rjx-mirror/Ryujinx.Memory/AddressSpaceManager.cs
Caian Benedicto f7b2daf5ec
Fix virtual address overflow near ulong limit (#2044)
* Fix virtual address overflow near ulong limit

* Fix comments

* Improve overflow checking for large size values

* Add overflow checking to AddressSpaceManager class

* Add overflow protection to read and write functions
2021-02-28 11:48:04 +01:00

603 lines
20 KiB
C#

using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
namespace Ryujinx.Memory
{
/// <summary>
/// Represents a address space manager.
/// Supports virtual memory region mapping, address translation and read/write access to mapped regions.
/// </summary>
public sealed class AddressSpaceManager : IVirtualMemoryManager, IWritableBlock
{
public const int PageBits = 12;
public const int PageSize = 1 << PageBits;
public const int PageMask = PageSize - 1;
private const int PtLevelBits = 9; // 9 * 4 + 12 = 48 (max address space size)
private const int PtLevelSize = 1 << PtLevelBits;
private const int PtLevelMask = PtLevelSize - 1;
private const ulong Unmapped = ulong.MaxValue;
/// <summary>
/// Address space width in bits.
/// </summary>
public int AddressSpaceBits { get; }
private readonly ulong _addressSpaceSize;
private readonly MemoryBlock _backingMemory;
private readonly ulong[][][][] _pageTable;
/// <summary>
/// Creates a new instance of the 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>
public AddressSpaceManager(MemoryBlock backingMemory, ulong addressSpaceSize)
{
ulong asSize = PageSize;
int asBits = PageBits;
while (asSize < addressSpaceSize)
{
asSize <<= 1;
asBits++;
}
AddressSpaceBits = asBits;
_addressSpaceSize = asSize;
_backingMemory = backingMemory;
_pageTable = new ulong[PtLevelSize][][][];
}
/// <summary>
/// Maps a virtual memory range into a physical memory range.
/// </summary>
/// <remarks>
/// Addresses and size must be page aligned.
/// </remarks>
/// <param name="va">Virtual memory address</param>
/// <param name="pa">Physical memory address</param>
/// <param name="size">Size to be mapped</param>
public void Map(ulong va, ulong pa, ulong size)
{
AssertValidAddressAndSize(va, size);
while (size != 0)
{
PtMap(va, pa);
va += PageSize;
pa += PageSize;
size -= PageSize;
}
}
/// <summary>
/// Unmaps a previously mapped range of virtual memory.
/// </summary>
/// <param name="va">Virtual address of the range to be unmapped</param>
/// <param name="size">Size of the range to be unmapped</param>
public void Unmap(ulong va, ulong size)
{
AssertValidAddressAndSize(va, size);
while (size != 0)
{
PtUnmap(va);
va += PageSize;
size -= PageSize;
}
}
/// <summary>
/// Reads data from mapped memory.
/// </summary>
/// <typeparam name="T">Type of the data being read</typeparam>
/// <param name="va">Virtual address of the data in memory</param>
/// <returns>The data</returns>
/// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
public T Read<T>(ulong va) where T : unmanaged
{
return MemoryMarshal.Cast<byte, T>(GetSpan(va, Unsafe.SizeOf<T>()))[0];
}
/// <summary>
/// Reads data from mapped memory.
/// </summary>
/// <param name="va">Virtual address of the data in memory</param>
/// <param name="data">Span to store the data being read into</param>
/// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
public void Read(ulong va, Span<byte> data)
{
ReadImpl(va, data);
}
/// <summary>
/// Writes data to mapped memory.
/// </summary>
/// <typeparam name="T">Type of the data being written</typeparam>
/// <param name="va">Virtual address to write the data into</param>
/// <param name="value">Data to be written</param>
/// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
public void Write<T>(ulong va, T value) where T : unmanaged
{
Write(va, MemoryMarshal.Cast<T, byte>(MemoryMarshal.CreateSpan(ref value, 1)));
}
/// <summary>
/// Writes data to mapped memory.
/// </summary>
/// <param name="va">Virtual address to write the data into</param>
/// <param name="data">Data to be written</param>
/// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
public void Write(ulong va, ReadOnlySpan<byte> data)
{
if (data.Length == 0)
{
return;
}
