Ryujinx/Ryujinx.Cpu/AppleHv/HvMemoryManager.cs
gdkchan a53cfdab78
Initial Apple Hypervisor based CPU emulation (#4332)
* Initial Apple Hypervisor based CPU emulation implementation

* Add UseHypervisor Setting

* Add basic MacOS support to Avalonia

* Fix initialization

* Fix GTK build

* Fix/silence warnings

* Change exceptions to asserts on HvAddressSpaceRange

* Replace DllImport with LibraryImport

* Fix LibraryImport

* Remove unneeded usings

* Revert outdated change

* Set DiskCacheLoadState when using hypervisor too

* Fix HvExecutionContext PC value

* Address PR feedback

* Use existing entitlements.xml file on distribution folder

---------

Co-authored-by: riperiperi <rhy3756547@hotmail.com>
2023-01-29 08:37:52 -03:00

947 lines
30 KiB
C#

using ARMeilleure.Memory;
using Ryujinx.Cpu.Tracking;
using Ryujinx.Memory;
using Ryujinx.Memory.Range;
using Ryujinx.Memory.Tracking;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Threading;
namespace Ryujinx.Cpu.AppleHv
{
/// <summary>
/// Represents a CPU memory manager which maps guest virtual memory directly onto the Hypervisor page table.
/// </summary>
public class HvMemoryManager : MemoryManagerBase, IMemoryManager, IVirtualMemoryManagerTracked, IWritableBlock
{
public const int PageBits = 12;
public const int PageSize = 1 << PageBits;
public const int PageMask = PageSize - 1;
public const int PageToPteShift = 5; // 32 pages (2 bits each) in one ulong page table entry.
public const ulong BlockMappedMask = 0x5555555555555555; // First bit of each table entry set.
private enum HostMappedPtBits : ulong
{
Unmapped = 0,
Mapped,
WriteTracked,
ReadWriteTracked,
MappedReplicated = 0x5555555555555555,
WriteTrackedReplicated = 0xaaaaaaaaaaaaaaaa,
ReadWriteTrackedReplicated = ulong.MaxValue
}
private readonly InvalidAccessHandler _invalidAccessHandler;
private readonly ulong _addressSpaceSize;
private readonly HvAddressSpace _addressSpace;
internal HvAddressSpace AddressSpace => _addressSpace;
private readonly MemoryBlock _backingMemory;
private readonly PageTable<ulong> _pageTable;
private readonly ulong[] _pageBitmap;
public bool Supports4KBPages => true;
public int AddressSpaceBits { get; }
public IntPtr PageTablePointer => IntPtr.Zero;
public MemoryManagerType Type => MemoryManagerType.SoftwarePageTable;
public MemoryTracking Tracking { get; }
public event Action<ulong, ulong> UnmapEvent;
/// <summary>
/// Creates a new instance of the Hypervisor 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="invalidAccessHandler">Optional function to handle invalid memory accesses</param>
public HvMemoryManager(MemoryBlock backingMemory, ulong addressSpaceSize, InvalidAccessHandler invalidAccessHandler = null)
{
_backingMemory = backingMemory;
_pageTable = new PageTable<ulong>();
_invalidAccessHandler = invalidAccessHandler;
_addressSpaceSize = addressSpaceSize;
ulong asSize = PageSize;
int asBits = PageBits;
while (asSize < addressSpaceSize)
{
asSize <<= 1;
asBits++;
}
_addressSpace = new HvAddressSpace(backingMemory, asSize);
AddressSpaceBits = asBits;
_pageBitmap = new ulong[1 << (AddressSpaceBits - (PageBits + PageToPteShift))];
Tracking = new MemoryTracking(this, PageSize, invalidAccessHandler);
}
/// <summary>
/// Checks if the virtual address is part of the addressable space.
/// </summary>
/// <param name="va">Virtual address</param>
/// <returns>True if the virtual address is part of the addressable space</returns>
private bool ValidateAddress(ulong va)
{
return va < _addressSpaceSize;
}
/// <summary>
/// Checks if the combination of virtual address and size is part of the addressable space.
/// </summary>
/// <param name="va">Virtual address of the range</param>
