MemArena: Use placeholders on Windows.

1 files changed, 354 insertions, 14 deletions

diff --git a/Source/Core/Common/MemArenaWin.cpp b/Source/Core/Common/MemArenaWin.cpp
index 3229e417ab..6434627478 100644
--- a/Source/Core/Common/MemArenaWin.cpp
+++ b/Source/Core/Common/MemArenaWin.cpp
@@ -3,70 +3,410 @@
 
 #include "Common/MemArena.h"
 
+#include <algorithm>
 #include <cstddef>
 #include <cstdlib>
-#include <set>
 #include <string>
 
 #include <windows.h>
 
+#include "Common/Assert.h"
 #include "Common/CommonFuncs.h"
 #include "Common/CommonTypes.h"
+#include "Common/DynamicLibrary.h"
 #include "Common/Logging/Log.h"
 #include "Common/MsgHandler.h"
 #include "Common/StringUtil.h"
 
+using PVirtualAlloc2 = PVOID(WINAPI*)(HANDLE Process, PVOID BaseAddress, SIZE_T Size,
+                                      ULONG AllocationType, ULONG PageProtection,
+                                      MEM_EXTENDED_PARAMETER* ExtendedParameters,
+                                      ULONG ParameterCount);
+
+using PMapViewOfFile3 = PVOID(WINAPI*)(HANDLE FileMapping, HANDLE Process, PVOID BaseAddress,
+                                       ULONG64 Offset, SIZE_T ViewSize, ULONG AllocationType,
+                                       ULONG PageProtection,
+                                       MEM_EXTENDED_PARAMETER* ExtendedParameters,
+                                       ULONG ParameterCount);
+
+using PIsApiSetImplemented = BOOL(APIENTRY*)(PCSTR Contract);
+
 namespace Common
 {
-MemArena::MemArena() = default;
-MemArena::~MemArena() = default;
+struct WindowsMemoryRegion
+{
+  u8* m_start;
+  size_t m_size;
+  bool m_is_mapped;
+
+  WindowsMemoryRegion(u8* start, size_t size, bool is_mapped)
+      : m_start(start), m_size(size), m_is_mapped(is_mapped)
+  {
+  }
+};
+
+MemArena::MemArena()
+{
+  // Check if VirtualAlloc2 and MapViewOfFile3 are available, which provide functionality to reserve
+  // a memory region no other allocation may occupy while still allowing us to allocate and map
+  // stuff within it. If they're not available we'll instead fall back to the 'legacy' logic and
+  // just hope that nothing allocates in our address range.
+  DynamicLibrary kernelBase{"KernelBase.dll"};
+  if (!kernelBase.IsOpen())
+    return;
+
+  void* const ptr_IsApiSetImplemented = kernelBase.GetSymbolAddress("IsApiSetImplemented");
+  if (!ptr_IsApiSetImplemented)
+    return;
+  if (!static_cast<PIsApiSetImplemented>(ptr_IsApiSetImplemented)("api-ms-win-core-memory-l1-1-6"))
+    return;
+
+  const HMODULE handle = LoadLibraryW(L"api-ms-win-core-memory-l1-1-6.dll");
+  if (!handle)
+    return;
+
+  void* const address_VirtualAlloc2 = GetProcAddress(handle, "VirtualAlloc2FromApp");
+  void* const address_MapViewOfFile3 = GetProcAddress(handle, "MapViewOfFile3FromApp");
+  if (address_VirtualAlloc2 && address_MapViewOfFile3)
+  {
+    m_api_ms_win_core_memory_l1_1_6_handle = handle;
+    m_address_VirtualAlloc2 = address_VirtualAlloc2;
+    m_address_MapViewOfFile3 = address_MapViewOfFile3;
+  }
+  else
+  {
+    // at least one function is not available, use legacy logic
+    FreeLibrary(handle);
+  }
+}
+
+MemArena::~MemArena()
+{
+  ReleaseMemoryRegion();
+  ReleaseSHMSegment();
+  if (m_api_ms_win_core_memory_l1_1_6_handle)
+    FreeLibrary(static_cast<HMODULE>(m_api_ms_win_core_memory_l1_1_6_handle));
+}
 