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 = GetPhysicalAddressInternal(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 = GetPhysicalAddressInternal(va + (ulong)offset);
size = Math.Min(data.Length - offset, PageSize);
data.Slice(offset, size).CopyTo(_backingMemory.GetSpan(pa, size));
}
}
}
/// <summary>
/// Gets a read-only span of data from mapped memory.
/// </summary>
/// <remarks>
/// This may perform a allocation if the data is not contiguous in memory.
/// For this reason, the span is read-only, you can't modify the data.
/// </remarks>
/// <param name="va">Virtual address of the data</param>
/// <param name="size">Size of the data</param>
/// <param name="tracked">True if read tracking is triggered on the span</param>
/// <returns>A read-only span of the data</returns>
/// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
public ReadOnlySpan<byte> GetSpan(ulong va, int size, bool tracked = false)
{
if (size == 0)
{
return ReadOnlySpan<byte>.Empty;
}
if (IsContiguousAndMapped(va, size))
{
return _backingMemory.GetSpan(GetPhysicalAddressInternal(va), size);
}
else
{
Span<byte> data = new byte[size];
ReadImpl(va, data);
return data;
}
}
/// <summary>
/// Gets a region of memory that can be written to.
/// </summary>
/// <remarks>
/// If the requested region is not contiguous in physical memory,
/// this will perform an allocation, and flush the data (writing it
/// back to the backing memory) on disposal.
/// </remarks>
/// <param name="va">Virtual address of the data</param>
/// <param name="size">Size of the data</param>
/// <returns>A writable region of memory containing the data</returns>
/// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
public WritableRegion GetWritableRegion(ulong va, int size)
{
if (size == 0)
{
return new WritableRegion(null, va, Memory<byte>.Empty);
}
if (IsContiguousAndMapped(va, size))
{
return new WritableRegion(null, va, _backingMemory.GetMemory(GetPhysicalAddressInternal(va), size));
}
else
{
Memory<byte> memory = new byte[size];
GetSpan(va, size).CopyTo(memory.Span);
return new WritableRegion(this, va, memory);
}
}
/// <summary>
/// Gets a reference for the given type at the specified virtual memory address.
/// </summary>
/// <remarks>
/// The data must be located at a contiguous memory region.
/// </remarks>
/// <typeparam name="T">Type of the data to get the reference</typeparam>
/// <param name="va">Virtual address of the data</param>
/// <returns>A reference to the data in memory</returns>
/// <exception cref="MemoryNotContiguousException">Throw if the specified memory region is not contiguous in physical memory</exception>
public ref T GetRef<T>(ulong va) where T : unmanaged
{
if (!IsContiguous(va, Unsafe.SizeOf<T>()))
{
ThrowMemoryNotContiguous();
}
return ref _backingMemory.GetRef<T>(GetPhysicalAddressInternal(va));
}
/// <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, uint 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);
}
private 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;
}
/// <summary>
/// Gets the physical regions that make up the given virtual address region.
/// If any part of the virtual region is unmapped, null is returned.
/// </summary>
/// <param name="va">Virtual address of the range</param>
/// <param name="size">Size of the range</param>
/// <returns>Array of physical regions</returns>
public (ulong address, ulong size)[] GetPhysicalRegions(ulong va, ulong size)
{
throw new NotImplementedException();
}
private void ReadImpl(ulong va, Span<byte> data)
{
if (data.Length == 0)
{
return;
}
AssertValidAddressAndSize(va, (ulong)data.Length);
int offset = 0, size;
if ((va & PageMask) != 0)
{
ulong pa = GetPhysicalAddressInternal(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 = GetPhysicalAddressInternal(va + (ulong)offset);
size = Math.Min(data.Length - offset, PageSize);
_backingMemory.GetSpan(pa, size).CopyTo(data.Slice(offset, size));
}
}
/// <summary>
/// Checks if the page at a given virtual address is mapped.
/// </summary>
/// <param name="va">Virtual address to check</param>
