entry_address_mask = 0x000FFFFFFFFFF000ull;
        constexpr std::uint64_t internal_page_table_base = 0x0000007000000000ull;

        struct mapped_page
        {
            struct virtual_free_deleter
            {
                void operator()(std::uint8_t* page) const
                {
                    if (page != nullptr)
                    {
                        ::VirtualFree(page, 0, MEM_RELEASE);
                    }
                }
            };

            void* host_page = nullptr;
            UINT32 map_flags = 0;
            std::unique_ptr<std::uint8_t, virtual_free_deleter> owned_page;
        };

        [[noreturn]] void throw_hr(HRESULT hr, const char* action)
        {
            std::ostringstream stream;
            stream << action << " failed with HRESULT 0x" << std::hex << std::setw(8) << std::setfill('0')
                   << static_cast<std::uint32_t>(hr);
            throw std::runtime_error(stream.str());
        }

        void check_hr(HRESULT hr, const char* action)
        {
            if (FAILED(hr))
            {
                throw_hr(hr, action);
            }
        }

        class partition_handle
        {
          public:
            partition_handle()
            {
                check_hr(WHvCreatePartition(&handle_), "WHvCreatePartition");
            }

            partition_handle(const partition_handle&) = delete;
            partition_handle& operator=(const partition_handle&) = delete;

            ~partition_handle()
            {
                if (handle_ != nullptr)
                {
                    WHvDeletePartition(handle_);
                }
            }

            WHV_PARTITION_HANDLE get() const
            {
                return handle_;
            }

          private:
            WHV_PARTITION_HANDLE handle_ = nullptr;
        };

        class virtual_processor_handle
        {
          public:
            explicit virtual_processor_handle(WHV_PARTITION_HANDLE partition)
                : partition_(partition)
            {
                check_hr(WHvCreateVirtualProcessor(partition_, vp_index, 0), "WHvCreateVirtualProcessor");
            }

            virtual_processor_handle(const virtual_processor_handle&) = delete;
            virtual_processor_handle& operator=(const virtual_processor_handle&) = delete;

            ~virtual_processor_handle()
            {
                if (partition_ != nullptr)
                {
                    WHvDeleteVirtualProcessor(partition_, vp_index);
                }
            }

          private:
            WHV_PARTITION_HANDLE partition_ = nullptr;
        };

        trap_access_kind access_kind_from_whp(WHV_MEMORY_ACCESS_TYPE access_type)
        {
            switch (access_type)
            {
            case WHvMemoryAccessRead:
                return trap_access_kind::read;
            case WHvMemoryAccessWrite:
                return trap_access_kind::write;
            case WHvMemoryAccessExecute:
                return trap_access_kind::execute;
            default:
                throw std::runtime_error("Unknown WHP memory access type.");
            }
        }

        UINT32 normalize_map_flags(UINT32 map_flags)
        {
            if ((map_flags & (WHvMapGpaRangeFlagRead | WHvMapGpaRangeFlagWrite | WHvMapGpaRangeFlagExecute)) == 0)
            {
                throw std::runtime_error("Mapped page needs at least one access flag.");
            }

            return map_flags;
        }

        UINT32 to_whp_map_flags(map_access access)
        {
            UINT32 flags = 0;

            if ((access & map_access::read) != map_access::none)
            {
                flags |= WHvMapGpaRangeFlagRead;
            }

            if ((access & map_access::write) != map_access::none)
            {
                flags |= WHvMapGpaRangeFlagWrite;
            }

            if ((access & map_access::execute) != map_access::none)
            {
                flags |= WHvMapGpaRangeFlagExecute;
            }

            return normalize_map_flags(flags);
        }

        WHV_X64_SEGMENT_REGISTER make_code_segment()
        {
            WHV_X64_SEGMENT_REGISTER segment = {};
            segment.Base = 0;
            segment.Limit = 0xFFFFF;
            segment.Selector = 0x8;
            segment.SegmentType = 0xB;
            segment.NonSystemSegment = 1;
            segment.DescriptorPrivilegeLevel = 0;
            segment.Present = 1;
            segment.Long = 1;
            segment.Default = 0;
            segment.Granularity = 1;
            return segment;
        }

