misc: Implement address space size workarounds (#5191)

* misc: Implement address space size workarounds

This adds code to support userland with less than 39 bits of address
space available by testing reserving multiple sizes and reducing
guess address space when needed.

This is required for ARM64 support when the kernel is
configured to use 63..39 bits for kernel space.(meaning only 38 bits is available to userland)

* Address comments

* Fix 32 bits address space support and address more comments

src/Ryujinx.Cpu/AddressSpace.cs

@@ -5,7 +5,7 @@ using System;
 
 namespace Ryujinx.Cpu
 {
-    class AddressSpace : IDisposable
+    public class AddressSpace : IDisposable
     {
         private const ulong PageSize = 0x1000;
 
@@ -154,7 +154,9 @@ namespace Ryujinx.Cpu
         public MemoryBlock Base { get; }
         public MemoryBlock Mirror { get; }
 
-        public AddressSpace(MemoryBlock backingMemory, ulong asSize, bool supports4KBPages)
+        public ulong AddressSpaceSize { get; }
+
+        public AddressSpace(MemoryBlock backingMemory, MemoryBlock baseMemory, MemoryBlock mirrorMemory, ulong addressSpaceSize, bool supports4KBPages)
         {
             if (!supports4KBPages)
             {
@@ -163,17 +165,48 @@ namespace Ryujinx.Cpu
                 _privateTree = new IntrusiveRedBlackTree<PrivateMapping>();
                 _treeLock = new object();
 
-                _mappingTree.Add(new Mapping(0UL, asSize, MappingType.None));
-                _privateTree.Add(new PrivateMapping(0UL, asSize, default));
+                _mappingTree.Add(new Mapping(0UL, addressSpaceSize, MappingType.None));
+                _privateTree.Add(new PrivateMapping(0UL, addressSpaceSize, default));
             }
 
             _backingMemory = backingMemory;
             _supports4KBPages = supports4KBPages;
 
+            Base = baseMemory;
+            Mirror = mirrorMemory;
+            AddressSpaceSize = addressSpaceSize;
+        }
+
+        public static bool TryCreate(MemoryBlock backingMemory, ulong asSize, bool supports4KBPages, out AddressSpace addressSpace)
+        {
+            addressSpace = null;
+
             MemoryAllocationFlags asFlags = MemoryAllocationFlags.Reserve | MemoryAllocationFlags.ViewCompatible;
 
-            Base = new MemoryBlock(asSize, asFlags);
-            Mirror = new MemoryBlock(asSize, asFlags);
+            ulong minAddressSpaceSize = Math.Min(asSize, 1UL << 36);
+
+            // Attempt to create the address space with expected size or try to reduce it until it succeed.
+            for (ulong addressSpaceSize = asSize; addressSpaceSize >= minAddressSpaceSize; addressSpaceSize >>= 1)
+            {
+                MemoryBlock baseMemory = null;
+                MemoryBlock mirrorMemory = null;
+
+                try
+                {
+                    baseMemory = new MemoryBlock(addressSpaceSize, asFlags);
+                    mirrorMemory = new MemoryBlock(addressSpaceSize, asFlags);
+                    addressSpace = new AddressSpace(backingMemory, baseMemory, mirrorMemory, addressSpaceSize, supports4KBPages);
+
+                    break;
+                }
+                catch (OutOfMemoryException)
+                {
+                    baseMemory?.Dispose();
+                    mirrorMemory?.Dispose();
+                }
+            }
+
+            return addressSpace != null;
         }
 
         public void Map(ulong va, ulong pa, ulong size, MemoryMapFlags flags)

src/Ryujinx.Cpu/Jit/MemoryManagerHostMapped.cs

@@ -38,7 +38,8 @@ namespace Ryujinx.Cpu.Jit
         private readonly bool _unsafeMode;
 
         private readonly AddressSpace _addressSpace;
-        private readonly ulong _addressSpaceSize;
+
+        public ulong AddressSpaceSize { get; }
 
         private readonly PageTable<ulong> _pageTable;
 