 void MemArena::GrabSHMSegment(size_t size)
 {
   const std::string name = "dolphin-emu." + std::to_string(GetCurrentProcessId());
-  hMemoryMapping = CreateFileMapping(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE, 0,
-                                     static_cast<DWORD>(size), UTF8ToTStr(name).c_str());
+  m_memory_handle = CreateFileMapping(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE, 0,
+                                      static_cast<DWORD>(size), UTF8ToTStr(name).c_str());
 }
 
 void MemArena::ReleaseSHMSegment()
 {
-  CloseHandle(hMemoryMapping);
-  hMemoryMapping = 0;
+  if (!m_memory_handle)
+    return;
+  CloseHandle(m_memory_handle);
+  m_memory_handle = nullptr;
 }
 
 void* MemArena::CreateView(s64 offset, size_t size)
 {
-  return MapInMemoryRegion(offset, size, nullptr);
+  return MapViewOfFileEx(m_memory_handle, FILE_MAP_ALL_ACCESS, 0, (DWORD)((u64)offset), size,
+                         nullptr);
 }
 
 void MemArena::ReleaseView(void* view, size_t size)
 {
-  UnmapFromMemoryRegion(view, size);
+  UnmapViewOfFile(view);
 }
 
 u8* MemArena::ReserveMemoryRegion(size_t memory_size)
 {
-  u8* base = static_cast<u8*>(VirtualAlloc(nullptr, memory_size, MEM_RESERVE, PAGE_READWRITE));
-  if (!base)
+  if (m_reserved_region)
   {
-    PanicAlertFmt("Failed to map enough memory space: {}", GetLastErrorString());
+    PanicAlertFmt("Tried to reserve a second memory region from the same MemArena.");
     return nullptr;
   }
-  VirtualFree(base, 0, MEM_RELEASE);
+
+  u8* base;
+  if (m_api_ms_win_core_memory_l1_1_6_handle)
+  {
+    base = static_cast<u8*>(static_cast<PVirtualAlloc2>(m_address_VirtualAlloc2)(
+        nullptr, nullptr, memory_size, MEM_RESERVE | MEM_RESERVE_PLACEHOLDER, PAGE_NOACCESS,
+        nullptr, 0));
+    if (base)
+    {
+      m_reserved_region = base;
+      m_regions.emplace_back(base, memory_size, false);
+    }
+    else
+    {
+      PanicAlertFmt("Failed to map enough memory space: {}", GetLastErrorString());
+    }
+  }
+  else
+  {
+    NOTICE_LOG_FMT(MEMMAP, "VirtualAlloc2 and/or MapViewFromFile3 unavailable. "
+                           "Falling back to legacy memory mapping.");
+    base = static_cast<u8*>(VirtualAlloc(nullptr, memory_size, MEM_RESERVE, PAGE_READWRITE));
+    if (base)
+      VirtualFree(base, 0, MEM_RELEASE);
+    else
+      PanicAlertFmt("Failed to find enough memory space: {}", GetLastErrorString());
+  }
+
   return base;
 }
 