        WHV_X64_SEGMENT_REGISTER make_data_segment()
        {
            WHV_X64_SEGMENT_REGISTER segment = {};
            segment.Base = 0;
            segment.Limit = 0xFFFFF;
            segment.Selector = 0x10;
            segment.SegmentType = 0x3;
            segment.NonSystemSegment = 1;
            segment.DescriptorPrivilegeLevel = 0;
            segment.Present = 1;
            segment.Default = 0;
            segment.Granularity = 1;
            return segment;
        }

        trap_info build_trap_info(const WHV_MEMORY_ACCESS_CONTEXT& memory_access)
        {
            trap_info info = {};
            info.access_kind = access_kind_from_whp(static_cast<WHV_MEMORY_ACCESS_TYPE>(memory_access.AccessInfo.AccessType));
            info.guest_physical_address = memory_access.Gpa;
            info.guest_virtual_address = memory_access.Gva;
            info.guest_virtual_address_valid = memory_access.AccessInfo.GvaValid != 0;
            info.instruction_bytes.assign(memory_access.InstructionBytes,
                                          memory_access.InstructionBytes + memory_access.InstructionByteCount);
            return info;
        }
    } // namespace

    class emulator::implementation
    {
      public:
        explicit implementation(emulator_callbacks callbacks)
            : callbacks_(std::move(callbacks))
        {
            ensure_platform_support();
            configure_partition();
            virtual_processor_ = std::make_unique<virtual_processor_handle>(partition_.get());
            initialize_long_mode_page_tables();
        }

        void set_cpu_state(const cpu_state& state)
        {
            const std::array<WHV_REGISTER_NAME, 22> names = {
                WHvX64RegisterRip, WHvX64RegisterRsp,  WHvX64RegisterRflags, WHvX64RegisterRax,    WHvX64RegisterRbx, WHvX64RegisterRcx,
                WHvX64RegisterRdx, WHvX64RegisterRsi,  WHvX64RegisterRdi,    WHvX64RegisterRbp,    WHvX64RegisterCs,  WHvX64RegisterDs,
                WHvX64RegisterEs,  WHvX64RegisterFs,   WHvX64RegisterGs,     WHvX64RegisterSs,     WHvX64RegisterCr0, WHvX64RegisterCr4,
                WHvX64RegisterCr3, WHvX64RegisterEfer, WHvX64RegisterLstar,  WHvX64RegisterSfmask,
            };

            std::array<WHV_REGISTER_VALUE, names.size()> values = {};
            values[0].Reg64 = state.rip;
            values[1].Reg64 = state.rsp;
            values[2].Reg64 = state.rflags;
            values[3].Reg64 = state.rax;
            values[4].Reg64 = state.rbx;
            values[5].Reg64 = state.rcx;
            values[6].Reg64 = state.rdx;
            values[7].Reg64 = state.rsi;
            values[8].Reg64 = state.rdi;
            values[9].Reg64 = state.rbp;

            const WHV_X64_SEGMENT_REGISTER code_segment = make_code_segment();
            const WHV_X64_SEGMENT_REGISTER data_segment = make_data_segment();

            values[10].Segment = code_segment;
            values[11].Segment = data_segment;
            values[12].Segment = data_segment;
            values[13].Segment = data_segment;
            values[14].Segment = data_segment;
            values[15].Segment = data_segment;
            values[16].Reg64 = 0x80000001ull;
            values[17].Reg64 = 0x20ull;
            values[18].Reg64 = pml4_gpa_;
            values[19].Reg64 = (1ull << 8) | (1ull << 10) | (callbacks_.syscall ? 1ull : 0ull);
            values[20].Reg64 = callbacks_.syscall_intercept_address.value_or(0);
            values[21].Reg64 = 0;

