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wiicompiled/runtime/src/guest_flat_memory.cpp
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Michael G 5c76e2b0df feature: add apple silicon native macOS support (#81) 
* feature: add apple silicon native macOS support - #81

* (macos): Fix crash

This fixes a crash when viewing the rear camera

* fix(macos): keep interpolated presentation on main thread

* fix(macos): supply Retro-WFC payload during setup

* perf(windows): compile out flat-memory fallback check

* remove duplicate smoke test

* test(macos): name and focus host platform tests

* fix(macos): validate Retro-WFC payload cache

* fix(payload): preserve staged file access failures

* Limit flat-page checks to variable-page hosts

---------

Co-authored-by: patchzyy <64382339+patchzyy@users.noreply.github.com>
2026-09-01 18:57:15 +02:00

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#include "guest_flat_memory.h"
#include <algorithm>
#include <atomic>
#include <chrono>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <mutex>
#include <sstream>
#include <stdexcept>
#include <unordered_map>
#include "memory.h"
#include "ppc_runtime.h"
#include "recomp_mod_loader.h"
#include "runtime_log.h"
#include "system_bridge.h"
#if defined(_WIN32)
#ifndef NOMINMAX
#define NOMINMAX
#endif
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
#else
#include <cerrno>
#include <cstring>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#endif
namespace GuestFlat {
#if !defined(MKW_GUEST_FLAT_FIXED_PAGE_SIZE)
bool g_requiresCheckedAccess = false;
#endif
namespace {
#if defined(_WIN32)
// Placeholder / view constants. Declared here so the build does not depend on
// the exact Windows SDK version that first shipped them.
constexpr DWORD kMemReplacePlaceholder = 0x00004000;
constexpr DWORD kMemReservePlaceholder = 0x00040000;
constexpr DWORD kMemPreservePlaceholder = 0x00000002;
#endif
constexpr size_t kAllocationGranularity = 0x10000; // 64 KiB
constexpr size_t kHostPageSize = 0x1000;
// Only hosts that can expose a page larger than 4 KiB need to discover their
// size at runtime; see RequiresCheckedAccess() in guest_flat_memory.h.
#if !defined(MKW_GUEST_FLAT_FIXED_PAGE_SIZE)
size_t HostPageSize()
{
const long size = sysconf(_SC_PAGESIZE);
return size > 0 ? static_cast<size_t>(size) : kGuestPageSize;
}
#endif
// Named, platform-neutral protection modes so every fault-interception call site below (the
// MMIO window, the executable-write guard, deferred-EFB-read protection, the on-demand
// unmapped-block commit) can stay identical text on both platforms; only ProtectRange() and
// CommitPlaceholder() below branch on VirtualProtect vs. mprotect.
#if defined(_WIN32)
using ProtectionFlags = DWORD;
constexpr ProtectionFlags kProtNone = PAGE_NOACCESS;
constexpr ProtectionFlags kProtRead = PAGE_READONLY;
constexpr ProtectionFlags kProtReadWrite = PAGE_READWRITE;
#else
using ProtectionFlags = int;
constexpr ProtectionFlags kProtNone = PROT_NONE;
constexpr ProtectionFlags kProtRead = PROT_READ;
constexpr ProtectionFlags kProtReadWrite = PROT_READ | PROT_WRITE;
#endif
#if defined(_WIN32)
using VirtualAlloc2Fn = PVOID(WINAPI*)(HANDLE, PVOID, SIZE_T, ULONG, ULONG, void*, ULONG);
using MapViewOfFile3Fn = PVOID(WINAPI*)(HANDLE, HANDLE, PVOID, ULONG64, SIZE_T, ULONG, ULONG, void*, ULONG);
VirtualAlloc2Fn g_virtualAlloc2 = nullptr;
MapViewOfFile3Fn g_mapViewOfFile3 = nullptr;
#endif
uint8_t* g_base = nullptr;
bool g_initialized = false;
std::vector<RegionRequest> g_activeRegions;
#if defined(_WIN32)
PVOID g_vectoredHandle = nullptr;
#endif
std::mutex& StateMutex() {
static std::mutex mutex;
return mutex;
}
struct SectionKey {
Backing backing = Backing::Owned;
uint32_t ownedBase = 0;
bool operator==(const SectionKey& other) const {
return backing == other.backing && ownedBase == other.ownedBase;
}
};
struct SectionKeyHash {
size_t operator()(const SectionKey& key) const {
return (static_cast<size_t>(key.ownedBase) << 3) ^ static_cast<size_t>(key.backing);
}
};
struct Section {
#if defined(_WIN32)
HANDLE handle = nullptr;
#else
int fd = -1;
#endif
uint64_t size = 0;
uint8_t* hostView = nullptr;
};
std::unordered_map<SectionKey, Section, SectionKeyHash>& Sections() {
static std::unordered_map<SectionKey, Section, SectionKeyHash> sections;
return sections;
}
struct MappedRegion {
uint32_t guestBase = 0;
uint64_t guestSize = 0; // requested size (page-table authority)
uint64_t mappedSize = 0; // rounded to allocation granularity
uint64_t sectionOffset = 0;
uint8_t* hostView = nullptr; // section host view base
};
std::vector<MappedRegion>& MappedRegions() {
static std::vector<MappedRegion> regions;
return regions;
}
struct GuardedRange {
uint32_t start = 0;
uint32_t end = 0;
};
std::vector<GuardedRange>& ExecutableRanges() {
static std::vector<GuardedRange> ranges;
return ranges;
}
// 4 KiB guest pages currently PAGE_READONLY for the executable-write guard.