@@ -62,21 +63,21 @@ namespace Ryujinx.Cpu.Jit
         /// <summary>
         /// Creates a new instance of the host mapped memory manager.
         /// </summary>
-        /// <param name="backingMemory">Physical backing memory where virtual memory will be mapped to</param>
-        /// <param name="addressSpaceSize">Size of the address space</param>
+        /// <param name="addressSpace">Address space instance to use</param>
         /// <param name="unsafeMode">True if unmanaged access should not be masked (unsafe), false otherwise.</param>
         /// <param name="invalidAccessHandler">Optional function to handle invalid memory accesses</param>
-        public MemoryManagerHostMapped(MemoryBlock backingMemory, ulong addressSpaceSize, bool unsafeMode, InvalidAccessHandler invalidAccessHandler = null)
+        public MemoryManagerHostMapped(AddressSpace addressSpace, bool unsafeMode, InvalidAccessHandler invalidAccessHandler)
         {
+            _addressSpace = addressSpace;
             _pageTable = new PageTable<ulong>();
             _invalidAccessHandler = invalidAccessHandler;
             _unsafeMode = unsafeMode;
-            _addressSpaceSize = addressSpaceSize;
+            AddressSpaceSize = addressSpace.AddressSpaceSize;
 
             ulong asSize = PageSize;
             int asBits = PageBits;
 
-            while (asSize < addressSpaceSize)
+            while (asSize < AddressSpaceSize)
             {
                 asSize <<= 1;
                 asBits++;
@@ -86,8 +87,6 @@ namespace Ryujinx.Cpu.Jit
 
             _pageBitmap = new ulong[1 << (AddressSpaceBits - (PageBits + PageToPteShift))];
 
-            _addressSpace = new AddressSpace(backingMemory, asSize, Supports4KBPages);
-
             Tracking = new MemoryTracking(this, (int)MemoryBlock.GetPageSize(), invalidAccessHandler);
             _memoryEh = new MemoryEhMeilleure(_addressSpace.Base, _addressSpace.Mirror, Tracking);
         }
@@ -99,7 +98,7 @@ namespace Ryujinx.Cpu.Jit
         /// <returns>True if the virtual address is part of the addressable space</returns>
         private bool ValidateAddress(ulong va)
         {
-            return va < _addressSpaceSize;
+            return va < AddressSpaceSize;
         }
 
         /// <summary>
@@ -111,7 +110,7 @@ namespace Ryujinx.Cpu.Jit
         private bool ValidateAddressAndSize(ulong va, ulong size)
         {
             ulong endVa = va + size;
-            return endVa >= va && endVa >= size && endVa <= _addressSpaceSize;
+            return endVa >= va && endVa >= size && endVa <= AddressSpaceSize;
         }
 
         /// <summary>

src/Ryujinx.HLE/HOS/ArmProcessContext.cs

@@ -25,7 +25,15 @@ namespace Ryujinx.HLE.HOS
 
         public IVirtualMemoryManager AddressSpace => _memoryManager;
 
-        public ArmProcessContext(ulong pid, ICpuEngine cpuEngine, GpuContext gpuContext, T memoryManager, bool for64Bit)
+        public ulong AddressSpaceSize { get; }
+
+        public ArmProcessContext(
+            ulong pid,
+            ICpuEngine cpuEngine,
+            GpuContext gpuContext,
+            T memoryManager,
+            ulong addressSpaceSize,
+            bool for64Bit)
         {
             if (memoryManager is IRefCounted rc)
             {
@@ -38,6 +46,8 @@ namespace Ryujinx.HLE.HOS
             _gpuContext = gpuContext;
             _cpuContext = cpuEngine.CreateCpuContext(memoryManager, for64Bit);
             _memoryManager = memoryManager;
+
+            AddressSpaceSize = addressSpaceSize;
         }
 
         public IExecutionContext CreateExecutionContext(ExceptionCallbacks exceptionCallbacks)