/// <param name="size">Size of the range in bytes</param>
/// <returns>True if the combination of virtual address and size is part of the addressable space</returns>
private bool ValidateAddressAndSize(ulong va, ulong size)
{
ulong endVa = va + size;
return endVa >= va && endVa >= size && endVa <= _addressSpaceSize;
}
/// <summary>
/// Ensures the combination of virtual address and size is part of the addressable space.
/// </summary>
/// <param name="va">Virtual address of the range</param>
/// <param name="size">Size of the range in bytes</param>
/// <exception cref="InvalidMemoryRegionException">Throw when the memory region specified outside the addressable space</exception>
private void AssertValidAddressAndSize(ulong va, ulong size)
{
if (!ValidateAddressAndSize(va, size))
{
throw new InvalidMemoryRegionException($"va=0x{va:X16}, size=0x{size:X16}");
}
}
/// <summary>
/// Ensures the combination of virtual address and size is part of the addressable space and fully mapped.
/// </summary>
/// <param name="va">Virtual address of the range</param>
/// <param name="size">Size of the range in bytes</param>
private void AssertMapped(ulong va, ulong size)
{
if (!ValidateAddressAndSize(va, size) || !IsRangeMappedImpl(va, size))
{
throw new InvalidMemoryRegionException($"Not mapped: va=0x{va:X16}, size=0x{size:X16}");
}
}
/// <inheritdoc/>
public void Map(ulong va, ulong pa, ulong size, MemoryMapFlags flags)
{
AssertValidAddressAndSize(va, size);
PtMap(va, pa, size);
_addressSpace.MapUser(va, pa, size, MemoryPermission.ReadWriteExecute);
AddMapping(va, size);
Tracking.Map(va, size);
}
private void PtMap(ulong va, ulong pa, ulong size)
{
while (size != 0)
{
_pageTable.Map(va, pa);
va += PageSize;
pa += PageSize;
size -= PageSize;
}
}
/// <inheritdoc/>
public void MapForeign(ulong va, nuint hostPointer, ulong size)
{
throw new NotSupportedException();
}
/// <inheritdoc/>
public void Unmap(ulong va, ulong size)
{
AssertValidAddressAndSize(va, size);
UnmapEvent?.Invoke(va, size);
Tracking.Unmap(va, size);
RemoveMapping(va, size);
_addressSpace.UnmapUser(va, size);
PtUnmap(va, size);
}
private void PtUnmap(ulong va, ulong size)
{
while (size != 0)
{
_pageTable.Unmap(va);
va += PageSize;
size -= PageSize;
}
}
/// <inheritdoc/>
public T Read<T>(ulong va) where T : unmanaged
{
return MemoryMarshal.Cast<byte, T>(GetSpan(va, Unsafe.SizeOf<T>()))[0];
}
/// <inheritdoc/>
public T ReadTracked<T>(ulong va) where T : unmanaged
{
try
{
SignalMemoryTracking(va, (ulong)Unsafe.SizeOf<T>(), false);
return Read<T>(va);
}
catch (InvalidMemoryRegionException)
{
if (_invalidAccessHandler == null || !_invalidAccessHandler(va))
{
throw;
}
return default;
}
}
/// <inheritdoc/>
public void Read(ulong va, Span<byte> data)
{
ReadImpl(va, data);
}
/// <inheritdoc/>
public void Write<T>(ulong va, T value) where T : unmanaged
{
Write(va, MemoryMarshal.Cast<T, byte>(MemoryMarshal.CreateSpan(ref value, 1)));
}
/// <inheritdoc/>
public void Write(ulong va, ReadOnlySpan<byte> data)
{
if (data.Length == 0)
{
return;
}
SignalMemoryTracking(va, (ulong)data.Length, true);
WriteImpl(va, data);
}
/// <inheritdoc/>
public void WriteUntracked(ulong va, ReadOnlySpan<byte> data)
{
if (data.Length == 0)
{
return;
}
WriteImpl(va, data);
}
/// <inheritdoc/>
public bool WriteWithRedundancyCheck(ulong va, ReadOnlySpan<byte> data)
{
if (data.Length == 0)
{
return false;
}
SignalMemoryTracking(va, (ulong)data.Length, false);
if (IsContiguousAndMapped(va, data.Length))
{
var target = _backingMemory.GetSpan(GetPhysicalAddressInternal(va), data.Length);
bool changed = !data.SequenceEqual(target);
if (changed)
{
data.CopyTo(target);
}
return changed;
}
else
{
WriteImpl(va, data);