std::vector<uint8_t>& ExecutableProtectedPages() {
static std::vector<uint8_t> pages(1u << 20, 0); // 2^32 / 4 KiB
return pages;
}
std::vector<GuardedRange>& DeferredRanges() {
static std::vector<GuardedRange> ranges;
return ranges;
}
#if !defined(_WIN32)
// Windows disambiguates a racing "unmapped touch" fault via VirtualQuery (did some other thread
// already commit this 64 KiB block, and is it actually accessible enough to satisfy this access).
// mprotect has no query counterpart, so this tracks the same fact ourselves: one bit per 64 KiB
// block, set the first time this module ever commits it, checked-and-set under StateMutex() so
// two threads racing on the same never-yet-committed block still report/commit exactly once.
std::vector<uint8_t>& UnmappedCommittedBlocks() {
static std::vector<uint8_t> blocks(1u << 16, 0); // 2^32 / 64 KiB
return blocks;
}
#endif
std::atomic<uint32_t> g_countMmio{0};
std::atomic<uint32_t> g_countEfb{0};
std::atomic<uint32_t> g_countXGuard{0};
std::atomic<uint32_t> g_countUnmapped{0};
std::atomic<uint32_t> g_countUnmappedRegions{0};
// Full register dumps for the first few committed regions. The one-line record
// below is emitted for every region regardless; the dump is what the historical
// checked path produced for an unmapped access, and it stays useful only while
// the log is still readable - a pointer that walks a large stride would
// otherwise bury the run in 65536 dumps.
constexpr uint32_t kUnmappedCpuDumpLimit = 16;
uint64_t RoundUp(uint64_t value, uint64_t alignment) {
return (value + alignment - 1u) & ~(alignment - 1u);
}
std::string LastErrorText(const char* what) {
std::ostringstream oss;
#if defined(_WIN32)
oss << what << " failed (GetLastError=" << GetLastError() << ")";
#else
oss << what << " failed (" << std::strerror(errno) << ")";
#endif
return oss.str();
}
// Protects [address, address+size) with `protection`, bridging VirtualProtect (Windows) and
// mprotect (POSIX) so every fault-interception call site below can stay platform-neutral.
bool ProtectRange(uint8_t* address, uint64_t size, ProtectionFlags protection) {
#if defined(_WIN32)
DWORD previous = 0;
return VirtualProtect(address, static_cast<SIZE_T>(size), protection, &previous) != FALSE;
#else
return mprotect(address, static_cast<size_t>(size), protection) == 0;
#endif
}
#if defined(_WIN32)
void ResolvePlacementApi() {
if (g_virtualAlloc2 != nullptr && g_mapViewOfFile3 != nullptr) return;
HMODULE kernelBase = GetModuleHandleW(L"kernelbase.dll");
if (kernelBase == nullptr) kernelBase = LoadLibraryW(L"kernelbase.dll");
if (kernelBase != nullptr) {
g_virtualAlloc2 =
reinterpret_cast<VirtualAlloc2Fn>(GetProcAddress(kernelBase, "VirtualAlloc2"));
g_mapViewOfFile3 =
reinterpret_cast<MapViewOfFile3Fn>(GetProcAddress(kernelBase, "MapViewOfFile3"));
}
if (g_virtualAlloc2 == nullptr || g_mapViewOfFile3 == nullptr) {
throw std::runtime_error(
"Flat guest memory requires Windows 10 1803 or newer (VirtualAlloc2/MapViewOfFile3 "
"are unavailable on this system).");
}
}
#endif
void EnsureReservation() {
if (g_base != nullptr) return;
#if defined(_WIN32)
ResolvePlacementApi();
void* requested = reinterpret_cast<void*>(kFixedFlatGuestBase);
// One extra granule stays an uncommitted placeholder so an access that
// straddles 0xFFFFFFFF faults instead of corrupting whatever the allocator
// happened to place directly after the reservation.