            check_hr(
                WHvSetVirtualProcessorRegisters(partition_.get(), vp_index, names.data(), static_cast<UINT32>(names.size()), values.data()),
                "WHvSetVirtualProcessorRegisters");
        }

        void map_memory(const mapped_range& range)
        {
            if (range.host_address == nullptr)
            {
                throw std::runtime_error("map_memory requires a valid host address.");
            }

            if (range.size == 0)
            {
                throw std::runtime_error("map_memory requires a non-zero size.");
            }

            if (!is_page_aligned(reinterpret_cast<std::uint64_t>(range.host_address)))
            {
                throw std::runtime_error("Host address must be page aligned.");
            }

            if (!is_page_aligned(range.size))
            {
                throw std::runtime_error("Mapped size must be page aligned.");
            }

            const std::uint64_t guest_address = range.guest_address.value_or(reinterpret_cast<std::uint64_t>(range.host_address));
            if (!is_page_aligned(guest_address))
            {
                throw std::runtime_error("Guest address must be page aligned.");
            }

            const UINT32 map_flags = to_whp_map_flags(range.access);

            trap_response response = {};
            response.resolution = trap_resolution::map_page;
            response.access = range.access;
            response.host_page = range.host_address;

            for (std::size_t offset = 0; offset < range.size; offset += page_size)
            {
                const auto current_guest_address = guest_address + offset;
                auto* const current_host_address = static_cast<void*>(static_cast<std::uint8_t*>(range.host_address) + offset);
                response.host_page = current_host_address;
                map_page(current_guest_address, response, map_flags);
            }
        }

        void run()
        {
            bool running = true;

            while (running)
            {
                WHV_RUN_VP_EXIT_CONTEXT exit_context = {};
                check_hr(WHvRunVirtualProcessor(partition_.get(), vp_index, &exit_context, sizeof(exit_context)), "WHvRunVirtualProcessor");

                switch (exit_context.ExitReason)
                {
                case WHvRunVpExitReasonMemoryAccess:
                    handle_memory_access(exit_context.MemoryAccess, running);
                    break;
                case WHvRunVpExitReasonX64Cpuid:
                    handle_cpuid(exit_context.CpuidAccess, running);
                    break;
                case WHvRunVpExitReasonException:
                    handle_exception(exit_context);
                    running = false;
                    break;
                case WHvRunVpExitReasonUnsupportedFeature:
                    handle_unsupported_feature(exit_context);
                    running = false;
                    break;
                case WHvRunVpExitReasonX64Halt:
                    if (callbacks_.syscall && callbacks_.syscall_intercept_address.has_value() &&
                        align_down_to_page(exit_context.VpContext.Rip) == align_down_to_page(callbacks_.syscall_intercept_address.value()))
                    {
                        handle_syscall(running);
                    }
                    else
                    {
                        running = false;
                    }
                    break;
                default: {
                    std::ostringstream stream;
                    stream << "Unexpected exit reason: 0x" << std::hex << exit_context.ExitReason;
                    throw std::runtime_error(stream.str());
                }
                }
            }
        }

        register_snapshot read_registers() const
        {
            const std::array<WHV_REGISTER_NAME, 6> names = {
                WHvX64RegisterRip, WHvX64RegisterRax, WHvX64RegisterRbx, WHvX64RegisterRcx, WHvX64RegisterRdx, WHvX64RegisterRsp,
            };

            std::array<WHV_REGISTER_VALUE, names.size()> values = {};
            check_hr(
                WHvGetVirtualProcessorRegisters(partition_.get(), vp_index, names.data(), static_cast<UINT32>(names.size()), values.data()),
                "WHvGetVirtualProcessorRegisters");

            return {
                .rip = values[0].Reg64,
                .rax = values[1].Reg64,
                .rbx = values[2].Reg64,
                .rcx = values[3].Reg64,
                .rdx = values[4].Reg64,
                .rsp = values[5].Reg64,
            };
        }