src/Ryujinx.HLE/HOS/ArmProcessContextFactory.cs

@@ -1,4 +1,5 @@
 using Ryujinx.Common.Configuration;
+using Ryujinx.Common.Logging;
 using Ryujinx.Cpu;
 using Ryujinx.Cpu.AppleHv;
 using Ryujinx.Cpu.Jit;
@@ -49,7 +50,7 @@ namespace Ryujinx.HLE.HOS
             {
                 var cpuEngine = new HvEngine(_tickSource);
                 var memoryManager = new HvMemoryManager(context.Memory, addressSpaceSize, invalidAccessHandler);
-                processContext = new ArmProcessContext<HvMemoryManager>(pid, cpuEngine, _gpu, memoryManager, for64Bit);
+                processContext = new ArmProcessContext<HvMemoryManager>(pid, cpuEngine, _gpu, memoryManager, addressSpaceSize, for64Bit);
             }
             else
             {
@@ -57,23 +58,41 @@ namespace Ryujinx.HLE.HOS
 
                 if (!MemoryBlock.SupportsFlags(MemoryAllocationFlags.ViewCompatible))
                 {
+                    Logger.Warning?.Print(LogClass.Cpu, "Host system doesn't support views, falling back to software page table");
+
                     mode = MemoryManagerMode.SoftwarePageTable;
                 }
 
                 var cpuEngine = new JitEngine(_tickSource);
 
+                AddressSpace addressSpace = null;
+
+                if (mode == MemoryManagerMode.HostMapped || mode == MemoryManagerMode.HostMappedUnsafe)
+                {
+                    if (!AddressSpace.TryCreate(context.Memory, addressSpaceSize, MemoryBlock.GetPageSize() == MemoryManagerHostMapped.PageSize, out addressSpace))
+                    {
+                        Logger.Warning?.Print(LogClass.Cpu, "Address space creation failed, falling back to software page table");
+
+                        mode = MemoryManagerMode.SoftwarePageTable;
+                    }
+                }
+
                 switch (mode)
                 {
                     case MemoryManagerMode.SoftwarePageTable:
                         var memoryManager = new MemoryManager(context.Memory, addressSpaceSize, invalidAccessHandler);
-                        processContext = new ArmProcessContext<MemoryManager>(pid, cpuEngine, _gpu, memoryManager, for64Bit);
+                        processContext = new ArmProcessContext<MemoryManager>(pid, cpuEngine, _gpu, memoryManager, addressSpaceSize, for64Bit);
                         break;
 
                     case MemoryManagerMode.HostMapped:
                     case MemoryManagerMode.HostMappedUnsafe:
-                        bool unsafeMode = mode == MemoryManagerMode.HostMappedUnsafe;
-                        var memoryManagerHostMapped = new MemoryManagerHostMapped(context.Memory, addressSpaceSize, unsafeMode, invalidAccessHandler);
-                        processContext = new ArmProcessContext<MemoryManagerHostMapped>(pid, cpuEngine, _gpu, memoryManagerHostMapped, for64Bit);
+                        if (addressSpaceSize != addressSpace.AddressSpaceSize)
+                        {
+                            Logger.Warning?.Print(LogClass.Emulation, $"Allocated address space (0x{addressSpace.AddressSpaceSize:X}) is smaller than guest application requirements (0x{addressSpaceSize:X})");
+                        }
+
+                        var memoryManagerHostMapped = new MemoryManagerHostMapped(addressSpace, mode == MemoryManagerMode.HostMappedUnsafe, invalidAccessHandler);
+                        processContext = new ArmProcessContext<MemoryManagerHostMapped>(pid, cpuEngine, _gpu, memoryManagerHostMapped, addressSpace.AddressSpaceSize, for64Bit);
                         break;
 
                     default:

src/Ryujinx.HLE/HOS/Kernel/Memory/KPageTable.cs

@@ -13,7 +13,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
 
         protected override bool Supports4KBPages => _cpuMemory.Supports4KBPages;
 
-        public KPageTable(KernelContext context, IVirtualMemoryManager cpuMemory) : base(context)
+        public KPageTable(KernelContext context, IVirtualMemoryManager cpuMemory, ulong reservedAddressSpaceSize) : base(context, reservedAddressSpaceSize)
         {
             _cpuMemory = cpuMemory;
         }

src/Ryujinx.HLE/HOS/Kernel/Memory/KPageTableBase.cs

@@ -22,6 +22,8 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             0x40000000
         };
 