void* reserved = g_virtualAlloc2(GetCurrentProcess(), requested,
static_cast<SIZE_T>(kGuestSpaceSize + kAllocationGranularity),
MEM_RESERVE | kMemReservePlaceholder, PAGE_NOACCESS,
nullptr, 0);
if (reserved == nullptr) {
std::ostringstream oss;
oss << "Unable to reserve the 4 GiB flat guest address space at 0x" << std::hex
<< reinterpret_cast<uintptr_t>(requested) << std::dec
<< " (GetLastError=" << GetLastError()
<< "). The translated code addresses guest memory through this fixed base, so it "
"cannot fall back to another one. Something else in this process reserved the "
"16 TiB region first - an injected DLL, an overlay or a debugging tool is the "
"usual cause.";
throw std::runtime_error(oss.str());
}
if (reserved != requested) {
throw std::runtime_error(
"The flat guest reservation did not land on the fixed base the translated code was "
"compiled against.");
}
#else
void* requested = reinterpret_cast<void*>(kFixedFlatGuestBase);
// No MAP_FIXED here (and deliberately no MAP_FIXED_NOREPLACE, which needs Linux 4.17+ -
// this must work on kernels as old as 4.9): `requested` is only a hint. The kernel's
// get_unmapped_area honors a page-aligned hint when the whole range is free, so this lands
// on the fixed base in the normal case; if anything already occupies part of the range, the
// kernel silently picks a different address instead of clobbering it, which the check below
// catches - same "something got there first" contract as the Windows path, without needing
// a specific kernel version.
void* reserved = mmap(requested, kGuestSpaceSize + kAllocationGranularity, kProtNone,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
if (reserved == MAP_FAILED) {
std::ostringstream oss;
oss << "Unable to reserve the 4 GiB flat guest address space at 0x" << std::hex
<< reinterpret_cast<uintptr_t>(requested) << std::dec
<< " (" << std::strerror(errno)
<< "). The translated code addresses guest memory through this fixed base, so it "
"cannot fall back to another one.";
throw std::runtime_error(oss.str());
}
if (reserved != requested) {
munmap(reserved, kGuestSpaceSize + kAllocationGranularity);
std::ostringstream oss;
oss << "Unable to reserve the 4 GiB flat guest address space at 0x" << std::hex
<< reinterpret_cast<uintptr_t>(requested) << std::dec
<< ". Either something else in this process already occupies that address (an "
"injected library, an overlay or a debugging tool is the usual cause), or this "
"kernel's virtual address space does not reach that high (common on some 32-bit-"
"userspace-compatible or older AArch64 configurations, e.g. a kernel built for "
"39-bit virtual addresses) - in the latter case mmap() silently substitutes an "
"address near the top of the space it does have instead of honoring the request.";
throw std::runtime_error(oss.str());
}
#endif
g_base = static_cast<uint8_t*>(reserved);
}
#if defined(_WIN32)
// Carves `size` bytes out of the enclosing placeholder so a view or a private
// commit can replace it. Splitting an exact-size placeholder is a no-op that
// reports ERROR_INVALID_PARAMETER; the caller validates the replacement.
void SplitPlaceholder(uint8_t* address, uint64_t size) {
VirtualFree(address, static_cast<SIZE_T>(size), MEM_RELEASE | kMemPreservePlaceholder);
}
#endif
void MapGuestView(const Section& section, uint64_t sectionOffset, uint32_t guestBase,
uint64_t mappedSize) {
uint8_t* target = g_base + guestBase;
#if defined(_WIN32)
SplitPlaceholder(target, mappedSize);
void* view = g_mapViewOfFile3(section.handle, GetCurrentProcess(), target, sectionOffset,
static_cast<SIZE_T>(mappedSize), kMemReplacePlaceholder,
PAGE_READWRITE, nullptr, 0);
if (view == nullptr) {
std::ostringstream oss;
oss << "Unable to map guest region 0x" << std::hex << guestBase << " (+0x" << mappedSize
<< ") into the flat reservation" << std::dec << " (GetLastError=" << GetLastError()
<< ")";
throw std::runtime_error(oss.str());
}
#else
// MAP_FIXED is safe (and needs no particular kernel version) here specifically because we're
// deliberately overwriting a sub-range of the PROT_NONE reservation this module already owns
// exclusively (see EnsureReservation) - unlike the initial reservation itself, there's no
// "something else might already be there" concern to guard against.
void* view = mmap(target, static_cast<size_t>(mappedSize), kProtReadWrite,
MAP_SHARED | MAP_FIXED, section.fd, static_cast<off_t>(sectionOffset));
if (view == MAP_FAILED) {
std::ostringstream oss;
oss << "Unable to map guest region 0x" << std::hex << guestBase << " (+0x" << mappedSize
<< ") into the flat reservation" << std::dec << " (" << std::strerror(errno) << ")";
throw std::runtime_error(oss.str());
}
#endif
}
// Replaces a placeholder with private committed memory. Used for the MMIO
// window (read-only zeros) and for on-demand commits of stray guest pages.