      private:
        void ensure_platform_support()
        {
            BOOL hypervisor_present = FALSE;
            UINT32 bytes_written = 0;

            check_hr(WHvGetCapability(WHvCapabilityCodeHypervisorPresent, &hypervisor_present, sizeof(hypervisor_present), &bytes_written),
                     "WHvGetCapability(HypervisorPresent)");

            if (!hypervisor_present)
            {
                throw std::runtime_error("Hypervisor is not present. Enable Hyper-V and Windows Hypervisor Platform.");
            }

            check_hr(WHvGetCapability(WHvCapabilityCodeExtendedVmExits, &supported_exits_, sizeof(supported_exits_), &bytes_written),
                     "WHvGetCapability(ExtendedVmExits)");
        }

        void configure_partition()
        {
            UINT32 processor_count = 1;
            check_hr(WHvSetPartitionProperty(partition_.get(), WHvPartitionPropertyCodeProcessorCount, &processor_count,
                                             sizeof(processor_count)),
                     "WHvSetPartitionProperty(ProcessorCount)");

            WHV_EXTENDED_VM_EXITS enabled_exits = {};
            enabled_exits.ExceptionExit = supported_exits_.ExceptionExit ? 1 : 0;
            enabled_exits.X64CpuidExit = (callbacks_.cpuid && supported_exits_.X64CpuidExit) ? 1 : 0;

            check_hr(
                WHvSetPartitionProperty(partition_.get(), WHvPartitionPropertyCodeExtendedVmExits, &enabled_exits, sizeof(enabled_exits)),
                "WHvSetPartitionProperty(ExtendedVmExits)");

            if (callbacks_.cpuid)
            {
                const UINT32 cpuid_leaf_zero = 0;
                check_hr(WHvSetPartitionProperty(partition_.get(), WHvPartitionPropertyCodeCpuidExitList, &cpuid_leaf_zero,
                                                 sizeof(cpuid_leaf_zero)),
                         "WHvSetPartitionProperty(CpuidExitList)");
            }

            check_hr(WHvSetupPartition(partition_.get()), "WHvSetupPartition");
        }

        void handle_memory_access(const WHV_MEMORY_ACCESS_CONTEXT& memory_access, bool& running)
        {
            if (!callbacks_.memory_trap)
            {
                throw std::runtime_error("No memory trap handler is configured.");
            }

            const trap_response response = callbacks_.memory_trap(build_trap_info(memory_access));

            switch (response.resolution)
            {
            case trap_resolution::map_page:
                map_page(memory_access.Gpa, response);
                break;
            case trap_resolution::stop_emulation:
                running = false;
                break;
            case trap_resolution::deny_access:
                throw std::runtime_error("Trap handler denied access.");
            }
        }

        void handle_cpuid(const WHV_X64_CPUID_ACCESS_CONTEXT& cpuid_access, bool& running)
        {
            if (!callbacks_.cpuid)
            {
                throw std::runtime_error("Unexpected CPUID exit without a CPUID handler.");
            }

            cpuid_info info = {};
            info.leaf = static_cast<std::uint32_t>(cpuid_access.Rax);
            info.subleaf = static_cast<std::uint32_t>(cpuid_access.Rcx);
            info.default_eax = static_cast<std::uint32_t>(cpuid_access.DefaultResultRax);
            info.default_ebx = static_cast<std::uint32_t>(cpuid_access.DefaultResultRbx);
            info.default_ecx = static_cast<std::uint32_t>(cpuid_access.DefaultResultRcx);
            info.default_edx = static_cast<std::uint32_t>(cpuid_access.DefaultResultRdx);

            const cpuid_response response = callbacks_.cpuid(info);

