Support memory aliasing (#2954)

* Back to the origins: Make memory manager take guest PA rather than host address once again

* Direct mapping with alias support on Windows

* Fixes and remove more of the emulated shared memory

* Linux support

* Make shared and transfer memory not depend on SharedMemoryStorage

* More efficient view mapping on Windows (no more restricted to 4KB pages at a time)

* Handle potential access violations caused by partial unmap

* Implement host mapping using shared memory on Linux

* Add new GetPhysicalAddressChecked method, used to ensure the virtual address is mapped before address translation

Also align GetRef behaviour with software memory manager

* We don't need a mirrorable memory block for software memory manager mode

* Disable memory aliasing tests while we don't have shared memory support on Mac

* Shared memory & SIGBUS handler for macOS

* Fix typo + nits + re-enable memory tests

* Set MAP_JIT_DARWIN on x86 Mac too

* Add back the address space mirror

* Only set MAP_JIT_DARWIN if we are mapping as executable

* Disable aliasing tests again (still fails on Mac)

* Fix UnmapView4KB (by not casting size to int)

* Use ref counting on memory blocks to delay closing the shared memory handle until all blocks using it are disposed

* Address PR feedback

* Make RO hold a reference to the guest process memory manager to avoid early disposal

Co-authored-by: nastys <nastys@users.noreply.github.com>

6 files changed, 1490 insertions, 996 deletions

diff --git a/Ryujinx.Memory/WindowsShared/EmulatedSharedMemoryWindows.cs b/Ryujinx.Memory/WindowsShared/EmulatedSharedMemoryWindows.cs
deleted file mode 100644
index 1417f7d5..00000000
--- a/Ryujinx.Memory/WindowsShared/EmulatedSharedMemoryWindows.cs
+++ /dev/null
@@ -1,703 +0,0 @@
-using Ryujinx.Memory.Range;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Runtime.InteropServices;
-
-namespace Ryujinx.Memory.WindowsShared
-{
-    class EmulatedSharedMemoryWindows : IDisposable
-    {
-        private static readonly IntPtr InvalidHandleValue = new IntPtr(-1);
-        private static readonly IntPtr CurrentProcessHandle = new IntPtr(-1);
-
-        public const int MappingBits = 16; // Windows 64kb granularity.
-        public const ulong MappingGranularity = 1 << MappingBits;
-        public const ulong MappingMask = MappingGranularity - 1;
-
-        public const ulong BackingSize32GB = 32UL * 1024UL * 1024UL * 1024UL; // Reasonable max size of 32GB.
-
-        private class SharedMemoryMapping : INonOverlappingRange
-        {
-            public ulong Address { get; }
-
-            public ulong Size { get; private set; }
-
-            public ulong EndAddress { get; private set; }
-
-            public List<int> Blocks;
-
-            public SharedMemoryMapping(ulong address, ulong size, List<int> blocks = null)
-            {
-                Address = address;
-                Size = size;
-                EndAddress = address + size;
-
-                Blocks = blocks ?? new List<int>();
-            }
-
-            public bool OverlapsWith(ulong address, ulong size)
-            {
-                return Address < address + size && address < EndAddress;
-            }
-
-            public void ExtendTo(ulong endAddress, RangeList<SharedMemoryMapping> list)
-            {
-                EndAddress = endAddress;
-                Size = endAddress - Address;
-
-                list.UpdateEndAddress(this);
-            }
-
-            public void AddBlocks(IEnumerable<int> blocks)
-            {
-                if (Blocks.Count > 0 && blocks.Count() > 0 && Blocks.Last() == blocks.First())
-                {
-                    Blocks.AddRange(blocks.Skip(1));
-                }
-                else
-                {
-                    Blocks.AddRange(blocks);
-                }
-            }
-
-            public INonOverlappingRange Split(ulong splitAddress)
-            {
-                SharedMemoryMapping newRegion = new SharedMemoryMapping(splitAddress, EndAddress - splitAddress);
-
-                int end = (int)((EndAddress + MappingMask) >> MappingBits);
-                int start = (int)(Address >> MappingBits);
-
-                Size = splitAddress - Address;
-                EndAddress = splitAddress;
-
-                int splitEndBlock = (int)((splitAddress + MappingMask) >> MappingBits);
-                int splitStartBlock = (int)(splitAddress >> MappingBits);
-
-                newRegion.AddBlocks(Blocks.Skip(splitStartBlock - start));
-                Blocks.RemoveRange(splitEndBlock - start, end - splitEndBlock);
-
-                return newRegion;
-            }
-        }
-
-        [DllImport("kernel32.dll", SetLastError = true)]
-        private static extern IntPtr CreateFileMapping(
-            IntPtr hFile,
-            IntPtr lpFileMappingAttributes,
-            FileMapProtection flProtect,
-            uint dwMaximumSizeHigh,
-            uint dwMaximumSizeLow,
-            [MarshalAs(UnmanagedType.LPWStr)] string lpName);
-
-        [DllImport("kernel32.dll", SetLastError = true)]
-        private static extern bool CloseHandle(IntPtr hObject);
-
-        [DllImport("KernelBase.dll", SetLastError = true)]
-        private static extern IntPtr VirtualAlloc2(
-            IntPtr process,
-            IntPtr lpAddress,
-            IntPtr dwSize,
-            AllocationType flAllocationType,
-            MemoryProtection flProtect,
-            IntPtr extendedParameters,
-            ulong parameterCount);
-
-        [DllImport("kernel32.dll", SetLastError = true)]
-        private static extern bool VirtualFree(IntPtr lpAddress, IntPtr dwSize, AllocationType dwFreeType);
-
-        [DllImport("KernelBase.dll", SetLastError = true)]
-        private static extern IntPtr MapViewOfFile3(
-            IntPtr hFileMappingObject,
-            IntPtr process,
-            IntPtr baseAddress,
-            ulong offset,
-            IntPtr dwNumberOfBytesToMap,
-            ulong allocationType,
-            MemoryProtection dwDesiredAccess,
-            IntPtr extendedParameters,
-            ulong parameterCount);
-
-        [DllImport("KernelBase.dll", SetLastError = true)]
-        private static extern bool UnmapViewOfFile2(IntPtr process, IntPtr lpBaseAddress, ulong unmapFlags);
-
-        private ulong _size;
-
-        private object _lock = new object();
-
-        private ulong _backingSize;
-        private IntPtr _backingMemHandle;
-        private int _backingEnd;
-        private int _backingAllocated;
-        private Queue<int> _backingFreeList;
-
-        private List<ulong> _mappedBases;
-        private RangeList<SharedMemoryMapping> _mappings;
-        private SharedMemoryMapping[] _foundMappings = new SharedMemoryMapping[32];
-        private PlaceholderList _placeholders;
-
-        public EmulatedSharedMemoryWindows(ulong size)
-        {
-            ulong backingSize = BackingSize32GB;
-
-            _size = size;
-            _backingSize = backingSize;
-
-            _backingMemHandle = CreateFileMapping(
-                InvalidHandleValue,
-                IntPtr.Zero,
-                FileMapProtection.PageReadWrite | FileMapProtection.SectionReserve,
-                (uint)(backingSize >> 32),
-                (uint)backingSize,
-                null);
-
-            if (_backingMemHandle == IntPtr.Zero)
-            {
-                throw new OutOfMemoryException();
-            }
-
-            _backingFreeList = new Queue<int>();
-            _mappings = new RangeList<SharedMemoryMapping>();
-            _mappedBases = new List<ulong>();
-            _placeholders = new PlaceholderList(size >> MappingBits);
-        }
-
-        private (ulong granularStart, ulong granularEnd) GetAlignedRange(ulong address, ulong size)
-        {
-            return (address & (~MappingMask), (address + size + MappingMask) & (~MappingMask));
-        }
-
-        private void Commit(ulong address, ulong size)
-        {
-            (ulong granularStart, ulong granularEnd) = GetAlignedRange(address, size);
-
-            ulong endAddress = address + size;
-
-            lock (_lock)
-            {
-                // Search a bit before and after the new mapping.
-                // When adding our new mapping, we may need to join an existing mapping into our new mapping (or in some cases, to the other side!)
-                ulong searchStart = granularStart == 0 ? 0 : (granularStart - 1);
-                int mappingCount = _mappings.FindOverlapsNonOverlapping(searchStart, (granularEnd - searchStart) + 1, ref _foundMappings);
-
-                int first = -1;
-                int last = -1;
-                SharedMemoryMapping startOverlap = null;
-                SharedMemoryMapping endOverlap = null;
-
-                int lastIndex = (int)(address >> MappingBits);
-                int endIndex = (int)((endAddress + MappingMask) >> MappingBits);
-                int firstBlock = -1;
-                int endBlock = -1;
-
-                for (int i = 0; i < mappingCount; i++)
-                {
-                    SharedMemoryMapping mapping = _foundMappings[i];
-
-                    if (mapping.Address < address)
-                    {
-                        if (mapping.EndAddress >= address)
-                        {
-                            startOverlap = mapping;
-                        }
-
-                        if ((int)((mapping.EndAddress - 1) >> MappingBits) == lastIndex)
-                        {
-                            lastIndex = (int)((mapping.EndAddress + MappingMask) >> MappingBits);
-                            firstBlock = mapping.Blocks.Last();
-                        }
-                    }
-
-                    if (mapping.EndAddress > endAddress)
-                    {
-                        if (mapping.Address <= endAddress)
-                        {
-                            endOverlap = mapping;
-                        }
-
-                        if ((int)((mapping.Address) >> MappingBits) + 1 == endIndex)
-                        {
-                            endIndex = (int)((mapping.Address) >> MappingBits);
-                            endBlock = mapping.Blocks.First();
-                        }
-                    }
-
-                    if (mapping.OverlapsWith(address, size))
-                    {
-                        if (first == -1)
-                        {
-                            first = i;
-                        }
-
-                        last = i;
-                    }
-                }
-
-                if (startOverlap == endOverlap && startOverlap != null)
-                {
-                    // Already fully committed.
-                    return;
-                }
-
-                var blocks = new List<int>();
-                int lastBlock = -1;
-
-                if (firstBlock != -1)
-                {
-                    blocks.Add(firstBlock);
-                    lastBlock = firstBlock;
-                }
-
-                bool hasMapped = false;
-                Action map = () =>
-                {
-                    if (!hasMapped)
-                    {
-                        _placeholders.EnsurePlaceholders(address >> MappingBits, (granularEnd - granularStart) >> MappingBits, SplitPlaceholder);
-                        hasMapped = true;
-                    }
-
-                    // There's a gap between this index and the last. Allocate blocks to fill it.
-                    blocks.Add(MapBackingBlock(MappingGranularity * (ulong)lastIndex++));
-                };
-
-                if (first != -1)
-                {
-                    for (int i = first; i <= last; i++)
-                    {
-                        SharedMemoryMapping mapping = _foundMappings[i];
-                        int mapIndex = (int)(mapping.Address >> MappingBits);
-
-                        while (lastIndex < mapIndex)
-                        {
-                            map();
-                        }
-
-                        if (lastBlock == mapping.Blocks[0])