bool CommitPlaceholder(uint8_t* address, uint64_t size, ProtectionFlags protection) {
#if defined(_WIN32)
SplitPlaceholder(address, size);
void* result = g_virtualAlloc2(GetCurrentProcess(), address, static_cast<SIZE_T>(size),
MEM_RESERVE | MEM_COMMIT | kMemReplacePlaceholder, protection,
nullptr, 0);
return result != nullptr;
#else
// No separate reserve-vs-commit step is needed: the anonymous PROT_NONE reservation this
// range came from is already demand-zero backed, so mprotect() alone both "commits" and
// protects it.
return ProtectRange(address, size, protection);
#endif
}
// One definition of the two windows lives in memory_access.h; these are the
// names the fault handler below reads.
bool IsMmio(uint32_t address) { return MemoryInline::IsMmioAddress(address); }
bool IsGpuFifo(uint32_t address) { return MemoryInline::IsGpuFifoAddress(address); }
void ApplyExecutableProtectionLocked() {
if (g_base == nullptr || RequiresCheckedAccess()) return;
auto& protectedPages = ExecutableProtectedPages();
for (const auto& range : ExecutableRanges()) {
// Only pages fully inside the range are protected: edge pages often share a page with data
// (MKW's THP buffers do), so guarding them would fault legitimate stores; their writes still go through the checked path.
const uint64_t first = RoundUp(range.start, kHostPageSize);
const uint64_t last = static_cast<uint64_t>(range.end) & ~(kHostPageSize - 1u);
if (last <= first) continue;
for (uint64_t page = first; page < last; page += kHostPageSize) {
const uint32_t pageIndex = static_cast<uint32_t>(page >> 12);
if (protectedPages[pageIndex] != 0) continue;
if (ProtectRange(g_base + page, kHostPageSize, kProtRead)) {
protectedPages[pageIndex] = 1;
}
}
}
}
bool SameLayout(const std::vector<RegionRequest>& lhs, const std::vector<RegionRequest>& rhs) {
if (lhs.size() != rhs.size()) return false;
for (size_t index = 0; index < lhs.size(); ++index) {
if (lhs[index].base != rhs[index].base || lhs[index].size != rhs[index].size ||
lhs[index].backing != rhs[index].backing) {
return false;
}
}
return true;
}
uint64_t SectionOffsetFor(const RegionRequest& region) {
switch (region.backing) {
case Backing::Mem1:
return region.base & 0x01FFFFFFu; // 32 MiB MEM1 window
case Backing::Mem2:
return region.base & 0x0FFFFFFFu; // 256 MiB MEM2 window
case Backing::Owned:
default:
return 0;
}
}
SectionKey KeyFor(const RegionRequest& region) {
SectionKey key;
key.backing = region.backing;
key.ownedBase = region.backing == Backing::Owned ? region.base : 0;
return key;
}
void ZeroMappedStorage() {
for (auto& [key, section] : Sections()) {
(void)key;
if (section.hostView != nullptr && section.size != 0) {
std::memset(section.hostView, 0, static_cast<size_t>(section.size));
}
}
}
#if defined(_WIN32)
LONG CALLBACK FlatGuestVectoredHandler(EXCEPTION_POINTERS* info) {
const auto* record = info->ExceptionRecord;
if (record == nullptr || record->ExceptionCode != EXCEPTION_ACCESS_VIOLATION ||
record->NumberParameters < 2) {
return EXCEPTION_CONTINUE_SEARCH;
}
void* faultAddress = reinterpret_cast<void*>(record->ExceptionInformation[1]);
const bool isWrite = record->ExceptionInformation[0] != 0;
if (HandleAccessViolation(faultAddress, isWrite)) {
return EXCEPTION_CONTINUE_EXECUTION;
}
return EXCEPTION_CONTINUE_SEARCH;
}
void InstallVectoredHandler() {
if (g_vectoredHandle != nullptr) return;
g_vectoredHandle = AddVectoredExceptionHandler(1, FlatGuestVectoredHandler);
if (g_vectoredHandle == nullptr) {
throw std::runtime_error(LastErrorText("AddVectoredExceptionHandler"));
}
}
#endif
void ReportFatalGuestFault(const char* category, uint32_t guestAddress, bool isWrite,
const char* detail) {
RT_LOG(RT_TAG_MEMORY) << "FATAL " << category << std::endl;
std::cerr << " guest address: 0x" << std::hex << std::uppercase << std::setw(8)
<< std::setfill('0') << guestAddress << std::dec << std::setfill(' ') << std::endl;
std::cerr << " access: " << (isWrite ? "write" : "read") << std::endl;
// The fault record carries the faulting address but not the width of the
// access, so the size is genuinely unavailable on this path. The checked
// path (runtime/src/memory.cpp) reports the exact length instead.