            switch (response.resolution)
            {
            case cpuid_resolution::passthrough:
                write_cpuid_result(info.default_eax, info.default_ebx, info.default_ecx, info.default_edx);
                advance_rip();
                break;
            case cpuid_resolution::emulate:
                write_cpuid_result(response.eax, response.ebx, response.ecx, response.edx);
                advance_rip();
                break;
            case cpuid_resolution::stop_emulation:
                running = false;
                break;
            }
        }

        void handle_syscall(bool& running)
        {
            const syscall_info info = read_syscall_info();
            const syscall_response response = callbacks_.syscall(info);

            switch (response.resolution)
            {
            case syscall_resolution::emulate_and_return:
                write_syscall_result(info.return_rip, info.return_rflags, response.return_value);
                break;
            case syscall_resolution::stop_emulation:
                running = false;
                break;
            case syscall_resolution::deny:
                throw std::runtime_error("Syscall handler denied the syscall.");
            }
        }

        void map_page(std::uint64_t guest_physical_address, const trap_response& response)
        {
            map_page(guest_physical_address, response, to_whp_map_flags(response.access));
        }

        void map_page(std::uint64_t guest_physical_address, const trap_response& response, UINT32 map_flags)
        {
            const std::uint64_t page_base = align_down_to_page(guest_physical_address);

            auto& page = mapped_pages_[page_base];
            if (!page)
            {
                page = std::make_unique<mapped_page>();
            }

            if (page->host_page == nullptr)
            {
                if (response.host_page != nullptr)
                {
                    page->host_page = response.host_page;
                }
                else
                {
                    auto* raw_page =
                        static_cast<std::uint8_t*>(::VirtualAlloc(nullptr, page_size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE));
                    if (raw_page == nullptr)
                    {
                        throw std::runtime_error("VirtualAlloc failed while backing a guest page.");
                    }

                    std::memset(raw_page, 0, page_size);
                    if (!response.page_bytes.empty())
                    {
                        std::memcpy(raw_page, response.page_bytes.data(),
                                    (std::min)(response.page_bytes.size(), static_cast<size_t>(page_size)));
                    }

                    page->owned_page.reset(raw_page);
                    page->host_page = raw_page;
                }
            }

            if (page->map_flags != 0)
            {
                check_hr(WHvUnmapGpaRange(partition_.get(), page_base, page_size), "WHvUnmapGpaRange");
            }

            page->map_flags |= map_flags;

            check_hr(WHvMapGpaRange(partition_.get(), page->host_page, page_base, page_size,
                                    static_cast<WHV_MAP_GPA_RANGE_FLAGS>(page->map_flags)),
                     "WHvMapGpaRange");

            ensure_virtual_mapping(page_base);
        }

        void initialize_long_mode_page_tables()
        {
            pml4_gpa_ = allocate_internal_page();
        }

        std::uint64_t allocate_internal_page()
        {
            auto* raw_page = static_cast<std::uint8_t*>(::VirtualAlloc(nullptr, page_size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE));
            if (raw_page == nullptr)
            {
                throw std::runtime_error("VirtualAlloc failed while creating an internal page.");
            }

            std::memset(raw_page, 0, page_size);

            const std::uint64_t page_gpa = next_internal_gpa_;
            next_internal_gpa_ += page_size;

            auto page = std::make_unique<mapped_page>();
            page->owned_page.reset(raw_page);
            page->host_page = raw_page;
            page->map_flags = WHvMapGpaRangeFlagRead | WHvMapGpaRangeFlagWrite;

            check_hr(WHvMapGpaRange(partition_.get(), page->host_page, page_gpa, page_size,
                                    static_cast<WHV_MAP_GPA_RANGE_FLAGS>(page->map_flags)),
                     "WHvMapGpaRange");

            page_table_views_[page_gpa] = reinterpret_cast<std::uint64_t*>(raw_page);
            mapped_pages_[page_gpa] = std::move(page);
            return page_gpa;
        }

        std::uint64_t* get_page_table_entries(std::uint64_t page_gpa)
        {
            return page_table_views_.at(page_gpa);
        }