-                        {
-                            blocks.AddRange(mapping.Blocks.Skip(1));
-                        }
-                        else
-                        {
-                            blocks.AddRange(mapping.Blocks);
-                        }
-
-                        lastIndex = (int)((mapping.EndAddress - 1) >> MappingBits) + 1;
-                    }
-                }
-
-                while (lastIndex < endIndex)
-                {
-                    map();
-                }
-
-                if (endBlock != -1 && endBlock != lastBlock)
-                {
-                    blocks.Add(endBlock);
-                }
-
-                if (startOverlap != null && endOverlap != null)
-                {
-                    // Both sides should be coalesced. Extend the start overlap to contain the end overlap, and add together their blocks.
-
-                    _mappings.Remove(endOverlap);
-
-                    startOverlap.ExtendTo(endOverlap.EndAddress, _mappings);
-
-                    startOverlap.AddBlocks(blocks);
-                    startOverlap.AddBlocks(endOverlap.Blocks);
-                }
-                else if (startOverlap != null)
-                {
-                    startOverlap.ExtendTo(endAddress, _mappings);
-
-                    startOverlap.AddBlocks(blocks);
-                }
-                else
-                {
-                    var mapping = new SharedMemoryMapping(address, size, blocks);
-
-                    if (endOverlap != null)
-                    {
-                        mapping.ExtendTo(endOverlap.EndAddress, _mappings);
-
-                        mapping.AddBlocks(endOverlap.Blocks);
-
-                        _mappings.Remove(endOverlap);
-                    }
-
-                    _mappings.Add(mapping);
-                }
-            }
-        }
-
-        private void Decommit(ulong address, ulong size)
-        {
-            (ulong granularStart, ulong granularEnd) = GetAlignedRange(address, size);
-            ulong endAddress = address + size;
-
-            lock (_lock)
-            {
-                int mappingCount = _mappings.FindOverlapsNonOverlapping(granularStart, granularEnd - granularStart, ref _foundMappings);
-
-                int first = -1;
-                int last = -1;
-
-                for (int i = 0; i < mappingCount; i++)
-                {
-                    SharedMemoryMapping mapping = _foundMappings[i];
-
-                    if (mapping.OverlapsWith(address, size))
-                    {
-                        if (first == -1)
-                        {
-                            first = i;
-                        }
-
-                        last = i;
-                    }
-                }
-
-                if (first == -1)
-                {
-                    return; // Could not find any regions to decommit.
-                }
-
-                int lastReleasedBlock = -1;
-
-                bool releasedFirst = false;
-                bool releasedLast = false;
-
-                for (int i = last; i >= first; i--)
-                {
-                    SharedMemoryMapping mapping = _foundMappings[i];
-                    bool releaseEnd = true;
-                    bool releaseStart = true;
-
-                    if (i == last)
-                    {
-                        // If this is the last region, do not release the block if there is a page ahead of us, or the block continues after us. (it is keeping the block alive)
-                        releaseEnd = last == mappingCount - 1;
-
-                        // If the end region starts after the decommit end address, split and readd it after modifying its base address.
-                        if (mapping.EndAddress > endAddress)
-                        {
-                            var newMapping = (SharedMemoryMapping)mapping.Split(endAddress);
-                            _mappings.UpdateEndAddress(mapping);
-                            _mappings.Add(newMapping);
-
-                            if ((endAddress & MappingMask) != 0)
-                            {
-                                releaseEnd = false;
-                            }
-                        }
-
-                        releasedLast = releaseEnd;
-                    }
-
-                    if (i == first)
-                    {
-                        // If this is the first region, do not release the block if there is a region behind us. (it is keeping the block alive)
-                        releaseStart = first == 0;
-
-                        // If the first region starts before the decommit address, split it by modifying its end address.
-                        if (mapping.Address < address)
-                        {
-                            var oldMapping = mapping;
-                            mapping = (SharedMemoryMapping)mapping.Split(address);
-                            _mappings.UpdateEndAddress(oldMapping);
-
-                            if ((address & MappingMask) != 0)
-                            {
-                                releaseStart = false;
-                            }
-                        }
-
-                        releasedFirst = releaseStart;
-                    }
-
-                    _mappings.Remove(mapping);
-
-                    ulong releasePointer = (mapping.EndAddress + MappingMask) & (~MappingMask);
-                    for (int j = mapping.Blocks.Count - 1; j >= 0; j--)
-                    {
-                        int blockId = mapping.Blocks[j];
-
-                        releasePointer -= MappingGranularity;
-
-                        if (lastReleasedBlock == blockId)
-                        {
-                            // When committed regions are fragmented, multiple will have the same block id for their start/end granular block.
-                            // Avoid releasing these blocks twice.
-                            continue;
-                        }
-
-                        if ((j != 0 || releaseStart) && (j != mapping.Blocks.Count - 1 || releaseEnd))
-                        {
-                            ReleaseBackingBlock(releasePointer, blockId);
-                        }
-
-                        lastReleasedBlock = blockId;
-                    }
-                }
-
-                ulong placeholderStart = (granularStart >> MappingBits) + (releasedFirst ? 0UL : 1UL);
-                ulong placeholderEnd = (granularEnd >> MappingBits) - (releasedLast ? 0UL : 1UL);
-
-                if (placeholderEnd > placeholderStart)
-                {
-                    _placeholders.RemovePlaceholders(placeholderStart, placeholderEnd - placeholderStart, CoalescePlaceholder);
-                }
-            }
-        }
-
-        public bool CommitMap(IntPtr address, IntPtr size)
-        {
-            lock (_lock)
-            {
-                foreach (ulong mapping in _mappedBases)
-                {
-                    ulong offset = (ulong)address - mapping;
-
-                    if (offset < _size)
-                    {
-                        Commit(offset, (ulong)size);
-                        return true;
-                    }
-                }
-            }
-
-            return false;
-        }
-
-        public bool DecommitMap(IntPtr address, IntPtr size)
-        {
-            lock (_lock)
-            {
-                foreach (ulong mapping in _mappedBases)
-                {
-                    ulong offset = (ulong)address - mapping;
-
-                    if (offset < _size)
-                    {
-                        Decommit(offset, (ulong)size);
-                        return true;
-                    }
-                }
-            }
-
-            return false;
-        }
-
-        private int MapBackingBlock(ulong offset)
-        {
-            bool allocate = false;
-            int backing;
-
-            if (_backingFreeList.Count > 0)
-            {
-                backing = _backingFreeList.Dequeue();
-            }
-            else
-            {
-                if (_backingAllocated == _backingEnd)
-                {
-                    // Allocate the backing.
-                    _backingAllocated++;
-                    allocate = true;
-                }
-
-                backing = _backingEnd++;
-            }
-
-            ulong backingOffset = MappingGranularity * (ulong)backing;
-
-            foreach (ulong baseAddress in _mappedBases)
-            {
-                CommitToMap(baseAddress, offset, MappingGranularity, backingOffset, allocate);
-                allocate = false;
-            }
-
-            return backing;
-        }
-
-        private void ReleaseBackingBlock(ulong offset, int id)
-        {
-            foreach (ulong baseAddress in _mappedBases)
-            {
-                DecommitFromMap(baseAddress, offset);
-            }
-
-            if (_backingEnd - 1 == id)
-            {
-                _backingEnd = id;
-            }
-            else
-            {
-                _backingFreeList.Enqueue(id);
-            }
-        }
-
-        public IntPtr Map()
-        {
-            IntPtr newMapping = VirtualAlloc2(
-                CurrentProcessHandle,
-                IntPtr.Zero,
-                (IntPtr)_size,
-                AllocationType.Reserve | AllocationType.ReservePlaceholder,
-                MemoryProtection.NoAccess,
-                IntPtr.Zero,
-                0);
-
-            if (newMapping == IntPtr.Zero)
-            {
-                throw new OutOfMemoryException();
-            }
-
-            // Apply all existing mappings to the new mapping
-            lock (_lock)
-            {
-                int lastBlock = -1;
-                foreach (SharedMemoryMapping mapping in _mappings)
-                {
-                    ulong blockAddress = mapping.Address & (~MappingMask);
-                    foreach (int block in mapping.Blocks)
-                    {
-                        if (block != lastBlock)
-                        {
-                            ulong backingOffset = MappingGranularity * (ulong)block;
-
-                            CommitToMap((ulong)newMapping, blockAddress, MappingGranularity, backingOffset, false);
-
-                            lastBlock = block;
-                        }
-
-                        blockAddress += MappingGranularity;
-                    }
-                }
-
-                _mappedBases.Add((ulong)newMapping);
-            }
-
-            return newMapping;
-        }
-
-        private void SplitPlaceholder(ulong address, ulong size)
-        {
-            ulong byteAddress = address << MappingBits;
-            IntPtr byteSize = (IntPtr)(size << MappingBits);
-
-            foreach (ulong mapAddress in _mappedBases)
-            {
-                bool result = VirtualFree((IntPtr)(mapAddress + byteAddress), byteSize, AllocationType.PreservePlaceholder | AllocationType.Release);
-
-                if (!result)
-                {
-                    throw new InvalidOperationException("Placeholder could not be split.");
-                }
-            }
-        }
-
-        private void CoalescePlaceholder(ulong address, ulong size)
-        {
-            ulong byteAddress = address << MappingBits;
-            IntPtr byteSize = (IntPtr)(size << MappingBits);
-
-            foreach (ulong mapAddress in _mappedBases)
-            {
-                bool result = VirtualFree((IntPtr)(mapAddress + byteAddress), byteSize, AllocationType.CoalescePlaceholders | AllocationType.Release);
-
-                if (!result)
-                {
-                    throw new InvalidOperationException("Placeholder could not be coalesced.");
-                }
-            }
-        }
-
-        private void CommitToMap(ulong mapAddress, ulong address, ulong size, ulong backingOffset, bool allocate)
-        {
-            IntPtr targetAddress = (IntPtr)(mapAddress + address);
-
-            // Assume the placeholder worked (or already exists)