std::cerr << " access size: unknown (not recoverable from the fault record)" << std::endl;
std::cerr << " active func: 0x" << std::hex << std::uppercase
<< RecompMod::CurrentTranslatedExecutionAddress() << std::dec << std::nouppercase
<< std::endl;
std::cerr << " detail: " << detail << std::endl;
if (auto* cpu = TryGetCpuContext()) {
std::cerr << " guest pc: 0x" << std::hex << cpu->pc << " lr=0x" << cpu->lr << std::dec
<< std::endl;
SystemBridge::DumpCpuState(cpu);
}
std::cerr.flush();
std::ostringstream message;
message << "The game stopped because translated code performed a forbidden guest memory "
"access at 0x"
<< std::hex << std::uppercase << guestAddress << ".\n\n"
<< detail;
ShowRuntimeFatalPopup(category, message.str());
std::abort();
}
// Logged once per newly committed 64 KiB block since a silent commit would hide a wild guest pointer bug.
// Called with StateMutex() released so the register dump (which reads guest memory) can't deadlock against it.
void ReportUnmappedCommit(uint32_t guestAddress, uint64_t blockBase, bool isWrite,
uint32_t regionOrdinal) {
RT_LOG(RT_TAG_MEMORY) << "WARNING unmapped guest touch: no mapped region for 0x" << std::hex
<< std::uppercase << std::setw(8) << std::setfill('0') << guestAddress
<< std::setfill(' ') << " (" << (isWrite ? "write" : "read")
<< "); committed zero-filled block 0x" << blockBase << "-0x"
<< (blockBase + kAllocationGranularity) << " active=0x"
<< RecompMod::CurrentTranslatedExecutionAddress();
if (auto* cpu = TryGetCpuContext()) {
std::cerr << " pc=0x" << cpu->pc << " lr=0x" << cpu->lr << " r1=0x" << cpu->gpr[1];
}
std::cerr << std::dec << std::nouppercase << " region#" << regionOrdinal << std::endl;
if (regionOrdinal <= kUnmappedCpuDumpLimit) {
if (auto* cpu = TryGetCpuContext()) {
RT_LOG(RT_TAG_MEMORY) << "===== DUMPING CPU STATE (unmapped touch) =====" << std::endl;
SystemBridge::DumpCpuState(cpu);
}
if (regionOrdinal == kUnmappedCpuDumpLimit) {
RT_LOG(RT_TAG_MEMORY) << "further unmapped commits log the one-line record only; the "
"shutdown summary reports the totals."
<< std::endl;
}
}
std::cerr.flush();
}
} // namespace
bool IsActive() {
return g_initialized;
}
void Initialize(const std::vector<RegionRequest>& regions) {
std::lock_guard<std::mutex> lock(StateMutex());
#if !defined(MKW_GUEST_FLAT_FIXED_PAGE_SIZE)
g_requiresCheckedAccess = HostPageSize() > kGuestPageSize;
#endif
if (g_initialized) {
if (!SameLayout(g_activeRegions, regions)) {
throw std::runtime_error(
"The flat guest address space is mapped once per process; a second Memory::Init "
"requested a different region layout. Restart the process instead of remapping.");
}
// Re-init keeps the mapping and restores the pristine interception
// state: deferred ranges are gone, executable pages stay protected.
for (const auto& range : DeferredRanges()) {
const uint64_t first = static_cast<uint64_t>(range.start) & ~(kHostPageSize - 1u);
const uint64_t last = RoundUp(range.end, kHostPageSize);
ProtectRange(g_base + first, last - first, kProtReadWrite);
}
DeferredRanges().clear();
ZeroMappedStorage();
ApplyExecutableProtectionLocked();
return;
}
EnsureReservation();
// Size every section from the highest byte any of its regions reaches.