        std::uint64_t ensure_child_table(std::uint64_t table_gpa, std::size_t index)
        {
            auto* const table_entries = get_page_table_entries(table_gpa);
            auto& entry = table_entries[index];
            if ((entry & page_table_entry_present) == 0)
            {
                const std::uint64_t child_gpa = allocate_internal_page();
                entry = child_gpa | page_table_entry_present | page_table_entry_writable;
                return child_gpa;
            }

            return entry & page_table_entry_address_mask;
        }

        void ensure_virtual_mapping(std::uint64_t guest_address)
        {
            const std::uint64_t page_base = align_down_to_page(guest_address);
            const auto pml4_index = static_cast<std::size_t>((page_base >> 39) & 0x1FF);
            const auto pdpt_index = static_cast<std::size_t>((page_base >> 30) & 0x1FF);
            const auto pd_index = static_cast<std::size_t>((page_base >> 21) & 0x1FF);
            const auto pt_index = static_cast<std::size_t>((page_base >> 12) & 0x1FF);

            const std::uint64_t pdpt_gpa = ensure_child_table(pml4_gpa_, pml4_index);
            const std::uint64_t pd_gpa = ensure_child_table(pdpt_gpa, pdpt_index);
            const std::uint64_t pt_gpa = ensure_child_table(pd_gpa, pd_index);

            auto* const pt_entries = get_page_table_entries(pt_gpa);
            pt_entries[pt_index] = page_base | page_table_entry_present | page_table_entry_writable;
        }

        void handle_exception(const WHV_RUN_VP_EXIT_CONTEXT& exit_context)
        {
            const auto& exception = exit_context.VpException;
            std::ostringstream stream;
            stream << "Guest exception type=0x" << std::hex << static_cast<unsigned>(exception.ExceptionType) << " rip=0x"
                   << exit_context.VpContext.Rip;
            throw std::runtime_error(stream.str());
        }

        void handle_unsupported_feature(const WHV_RUN_VP_EXIT_CONTEXT& exit_context)
        {
            const auto& unsupported_feature = exit_context.UnsupportedFeature;
            std::ostringstream stream;
            stream << "Unsupported feature exit. code=0x" << std::hex << unsupported_feature.FeatureCode << " rip=0x"
                   << exit_context.VpContext.Rip;
            throw std::runtime_error(stream.str());
        }

        void advance_rip()
        {
            const std::array<WHV_REGISTER_NAME, 1> names = {WHvX64RegisterRip};
            std::array<WHV_REGISTER_VALUE, 1> values = {};

            check_hr(
                WHvGetVirtualProcessorRegisters(partition_.get(), vp_index, names.data(), static_cast<UINT32>(names.size()), values.data()),
                "WHvGetVirtualProcessorRegisters");

            values[0].Reg64 += 2;

            check_hr(
                WHvSetVirtualProcessorRegisters(partition_.get(), vp_index, names.data(), static_cast<UINT32>(names.size()), values.data()),
                "WHvSetVirtualProcessorRegisters");
        }

        void write_cpuid_result(std::uint32_t eax, std::uint32_t ebx, std::uint32_t ecx, std::uint32_t edx)
        {
            const std::array<WHV_REGISTER_NAME, 4> names = {
                WHvX64RegisterRax,
                WHvX64RegisterRbx,
                WHvX64RegisterRcx,
                WHvX64RegisterRdx,
            };

            std::array<WHV_REGISTER_VALUE, 4> values = {};
            values[0].Reg64 = eax;
            values[1].Reg64 = ebx;
            values[2].Reg64 = ecx;
            values[3].Reg64 = edx;

            check_hr(
                WHvSetVirtualProcessorRegisters(partition_.get(), vp_index, names.data(), static_cast<UINT32>(names.size()), values.data()),
                "WHvSetVirtualProcessorRegisters");
        }