-            // Map the backing memory into the mapped location.
-
-            IntPtr mapped = MapViewOfFile3(
-                _backingMemHandle,
-                CurrentProcessHandle,
-                targetAddress,
-                backingOffset,
-                (IntPtr)MappingGranularity,
-                0x4000, // REPLACE_PLACEHOLDER
-                MemoryProtection.ReadWrite,
-                IntPtr.Zero,
-                0);
-
-            if (mapped == IntPtr.Zero)
-            {
-                throw new InvalidOperationException($"Could not map view of backing memory. (va=0x{address:X16} size=0x{size:X16}, error code {Marshal.GetLastWin32Error()})");
-            }
-
-            if (allocate)
-            {
-                // Commit this part of the shared memory.
-                VirtualAlloc2(CurrentProcessHandle, targetAddress, (IntPtr)MappingGranularity, AllocationType.Commit, MemoryProtection.ReadWrite, IntPtr.Zero, 0);
-            }
-        }
-
-        private void DecommitFromMap(ulong baseAddress, ulong address)
-        {
-            UnmapViewOfFile2(CurrentProcessHandle, (IntPtr)(baseAddress + address), 2);
-        }
-
-        public bool Unmap(ulong baseAddress)
-        {
-            lock (_lock)
-            {
-                if (_mappedBases.Remove(baseAddress))
-                {
-                    int lastBlock = -1;
-
-                    foreach (SharedMemoryMapping mapping in _mappings)
-                    {
-                        ulong blockAddress = mapping.Address & (~MappingMask);
-                        foreach (int block in mapping.Blocks)
-                        {
-                            if (block != lastBlock)
-                            {
-                                DecommitFromMap(baseAddress, blockAddress);
-
-                                lastBlock = block;
-                            }
-
-                            blockAddress += MappingGranularity;
-                        }
-                    }
-
-                    if (!VirtualFree((IntPtr)baseAddress, (IntPtr)0, AllocationType.Release))
-                    {
-                        throw new InvalidOperationException("Couldn't free mapping placeholder.");
-                    }
-
-                    return true;
-                }
-
-                return false;
-            }
-        }
-
-        public void Dispose()
-        {
-            // Remove all file mappings
-            lock (_lock)
-            {
-                foreach (ulong baseAddress in _mappedBases.ToArray())
-                {
-                    Unmap(baseAddress);
-                }
-            }
-
-            // Finally, delete the file mapping.
-            CloseHandle(_backingMemHandle);
-        }
-    }
-}
diff --git a/Ryujinx.Memory/WindowsShared/IntervalTree.cs b/Ryujinx.Memory/WindowsShared/IntervalTree.cs
new file mode 100644
index 00000000..eac5c545
--- /dev/null
+++ b/Ryujinx.Memory/WindowsShared/IntervalTree.cs
@@ -0,0 +1,740 @@
+using System;
+using System.Collections.Generic;
+
+namespace Ryujinx.Memory.WindowsShared
+{
+    /// <summary>
+    /// An Augmented Interval Tree based off of the "TreeDictionary"'s Red-Black Tree. Allows fast overlap checking of ranges.
+    /// </summary>
+    /// <typeparam name="K">Key</typeparam>
+    /// <typeparam name="V">Value</typeparam>
+    class IntervalTree<K, V> where K : IComparable<K>
+    {
+        private const int ArrayGrowthSize = 32;
+
+        private const bool Black = true;
+        private const bool Red = false;
+        private IntervalTreeNode<K, V> _root = null;
+        private int _count = 0;
+
+        public int Count => _count;
+
+        public IntervalTree() { }
+
+        #region Public Methods
+
+        /// <summary>
+        /// Gets the values of the interval whose key is <paramref name="key"/>.
+        /// </summary>
+        /// <param name="key">Key of the node value to get</param>
+        /// <param name="value">Value with the given <paramref name="key"/></param>
+        /// <returns>True if the key is on the dictionary, false otherwise</returns>
+        public bool TryGet(K key, out V value)
+        {
+            IntervalTreeNode<K, V> node = GetNode(key);
+
+            if (node == null)
+            {
+                value = default;
+                return false;
+            }
+
+            value = node.Value;
+            return true;
+        }
+
+        /// <summary>
+        /// Returns the start addresses of the intervals whose start and end keys overlap the given range.
+        /// </summary>
+        /// <param name="start">Start of the range</param>
+        /// <param name="end">End of the range</param>
+        /// <param name="overlaps">Overlaps array to place results in</param>
+        /// <param name="overlapCount">Index to start writing results into the array. Defaults to 0</param>
+        /// <returns>Number of intervals found</returns>
+        public int Get(K start, K end, ref IntervalTreeNode<K, V>[] overlaps, int overlapCount = 0)
+        {
+            GetNodes(_root, start, end, ref overlaps, ref overlapCount);
+
+            return overlapCount;
+        }
+
+        /// <summary>
+        /// Adds a new interval into the tree whose start is <paramref name="start"/>, end is <paramref name="end"/> and value is <paramref name="value"/>.
+        /// </summary>
+        /// <param name="start">Start of the range to add</param>
+        /// <param name="end">End of the range to insert</param>
+        /// <param name="value">Value to add</param>
+        /// <exception cref="ArgumentNullException"><paramref name="value"/> is null</exception>
+        public void Add(K start, K end, V value)
+        {
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            BSTInsert(start, end, value, null, out _);
+        }
+
+        /// <summary>
+        /// Removes a value from the tree, searching for it with <paramref name="key"/>.
+        /// </summary>
+        /// <param name="key">Key of the node to remove</param>
+        /// <returns>Number of deleted values</returns>
+        public int Remove(K key)
+        {
+            return Remove(GetNode(key));
+        }
+
+        /// <summary>
+        /// Removes a value from the tree, searching for it with <paramref name="key"/>.
+        /// </summary>
+        /// <param name="nodeToDelete">Node to be removed</param>
+        /// <returns>Number of deleted values</returns>
+        public int Remove(IntervalTreeNode<K, V> nodeToDelete)
+        {
+            if (nodeToDelete == null)
+            {
+                return 0;
+            }
+
+            Delete(nodeToDelete);
+
+            _count--;
+
+            return 1;
+        }
+
+        /// <summary>
+        /// Adds all the nodes in the dictionary into <paramref name="list"/>.
+        /// </summary>
+        /// <returns>A list of all values sorted by Key Order</returns>
+        public List<V> AsList()
+        {
+            List<V> list = new List<V>();
+
+            AddToList(_root, list);
+
+            return list;
+        }
+
+        #endregion
+
+        #region Private Methods (BST)
+
+        /// <summary>
+        /// Adds all values that are children of or contained within <paramref name="node"/> into <paramref name="list"/>, in Key Order.
+        /// </summary>
+        /// <param name="node">The node to search for values within</param>
+        /// <param name="list">The list to add values to</param>
+        private void AddToList(IntervalTreeNode<K, V> node, List<V> list)
+        {
+            if (node == null)
+            {
+                return;
+            }
+
+            AddToList(node.Left, list);
+
+            list.Add(node.Value);
+
+            AddToList(node.Right, list);
+        }
+
+        /// <summary>
+        /// Retrieve the node reference whose key is <paramref name="key"/>, or null if no such node exists.
+        /// </summary>
+        /// <param name="key">Key of the node to get</param>
+        /// <exception cref="ArgumentNullException"><paramref name="key"/> is null</exception>
+        /// <returns>Node reference in the tree</returns>
+        private IntervalTreeNode<K, V> GetNode(K key)
+        {
+            if (key == null)
+            {
+                throw new ArgumentNullException(nameof(key));
+            }
+
+            IntervalTreeNode<K, V> node = _root;
+            while (node != null)
+            {
+                int cmp = key.CompareTo(node.Start);
+                if (cmp < 0)
+                {
+                    node = node.Left;
+                }
+                else if (cmp > 0)
+                {
+                    node = node.Right;
+                }
+                else
+                {
+                    return node;
+                }
+            }
+            return null;
+        }
+
+        /// <summary>
+        /// Retrieve all nodes that overlap the given start and end keys.
+        /// </summary>
+        /// <param name="start">Start of the range</param>
+        /// <param name="end">End of the range</param>
+        /// <param name="overlaps">Overlaps array to place results in</param>
+        /// <param name="overlapCount">Overlaps count to update</param>
+        private void GetNodes(IntervalTreeNode<K, V> node, K start, K end, ref IntervalTreeNode<K, V>[] overlaps, ref int overlapCount)
+        {
+            if (node == null || start.CompareTo(node.Max) >= 0)
+            {
+                return;
+            }
+
+            GetNodes(node.Left, start, end, ref overlaps, ref overlapCount);
+
+            bool endsOnRight = end.CompareTo(node.Start) > 0;
+            if (endsOnRight)
+            {
+                if (start.CompareTo(node.End) < 0)
+                {
+                    if (overlaps.Length >= overlapCount)
+                    {
+                        Array.Resize(ref overlaps, overlapCount + ArrayGrowthSize);
+                    }
+
+                    overlaps[overlapCount++] = node;
+                }
+
+                GetNodes(node.Right, start, end, ref overlaps, ref overlapCount);
+            }
+        }
+
+        /// <summary>
+        /// Propagate an increase in max value starting at the given node, heading up the tree.
+        /// This should only be called if the max increases - not for rebalancing or removals.
+        /// </summary>
+        /// <param name="node">The node to start propagating from</param>
+        private void PropagateIncrease(IntervalTreeNode<K, V> node)
+        {
+            K max = node.Max;
+            IntervalTreeNode<K, V> ptr = node;
+
+            while ((ptr = ptr.Parent) != null)
+            {
+                if (max.CompareTo(ptr.Max) > 0)
+                {
+                    ptr.Max = max;
+                }
+                else
+                {
+                    break;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Propagate recalculating max value starting at the given node, heading up the tree.
+        /// This fully recalculates the max value from all children when there is potential for it to decrease.
+        /// </summary>
+        /// <param name="node">The node to start propagating from</param>
+        private void PropagateFull(IntervalTreeNode<K, V> node)
+        {
+            IntervalTreeNode<K, V> ptr = node;
+
+            do
+            {
+                K max = ptr.End;
+
+                if (ptr.Left != null && ptr.Left.Max.CompareTo(max) > 0)
+                {
+                    max = ptr.Left.Max;
+                }
+
+                if (ptr.Right != null && ptr.Right.Max.CompareTo(max) > 0)
+                {
+                    max = ptr.Right.Max;
+                }
+
+                ptr.Max = max;
+            } while ((ptr = ptr.Parent) != null);
+        }
+
+        /// <summary>
+        /// Insertion Mechanism for the interval tree. Similar to a BST insert, with the start of the range as the key.