 void MemArena::ReleaseMemoryRegion()
 {
+  if (m_api_ms_win_core_memory_l1_1_6_handle && m_reserved_region)
+  {
+    // user should have unmapped everything by this point, check if that's true and yell if not
+    // (it indicates a bug in the emulated memory mapping logic)
+    size_t mapped_region_count = 0;
+    for (const auto& r : m_regions)
+    {
+      if (r.m_is_mapped)
+        ++mapped_region_count;
+    }
+
+    if (mapped_region_count > 0)
+    {
+      PanicAlertFmt("Error while releasing fastmem region: {} regions are still mapped!",
+                    mapped_region_count);
+    }
+
+    // then free memory
+    VirtualFree(m_reserved_region, 0, MEM_RELEASE);
+    m_reserved_region = nullptr;
+    m_regions.clear();
+  }
+}
+
+WindowsMemoryRegion* MemArena::EnsureSplitRegionForMapping(void* start_address, size_t size)
+{
+  u8* const address = static_cast<u8*>(start_address);
+  auto& regions = m_regions;
+  if (regions.empty())
+  {
+    NOTICE_LOG_FMT(MEMMAP, "Tried to map a memory region without reserving a memory block first.");
+    return nullptr;
+  }
+
+  // find closest region that is <= the given address by using upper bound and decrementing
+  auto it = std::upper_bound(
+      regions.begin(), regions.end(), address,
+      [](u8* addr, const WindowsMemoryRegion& region) { return addr < region.m_start; });
+  if (it == regions.begin())
+  {
+    // this should never happen, implies that the given address is before the start of the
+    // reserved memory block
+    NOTICE_LOG_FMT(MEMMAP, "Invalid address {} given to map.", fmt::ptr(address));
+    return nullptr;
+  }
+  --it;
+
+  if (it->m_is_mapped)
+  {
+    NOTICE_LOG_FMT(MEMMAP,
+                   "Address to map {} with a size of 0x{:x} overlaps with existing mapping "
+                   "at {}.",
+                   fmt::ptr(address), size, fmt::ptr(it->m_start));
+    return nullptr;
+  }
+
+  const size_t mapping_index = it - regions.begin();
+  u8* const mapping_address = it->m_start;
+  const size_t mapping_size = it->m_size;
+  if (mapping_address == address)
+  {
+    // if this region is already split up correctly we don't have to do anything
+    if (mapping_size == size)
+      return &*it;
+
+    // if this region is smaller than the requested size we can't map
+    if (mapping_size < size)
+    {
+      NOTICE_LOG_FMT(MEMMAP,
+                     "Not enough free space at address {} to map 0x{:x} bytes (0x{:x} available).",
+                     fmt::ptr(mapping_address), size, mapping_size);
+      return nullptr;
+    }
+
+    // split region
+    if (!VirtualFree(address, size, MEM_RELEASE | MEM_PRESERVE_PLACEHOLDER))
+    {
+      NOTICE_LOG_FMT(MEMMAP, "Region splitting failed: {}", GetLastErrorString());
+      return nullptr;
+    }
+
+    // update tracked mappings and return the first of the two
+    it->m_size = size;
+    u8* const new_mapping_start = address + size;
+    const size_t new_mapping_size = mapping_size - size;
+    regions.insert(it + 1, WindowsMemoryRegion(new_mapping_start, new_mapping_size, false));
+    return &regions[mapping_index];
+  }
+
+  ASSERT(mapping_address < address);
+
+  // is there enough space to map this?
+  const size_t size_before = static_cast<size_t>(address - mapping_address);
+  const size_t minimum_size = size + size_before;
+  if (mapping_size < minimum_size)
+  {
+    NOTICE_LOG_FMT(MEMMAP,
+                   "Not enough free space at address {} to map memory region (need 0x{:x} "
+                   "bytes, but only 0x{:x} available).",
+                   fmt::ptr(address), minimum_size, mapping_size);
+    return nullptr;
+  }
+
+  // split region
+  if (!VirtualFree(address, size, MEM_RELEASE | MEM_PRESERVE_PLACEHOLDER))
+  {
+    NOTICE_LOG_FMT(MEMMAP, "Region splitting failed: {}", GetLastErrorString());
+    return nullptr;
+  }
+
+  // do we now have two regions or three regions?
+  if (mapping_size == minimum_size)
+  {
+    // split into two; update tracked mappings and return the second one
+    it->m_size = size_before;
+    u8* const new_mapping_start = address;
+    const size_t new_mapping_size = size;
+    regions.insert(it + 1, WindowsMemoryRegion(new_mapping_start, new_mapping_size, false));
+    return &regions[mapping_index + 1];
+  }
+  else
+  {
+    // split into three; update tracked mappings and return the middle one
+    it->m_size = size_before;
+    u8* const middle_mapping_start = address;
+    const size_t middle_mapping_size = size;
+    u8* const after_mapping_start = address + size;
+    const size_t after_mapping_size = mapping_size - minimum_size;
+    regions.insert(it + 1, WindowsMemoryRegion(after_mapping_start, after_mapping_size, false));
+    regions.insert(regions.begin() + mapping_index + 1,
+                   WindowsMemoryRegion(middle_mapping_start, middle_mapping_size, false));
+    return &regions[mapping_index + 1];
+  }
 }
 