std::unordered_map<SectionKey, uint64_t, SectionKeyHash> sizes;
for (const auto& region : regions) {
if (region.size == 0) continue;
if ((region.base % kAllocationGranularity) != 0) {
std::ostringstream oss;
oss << "Guest region base 0x" << std::hex << region.base
<< " is not 64 KiB aligned; the flat mapping cannot place it.";
throw std::runtime_error(oss.str());
}
const uint64_t end = SectionOffsetFor(region) + region.size;
auto& current = sizes[KeyFor(region)];
current = std::max(current, end);
}
for (auto& [key, size] : sizes) {
const uint64_t rounded = RoundUp(size, kAllocationGranularity);
Section section;
section.size = rounded;
#if defined(_WIN32)
section.handle = CreateFileMappingW(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE,
static_cast<DWORD>(rounded >> 32),
static_cast<DWORD>(rounded & 0xFFFFFFFFu), nullptr);
if (section.handle == nullptr) {
throw std::runtime_error(LastErrorText("CreateFileMapping for guest RAM"));
}
section.hostView = static_cast<uint8_t*>(
MapViewOfFile(section.handle, FILE_MAP_ALL_ACCESS, 0, 0, static_cast<SIZE_T>(rounded)));
if (section.hostView == nullptr) {
throw std::runtime_error(LastErrorText("MapViewOfFile for the host guest-RAM alias"));
}
#else
// The section is an anonymous shared-memory object: the SAME physical pages get mapped
// twice below (once here as the always-accessible host view, once per-region as the
// guest view whose protection the fault handler controls), the same "one backing store,
// two VA aliases" trick CreateFileMapping/MapViewOfFile(3) gives Windows.
section.fd = memfd_create("wiicompiled-guest-ram", MFD_CLOEXEC);
if (section.fd < 0) {
throw std::runtime_error(LastErrorText("memfd_create for guest RAM"));
}
if (ftruncate(section.fd, static_cast<off_t>(rounded)) != 0) {
throw std::runtime_error(LastErrorText("ftruncate for guest RAM"));
}
section.hostView = static_cast<uint8_t*>(
mmap(nullptr, static_cast<size_t>(rounded), kProtReadWrite, MAP_SHARED, section.fd, 0));
if (section.hostView == MAP_FAILED) {
section.hostView = nullptr;
throw std::runtime_error(LastErrorText("mmap for the host guest-RAM alias"));
}
#endif
Sections()[key] = section;
}
for (const auto& region : regions) {
if (region.size == 0) continue;
const auto& section = Sections()[KeyFor(region)];
const uint64_t offset = SectionOffsetFor(region);
const uint64_t mappedSize =
std::min<uint64_t>(RoundUp(region.size, kAllocationGranularity), section.size - offset);
MapGuestView(section, offset, region.base, mappedSize);
MappedRegions().push_back(
MappedRegion{region.base, region.size, mappedSize, offset, section.hostView});
}
// MMIO stays inaccessible in both directions so the vectored handler can report missing HLE; the old
// PAGE_READONLY read window that returned zero turned missing devices into silent hangs instead.
if (!CommitPlaceholder(g_base + 0xCC000000u, 0x02000000u, kProtNone)) {
throw std::runtime_error(LastErrorText("committing the no-access MMIO window"));
}
ApplyExecutableProtectionLocked();
#if defined(_WIN32)
InstallVectoredHandler();
#endif
// Freshly created section objects are demand-zero, so no explicit clear is
// needed on the first mapping (that would fault in all 152 MiB at startup).
g_activeRegions = regions;
g_initialized = true;
RT_LOG(RT_TAG_MEMORY) << "guest address space reserved at 0x" << std::hex
<< reinterpret_cast<uintptr_t>(g_base) << std::dec << " (" << MappedRegions().size()
<< " regions, " << Sections().size() << " backing stores)" << std::endl;
}
uint8_t* HostPointer(uint32_t guestAddress) {
if (!g_initialized) return nullptr;
for (const auto& region : MappedRegions()) {
if (guestAddress < region.guestBase) continue;
const uint64_t offset = static_cast<uint64_t>(guestAddress) - region.guestBase;
if (offset >= region.guestSize) continue;
return region.hostView + region.sectionOffset + offset;
}
return nullptr;
}
void ProtectDeferredRange(uint32_t address, size_t length) {
if (RequiresCheckedAccess() || !g_initialized || length == 0) return;
const uint64_t end = static_cast<uint64_t>(address) + length;
if (end > kGuestSpaceSize) return;
std::lock_guard<std::mutex> lock(StateMutex());
const uint64_t first = static_cast<uint64_t>(address) & ~(kHostPageSize - 1u);
const uint64_t last = RoundUp(end, kHostPageSize);
if (!ProtectRange(g_base + first, last - first, kProtNone)) {
// An unmapped destination cannot be trapped; the checked path still
// clears the readable bias, so nothing silently reads stale bytes.