+        /// Iterates the tree starting from the root and inserts a new node where all children in the left subtree are less than <paramref name="start"/>, and all children in the right subtree are greater than <paramref name="start"/>.
+        /// Each node can contain multiple values, and has an end address which is the maximum of all those values.
+        /// Post insertion, the "max" value of the node and all parents are updated.
+        /// </summary>
+        /// <param name="start">Start of the range to insert</param>
+        /// <param name="end">End of the range to insert</param>
+        /// <param name="value">Value to insert</param>
+        /// <param name="updateFactoryCallback">Optional factory used to create a new value if <paramref name="start"/> is already on the tree</param>
+        /// <param name="outNode">Node that was inserted or modified</param>
+        /// <returns>True if <paramref name="start"/> was not yet on the tree, false otherwise</returns>
+        private bool BSTInsert(K start, K end, V value, Func<K, V, V> updateFactoryCallback, out IntervalTreeNode<K, V> outNode)
+        {
+            IntervalTreeNode<K, V> parent = null;
+            IntervalTreeNode<K, V> node = _root;
+
+            while (node != null)
+            {
+                parent = node;
+                int cmp = start.CompareTo(node.Start);
+                if (cmp < 0)
+                {
+                    node = node.Left;
+                }
+                else if (cmp > 0)
+                {
+                    node = node.Right;
+                }
+                else
+                {
+                    outNode = node;
+
+                    if (updateFactoryCallback != null)
+                    {
+                        // Replace
+                        node.Value = updateFactoryCallback(start, node.Value);
+
+                        int endCmp = end.CompareTo(node.End);
+
+                        if (endCmp > 0)
+                        {
+                            node.End = end;
+                            if (end.CompareTo(node.Max) > 0)
+                            {
+                                node.Max = end;
+                                PropagateIncrease(node);
+                                RestoreBalanceAfterInsertion(node);
+                            }
+                        }
+                        else if (endCmp < 0)
+                        {
+                            node.End = end;
+                            PropagateFull(node);
+                        }
+                    }
+
+                    return false;
+                }
+            }
+            IntervalTreeNode<K, V> newNode = new IntervalTreeNode<K, V>(start, end, value, parent);
+            if (newNode.Parent == null)
+            {
+                _root = newNode;
+            }
+            else if (start.CompareTo(parent.Start) < 0)
+            {
+                parent.Left = newNode;
+            }
+            else
+            {
+                parent.Right = newNode;
+            }
+
+            PropagateIncrease(newNode);
+            _count++;
+            RestoreBalanceAfterInsertion(newNode);
+            outNode = newNode;
+            return true;
+        }
+
+        /// <summary>
+        /// Removes the value from the dictionary after searching for it with <paramref name="key">.
+        /// </summary>
+        /// <param name="key">Tree node to be removed</param>
+        private void Delete(IntervalTreeNode<K, V> nodeToDelete)
+        {
+            IntervalTreeNode<K, V> replacementNode;
+
+            if (LeftOf(nodeToDelete) == null || RightOf(nodeToDelete) == null)
+            {
+                replacementNode = nodeToDelete;
+            }
+            else
+            {
+                replacementNode = PredecessorOf(nodeToDelete);
+            }
+
+            IntervalTreeNode<K, V> tmp = LeftOf(replacementNode) ?? RightOf(replacementNode);
+
+            if (tmp != null)
+            {
+                tmp.Parent = ParentOf(replacementNode);
+            }
+
+            if (ParentOf(replacementNode) == null)
+            {
+                _root = tmp;
+            }
+            else if (replacementNode == LeftOf(ParentOf(replacementNode)))
+            {
+                ParentOf(replacementNode).Left = tmp;
+            }
+            else
+            {
+                ParentOf(replacementNode).Right = tmp;
+            }
+
+            if (replacementNode != nodeToDelete)
+            {
+                nodeToDelete.Start = replacementNode.Start;
+                nodeToDelete.Value = replacementNode.Value;
+                nodeToDelete.End = replacementNode.End;
+                nodeToDelete.Max = replacementNode.Max;
+            }
+
+            PropagateFull(replacementNode);
+
+            if (tmp != null && ColorOf(replacementNode) == Black)
+            {
+                RestoreBalanceAfterRemoval(tmp);
+            }
+        }
+
+        /// <summary>
+        /// Returns the node with the largest key where <paramref name="node"/> is considered the root node.
+        /// </summary>
+        /// <param name="node">Root Node</param>
+        /// <returns>Node with the maximum key in the tree of <paramref name="node"/></returns>
+        private static IntervalTreeNode<K, V> Maximum(IntervalTreeNode<K, V> node)
+        {
+            IntervalTreeNode<K, V> tmp = node;
+            while (tmp.Right != null)
+            {
+                tmp = tmp.Right;
+            }
+
+            return tmp;
+        }
+
+        /// <summary>
+        /// Finds the node whose key is immediately less than <paramref name="node"/>.
+        /// </summary>
+        /// <param name="node">Node to find the predecessor of</param>
+        /// <returns>Predecessor of <paramref name="node"/></returns>
+        private static IntervalTreeNode<K, V> PredecessorOf(IntervalTreeNode<K, V> node)
+        {
+            if (node.Left != null)
+            {
+                return Maximum(node.Left);
+            }
+            IntervalTreeNode<K, V> parent = node.Parent;
+            while (parent != null && node == parent.Left)
+            {
+                node = parent;
+                parent = parent.Parent;
+            }
+            return parent;
+        }
+
+        #endregion
+
+        #region Private Methods (RBL)
+
+        private void RestoreBalanceAfterRemoval(IntervalTreeNode<K, V> balanceNode)
+        {
+            IntervalTreeNode<K, V> ptr = balanceNode;
+
+            while (ptr != _root && ColorOf(ptr) == Black)
+            {
+                if (ptr == LeftOf(ParentOf(ptr)))
+                {
+                    IntervalTreeNode<K, V> sibling = RightOf(ParentOf(ptr));
+
+                    if (ColorOf(sibling) == Red)
+                    {
+                        SetColor(sibling, Black);
+                        SetColor(ParentOf(ptr), Red);
+                        RotateLeft(ParentOf(ptr));
+                        sibling = RightOf(ParentOf(ptr));
+                    }
+                    if (ColorOf(LeftOf(sibling)) == Black && ColorOf(RightOf(sibling)) == Black)
+                    {
+                        SetColor(sibling, Red);
+                        ptr = ParentOf(ptr);
+                    }
+                    else
+                    {
+                        if (ColorOf(RightOf(sibling)) == Black)
+                        {
+                            SetColor(LeftOf(sibling), Black);
+                            SetColor(sibling, Red);
+                            RotateRight(sibling);
+                            sibling = RightOf(ParentOf(ptr));
+                        }
+                        SetColor(sibling, ColorOf(ParentOf(ptr)));
+                        SetColor(ParentOf(ptr), Black);
+                        SetColor(RightOf(sibling), Black);
+                        RotateLeft(ParentOf(ptr));
+                        ptr = _root;
+                    }
+                }
+                else
+                {
+                    IntervalTreeNode<K, V> sibling = LeftOf(ParentOf(ptr));
+
+                    if (ColorOf(sibling) == Red)
+                    {
+                        SetColor(sibling, Black);
+                        SetColor(ParentOf(ptr), Red);
+                        RotateRight(ParentOf(ptr));
+                        sibling = LeftOf(ParentOf(ptr));
+                    }
+                    if (ColorOf(RightOf(sibling)) == Black && ColorOf(LeftOf(sibling)) == Black)
+                    {
+                        SetColor(sibling, Red);
+                        ptr = ParentOf(ptr);
+                    }
+                    else
+                    {
+                        if (ColorOf(LeftOf(sibling)) == Black)
+                        {
+                            SetColor(RightOf(sibling), Black);
+                            SetColor(sibling, Red);
+                            RotateLeft(sibling);
+                            sibling = LeftOf(ParentOf(ptr));
+                        }
+                        SetColor(sibling, ColorOf(ParentOf(ptr)));
+                        SetColor(ParentOf(ptr), Black);
+                        SetColor(LeftOf(sibling), Black);
+                        RotateRight(ParentOf(ptr));
+                        ptr = _root;
+                    }
+                }
+            }
+            SetColor(ptr, Black);
+        }
+
+        private void RestoreBalanceAfterInsertion(IntervalTreeNode<K, V> balanceNode)
+        {
+            SetColor(balanceNode, Red);
+            while (balanceNode != null && balanceNode != _root && ColorOf(ParentOf(balanceNode)) == Red)
+            {
+                if (ParentOf(balanceNode) == LeftOf(ParentOf(ParentOf(balanceNode))))
+                {
+                    IntervalTreeNode<K, V> sibling = RightOf(ParentOf(ParentOf(balanceNode)));
+
+                    if (ColorOf(sibling) == Red)
+                    {
+                        SetColor(ParentOf(balanceNode), Black);
+                        SetColor(sibling, Black);
+                        SetColor(ParentOf(ParentOf(balanceNode)), Red);
+                        balanceNode = ParentOf(ParentOf(balanceNode));
+                    }
+                    else
+                    {
+                        if (balanceNode == RightOf(ParentOf(balanceNode)))
+                        {
+                            balanceNode = ParentOf(balanceNode);
+                            RotateLeft(balanceNode);
+                        }
+                        SetColor(ParentOf(balanceNode), Black);
+                        SetColor(ParentOf(ParentOf(balanceNode)), Red);
+                        RotateRight(ParentOf(ParentOf(balanceNode)));
+                    }
+                }
+                else
+                {
+                    IntervalTreeNode<K, V> sibling = LeftOf(ParentOf(ParentOf(balanceNode)));
+
+                    if (ColorOf(sibling) == Red)
+                    {
+                        SetColor(ParentOf(balanceNode), Black);
+                        SetColor(sibling, Black);
+                        SetColor(ParentOf(ParentOf(balanceNode)), Red);
+                        balanceNode = ParentOf(ParentOf(balanceNode));
+                    }
+                    else
+                    {
+                        if (balanceNode == LeftOf(ParentOf(balanceNode)))
+                        {
+                            balanceNode = ParentOf(balanceNode);
+                            RotateRight(balanceNode);
+                        }
+                        SetColor(ParentOf(balanceNode), Black);
+                        SetColor(ParentOf(ParentOf(balanceNode)), Red);
+                        RotateLeft(ParentOf(ParentOf(balanceNode)));
+                    }
+                }
+            }
+            SetColor(_root, Black);
+        }
+
+        private void RotateLeft(IntervalTreeNode<K, V> node)
+        {
+            if (node != null)
+            {
+                IntervalTreeNode<K, V> right = RightOf(node);
+                node.Right = LeftOf(right);