        syscall_info read_syscall_info()
        {
            const std::array<WHV_REGISTER_NAME, 8> names = {
                WHvX64RegisterRax, WHvX64RegisterRcx, WHvX64RegisterRdx, WHvX64RegisterR8,
                WHvX64RegisterR9,  WHvX64RegisterR10, WHvX64RegisterR11, WHvX64RegisterRsp,
            };

            std::array<WHV_REGISTER_VALUE, 8> values = {};
            check_hr(
                WHvGetVirtualProcessorRegisters(partition_.get(), vp_index, names.data(), static_cast<UINT32>(names.size()), values.data()),
                "WHvGetVirtualProcessorRegisters");

            syscall_info info = {};
            info.number = values[0].Reg64;
            info.return_rip = values[1].Reg64;
            info.arg1 = values[2].Reg64;
            info.arg2 = values[3].Reg64;
            info.arg3 = values[4].Reg64;
            info.arg0 = values[5].Reg64;
            info.return_rflags = values[6].Reg64;
            info.stack_pointer = values[7].Reg64;
            return info;
        }

        void write_syscall_result(std::uint64_t return_rip, std::uint64_t return_rflags, std::uint64_t return_value)
        {
            const std::array<WHV_REGISTER_NAME, 3> names = {
                WHvX64RegisterRip,
                WHvX64RegisterRflags,
                WHvX64RegisterRax,
            };

            std::array<WHV_REGISTER_VALUE, 3> values = {};
            values[0].Reg64 = return_rip;
            values[1].Reg64 = return_rflags;
            values[2].Reg64 = return_value;

            check_hr(
                WHvSetVirtualProcessorRegisters(partition_.get(), vp_index, names.data(), static_cast<UINT32>(names.size()), values.data()),
                "WHvSetVirtualProcessorRegisters");
        }

        partition_handle partition_;
        std::unique_ptr<virtual_processor_handle> virtual_processor_;
        emulator_callbacks callbacks_;
        WHV_EXTENDED_VM_EXITS supported_exits_ = {};
        std::unordered_map<std::uint64_t, std::unique_ptr<mapped_page>> mapped_pages_;
        std::unordered_map<std::uint64_t, std::uint64_t*> page_table_views_;
        std::uint64_t pml4_gpa_ = 0;
        std::uint64_t next_internal_gpa_ = internal_page_table_base;
    };

    emulator::emulator(emulator_callbacks callbacks)
        : implementation_(std::make_unique<implementation>(std::move(callbacks)))
    {
    }

    emulator::emulator(memory_trap_handler trap_handler_callback)
        : emulator(emulator_callbacks{.memory_trap = std::move(trap_handler_callback)})
    {
    }

    emulator::~emulator() = default;
    emulator::emulator(emulator&&) noexcept = default;
    emulator& emulator::operator=(emulator&&) noexcept = default;

    void emulator::set_cpu_state(const cpu_state& state)
    {
        implementation_->set_cpu_state(state);
    }

    void emulator::map_memory(const mapped_range& range)
    {
        implementation_->map_memory(range);
    }

    void emulator::run()
    {
        implementation_->run();
    }

    register_snapshot emulator::read_registers() const
    {
        return implementation_->read_registers();
    }

    std::uint64_t align_down_to_page(std::uint64_t value)
    {
        return value & ~(page_size - 1);
    }

    bool is_page_aligned(std::uint64_t value)
    {
        return (value % page_size) == 0;
    }

    map_access operator|(map_access left, map_access right)
    {
        return static_cast<map_access>(static_cast<std::uint32_t>(left) | static_cast<std::uint32_t>(right));
    }

    map_access operator&(map_access left, map_access right)
    {
        return static_cast<map_access>(static_cast<std::uint32_t>(left) & static_cast<std::uint32_t>(right));
    }

    map_access& operator|=(map_access& left, map_access right)
    {
        left = left | right;
        return left;
    }

    std::string to_hex(std::uint64_t value)
    {
        std::ostringstream stream;
        stream << "0x" << std::hex << value;
        return stream.str();
    }
} // namespace vmtrace