+        private const ulong RegionAlignment = 0x200000;
+
         public const int PageSize = 0x1000;
 
         private const int KMemoryBlockSize = 0x40;
@@ -53,6 +55,9 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
         public ulong TlsIoRegionStart { get; private set; }
         public ulong TlsIoRegionEnd { get; private set; }
 
+        public ulong AslrRegionStart { get; private set; }
+        public ulong AslrRegionEnd { get; private set; }
+
         private ulong _heapCapacity;
 
         public ulong PhysicalMemoryUsage { get; private set; }
@@ -61,10 +66,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
 
         private MemoryRegion _memRegion;
 
-        private bool _aslrDisabled;
-
-        public int AddrSpaceWidth { get; private set; }
-
+        private bool _allocateFromBack;
         private bool _isKernel;
 
         private bool _aslrEnabled;
@@ -78,7 +80,9 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
         private MemoryFillValue _heapFillValue;
         private MemoryFillValue _ipcFillValue;
 
-        public KPageTableBase(KernelContext context)
+        private ulong _reservedAddressSpaceSize;
+
+        public KPageTableBase(KernelContext context, ulong reservedAddressSpaceSize)
         {
             Context = context;
 
@@ -88,6 +92,8 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
 
             _heapFillValue = MemoryFillValue.Zero;
             _ipcFillValue = MemoryFillValue.Zero;
+
+            _reservedAddressSpaceSize = reservedAddressSpaceSize;
         }
 
         private static readonly int[] AddrSpaceSizes = new int[] { 32, 36, 32, 39 };
@@ -95,7 +101,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
         public Result InitializeForProcess(
             AddressSpaceType addrSpaceType,
             bool aslrEnabled,
-            bool aslrDisabled,
+            bool fromBack,
             MemoryRegion memRegion,
             ulong address,
             ulong size,
@@ -114,7 +120,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             Result result = CreateUserAddressSpace(
                 addrSpaceType,
                 aslrEnabled,
-                aslrDisabled,
+                fromBack,
                 addrSpaceBase,
                 addrSpaceSize,
                 memRegion,
@@ -130,7 +136,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             return result;
         }
 
-        private class Region
+        private struct Region
         {
             public ulong Start;
             public ulong End;
@@ -141,7 +147,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
         private Result CreateUserAddressSpace(
             AddressSpaceType addrSpaceType,
             bool aslrEnabled,
-            bool aslrDisabled,
+            bool fromBack,
             ulong addrSpaceStart,
             ulong addrSpaceEnd,
             MemoryRegion memRegion,
@@ -159,7 +165,6 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             ulong codeRegionSize;
             ulong stackAndTlsIoStart;
             ulong stackAndTlsIoEnd;
-            ulong baseAddress;
 
             switch (addrSpaceType)
             {
@@ -170,10 +175,10 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
                     tlsIoRegion.Size = 0;
                     CodeRegionStart = 0x200000;
                     codeRegionSize = 0x3fe00000;
+                    AslrRegionStart = 0x200000;
+                    AslrRegionEnd = AslrRegionStart + 0xffe00000;
                     stackAndTlsIoStart = 0x200000;
                     stackAndTlsIoEnd = 0x40000000;
-                    baseAddress = 0x200000;
-                    AddrSpaceWidth = 32;
                     break;
 
                 case AddressSpaceType.Addr36Bits:
@@ -183,10 +188,10 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
                     tlsIoRegion.Size = 0;
                     CodeRegionStart = 0x8000000;
                     codeRegionSize = 0x78000000;
+                    AslrRegionStart = 0x8000000;
+                    AslrRegionEnd = AslrRegionStart + 0xff8000000;
                     stackAndTlsIoStart = 0x8000000;
                     stackAndTlsIoEnd = 0x80000000;
-                    baseAddress = 0x8000000;
-                    AddrSpaceWidth = 36;
                     break;
 
                 case AddressSpaceType.Addr32BitsNoMap:
@@ -196,23 +201,42 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
                     tlsIoRegion.Size = 0;
                     CodeRegionStart = 0x200000;
                     codeRegionSize = 0x3fe00000;
+                    AslrRegionStart = 0x200000;
+                    AslrRegionEnd = AslrRegionStart + 0xffe00000;
                     stackAndTlsIoStart = 0x200000;
                     stackAndTlsIoEnd = 0x40000000;
-                    baseAddress = 0x200000;
-                    AddrSpaceWidth = 32;
                     break;
 