+                if (node.Right != null)
+                {
+                    node.Right.Parent = node;
+                }
+                IntervalTreeNode<K, V> nodeParent = ParentOf(node);
+                right.Parent = nodeParent;
+                if (nodeParent == null)
+                {
+                    _root = right;
+                }
+                else if (node == LeftOf(nodeParent))
+                {
+                    nodeParent.Left = right;
+                }
+                else
+                {
+                    nodeParent.Right = right;
+                }
+                right.Left = node;
+                node.Parent = right;
+
+                PropagateFull(node);
+            }
+        }
+
+        private void RotateRight(IntervalTreeNode<K, V> node)
+        {
+            if (node != null)
+            {
+                IntervalTreeNode<K, V> left = LeftOf(node);
+                node.Left = RightOf(left);
+                if (node.Left != null)
+                {
+                    node.Left.Parent = node;
+                }
+                IntervalTreeNode<K, V> nodeParent = ParentOf(node);
+                left.Parent = nodeParent;
+                if (nodeParent == null)
+                {
+                    _root = left;
+                }
+                else if (node == RightOf(nodeParent))
+                {
+                    nodeParent.Right = left;
+                }
+                else
+                {
+                    nodeParent.Left = left;
+                }
+                left.Right = node;
+                node.Parent = left;
+
+                PropagateFull(node);
+            }
+        }
+
+        #endregion
+
+        #region Safety-Methods
+
+        // These methods save memory by allowing us to forego sentinel nil nodes, as well as serve as protection against NullReferenceExceptions.
+
+        /// <summary>
+        /// Returns the color of <paramref name="node"/>, or Black if it is null.
+        /// </summary>
+        /// <param name="node">Node</param>
+        /// <returns>The boolean color of <paramref name="node"/>, or black if null</returns>
+        private static bool ColorOf(IntervalTreeNode<K, V> node)
+        {
+            return node == null || node.Color;
+        }
+
+        /// <summary>
+        /// Sets the color of <paramref name="node"/> node to <paramref name="color"/>.
+        /// <br></br>
+        /// This method does nothing if <paramref name="node"/> is null.
+        /// </summary>
+        /// <param name="node">Node to set the color of</param>
+        /// <param name="color">Color (Boolean)</param>
+        private static void SetColor(IntervalTreeNode<K, V> node, bool color)
+        {
+            if (node != null)
+            {
+                node.Color = color;
+            }
+        }
+
+        /// <summary>
+        /// This method returns the left node of <paramref name="node"/>, or null if <paramref name="node"/> is null.
+        /// </summary>
+        /// <param name="node">Node to retrieve the left child from</param>
+        /// <returns>Left child of <paramref name="node"/></returns>
+        private static IntervalTreeNode<K, V> LeftOf(IntervalTreeNode<K, V> node)
+        {
+            return node?.Left;
+        }
+
+        /// <summary>
+        /// This method returns the right node of <paramref name="node"/>, or null if <paramref name="node"/> is null.
+        /// </summary>
+        /// <param name="node">Node to retrieve the right child from</param>
+        /// <returns>Right child of <paramref name="node"/></returns>
+        private static IntervalTreeNode<K, V> RightOf(IntervalTreeNode<K, V> node)
+        {
+            return node?.Right;
+        }
+
+        /// <summary>
+        /// Returns the parent node of <paramref name="node"/>, or null if <paramref name="node"/> is null.
+        /// </summary>
+        /// <param name="node">Node to retrieve the parent from</param>
+        /// <returns>Parent of <paramref name="node"/></returns>
+        private static IntervalTreeNode<K, V> ParentOf(IntervalTreeNode<K, V> node)
+        {
+            return node?.Parent;
+        }
+
+        #endregion
+
+        public bool ContainsKey(K key)
+        {
+            return GetNode(key) != null;
+        }
+
+        public void Clear()
+        {
+            _root = null;
+            _count = 0;
+        }
+    }
+
+    /// <summary>
+    /// Represents a node in the IntervalTree which contains start and end keys of type K, and a value of generic type V.
+    /// </summary>
+    /// <typeparam name="K">Key type of the node</typeparam>
+    /// <typeparam name="V">Value type of the node</typeparam>
+    class IntervalTreeNode<K, V>
+    {
+        public bool Color = true;
+        public IntervalTreeNode<K, V> Left = null;
+        public IntervalTreeNode<K, V> Right = null;
+        public IntervalTreeNode<K, V> Parent = null;
+
+        /// <summary>
+        /// The start of the range.
+        /// </summary>
+        public K Start;
+
+        /// <summary>
+        /// The end of the range.
+        /// </summary>
+        public K End;
+
+        /// <summary>
+        /// The maximum end value of this node and all its children.
+        /// </summary>
+        public K Max;
+
+        /// <summary>
+        /// Value stored on this node.
+        /// </summary>
+        public V Value;
+
+        public IntervalTreeNode(K start, K end, V value, IntervalTreeNode<K, V> parent)
+        {
+            Start = start;
+            End = end;
+            Max = end;
+            Value = value;
+            Parent = parent;
+        }
+    }
+}
diff --git a/Ryujinx.Memory/WindowsShared/PlaceholderList.cs b/Ryujinx.Memory/WindowsShared/PlaceholderList.cs
deleted file mode 100644
index 848e410e..00000000
--- a/Ryujinx.Memory/WindowsShared/PlaceholderList.cs
+++ /dev/null
@@ -1,293 +0,0 @@
-using Ryujinx.Memory.Range;
-using System;
-using System.Diagnostics;
-
-namespace Ryujinx.Memory.WindowsShared
-{
-    /// <summary>
-    /// A specialized list used for keeping track of Windows 10's memory placeholders.
-    /// This is used to make splitting a large placeholder into equally small
-    /// granular chunks much easier, while avoiding slowdown due to a large number of
-    /// placeholders by coalescing adjacent granular placeholders after they are unused.
-    /// </summary>
-    class PlaceholderList
-    {
-        private class PlaceholderBlock : IRange
-        {
-            public ulong Address { get; }
-            public ulong Size { get; private set; }
-            public ulong EndAddress { get; private set; }
-            public bool IsGranular { get; set; }
-
-            public PlaceholderBlock(ulong id, ulong size, bool isGranular)
-            {
-                Address = id;
-                Size = size;
-                EndAddress = id + size;
-                IsGranular = isGranular;
-            }
-
-            public bool OverlapsWith(ulong address, ulong size)
-            {
-                return Address < address + size && address < EndAddress;
-            }
-
-            public void ExtendTo(ulong end, RangeList<PlaceholderBlock> list)
-            {
-                EndAddress = end;
-                Size = end - Address;
-
-                list.UpdateEndAddress(this);
-            }
-        }
-
-        private RangeList<PlaceholderBlock> _placeholders;
-        private PlaceholderBlock[] _foundBlocks = new PlaceholderBlock[32];
-
-        /// <summary>
-        /// Create a new list to manage placeholders.
-        /// Note that a size is measured in granular placeholders.
-        /// If the placeholder granularity is 65536 bytes, then a 65536 region will be covered by 1 placeholder granularity.
-        /// </summary>
-        /// <param name="size">Size measured in granular placeholders</param>
-        public PlaceholderList(ulong size)
-        {
-            _placeholders = new RangeList<PlaceholderBlock>();
-
-            _placeholders.Add(new PlaceholderBlock(0, size, false));
-        }
-
-        /// <summary>
-        /// Ensure that the given range of placeholders is granular.
-        /// </summary>
-        /// <param name="id">Start of the range, measured in granular placeholders</param>
-        /// <param name="size">Size of the range, measured in granular placeholders</param>
-        /// <param name="splitPlaceholderCallback">Callback function to run when splitting placeholders, calls with (start, middle)</param>
-        public void EnsurePlaceholders(ulong id, ulong size, Action<ulong, ulong> splitPlaceholderCallback)
-        {
-            // Search 1 before and after the placeholders, as we may need to expand/join granular regions surrounding the requested area.
-
-            ulong endId = id + size;
-            ulong searchStartId = id == 0 ? 0 : (id - 1);
-            int blockCount = _placeholders.FindOverlapsNonOverlapping(searchStartId, (endId - searchStartId) + 1, ref _foundBlocks);
-
-            PlaceholderBlock first = _foundBlocks[0];
-            PlaceholderBlock last = _foundBlocks[blockCount - 1];
-            bool overlapStart = first.EndAddress >= id && id != 0;
-            bool overlapEnd = last.Address <= endId;
-
-            for (int i = 0; i < blockCount; i++)
-            {
-                // Go through all non-granular blocks in the range and create placeholders.
-                PlaceholderBlock block = _foundBlocks[i];
-
-                if (block.Address <= id && block.EndAddress >= endId && block.IsGranular)
-                {
-                    return; // The region we're searching for is already granular.
-                }
-
-                if (!block.IsGranular)
-                {
-                    ulong placeholderStart = Math.Max(block.Address, id);
-                    ulong placeholderEnd = Math.Min(block.EndAddress - 1, endId);
-
-                    if (placeholderStart != block.Address && placeholderStart != block.EndAddress)
-                    {
-                        splitPlaceholderCallback(block.Address, placeholderStart - block.Address);
-                    }
-
-                    for (ulong j = placeholderStart; j < placeholderEnd; j++)
-                    {
-                        splitPlaceholderCallback(j, 1);
-                    }
-                }
-
-                if (!((block == first && overlapStart) || (block == last && overlapEnd)))
-                {
-                    // Remove blocks that will be replaced
-                    _placeholders.Remove(block);
-                }
-            }
-
-            if (overlapEnd)
-            {
-                if (!(first == last && overlapStart))
-                {
-                    _placeholders.Remove(last);
-                }
-
-                if (last.IsGranular)
-                {
-                    endId = last.EndAddress;
-                }
-                else if (last.EndAddress != endId)
-                {
-                    _placeholders.Add(new PlaceholderBlock(endId, last.EndAddress - endId, false));
-                }
-            }
-
-            if (overlapStart && first.IsGranular)
-            {
-                first.ExtendTo(endId, _placeholders);
-            }
-            else
-            {
-                if (overlapStart)
-                {
-                    first.ExtendTo(id, _placeholders);
-                }
-
-                _placeholders.Add(new PlaceholderBlock(id, endId - id, true));
-            }
-
-            ValidateList();
-        }
-
-        /// <summary>
-        /// Coalesces placeholders in a given region, as they are not being used.
-        /// This assumes that the region only contains placeholders - all views and allocations must have been replaced with placeholders.
-        /// </summary>
-        /// <param name="id">Start of the range, measured in granular placeholders</param>
-        /// <param name="size">Size of the range, measured in granular placeholders</param>