return;
}
DeferredRanges().push_back(GuardedRange{address, static_cast<uint32_t>(end)});
}
void UnprotectDeferredRange(uint32_t address, size_t length) {
if (RequiresCheckedAccess() || !g_initialized || length == 0) return;
std::lock_guard<std::mutex> lock(StateMutex());
auto& ranges = DeferredRanges();
const uint64_t end = static_cast<uint64_t>(address) + length;
const auto it = std::find_if(ranges.begin(), ranges.end(), [&](const GuardedRange& range) {
return range.start == address && range.end == static_cast<uint32_t>(end);
});
if (it == ranges.end()) return;
ranges.erase(it);
const uint64_t first = static_cast<uint64_t>(address) & ~(kHostPageSize - 1u);
const uint64_t last = RoundUp(end, kHostPageSize);
ProtectRange(g_base + first, last - first, kProtReadWrite);
}
void RegisterExecutableRange(uint32_t start, uint32_t end) {
if (RequiresCheckedAccess() || end <= start) return;
std::lock_guard<std::mutex> lock(StateMutex());
auto& ranges = ExecutableRanges();
if (std::any_of(ranges.begin(), ranges.end(), [&](const GuardedRange& range) {
return range.start == start && range.end == end;
})) {
return;
}
ranges.push_back(GuardedRange{start, end});
ApplyExecutableProtectionLocked();
}
FaultCounters Counters() {
FaultCounters counters;
counters.mmio = g_countMmio.load(std::memory_order_relaxed);
counters.efb = g_countEfb.load(std::memory_order_relaxed);
counters.xguard = g_countXGuard.load(std::memory_order_relaxed);
counters.unmapped = g_countUnmapped.load(std::memory_order_relaxed);
counters.unmappedRegions = g_countUnmappedRegions.load(std::memory_order_relaxed);
return counters;
}
void LogFaultSummary() noexcept {
static std::atomic<bool> reported{false};
if (reported.exchange(true, std::memory_order_relaxed)) return;
const FaultCounters counters = Counters();
if (counters.unmapped == 0) {
RT_LOG(RT_TAG_MEMORY) << "shutdown summary: no unmapped guest touches (efb="
<< counters.efb << " xguard=" << counters.xguard << " mmio=" << counters.mmio
<< ")" << std::endl;
std::cerr.flush();
return;
}
RT_LOG(RT_TAG_MEMORY) << "WARNING shutdown summary: " << counters.unmapped
<< " unmapped guest touches across " << counters.unmappedRegions
<< " distinct 64 KiB regions were absorbed by on-demand commits. Each one is a "
"guest pointer that addressed nothing; search the log for "
"'[" RT_TAG_MEMORY "] WARNING unmapped guest touch' for the faulting addresses."
<< std::endl;
RT_LOG(RT_TAG_MEMORY) << "shutdown summary: efb=" << counters.efb
<< " xguard=" << counters.xguard << " mmio=" << counters.mmio << std::endl;
std::cerr.flush();
}
bool HandleAccessViolation(void* faultAddress, bool isWrite) noexcept {
if (!g_initialized || faultAddress == nullptr) return false;
const uintptr_t fault = reinterpret_cast<uintptr_t>(faultAddress);
const uintptr_t base = reinterpret_cast<uintptr_t>(g_base);
if (fault < base || fault - base >= kGuestSpaceSize) return false;
const uint32_t guestAddress = static_cast<uint32_t>(fault - base);
// 1) Deferred (EFB) read: materialize the pending copy and drop the trap for the whole 4 KiB page span,
// not just the registered range, since protection is page-granular. Leaving a range registered but
// unprotected would serve stale bytes without ever faulting again.
{
bool covered = false;
uint32_t rangeStart = 0;
uint32_t rangeEnd = 0;
uint64_t spanFirst = 0;
uint64_t spanLast = 0;
{
std::lock_guard<std::mutex> lock(StateMutex());
auto& ranges = DeferredRanges();
const auto it = std::find_if(ranges.begin(), ranges.end(), [&](const GuardedRange& r) {
const uint64_t first = static_cast<uint64_t>(r.start) & ~(kHostPageSize - 1u);
const uint64_t last = RoundUp(r.end, kHostPageSize);
return guestAddress >= first && guestAddress < last;
});
if (it != ranges.end()) {
covered = true;
rangeStart = it->start;
rangeEnd = it->end;
ranges.erase(it);
spanFirst = static_cast<uint64_t>(rangeStart) & ~(kHostPageSize - 1u);
spanLast = RoundUp(rangeEnd, kHostPageSize);
ProtectRange(g_base + spanFirst, spanLast - spanFirst, kProtReadWrite);
}
}
if (covered) {
g_countEfb.fetch_add(1, std::memory_order_relaxed);
try {
MemoryInline::ResolveDeferredReads(
static_cast<uint32_t>(spanFirst), static_cast<size_t>(spanLast - spanFirst));
} catch (const std::exception& error) {
ReportFatalGuestFault("deferred read materialization failed", guestAddress, isWrite,
error.what());
}
return true;
}
}
// 2) Executable-write guard. Only writes trap (the pages are PAGE_READONLY),
// so a fault here is exactly the event the guard exists to report.