                 case AddressSpaceType.Addr39Bits:
-                    aliasRegion.Size = 0x1000000000;
-                    heapRegion.Size = 0x180000000;
-                    stackRegion.Size = 0x80000000;
-                    tlsIoRegion.Size = 0x1000000000;
-                    CodeRegionStart = BitUtils.AlignDown<ulong>(address, 0x200000);
-                    codeRegionSize = BitUtils.AlignUp<ulong>(endAddr, 0x200000) - CodeRegionStart;
-                    stackAndTlsIoStart = 0;
-                    stackAndTlsIoEnd = 0;
-                    baseAddress = 0x8000000;
-                    AddrSpaceWidth = 39;
+                    if (_reservedAddressSpaceSize < addrSpaceEnd)
+                    {
+                        int addressSpaceWidth = (int)ulong.Log2(_reservedAddressSpaceSize);
+
+                        aliasRegion.Size = 1UL << (addressSpaceWidth - 3);
+                        heapRegion.Size = 0x180000000;
+                        stackRegion.Size = 1UL << (addressSpaceWidth - 8);
+                        tlsIoRegion.Size = 1UL << (addressSpaceWidth - 3);
+                        CodeRegionStart = BitUtils.AlignDown<ulong>(address, RegionAlignment);
+                        codeRegionSize = BitUtils.AlignUp<ulong>(endAddr, RegionAlignment) - CodeRegionStart;
+                        stackAndTlsIoStart = 0;
+                        stackAndTlsIoEnd = 0;
+                        AslrRegionStart = 0x8000000;
+                        addrSpaceEnd = 1UL << addressSpaceWidth;
+                        AslrRegionEnd = addrSpaceEnd;
+                    }
+                    else
+                    {
+                        aliasRegion.Size = 0x1000000000;
+                        heapRegion.Size = 0x180000000;
+                        stackRegion.Size = 0x80000000;
+                        tlsIoRegion.Size = 0x1000000000;
+                        CodeRegionStart = BitUtils.AlignDown(address, RegionAlignment);
+                        codeRegionSize = BitUtils.AlignUp(endAddr, RegionAlignment) - CodeRegionStart;
+                        AslrRegionStart = 0x8000000;
+                        AslrRegionEnd = AslrRegionStart + 0x7ff8000000;
+                        stackAndTlsIoStart = 0;
+                        stackAndTlsIoEnd = 0;
+                    }
                     break;
 
                 default: throw new ArgumentException(nameof(addrSpaceType));
@@ -223,11 +247,11 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             ulong mapBaseAddress;
             ulong mapAvailableSize;
 
-            if (CodeRegionStart - baseAddress >= addrSpaceEnd - CodeRegionEnd)
+            if (CodeRegionStart - AslrRegionStart >= addrSpaceEnd - CodeRegionEnd)
             {
                 // Has more space before the start of the code region.
-                mapBaseAddress = baseAddress;
-                mapAvailableSize = CodeRegionStart - baseAddress;
+                mapBaseAddress = AslrRegionStart;
+                mapAvailableSize = CodeRegionStart - AslrRegionStart;
             }
             else
             {
@@ -254,14 +278,14 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
 
             if (aslrEnabled)
             {
-                aliasRegion.AslrOffset = GetRandomValue(0, aslrMaxOffset >> 21) << 21;
-                heapRegion.AslrOffset = GetRandomValue(0, aslrMaxOffset >> 21) << 21;
-                stackRegion.AslrOffset = GetRandomValue(0, aslrMaxOffset >> 21) << 21;
-                tlsIoRegion.AslrOffset = GetRandomValue(0, aslrMaxOffset >> 21) << 21;
+                aliasRegion.AslrOffset = GetRandomValue(0, aslrMaxOffset / RegionAlignment) * RegionAlignment;
+                heapRegion.AslrOffset = GetRandomValue(0, aslrMaxOffset / RegionAlignment) * RegionAlignment;
+                stackRegion.AslrOffset = GetRandomValue(0, aslrMaxOffset / RegionAlignment) * RegionAlignment;
+                tlsIoRegion.AslrOffset = GetRandomValue(0, aslrMaxOffset / RegionAlignment) * RegionAlignment;
             }
 