-        /// <param name="coalescePlaceholderCallback">Callback function to run when coalescing two placeholders, calls with (start, end)</param>
-        public void RemovePlaceholders(ulong id, ulong size, Action<ulong, ulong> coalescePlaceholderCallback)
-        {
-            ulong endId = id + size;
-            int blockCount = _placeholders.FindOverlapsNonOverlapping(id, size, ref _foundBlocks);
-
-            PlaceholderBlock first = _foundBlocks[0];
-            PlaceholderBlock last = _foundBlocks[blockCount - 1];
-
-            // All granular blocks must have non-granular blocks surrounding them, unless they start at 0.
-            // We must extend the non-granular blocks into the granular ones. This does mean that we need to search twice.
-
-            if (first.IsGranular || last.IsGranular)
-            {
-                ulong surroundStart = Math.Max(0, (first.IsGranular && first.Address != 0) ? first.Address - 1 : id);
-                blockCount = _placeholders.FindOverlapsNonOverlapping(
-                    surroundStart,
-                    (last.IsGranular ? last.EndAddress + 1 : endId) - surroundStart,
-                    ref _foundBlocks);
-
-                first = _foundBlocks[0];
-                last = _foundBlocks[blockCount - 1];
-            }
-
-            if (first == last)
-            {
-                return; // Already coalesced.
-            }
-
-            PlaceholderBlock extendBlock = id == 0 ? null : first;
-            bool newBlock = false;
-            for (int i = extendBlock == null ? 0 : 1; i < blockCount; i++)
-            {
-                // Go through all granular blocks in the range and extend placeholders.
-                PlaceholderBlock block = _foundBlocks[i];
-
-                ulong blockEnd = block.EndAddress;
-                ulong extendFrom;
-                ulong extent = Math.Min(blockEnd, endId);
-
-                if (block.Address < id && blockEnd > id)
-                {
-                    block.ExtendTo(id, _placeholders);
-                    extendBlock = null;
-                }
-                else
-                {
-                    _placeholders.Remove(block);
-                }
-
-                if (extendBlock == null)
-                {
-                    extendFrom = id;
-                    extendBlock = new PlaceholderBlock(id, extent - id, false);
-                    _placeholders.Add(extendBlock);
-
-                    if (blockEnd > extent)
-                    {
-                        _placeholders.Add(new PlaceholderBlock(extent, blockEnd - extent, true));
-
-                        // Skip the next non-granular block, and extend from that into the granular block afterwards.
-                        // (assuming that one is still in the requested range)
-
-                        if (i + 1 < blockCount)
-                        {
-                            extendBlock = _foundBlocks[i + 1];
-                        }
-
-                        i++;
-                    }
-
-                    newBlock = true;
-                }
-                else
-                {
-                    extendFrom = extendBlock.Address;
-                    extendBlock.ExtendTo(block.IsGranular ? extent : block.EndAddress, _placeholders);
-                }
-
-                if (block.IsGranular)
-                {
-                    ulong placeholderStart = Math.Max(block.Address, id);
-                    ulong placeholderEnd = extent;
-
-                    if (newBlock)
-                    {
-                        placeholderStart++;
-                        newBlock = false;
-                    }
-
-                    for (ulong j = placeholderStart; j < placeholderEnd; j++)
-                    {
-                        coalescePlaceholderCallback(extendFrom, (j + 1) - extendFrom);
-                    }
-
-                    if (extent < block.EndAddress)
-                    {
-                        _placeholders.Add(new PlaceholderBlock(placeholderEnd, block.EndAddress - placeholderEnd, true));
-                        ValidateList();
-                        return;
-                    }
-                }
-                else
-                {
-                    coalescePlaceholderCallback(extendFrom, block.EndAddress - extendFrom);
-                }
-            }
-
-            ValidateList();
-        }
-
-        /// <summary>
-        /// Ensure that the placeholder list is valid.
-        /// A valid list should not have any gaps between the placeholders,
-        /// and there may be no placehonders with the same IsGranular value next to each other.
-        /// </summary>
-        [Conditional("DEBUG")]
-        private void ValidateList()
-        {
-            bool isGranular = false;
-            bool first = true;
-            ulong lastAddress = 0;
-
-            foreach (var placeholder in _placeholders)
-            {
-                if (placeholder.Address != lastAddress)
-                {
-                    throw new InvalidOperationException("Gap in placeholder list.");
-                }
-
-                if (isGranular == placeholder.IsGranular && !first)
-                {
-                    throw new InvalidOperationException("Placeholder list not alternating.");
-                }
-
-                first = false;
-                isGranular = placeholder.IsGranular;
-                lastAddress = placeholder.EndAddress;
-            }
-        }
-    }
-}
diff --git a/Ryujinx.Memory/WindowsShared/PlaceholderManager.cs b/Ryujinx.Memory/WindowsShared/PlaceholderManager.cs
new file mode 100644
index 00000000..a16a8c7f
--- /dev/null
+++ b/Ryujinx.Memory/WindowsShared/PlaceholderManager.cs
@@ -0,0 +1,633 @@
+using System;
+using System.Diagnostics;
+using System.Threading;
+
+namespace Ryujinx.Memory.WindowsShared
+{
+    /// <summary>
+    /// Windows memory placeholder manager.
+    /// </summary>
+    class PlaceholderManager
+    {
+        private const ulong MinimumPageSize = 0x1000;
+
+        [ThreadStatic]
+        private static int _threadLocalPartialUnmapsCount;
+
+        private readonly IntervalTree<ulong, ulong> _mappings;
+        private readonly IntervalTree<ulong, MemoryPermission> _protections;
+        private readonly ReaderWriterLock _partialUnmapLock;
+        private int _partialUnmapsCount;
+
+        /// <summary>
+        /// Creates a new instance of the Windows memory placeholder manager.
+        /// </summary>
+        public PlaceholderManager()
+        {
+            _mappings = new IntervalTree<ulong, ulong>();
+            _protections = new IntervalTree<ulong, MemoryPermission>();
+            _partialUnmapLock = new ReaderWriterLock();
+        }
+
+        /// <summary>
+        /// Reserves a range of the address space to be later mapped as shared memory views.
+        /// </summary>
+        /// <param name="address">Start address of the region to reserve</param>
+        /// <param name="size">Size in bytes of the region to reserve</param>
+        public void ReserveRange(ulong address, ulong size)
+        {
+            lock (_mappings)
+            {
+                _mappings.Add(address, address + size, ulong.MaxValue);
+            }
+        }
+
+        /// <summary>
+        /// Maps a shared memory view on a previously reserved memory region.
+        /// </summary>
+        /// <param name="sharedMemory">Shared memory that will be the backing storage for the view</param>
+        /// <param name="srcOffset">Offset in the shared memory to map</param>
+        /// <param name="location">Address to map the view into</param>
+        /// <param name="size">Size of the view in bytes</param>
+        public void MapView(IntPtr sharedMemory, ulong srcOffset, IntPtr location, IntPtr size)
+        {
+            _partialUnmapLock.AcquireReaderLock(Timeout.Infinite);
+
+            try
+            {
+                UnmapViewInternal(sharedMemory, location, size);
+                MapViewInternal(sharedMemory, srcOffset, location, size);
+            }
+            finally
+            {
+                _partialUnmapLock.ReleaseReaderLock();
+            }
+        }
+
+        /// <summary>
+        /// Maps a shared memory view on a previously reserved memory region.
+        /// </summary>
+        /// <param name="sharedMemory">Shared memory that will be the backing storage for the view</param>
+        /// <param name="srcOffset">Offset in the shared memory to map</param>
+        /// <param name="location">Address to map the view into</param>
+        /// <param name="size">Size of the view in bytes</param>
+        /// <exception cref="WindowsApiException">Thrown when the Windows API returns an error mapping the memory</exception>
+        private void MapViewInternal(IntPtr sharedMemory, ulong srcOffset, IntPtr location, IntPtr size)
+        {
+            SplitForMap((ulong)location, (ulong)size, srcOffset);
+
+            var ptr = WindowsApi.MapViewOfFile3(
+                sharedMemory,
+                WindowsApi.CurrentProcessHandle,
+                location,
+                srcOffset,
+                size,
+                0x4000,
+                MemoryProtection.ReadWrite,
+                IntPtr.Zero,
+                0);
+
+            if (ptr == IntPtr.Zero)
+            {
+                throw new WindowsApiException("MapViewOfFile3");
+            }
+        }
+
+        /// <summary>
+        /// Splits a larger placeholder, slicing at the start and end address, for a new memory mapping.
+        /// </summary>
+        /// <param name="address">Address to split</param>
+        /// <param name="size">Size of the new region</param>
+        /// <param name="backingOffset">Offset in the shared memory that will be mapped</param>
+        private void SplitForMap(ulong address, ulong size, ulong backingOffset)
+        {
+            ulong endAddress = address + size;
+
+            var overlaps = Array.Empty<IntervalTreeNode<ulong, ulong>>();
+
+            lock (_mappings)
+            {
+                int count = _mappings.Get(address, endAddress, ref overlaps);
+
+                Debug.Assert(count == 1);
+                Debug.Assert(!IsMapped(overlaps[0].Value));
+
+                var overlap = overlaps[0];
+
+                // Tree operations might modify the node start/end values, so save a copy before we modify the tree.
+                ulong overlapStart = overlap.Start;
+                ulong overlapEnd = overlap.End;
+                ulong overlapValue = overlap.Value;
+
+                _mappings.Remove(overlap);
+
+                bool overlapStartsBefore = overlapStart < address;
+                bool overlapEndsAfter = overlapEnd > endAddress;
+
+                if (overlapStartsBefore && overlapEndsAfter)
+                {
+                    CheckFreeResult(WindowsApi.VirtualFree(
+                        (IntPtr)address,
+                        (IntPtr)size,
+                        AllocationType.Release | AllocationType.PreservePlaceholder));
+
+                    _mappings.Add(overlapStart, address, overlapValue);
+                    _mappings.Add(endAddress, overlapEnd, AddBackingOffset(overlapValue, endAddress - overlapStart));
+                }
+                else if (overlapStartsBefore)
+                {
+                    ulong overlappedSize = overlapEnd - address;
+
+                    CheckFreeResult(WindowsApi.VirtualFree(
+                        (IntPtr)address,
+                        (IntPtr)overlappedSize,
+                        AllocationType.Release | AllocationType.PreservePlaceholder));
+
+                    _mappings.Add(overlapStart, address, overlapValue);
+                }
+                else if (overlapEndsAfter)
+                {
+                    ulong overlappedSize = endAddress - overlapStart;
+
+                    CheckFreeResult(WindowsApi.VirtualFree(
+                        (IntPtr)overlapStart,
+                        (IntPtr)overlappedSize,
+                        AllocationType.Release | AllocationType.PreservePlaceholder));