return true;
}
}
private void WriteImpl(ulong va, ReadOnlySpan<byte> data)
{
try
{
AssertValidAddressAndSize(va, (ulong)data.Length);
if (IsContiguousAndMapped(va, data.Length))
{
data.CopyTo(_backingMemory.GetSpan(GetPhysicalAddressInternal(va), data.Length));
}
else
{
int offset = 0, size;
if ((va & PageMask) != 0)
{
ulong pa = GetPhysicalAddressChecked(va);
size = Math.Min(data.Length, PageSize - (int)(va & PageMask));
data.Slice(0, size).CopyTo(_backingMemory.GetSpan(pa, size));
offset += size;
}
for (; offset < data.Length; offset += size)
{
ulong pa = GetPhysicalAddressChecked(va + (ulong)offset);
size = Math.Min(data.Length - offset, PageSize);
data.Slice(offset, size).CopyTo(_backingMemory.GetSpan(pa, size));
}
}
}
catch (InvalidMemoryRegionException)
{
if (_invalidAccessHandler == null || !_invalidAccessHandler(va))
{
throw;
}
}
}
/// <inheritdoc/>
public ReadOnlySpan<byte> GetSpan(ulong va, int size, bool tracked = false)
{
if (size == 0)
{
return ReadOnlySpan<byte>.Empty;
}
if (tracked)
{
SignalMemoryTracking(va, (ulong)size, false);
}
if (IsContiguousAndMapped(va, size))
{
return _backingMemory.GetSpan(GetPhysicalAddressInternal(va), size);
}
else
{
Span<byte> data = new byte[size];
ReadImpl(va, data);
return data;
}
}
/// <inheritdoc/>
public WritableRegion GetWritableRegion(ulong va, int size, bool tracked = false)
{
if (size == 0)
{
return new WritableRegion(null, va, Memory<byte>.Empty);
}
if (tracked)
{
SignalMemoryTracking(va, (ulong)size, true);
}
if (IsContiguousAndMapped(va, size))
{
return new WritableRegion(null, va, _backingMemory.GetMemory(GetPhysicalAddressInternal(va), size));
}
else
{
Memory<byte> memory = new byte[size];
ReadImpl(va, memory.Span);
return new WritableRegion(this, va, memory);
}
}
/// <inheritdoc/>
public ref T GetRef<T>(ulong va) where T : unmanaged
{
if (!IsContiguous(va, Unsafe.SizeOf<T>()))
{
ThrowMemoryNotContiguous();
}
SignalMemoryTracking(va, (ulong)Unsafe.SizeOf<T>(), true);
return ref _backingMemory.GetRef<T>(GetPhysicalAddressChecked(va));
}
/// <inheritdoc/>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsMapped(ulong va)
{
return ValidateAddress(va) && IsMappedImpl(va);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private bool IsMappedImpl(ulong va)
{
ulong page = va >> PageBits;
int bit = (int)((page & 31) << 1);
int pageIndex = (int)(page >> PageToPteShift);
ref ulong pageRef = ref _pageBitmap[pageIndex];
ulong pte = Volatile.Read(ref pageRef);
return ((pte >> bit) & 3) != 0;
}
/// <inheritdoc/>
public bool IsRangeMapped(ulong va, ulong size)
{
AssertValidAddressAndSize(va, size);
return IsRangeMappedImpl(va, size);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void GetPageBlockRange(ulong pageStart, ulong pageEnd, out ulong startMask, out ulong endMask, out int pageIndex, out int pageEndIndex)
{
startMask = ulong.MaxValue << ((int)(pageStart & 31) << 1);
endMask = ulong.MaxValue >> (64 - ((int)(pageEnd & 31) << 1));
pageIndex = (int)(pageStart >> PageToPteShift);
pageEndIndex = (int)((pageEnd - 1) >> PageToPteShift);
}
private bool IsRangeMappedImpl(ulong va, ulong size)
{
int pages = GetPagesCount(va, size, out _);
if (pages == 1)
{
return IsMappedImpl(va);
}
ulong pageStart = va >> PageBits;
ulong pageEnd = pageStart + (ulong)pages;
GetPageBlockRange(pageStart, pageEnd, out ulong startMask, out ulong endMask, out int pageIndex, out int pageEndIndex);
// Check if either bit in each 2 bit page entry is set.
// OR the block with itself shifted down by 1, and check the first bit of each entry.
ulong mask = BlockMappedMask & startMask;
while (pageIndex <= pageEndIndex)
{
if (pageIndex == pageEndIndex)
{
mask &= endMask;
}