{
const uint32_t pageIndex = guestAddress >> 12;
bool guarded = false;
{
std::lock_guard<std::mutex> lock(StateMutex());
guarded = ExecutableProtectedPages()[pageIndex] != 0;
}
if (guarded) {
g_countXGuard.fetch_add(1, std::memory_order_relaxed);
// Aborts inside CheckExecutableWrite for an unsupported patch; the
// width and value are not recoverable from the fault record, so the
// report carries the exact address instead.
if (!RecompMod::HandleExecutableWrite(guestAddress, 1, 0)) {
// A permitted write (the REL loader relocating its own text).
// Those arrive in bulk, so the page is opened permanently
// rather than trapping every relocation.
std::lock_guard<std::mutex> lock(StateMutex());
if (ProtectRange(g_base + (static_cast<uint64_t>(pageIndex) << 12), kHostPageSize,
kProtReadWrite)) {
ExecutableProtectedPages()[pageIndex] = 0;
}
}
return true;
}
}
// 3) MMIO. PAGE_NOACCESS makes both directions faults: a write has no backing device (including a GPU
// FIFO store the translator failed to lower), and a read would have to invent a register value;
// answering zero would turn a missing device into a silent hang, so both are reported instead.
if (IsMmio(guestAddress)) {
g_countMmio.fetch_add(1, std::memory_order_relaxed);
if (IsGpuFifo(guestAddress)) {
if (isWrite) {
ReportFatalGuestFault(
"GPU FIFO write reached the flat memory path", guestAddress, isWrite,
"Gather-pipe stores must be lowered to GX_HLE_FIFO_Write*; the written value "
"cannot be recovered from a fault. Fix the translator lowering for this "
"store.");
}
ReportFatalGuestFault(
"GPU FIFO read blocked", guestAddress, isWrite,
"The gather pipe is write-only; nothing can be read back from it. The guest code "
"that issued this load needs GX HLE, not a memory access.");
}
if (isWrite) {
ReportFatalGuestFault("MMIO write blocked (non-GPU)", guestAddress, isWrite,
"Hardware registers have no backing store. Add HLE for this "
"device instead of letting the write land.");
}
ReportFatalGuestFault("MMIO read blocked (non-GPU)", guestAddress, isWrite,
"Hardware registers have no backing store. Answering zero would "
"hang the caller in a status poll instead of reporting the gap; "
"add HLE for this device.");
return true;
}
// 4) Unmapped address: commit the block on demand (reproducing the old zero-fill sparse-map behavior)
// and report it, since a commit here means a wild guest pointer that would otherwise walk over silently.
const uint64_t blockBase = static_cast<uint64_t>(guestAddress) & ~(kAllocationGranularity - 1u);
g_countUnmapped.fetch_add(1, std::memory_order_relaxed);
bool committed = false;
{
std::lock_guard<std::mutex> lock(StateMutex());
#if defined(_WIN32)
MEMORY_BASIC_INFORMATION mbi{};
if (VirtualQuery(g_base + blockBase, &mbi, sizeof(mbi)) == 0) return false;
if (mbi.State == MEM_COMMIT) {
// Another thread already committed this block: re-running the
// access succeeds. Any other committed-but-inaccessible state is
// not ours to fix - resuming would fault forever, so hand the
// exception to the crash reporter instead.
const bool writable = (mbi.Protect & (PAGE_READWRITE | PAGE_WRITECOPY |
PAGE_EXECUTE_READWRITE | PAGE_EXECUTE_WRITECOPY)) != 0;
const bool readable = writable || (mbi.Protect & (PAGE_READONLY | PAGE_EXECUTE_READ |
PAGE_EXECUTE)) != 0;
return isWrite ? writable : readable;
}
#else
// mprotect has no VirtualQuery counterpart to ask "is this block already committed and
// how", so this module tracks the same fact itself (UnmappedCommittedBlocks, checked and
// set under this same lock): once a block has been committed READ|WRITE by an earlier
// call here (this thread's or a racing one's), every subsequent fault on it is a no-op
// resume - there is no POSIX equivalent of "committed but insufficiently permissioned"
// for a block only this function ever touches.
const uint32_t blockIndex = static_cast<uint32_t>(blockBase / kAllocationGranularity);
if (UnmappedCommittedBlocks()[blockIndex] != 0) {
return true;
}
#endif
if (!CommitPlaceholder(g_base + blockBase, kAllocationGranularity, kProtReadWrite)) {
return false;
}
#if !defined(_WIN32)
UnmappedCommittedBlocks()[blockIndex] = 1;
#endif
committed = true;
}
if (committed) {
const uint32_t ordinal = g_countUnmappedRegions.fetch_add(1, std::memory_order_relaxed) + 1u;
ReportUnmappedCommit(guestAddress, blockBase, isWrite, ordinal);
}
return true;
}
} // namespace GuestFlat
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