+
+                    _mappings.Add(endAddress, overlapEnd, AddBackingOffset(overlapValue, overlappedSize));
+                }
+
+                _mappings.Add(address, endAddress, backingOffset);
+            }
+        }
+
+        /// <summary>
+        /// Unmaps a view that has been previously mapped with <see cref="MapView"/>.
+        /// </summary>
+        /// <remarks>
+        /// For "partial unmaps" (when not the entire mapped range is being unmapped), it might be
+        /// necessary to unmap the whole range and then remap the sub-ranges that should remain mapped.
+        /// </remarks>
+        /// <param name="sharedMemory">Shared memory that the view being unmapped belongs to</param>
+        /// <param name="location">Address to unmap</param>
+        /// <param name="size">Size of the region to unmap in bytes</param>
+        public void UnmapView(IntPtr sharedMemory, IntPtr location, IntPtr size)
+        {
+            _partialUnmapLock.AcquireReaderLock(Timeout.Infinite);
+
+            try
+            {
+                UnmapViewInternal(sharedMemory, location, size);
+            }
+            finally
+            {
+                _partialUnmapLock.ReleaseReaderLock();
+            }
+        }
+
+        /// <summary>
+        /// Unmaps a view that has been previously mapped with <see cref="MapView"/>.
+        /// </summary>
+        /// <remarks>
+        /// For "partial unmaps" (when not the entire mapped range is being unmapped), it might be
+        /// necessary to unmap the whole range and then remap the sub-ranges that should remain mapped.
+        /// </remarks>
+        /// <param name="sharedMemory">Shared memory that the view being unmapped belongs to</param>
+        /// <param name="location">Address to unmap</param>
+        /// <param name="size">Size of the region to unmap in bytes</param>
+        /// <exception cref="WindowsApiException">Thrown when the Windows API returns an error unmapping or remapping the memory</exception>
+        private void UnmapViewInternal(IntPtr sharedMemory, IntPtr location, IntPtr size)
+        {
+            ulong startAddress = (ulong)location;
+            ulong unmapSize = (ulong)size;
+            ulong endAddress = startAddress + unmapSize;
+
+            var overlaps = Array.Empty<IntervalTreeNode<ulong, ulong>>();
+            int count = 0;
+
+            lock (_mappings)
+            {
+                count = _mappings.Get(startAddress, endAddress, ref overlaps);
+            }
+
+            for (int index = 0; index < count; index++)
+            {
+                var overlap = overlaps[index];
+
+                if (IsMapped(overlap.Value))
+                {
+                    if (!WindowsApi.UnmapViewOfFile2(WindowsApi.CurrentProcessHandle, (IntPtr)overlap.Start, 2))
+                    {
+                        throw new WindowsApiException("UnmapViewOfFile2");
+                    }
+
+                    // Tree operations might modify the node start/end values, so save a copy before we modify the tree.
+                    ulong overlapStart = overlap.Start;
+                    ulong overlapEnd = overlap.End;
+                    ulong overlapValue = overlap.Value;
+
+                    _mappings.Remove(overlap);
+                    _mappings.Add(overlapStart, overlapEnd, ulong.MaxValue);
+
+                    bool overlapStartsBefore = overlapStart < startAddress;
+                    bool overlapEndsAfter = overlapEnd > endAddress;
+
+                    if (overlapStartsBefore || overlapEndsAfter)
+                    {
+                        // If the overlap extends beyond the region we are unmapping,
+                        // then we need to re-map the regions that are supposed to remain mapped.
+                        // This is necessary because Windows does not support partial view unmaps.
+                        // That is, you can only fully unmap a view that was previously mapped, you can't just unmap a chunck of it.
+
+                        LockCookie lockCookie = _partialUnmapLock.UpgradeToWriterLock(Timeout.Infinite);
+
+                        _partialUnmapsCount++;
+
+                        if (overlapStartsBefore)
+                        {
+                            ulong remapSize = startAddress - overlapStart;
+
+                            MapViewInternal(sharedMemory, overlapValue, (IntPtr)overlapStart, (IntPtr)remapSize);
+                            RestoreRangeProtection(overlapStart, remapSize);
+                        }
+
+                        if (overlapEndsAfter)
+                        {
+                            ulong overlappedSize = endAddress - overlapStart;
+                            ulong remapBackingOffset = overlapValue + overlappedSize;
+                            ulong remapAddress = overlapStart + overlappedSize;
+                            ulong remapSize = overlapEnd - endAddress;
+
+                            MapViewInternal(sharedMemory, remapBackingOffset, (IntPtr)remapAddress, (IntPtr)remapSize);
+                            RestoreRangeProtection(remapAddress, remapSize);
+                        }
+
+                        _partialUnmapLock.DowngradeFromWriterLock(ref lockCookie);
+                    }
+                }
+            }
+
+            CoalesceForUnmap(startAddress, unmapSize);
+            RemoveProtection(startAddress, unmapSize);
+        }
+
+        /// <summary>
+        /// Coalesces adjacent placeholders after unmap.
+        /// </summary>
+        /// <param name="address">Address of the region that was unmapped</param>
+        /// <param name="size">Size of the region that was unmapped in bytes</param>
+        private void CoalesceForUnmap(ulong address, ulong size)
+        {
+            ulong endAddress = address + size;
+            var overlaps = Array.Empty<IntervalTreeNode<ulong, ulong>>();
+            int unmappedCount = 0;
+
+            lock (_mappings)
+            {
+                int count = _mappings.Get(address - MinimumPageSize, endAddress + MinimumPageSize, ref overlaps);
+                if (count < 2)
+                {
+                    // Nothing to coalesce if we only have 1 or no overlaps.
+                    return;
+                }
+
+                for (int index = 0; index < count; index++)
+                {
+                    var overlap = overlaps[index];
+
+                    if (!IsMapped(overlap.Value))
+                    {
+                        if (address > overlap.Start)
+                        {
+                            address = overlap.Start;
+                        }
+
+                        if (endAddress < overlap.End)
+                        {
+                            endAddress = overlap.End;
+                        }
+
+                        _mappings.Remove(overlap);
+
+                        unmappedCount++;
+                    }
+                }
+
+                _mappings.Add(address, endAddress, ulong.MaxValue);
+            }
+
+            if (unmappedCount > 1)
+            {
+                size = endAddress - address;
+
+                CheckFreeResult(WindowsApi.VirtualFree(
+                    (IntPtr)address,
+                    (IntPtr)size,
+                    AllocationType.Release | AllocationType.CoalescePlaceholders));
+            }
+        }
+
+        /// <summary>
+        /// Reprotects a region of memory that has been mapped.
+        /// </summary>
+        /// <param name="address">Address of the region to reprotect</param>
+        /// <param name="size">Size of the region to reprotect in bytes</param>
+        /// <param name="permission">New permissions</param>
+        /// <returns>True if the reprotection was successful, false otherwise</returns>
+        public bool ReprotectView(IntPtr address, IntPtr size, MemoryPermission permission)
+        {
+            _partialUnmapLock.AcquireReaderLock(Timeout.Infinite);
+
+            try
+            {
+                return ReprotectViewInternal(address, size, permission, false);
+            }
+            finally
+            {
+                _partialUnmapLock.ReleaseReaderLock();
+            }
+        }
+
+        /// <summary>
+        /// Reprotects a region of memory that has been mapped.
+        /// </summary>
+        /// <param name="address">Address of the region to reprotect</param>
+        /// <param name="size">Size of the region to reprotect in bytes</param>
+        /// <param name="permission">New permissions</param>
+        /// <param name="throwOnError">Throw an exception instead of returning an error if the operation fails</param>
+        /// <returns>True if the reprotection was successful or if <paramref name="throwOnError"/> is true, false otherwise</returns>
+        /// <exception cref="WindowsApiException">If <paramref name="throwOnError"/> is true, it is thrown when the Windows API returns an error reprotecting the memory</exception>
+        private bool ReprotectViewInternal(IntPtr address, IntPtr size, MemoryPermission permission, bool throwOnError)
+        {
+            ulong reprotectAddress = (ulong)address;
+            ulong reprotectSize = (ulong)size;
+            ulong endAddress = reprotectAddress + reprotectSize;
+
+            var overlaps = Array.Empty<IntervalTreeNode<ulong, ulong>>();
+            int count = 0;
+
+            lock (_mappings)
+            {
+                count = _mappings.Get(reprotectAddress, endAddress, ref overlaps);
+            }
+
+            bool success = true;
+
+            for (int index = 0; index < count; index++)
+            {
+                var overlap = overlaps[index];
+
+                ulong mappedAddress = overlap.Start;
+                ulong mappedSize = overlap.End - overlap.Start;
+
+                if (mappedAddress < reprotectAddress)
+                {
+                    ulong delta = reprotectAddress - mappedAddress;
+                    mappedAddress = reprotectAddress;
+                    mappedSize -= delta;
+                }
+
+                ulong mappedEndAddress = mappedAddress + mappedSize;
+
+                if (mappedEndAddress > endAddress)
+                {
+                    ulong delta = mappedEndAddress - endAddress;
+                    mappedSize -= delta;
+                }
+
+                if (!WindowsApi.VirtualProtect((IntPtr)mappedAddress, (IntPtr)mappedSize, WindowsApi.GetProtection(permission), out _))
+                {
+                    if (throwOnError)
+                    {
+                        throw new WindowsApiException("VirtualProtect");
+                    }
+
+                    success = false;
+                }
+
+                // We only keep track of "non-standard" protections,
+                // that is, everything that is not just RW (which is the default when views are mapped).
+                if (permission == MemoryPermission.ReadAndWrite)
+                {
+                    RemoveProtection(mappedAddress, mappedSize);
+                }
+                else
+                {
+                    AddProtection(mappedAddress, mappedSize, permission);
+                }
+            }
+
+            return success;
+        }
+
+        /// <summary>
+        /// Checks the result of a VirtualFree operation, throwing if needed.
+        /// </summary>
+        /// <param name="success">Operation result</param>
+        /// <exception cref="WindowsApiException">Thrown if <paramref name="success"/> is false</exception>
+        private static void CheckFreeResult(bool success)
+        {
+            if (!success)
+            {
+                throw new WindowsApiException("VirtualFree");
+            }
+        }
+
+        /// <summary>
+        /// Adds an offset to a backing offset. This will do nothing if the backing offset is the special "unmapped" value.
+        /// </summary>
+        /// <param name="backingOffset">Backing offset</param>
+        /// <param name="offset">Offset to be added</param>