ref ulong pageRef = ref _pageBitmap[pageIndex++];
ulong pte = Volatile.Read(ref pageRef);
pte |= pte >> 1;
if ((pte & mask) != mask)
{
return false;
}
mask = BlockMappedMask;
}
return true;
}
private static void ThrowMemoryNotContiguous() => throw new MemoryNotContiguousException();
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private bool IsContiguousAndMapped(ulong va, int size) => IsContiguous(va, size) && IsMapped(va);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private bool IsContiguous(ulong va, int size)
{
if (!ValidateAddress(va) || !ValidateAddressAndSize(va, (ulong)size))
{
return false;
}
int pages = GetPagesCount(va, (uint)size, out va);
for (int page = 0; page < pages - 1; page++)
{
if (!ValidateAddress(va + PageSize))
{
return false;
}
if (GetPhysicalAddressInternal(va) + PageSize != GetPhysicalAddressInternal(va + PageSize))
{
return false;
}
va += PageSize;
}
return true;
}
/// <inheritdoc/>
public IEnumerable<HostMemoryRange> GetHostRegions(ulong va, ulong size)
{
if (size == 0)
{
return Enumerable.Empty<HostMemoryRange>();
}
var guestRegions = GetPhysicalRegionsImpl(va, size);
if (guestRegions == null)
{
return null;
}
var regions = new HostMemoryRange[guestRegions.Count];
for (int i = 0; i < regions.Length; i++)
{
var guestRegion = guestRegions[i];
IntPtr pointer = _backingMemory.GetPointer(guestRegion.Address, guestRegion.Size);
regions[i] = new HostMemoryRange((nuint)(ulong)pointer, guestRegion.Size);
}
return regions;
}
/// <inheritdoc/>
public IEnumerable<MemoryRange> GetPhysicalRegions(ulong va, ulong size)
{
if (size == 0)
{
return Enumerable.Empty<MemoryRange>();
}
return GetPhysicalRegionsImpl(va, size);
}
private List<MemoryRange> GetPhysicalRegionsImpl(ulong va, ulong size)
{
if (!ValidateAddress(va) || !ValidateAddressAndSize(va, size))
{
return null;
}
int pages = GetPagesCount(va, (uint)size, out va);
var regions = new List<MemoryRange>();
ulong regionStart = GetPhysicalAddressInternal(va);
ulong regionSize = PageSize;
for (int page = 0; page < pages - 1; page++)
{
if (!ValidateAddress(va + PageSize))
{
return null;
}
ulong newPa = GetPhysicalAddressInternal(va + PageSize);
if (GetPhysicalAddressInternal(va) + PageSize != newPa)
{
regions.Add(new MemoryRange(regionStart, regionSize));
regionStart = newPa;
regionSize = 0;
}
va += PageSize;
regionSize += PageSize;
}
regions.Add(new MemoryRange(regionStart, regionSize));
return regions;
}
private void ReadImpl(ulong va, Span<byte> data)
{
if (data.Length == 0)
{
return;
}
try
{
AssertValidAddressAndSize(va, (ulong)data.Length);
int offset = 0, size;
if ((va & PageMask) != 0)
{
ulong pa = GetPhysicalAddressChecked(va);
size = Math.Min(data.Length, PageSize - (int)(va & PageMask));
_backingMemory.GetSpan(pa, size).CopyTo(data.Slice(0, size));
offset += size;
}
for (; offset < data.Length; offset += size)
{
ulong pa = GetPhysicalAddressChecked(va + (ulong)offset);
size = Math.Min(data.Length - offset, PageSize);
_backingMemory.GetSpan(pa, size).CopyTo(data.Slice(offset, size));
}
}
catch (InvalidMemoryRegionException)
{
if (_invalidAccessHandler == null || !_invalidAccessHandler(va))
{
throw;
}
}
}
/// <inheritdoc/>
/// <remarks>
/// This function also validates that the given range is both valid and mapped, and will throw if it is not.
/// </remarks>
public void SignalMemoryTracking(ulong va, ulong size, bool write, bool precise = false)
{
AssertValidAddressAndSize(va, size);
if (precise)
{
Tracking.VirtualMemoryEvent(va, size, write, precise: true);
return;
}
// Software table, used for managed memory tracking.
int pages = GetPagesCount(va, size, out _);
ulong pageStart = va >> PageBits;
if (pages == 1)
{