             // Regions are sorted based on ASLR offset.
-            // When ASLR is disabled, the order is Map, Heap, NewMap and TlsIo.
+            // When ASLR is disabled, the order is Alias, Heap, Stack and TlsIo.
             aliasRegion.Start = mapBaseAddress + aliasRegion.AslrOffset;
             aliasRegion.End = aliasRegion.Start + aliasRegion.Size;
             heapRegion.Start = mapBaseAddress + heapRegion.AslrOffset;
@@ -271,12 +295,15 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             tlsIoRegion.Start = mapBaseAddress + tlsIoRegion.AslrOffset;
             tlsIoRegion.End = tlsIoRegion.Start + tlsIoRegion.Size;
 
-            SortRegion(heapRegion, aliasRegion);
+            SortRegion(ref aliasRegion, ref heapRegion, true);
 
             if (stackRegion.Size != 0)
             {
-                SortRegion(stackRegion, aliasRegion);
-                SortRegion(stackRegion, heapRegion);
+                stackRegion.Start = mapBaseAddress + stackRegion.AslrOffset;
+                stackRegion.End = stackRegion.Start + stackRegion.Size;
+
+                SortRegion(ref aliasRegion, ref stackRegion);
+                SortRegion(ref heapRegion, ref stackRegion);
             }
             else
             {
@@ -286,9 +313,16 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
 
             if (tlsIoRegion.Size != 0)
             {
-                SortRegion(tlsIoRegion, aliasRegion);
-                SortRegion(tlsIoRegion, heapRegion);
-                SortRegion(tlsIoRegion, stackRegion);
+                tlsIoRegion.Start = mapBaseAddress + tlsIoRegion.AslrOffset;
+                tlsIoRegion.End = tlsIoRegion.Start + tlsIoRegion.Size;
+
+                SortRegion(ref aliasRegion, ref tlsIoRegion);
+                SortRegion(ref heapRegion, ref tlsIoRegion);
+
+                if (stackRegion.Size != 0)
+                {
+                    SortRegion(ref stackRegion, ref tlsIoRegion);
+                }
             }
             else
             {
@@ -312,11 +346,27 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             PhysicalMemoryUsage = 0;
 
             _memRegion = memRegion;
-            _aslrDisabled = aslrDisabled;
+            _allocateFromBack = fromBack;
 
             return _blockManager.Initialize(addrSpaceStart, addrSpaceEnd, slabManager);
         }
 
+        private static void SortRegion(ref Region lhs, ref Region rhs, bool checkForEquality = false)
+        {
+            bool res = checkForEquality ? lhs.AslrOffset <= rhs.AslrOffset : lhs.AslrOffset < rhs.AslrOffset;
+
+            if (res)
+            {
+                rhs.Start += lhs.Size;
+                rhs.End += lhs.Size;
+            }
+            else
+            {
+                lhs.Start += rhs.Size;
+                lhs.End += rhs.Size;
+            }
+        }
+
         private ulong GetRandomValue(ulong min, ulong max)
         {
             return (ulong)GetRandomValue((long)min, (long)max);
@@ -332,20 +382,6 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             return _randomNumberGenerator.GenRandomNumber(min, max);
         }
 
-        private static void SortRegion(Region lhs, Region rhs)
-        {
-            if (lhs.AslrOffset < rhs.AslrOffset)
-            {
-                rhs.Start += lhs.Size;
-                rhs.End += lhs.Size;
-            }
-            else
-            {
-                lhs.Start += rhs.Size;
-                lhs.End += rhs.Size;
-            }
-        }
-
         public Result MapPages(ulong address, KPageList pageList, MemoryState state, KMemoryPermission permission)
         {
             ulong pagesCount = pageList.GetPagesCount();
@@ -1827,7 +1863,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             // If not, allocate a new page and copy the unaligned chunck.
             if (addressTruncated < addressRounded)
             {
-                dstFirstPagePa = GetMemoryRegionManager().AllocatePagesContiguous(Context, 1, _aslrDisabled);
+                dstFirstPagePa = GetMemoryRegionManager().AllocatePagesContiguous(Context, 1, _allocateFromBack);
 