 void* MemArena::MapInMemoryRegion(s64 offset, size_t size, void* base)
 {
-  return MapViewOfFileEx(hMemoryMapping, FILE_MAP_ALL_ACCESS, 0, (DWORD)((u64)offset), size, base);
+  if (m_api_ms_win_core_memory_l1_1_6_handle)
+  {
+    WindowsMemoryRegion* const region = EnsureSplitRegionForMapping(base, size);
+    if (!region)
+    {
+      PanicAlertFmt("Splitting memory region failed.");
+      return nullptr;
+    }
+
+    void* rv = static_cast<PMapViewOfFile3>(m_address_MapViewOfFile3)(
+        m_memory_handle, nullptr, base, offset, size, MEM_REPLACE_PLACEHOLDER, PAGE_READWRITE,
+        nullptr, 0);
+    if (rv)
+    {
+      region->m_is_mapped = true;
+    }
+    else
+    {
+      PanicAlertFmt("Mapping memory region failed: {}", GetLastErrorString());
+
+      // revert the split, if any
+      JoinRegionsAfterUnmap(base, size);
+    }
+    return rv;
+  }
+
+  return MapViewOfFileEx(m_memory_handle, FILE_MAP_ALL_ACCESS, 0, (DWORD)((u64)offset), size, base);
+}
+
+bool MemArena::JoinRegionsAfterUnmap(void* start_address, size_t size)
+{
+  u8* const address = static_cast<u8*>(start_address);
+  auto& regions = m_regions;
+  if (regions.empty())
+  {
+    NOTICE_LOG_FMT(MEMMAP,
+                   "Tried to unmap a memory region without reserving a memory block first.");
+    return false;
+  }
+
+  // there should be a mapping that matches the request exactly, find it
+  auto it = std::lower_bound(
+      regions.begin(), regions.end(), address,
+      [](const WindowsMemoryRegion& region, u8* addr) { return region.m_start < addr; });
+  if (it == regions.end() || it->m_start != address || it->m_size != size)
+  {
+    // didn't find it, we were given bogus input
+    NOTICE_LOG_FMT(MEMMAP, "Invalid address/size given to unmap.");
+    return false;
+  }
+  it->m_is_mapped = false;
+
+  const bool can_join_with_preceding = it != regions.begin() && !(it - 1)->m_is_mapped;
+  const bool can_join_with_succeeding = (it + 1) != regions.end() && !(it + 1)->m_is_mapped;
+  if (can_join_with_preceding && can_join_with_succeeding)
+  {
+    // join three mappings to one
+    auto it_preceding = it - 1;
+    auto it_succeeding = it + 1;
+    const size_t total_size = it_preceding->m_size + size + it_succeeding->m_size;
+    if (!VirtualFree(it_preceding->m_start, total_size, MEM_RELEASE | MEM_COALESCE_PLACEHOLDERS))
+    {
+      NOTICE_LOG_FMT(MEMMAP, "Region coalescing failed: {}", GetLastErrorString());
+      return false;
+    }
+
+    it_preceding->m_size = total_size;
+    regions.erase(it, it + 2);
+  }
+  else if (can_join_with_preceding && !can_join_with_succeeding)
+  {
+    // join two mappings to one
+    auto it_preceding = it - 1;
+    const size_t total_size = it_preceding->m_size + size;
+    if (!VirtualFree(it_preceding->m_start, total_size, MEM_RELEASE | MEM_COALESCE_PLACEHOLDERS))
+    {
+      NOTICE_LOG_FMT(MEMMAP, "Region coalescing failed: {}", GetLastErrorString());
+      return false;
+    }
+
+    it_preceding->m_size = total_size;
+    regions.erase(it);
+  }
+  else if (!can_join_with_preceding && can_join_with_succeeding)
+  {
+    // join two mappings to one
+    auto it_succeeding = it + 1;
+    const size_t total_size = size + it_succeeding->m_size;
+    if (!VirtualFree(it->m_start, total_size, MEM_RELEASE | MEM_COALESCE_PLACEHOLDERS))
+    {
+      NOTICE_LOG_FMT(MEMMAP, "Region coalescing failed: {}", GetLastErrorString());
+      return false;
+    }
+
+    it->m_size = total_size;
+    regions.erase(it_succeeding);
+  }
+  return true;
 }
 
 void MemArena::UnmapFromMemoryRegion(void* view, size_t size)
 {
+  if (m_api_ms_win_core_memory_l1_1_6_handle)
+  {
+    if (UnmapViewOfFileEx(view, MEM_PRESERVE_PLACEHOLDER))
+    {
+      if (!JoinRegionsAfterUnmap(view, size))
+        PanicAlertFmt("Joining memory region failed.");
+    }
+    else
+    {
+      PanicAlertFmt("Unmapping memory region failed: {}", GetLastErrorString());
+    }
+    return;
+  }
+
   UnmapViewOfFile(view);
 }
 }  // namespace Common