ulong tag = (ulong)(write ? HostMappedPtBits.WriteTracked : HostMappedPtBits.ReadWriteTracked);
int bit = (int)((pageStart & 31) << 1);
int pageIndex = (int)(pageStart >> PageToPteShift);
ref ulong pageRef = ref _pageBitmap[pageIndex];
ulong pte = Volatile.Read(ref pageRef);
ulong state = ((pte >> bit) & 3);
if (state >= tag)
{
Tracking.VirtualMemoryEvent(va, size, write);
return;
}
else if (state == 0)
{
ThrowInvalidMemoryRegionException($"Not mapped: va=0x{va:X16}, size=0x{size:X16}");
}
}
else
{
ulong pageEnd = pageStart + (ulong)pages;
GetPageBlockRange(pageStart, pageEnd, out ulong startMask, out ulong endMask, out int pageIndex, out int pageEndIndex);
ulong mask = startMask;
ulong anyTrackingTag = (ulong)HostMappedPtBits.WriteTrackedReplicated;
while (pageIndex <= pageEndIndex)
{
if (pageIndex == pageEndIndex)
{
mask &= endMask;
}
ref ulong pageRef = ref _pageBitmap[pageIndex++];
ulong pte = Volatile.Read(ref pageRef);
ulong mappedMask = mask & BlockMappedMask;
ulong mappedPte = pte | (pte >> 1);
if ((mappedPte & mappedMask) != mappedMask)
{
ThrowInvalidMemoryRegionException($"Not mapped: va=0x{va:X16}, size=0x{size:X16}");
}
pte &= mask;
if ((pte & anyTrackingTag) != 0) // Search for any tracking.
{
// Writes trigger any tracking.
// Only trigger tracking from reads if both bits are set on any page.
if (write || (pte & (pte >> 1) & BlockMappedMask) != 0)
{
Tracking.VirtualMemoryEvent(va, size, write);
break;
}
}
mask = ulong.MaxValue;
}
}
}
/// <summary>
/// Computes the number of pages in a virtual address range.
/// </summary>
/// <param name="va">Virtual address of the range</param>
/// <param name="size">Size of the range</param>
/// <param name="startVa">The virtual address of the beginning of the first page</param>
/// <remarks>This function does not differentiate between allocated and unallocated pages.</remarks>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private int GetPagesCount(ulong va, ulong size, out ulong startVa)
{
// WARNING: Always check if ulong does not overflow during the operations.
startVa = va & ~(ulong)PageMask;
ulong vaSpan = (va - startVa + size + PageMask) & ~(ulong)PageMask;
return (int)(vaSpan / PageSize);
}
/// <inheritdoc/>
public void TrackingReprotect(ulong va, ulong size, MemoryPermission protection)
{
// Protection is inverted on software pages, since the default value is 0.
protection = (~protection) & MemoryPermission.ReadAndWrite;
int pages = GetPagesCount(va, size, out va);
ulong pageStart = va >> PageBits;
if (pages == 1)
{
ulong protTag = protection switch
{
MemoryPermission.None => (ulong)HostMappedPtBits.Mapped,
MemoryPermission.Write => (ulong)HostMappedPtBits.WriteTracked,
_ => (ulong)HostMappedPtBits.ReadWriteTracked,
};
int bit = (int)((pageStart & 31) << 1);
ulong tagMask = 3UL << bit;
ulong invTagMask = ~tagMask;
ulong tag = protTag << bit;
int pageIndex = (int)(pageStart >> PageToPteShift);
ref ulong pageRef = ref _pageBitmap[pageIndex];
ulong pte;
do
{
pte = Volatile.Read(ref pageRef);
}
while ((pte & tagMask) != 0 && Interlocked.CompareExchange(ref pageRef, (pte & invTagMask) | tag, pte) != pte);
}
else
{
ulong pageEnd = pageStart + (ulong)pages;
GetPageBlockRange(pageStart, pageEnd, out ulong startMask, out ulong endMask, out int pageIndex, out int pageEndIndex);
ulong mask = startMask;
ulong protTag = protection switch
{
MemoryPermission.None => (ulong)HostMappedPtBits.MappedReplicated,
MemoryPermission.Write => (ulong)HostMappedPtBits.WriteTrackedReplicated,
_ => (ulong)HostMappedPtBits.ReadWriteTrackedReplicated,
};
while (pageIndex <= pageEndIndex)
{
if (pageIndex == pageEndIndex)
{
mask &= endMask;
}
ref ulong pageRef = ref _pageBitmap[pageIndex++];
ulong pte;
ulong mappedMask;