+        /// <returns>Added offset or just <paramref name="backingOffset"/> if the region is unmapped</returns>
+        private static ulong AddBackingOffset(ulong backingOffset, ulong offset)
+        {
+            if (backingOffset == ulong.MaxValue)
+            {
+                return backingOffset;
+            }
+
+            return backingOffset + offset;
+        }
+
+        /// <summary>
+        /// Checks if a region is unmapped.
+        /// </summary>
+        /// <param name="backingOffset">Backing offset to check</param>
+        /// <returns>True if the backing offset is the special "unmapped" value, false otherwise</returns>
+        private static bool IsMapped(ulong backingOffset)
+        {
+            return backingOffset != ulong.MaxValue;
+        }
+
+        /// <summary>
+        /// Adds a protection to the list of protections.
+        /// </summary>
+        /// <param name="address">Address of the protected region</param>
+        /// <param name="size">Size of the protected region in bytes</param>
+        /// <param name="permission">Memory permissions of the region</param>
+        private void AddProtection(ulong address, ulong size, MemoryPermission permission)
+        {
+            ulong endAddress = address + size;
+            var overlaps = Array.Empty<IntervalTreeNode<ulong, MemoryPermission>>();
+            int count = 0;
+
+            lock (_protections)
+            {
+                count = _protections.Get(address, endAddress, ref overlaps);
+
+                Debug.Assert(count > 0);
+
+                if (count == 1 &&
+                    overlaps[0].Start <= address &&
+                    overlaps[0].End >= endAddress &&
+                    overlaps[0].Value == permission)
+                {
+                    return;
+                }
+
+                ulong startAddress = address;
+
+                for (int index = 0; index < count; index++)
+                {
+                    var protection = overlaps[index];
+
+                    ulong protAddress = protection.Start;
+                    ulong protEndAddress = protection.End;
+                    MemoryPermission protPermission = protection.Value;
+
+                    _protections.Remove(protection);
+
+                    if (protection.Value == permission)
+                    {
+                        if (startAddress > protAddress)
+                        {
+                            startAddress = protAddress;
+                        }
+
+                        if (endAddress < protEndAddress)
+                        {
+                            endAddress = protEndAddress;
+                        }
+                    }
+                    else
+                    {
+                        if (startAddress > protAddress)
+                        {
+                            _protections.Add(protAddress, startAddress, protPermission);
+                        }
+
+                        if (endAddress < protEndAddress)
+                        {
+                            _protections.Add(endAddress, protEndAddress, protPermission);
+                        }
+                    }
+                }
+
+                _protections.Add(startAddress, endAddress, permission);
+            }
+        }
+
+        /// <summary>
+        /// Removes protection from the list of protections.
+        /// </summary>
+        /// <param name="address">Address of the protected region</param>
+        /// <param name="size">Size of the protected region in bytes</param>
+        private void RemoveProtection(ulong address, ulong size)
+        {
+            ulong endAddress = address + size;
+            var overlaps = Array.Empty<IntervalTreeNode<ulong, MemoryPermission>>();
+            int count = 0;
+
+            lock (_protections)
+            {
+                count = _protections.Get(address, endAddress, ref overlaps);
+
+                for (int index = 0; index < count; index++)
+                {
+                    var protection = overlaps[index];
+
+                    ulong protAddress = protection.Start;
+                    ulong protEndAddress = protection.End;
+                    MemoryPermission protPermission = protection.Value;
+
+                    _protections.Remove(protection);
+
+                    if (address > protAddress)
+                    {
+                        _protections.Add(protAddress, address, protPermission);
+                    }
+
+                    if (endAddress < protEndAddress)
+                    {
+                        _protections.Add(endAddress, protEndAddress, protPermission);
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Restores the protection of a given memory region that was remapped, using the protections list.
+        /// </summary>
+        /// <param name="address">Address of the remapped region</param>
+        /// <param name="size">Size of the remapped region in bytes</param>
+        private void RestoreRangeProtection(ulong address, ulong size)
+        {
+            ulong endAddress = address + size;
+            var overlaps = Array.Empty<IntervalTreeNode<ulong, MemoryPermission>>();
+            int count = 0;
+
+            lock (_protections)
+            {
+                count = _protections.Get(address, endAddress, ref overlaps);
+            }
+
+            ulong startAddress = address;
+
+            for (int index = 0; index < count; index++)
+            {
+                var protection = overlaps[index];
+
+                ulong protAddress = protection.Start;
+                ulong protEndAddress = protection.End;
+
+                if (protAddress < address)
+                {
+                    protAddress = address;
+                }
+
+                if (protEndAddress > endAddress)
+                {
+                    protEndAddress = endAddress;
+                }
+
+                ReprotectViewInternal((IntPtr)protAddress, (IntPtr)(protEndAddress - protAddress), protection.Value, true);
+            }
+        }
+
+        /// <summary>
+        /// Checks if an access violation handler should retry execution due to a fault caused by partial unmap.
+        /// </summary>
+        /// <remarks>
+        /// Due to Windows limitations, <see cref="UnmapView"/> might need to unmap more memory than requested.
+        /// The additional memory that was unmapped is later remapped, however this leaves a time gap where the
+        /// memory might be accessed but is unmapped. Users of the API must compensate for that by catching the
+        /// access violation and retrying if it happened between the unmap and remap operation.
+        /// This method can be used to decide if retrying in such cases is necessary or not.
+        /// </remarks>
+        /// <returns>True if execution should be retried, false otherwise</returns>
+        public bool RetryFromAccessViolation()
+        {
+            _partialUnmapLock.AcquireReaderLock(Timeout.Infinite);
+
+            bool retry = _threadLocalPartialUnmapsCount != _partialUnmapsCount;
+            if (retry)
+            {
+                _threadLocalPartialUnmapsCount = _partialUnmapsCount;
+            }
+
+            _partialUnmapLock.ReleaseReaderLock();
+
+            return retry;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Ryujinx.Memory/WindowsShared/WindowsApi.cs b/Ryujinx.Memory/WindowsShared/WindowsApi.cs
new file mode 100644
index 00000000..297bd1ee
--- /dev/null
+++ b/Ryujinx.Memory/WindowsShared/WindowsApi.cs
@@ -0,0 +1,93 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Memory.WindowsShared
+{
+    static class WindowsApi
+    {
+        public static readonly IntPtr InvalidHandleValue = new IntPtr(-1);
+        public static readonly IntPtr CurrentProcessHandle = new IntPtr(-1);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        public static extern IntPtr VirtualAlloc(
+            IntPtr lpAddress,
+            IntPtr dwSize,
+            AllocationType flAllocationType,
+            MemoryProtection flProtect);
+
+        [DllImport("KernelBase.dll", SetLastError = true)]
+        public static extern IntPtr VirtualAlloc2(
+            IntPtr process,
+            IntPtr lpAddress,
+            IntPtr dwSize,
+            AllocationType flAllocationType,
+            MemoryProtection flProtect,
+            IntPtr extendedParameters,
+            ulong parameterCount);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        public static extern bool VirtualProtect(
+            IntPtr lpAddress,
+            IntPtr dwSize,
+            MemoryProtection flNewProtect,
+            out MemoryProtection lpflOldProtect);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        public static extern bool VirtualFree(IntPtr lpAddress, IntPtr dwSize, AllocationType dwFreeType);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        public static extern IntPtr CreateFileMapping(
+            IntPtr hFile,
+            IntPtr lpFileMappingAttributes,
+            FileMapProtection flProtect,
+            uint dwMaximumSizeHigh,
+            uint dwMaximumSizeLow,
+            [MarshalAs(UnmanagedType.LPWStr)] string lpName);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        public static extern bool CloseHandle(IntPtr hObject);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        public static extern IntPtr MapViewOfFile(
+            IntPtr hFileMappingObject,
+            uint dwDesiredAccess,
+            uint dwFileOffsetHigh,
+            uint dwFileOffsetLow,
+            IntPtr dwNumberOfBytesToMap);
+
+        [DllImport("KernelBase.dll", SetLastError = true)]
+        public static extern IntPtr MapViewOfFile3(
+            IntPtr hFileMappingObject,
+            IntPtr process,
+            IntPtr baseAddress,
+            ulong offset,
+            IntPtr dwNumberOfBytesToMap,
+            ulong allocationType,
+            MemoryProtection dwDesiredAccess,
+            IntPtr extendedParameters,
+            ulong parameterCount);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        public static extern bool UnmapViewOfFile(IntPtr lpBaseAddress);
+
+        [DllImport("KernelBase.dll", SetLastError = true)]
+        public static extern bool UnmapViewOfFile2(IntPtr process, IntPtr lpBaseAddress, ulong unmapFlags);
+
+        [DllImport("kernel32.dll")]
+        public static extern uint GetLastError();
+
+        public static MemoryProtection GetProtection(MemoryPermission permission)
+        {
+            return permission switch
+            {
+                MemoryPermission.None => MemoryProtection.NoAccess,
+                MemoryPermission.Read => MemoryProtection.ReadOnly,
+                MemoryPermission.ReadAndWrite => MemoryProtection.ReadWrite,
+                MemoryPermission.ReadAndExecute => MemoryProtection.ExecuteRead,
+                MemoryPermission.ReadWriteExecute => MemoryProtection.ExecuteReadWrite,
+                MemoryPermission.Execute => MemoryProtection.Execute,
+                _ => throw new MemoryProtectionException(permission)
+            };
+        }
+    }
+}
\ No newline at end of file
diff --git a/Ryujinx.Memory/WindowsShared/WindowsApiException.cs b/Ryujinx.Memory/WindowsShared/WindowsApiException.cs
new file mode 100644
index 00000000..3140d705
--- /dev/null
+++ b/Ryujinx.Memory/WindowsShared/WindowsApiException.cs
@@ -0,0 +1,24 @@
+using System;
+
+namespace Ryujinx.Memory.WindowsShared
+{
+    class WindowsApiException : Exception
+    {
+        public WindowsApiException()
+        {
+        }
+
+        public WindowsApiException(string functionName) : base(CreateMessage(functionName))
+        {
+        }
+
+        public WindowsApiException(string functionName, Exception inner) : base(CreateMessage(functionName), inner)
+        {
+        }
+
+        private static string CreateMessage(string functionName)
+        {
+            return $"{functionName} returned error code 0x{WindowsApi.GetLastError():X}.";
+        }
+    }
+}
\ No newline at end of file