                 if (dstFirstPagePa == 0)
                 {
@@ -1841,7 +1877,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
             // If not, allocate a new page and copy the unaligned chunck.
             if (endAddrTruncated < endAddrRounded && (addressTruncated == addressRounded || addressTruncated < endAddrTruncated))
             {
-                dstLastPagePa = GetMemoryRegionManager().AllocatePagesContiguous(Context, 1, _aslrDisabled);
+                dstLastPagePa = GetMemoryRegionManager().AllocatePagesContiguous(Context, 1, _allocateFromBack);
 
                 if (dstLastPagePa == 0)
                 {
@@ -2799,38 +2835,12 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
 
         public ulong GetAddrSpaceBaseAddr()
         {
-            if (AddrSpaceWidth == 36 || AddrSpaceWidth == 39)
-            {
-                return 0x8000000;
-            }
-            else if (AddrSpaceWidth == 32)
-            {
-                return 0x200000;
-            }
-            else
-            {
-                throw new InvalidOperationException("Invalid address space width!");
-            }
+            return AslrRegionStart;
         }
 
         public ulong GetAddrSpaceSize()
         {
-            if (AddrSpaceWidth == 36)
-            {
-                return 0xff8000000;
-            }
-            else if (AddrSpaceWidth == 39)
-            {
-                return 0x7ff8000000;
-            }
-            else if (AddrSpaceWidth == 32)
-            {
-                return 0xffe00000;
-            }
-            else
-            {
-                throw new InvalidOperationException("Invalid address space width!");
-            }
+            return AslrRegionEnd - AslrRegionStart;
         }
 
         private static ulong GetDramAddressFromPa(ulong pa)

src/Ryujinx.HLE/HOS/Kernel/Process/IProcessContext.cs

@@ -8,6 +8,8 @@ namespace Ryujinx.HLE.HOS.Kernel.Process
     {
         IVirtualMemoryManager AddressSpace { get; }
 
+        ulong AddressSpaceSize { get; }
+
         IExecutionContext CreateExecutionContext(ExceptionCallbacks exceptionCallbacks);
         void Execute(IExecutionContext context, ulong codeAddress);
         void InvalidateCacheRegion(ulong address, ulong size);

src/Ryujinx.HLE/HOS/Kernel/Process/KProcess.cs

@@ -1082,7 +1082,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Process
 
             Context = _contextFactory.Create(KernelContext, Pid, 1UL << addrSpaceBits, InvalidAccessHandler, for64Bit);
 
-            MemoryManager = new KPageTable(KernelContext, CpuMemory);
+            MemoryManager = new KPageTable(KernelContext, CpuMemory, Context.AddressSpaceSize);
         }
 
         private bool InvalidAccessHandler(ulong va)

src/Ryujinx.HLE/HOS/Kernel/Process/ProcessContext.cs

@@ -8,9 +8,12 @@ namespace Ryujinx.HLE.HOS.Kernel.Process
     {
         public IVirtualMemoryManager AddressSpace { get; }
 
-        public ProcessContext(IVirtualMemoryManager asManager)
+        public ulong AddressSpaceSize { get; }
+
+        public ProcessContext(IVirtualMemoryManager asManager, ulong addressSpaceSize)
         {
             AddressSpace = asManager;
+            AddressSpaceSize = addressSpaceSize;
         }
 
         public IExecutionContext CreateExecutionContext(ExceptionCallbacks exceptionCallbacks)

src/Ryujinx.HLE/HOS/Kernel/Process/ProcessContextFactory.cs

@@ -6,7 +6,7 @@ namespace Ryujinx.HLE.HOS.Kernel.Process
     {
         public IProcessContext Create(KernelContext context, ulong pid, ulong addressSpaceSize, InvalidAccessHandler invalidAccessHandler, bool for64Bit)
         {
-            return new ProcessContext(new AddressSpaceManager(context.Memory, addressSpaceSize));
+            return new ProcessContext(new AddressSpaceManager(context.Memory, addressSpaceSize), addressSpaceSize);
         }
     }
 }