/// <returns>True if the address is mapped, false otherwise</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsMapped(ulong va)
{
if (!ValidateAddress(va))
{
return false;
}
return PtRead(va) != Unmapped;
}
/// <summary>
/// Checks if a memory range is mapped.
/// </summary>
/// <param name="va">Virtual address of the range</param>
/// <param name="size">Size of the range in bytes</param>
/// <returns>True if the entire range is mapped, false otherwise</returns>
public bool IsRangeMapped(ulong va, ulong size)
{
if (size == 0UL)
{
return true;
}
if (!ValidateAddressAndSize(va, size))
{
return false;
}
int pages = GetPagesCount(va, (uint)size, out va);
for (int page = 0; page < pages; page++)
{
if (!IsMapped(va))
{
return false;
}
va += PageSize;
}
return true;
}
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>
/// Performs address translation of the address inside a mapped memory range.
/// </summary>
/// <remarks>
/// If the address is invalid or unmapped, -1 will be returned.
/// </remarks>
/// <param name="va">Virtual address to be translated</param>
/// <returns>The physical address</returns>
public ulong GetPhysicalAddress(ulong va)
{
// We return -1L if the virtual address is invalid or unmapped.
if (!ValidateAddress(va) || !IsMapped(va))
{
return ulong.MaxValue;
}
return GetPhysicalAddressInternal(va);
}
private ulong GetPhysicalAddressInternal(ulong va)
{
return PtRead(va) + (va & PageMask);
}
/// <summary>
/// Reprotect a region of virtual memory for tracking. Sets software protection bits.
/// </summary>
/// <param name="va">Virtual address base</param>
/// <param name="size">Size of the region to protect</param>
/// <param name="protection">Memory protection to set</param>
public void TrackingReprotect(ulong va, ulong size, MemoryPermission protection)
{
throw new NotImplementedException();
}
private ulong PtRead(ulong va)
{
int l3 = (int)(va >> PageBits) & PtLevelMask;
int l2 = (int)(va >> (PageBits + PtLevelBits)) & PtLevelMask;
int l1 = (int)(va >> (PageBits + PtLevelBits * 2)) & PtLevelMask;
int l0 = (int)(va >> (PageBits + PtLevelBits * 3)) & PtLevelMask;
if (_pageTable[l0] == null)
{
return Unmapped;
}
if (_pageTable[l0][l1] == null)
{
return Unmapped;
}
if (_pageTable[l0][l1][l2] == null)
{
return Unmapped;
}
return _pageTable[l0][l1][l2][l3];
}
private void PtMap(ulong va, ulong value)
{
int l3 = (int)(va >> PageBits) & PtLevelMask;
int l2 = (int)(va >> (PageBits + PtLevelBits)) & PtLevelMask;
int l1 = (int)(va >> (PageBits + PtLevelBits * 2)) & PtLevelMask;
int l0 = (int)(va >> (PageBits + PtLevelBits * 3)) & PtLevelMask;
if (_pageTable[l0] == null)
{
_pageTable[l0] = new ulong[PtLevelSize][][];
}
if (_pageTable[l0][l1] == null)
{
_pageTable[l0][l1] = new ulong[PtLevelSize][];
}
if (_pageTable[l0][l1][l2] == null)
{
_pageTable[l0][l1][l2] = new ulong[PtLevelSize];
for (int i = 0; i < _pageTable[l0][l1][l2].Length; i++)
{
_pageTable[l0][l1][l2][i] = Unmapped;
}
}
_pageTable[l0][l1][l2][l3] = value;
}
private void PtUnmap(ulong va)
{
int l3 = (int)(va >> PageBits) & PtLevelMask;
int l2 = (int)(va >> (PageBits + PtLevelBits)) & PtLevelMask;
int l1 = (int)(va >> (PageBits + PtLevelBits * 2)) & PtLevelMask;
int l0 = (int)(va >> (PageBits + PtLevelBits * 3)) & PtLevelMask;
if (_pageTable[l0] == null)
{
return;
}
if (_pageTable[l0][l1] == null)
{
return;
}
if (_pageTable[l0][l1][l2] == null)
{
return;
}
_pageTable[l0][l1][l2][l3] = Unmapped;
bool empty = true;
for (int i = 0; i < _pageTable[l0][l1][l2].Length; i++)
{
empty &= (_pageTable[l0][l1][l2][i] == Unmapped);
}
if (empty)
{
_pageTable[l0][l1][l2] = null;
RemoveIfAllNull(l0, l1);
}
}
private void RemoveIfAllNull(int l0, int l1)
{
bool empty = true;
for (int i = 0; i < _pageTable[l0][l1].Length; i++)
{
empty &= (_pageTable[l0][l1][i] == null);
}
if (empty)
{
_pageTable[l0][l1] = null;
RemoveIfAllNull(l0);
}
}
private void RemoveIfAllNull(int l0)
{
bool empty = true;
for (int i = 0; i < _pageTable[l0].Length; i++)
{
empty &= (_pageTable[l0][i] == null);
}
if (empty)
{
_pageTable[l0] = null;
}
}
public void SignalMemoryTracking(ulong va, ulong size, bool write)
{
// Only the ARM Memory Manager has tracking for now.
}
}
}