// Change the protection of all 2 bit entries that are mapped.
do
{
pte = Volatile.Read(ref pageRef);
mappedMask = pte | (pte >> 1);
mappedMask |= (mappedMask & BlockMappedMask) << 1;
mappedMask &= mask; // Only update mapped pages within the given range.
}
while (Interlocked.CompareExchange(ref pageRef, (pte & (~mappedMask)) | (protTag & mappedMask), pte) != pte);
mask = ulong.MaxValue;
}
}
protection = protection switch
{
MemoryPermission.None => MemoryPermission.ReadAndWrite,
MemoryPermission.Write => MemoryPermission.Read,
_ => MemoryPermission.None
};
_addressSpace.ReprotectUser(va, size, protection);
}
/// <inheritdoc/>
public CpuRegionHandle BeginTracking(ulong address, ulong size)
{
return new CpuRegionHandle(Tracking.BeginTracking(address, size));
}
/// <inheritdoc/>
public CpuMultiRegionHandle BeginGranularTracking(ulong address, ulong size, IEnumerable<IRegionHandle> handles, ulong granularity)
{
return new CpuMultiRegionHandle(Tracking.BeginGranularTracking(address, size, handles, granularity));
}
/// <inheritdoc/>
public CpuSmartMultiRegionHandle BeginSmartGranularTracking(ulong address, ulong size, ulong granularity)
{
return new CpuSmartMultiRegionHandle(Tracking.BeginSmartGranularTracking(address, size, granularity));
}
/// <summary>
/// Adds the given address mapping to the page table.
/// </summary>
/// <param name="va">Virtual memory address</param>
/// <param name="size">Size to be mapped</param>
private void AddMapping(ulong va, ulong size)
{
int pages = GetPagesCount(va, size, out _);
ulong pageStart = va >> PageBits;
ulong pageEnd = pageStart + (ulong)pages;
GetPageBlockRange(pageStart, pageEnd, out ulong startMask, out ulong endMask, out int pageIndex, out int pageEndIndex);
ulong mask = startMask;
while (pageIndex <= pageEndIndex)
{
if (pageIndex == pageEndIndex)
{
mask &= endMask;
}
ref ulong pageRef = ref _pageBitmap[pageIndex++];
ulong pte;
ulong mappedMask;
// Map all 2-bit entries that are unmapped.
do
{
pte = Volatile.Read(ref pageRef);
mappedMask = pte | (pte >> 1);
mappedMask |= (mappedMask & BlockMappedMask) << 1;
mappedMask |= ~mask; // Treat everything outside the range as mapped, thus unchanged.
}
while (Interlocked.CompareExchange(ref pageRef, (pte & mappedMask) | (BlockMappedMask & (~mappedMask)), pte) != pte);
mask = ulong.MaxValue;
}
}
/// <summary>
/// Removes the given address mapping from the page table.
/// </summary>
/// <param name="va">Virtual memory address</param>
/// <param name="size">Size to be unmapped</param>
private void RemoveMapping(ulong va, ulong size)
{
int pages = GetPagesCount(va, size, out _);
ulong pageStart = va >> PageBits;
ulong pageEnd = pageStart + (ulong)pages;
GetPageBlockRange(pageStart, pageEnd, out ulong startMask, out ulong endMask, out int pageIndex, out int pageEndIndex);
startMask = ~startMask;
endMask = ~endMask;
ulong mask = startMask;
while (pageIndex <= pageEndIndex)
{
if (pageIndex == pageEndIndex)
{
mask |= endMask;
}
ref ulong pageRef = ref _pageBitmap[pageIndex++];
ulong pte;
do
{
pte = Volatile.Read(ref pageRef);
}
while (Interlocked.CompareExchange(ref pageRef, pte & mask, pte) != pte);
mask = 0;
}
}
private ulong GetPhysicalAddressChecked(ulong va)
{
if (!IsMapped(va))
{
ThrowInvalidMemoryRegionException($"Not mapped: va=0x{va:X16}");
}
return GetPhysicalAddressInternal(va);
}
private ulong GetPhysicalAddressInternal(ulong va)
{
return _pageTable.Read(va) + (va & PageMask);
}
/// <summary>
/// Disposes of resources used by the memory manager.
/// </summary>
protected override void Destroy()
{
_addressSpace.Dispose();
}
private static void ThrowInvalidMemoryRegionException(string message) => throw new InvalidMemoryRegionException(message);
}
}