0
0
Fork 0
mirror of https://github.com/GreemDev/Ryujinx.git synced 2024-12-23 04:35:46 +00:00
Ryujinx/src/Ryujinx.Cpu/ManagedPageFlags.cs

390 lines
14 KiB
C#
Raw Normal View History

using Ryujinx.Memory;
using Ryujinx.Memory.Tracking;
using System;
using System.Runtime.CompilerServices;
using System.Threading;
namespace Ryujinx.Cpu
{
/// <summary>
/// A page bitmap that keeps track of mapped state and tracking protection
/// for managed memory accesses (not using host page protection).
/// </summary>
internal readonly struct ManagedPageFlags
{
public const int PageBits = 12;
public const int PageSize = 1 << PageBits;
public const int PageMask = PageSize - 1;
private readonly ulong[] _pageBitmap;
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 ManagedPtBits : ulong
{
Unmapped = 0,
Mapped,
WriteTracked,
ReadWriteTracked,
MappedReplicated = 0x5555555555555555,
WriteTrackedReplicated = 0xaaaaaaaaaaaaaaaa,
ReadWriteTrackedReplicated = ulong.MaxValue,
}
public ManagedPageFlags(int addressSpaceBits)
{
int bits = Math.Max(0, addressSpaceBits - (PageBits + PageToPteShift));
_pageBitmap = new ulong[1 << bits];
}
/// <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 static 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);
}
/// <summary>
/// Checks if the page at a given CPU 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 readonly bool IsMapped(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;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static 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);
}
/// <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 readonly bool IsRangeMapped(ulong va, ulong size)
{
int pages = GetPagesCount(va, size, out _);
if (pages == 1)
{
return IsMapped(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;
}
/// <summary>
/// Reprotect a region of virtual memory for tracking.
/// </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 readonly 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)ManagedPtBits.Mapped,
MemoryPermission.Write => (ulong)ManagedPtBits.WriteTracked,
_ => (ulong)ManagedPtBits.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)ManagedPtBits.MappedReplicated,
MemoryPermission.Write => (ulong)ManagedPtBits.WriteTrackedReplicated,
_ => (ulong)ManagedPtBits.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;
}
}
}
/// <summary>
/// Alerts the memory tracking that a given region has been read from or written to.
/// This should be called before read/write is performed.
/// </summary>
/// <param name="tracking">Memory tracking structure to call when pages are protected</param>
/// <param name="va">Virtual address of the region</param>
/// <param name="size">Size of the region</param>
/// <param name="write">True if the region was written, false if read</param>
/// <param name="exemptId">Optional ID of the handles that should not be signalled</param>
/// <remarks>
/// This function also validates that the given range is both valid and mapped, and will throw if it is not.
/// </remarks>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public readonly void SignalMemoryTracking(MemoryTracking tracking, ulong va, ulong size, bool write, int? exemptId = null)
{
// Software table, used for managed memory tracking.
int pages = GetPagesCount(va, size, out _);
ulong pageStart = va >> PageBits;
if (pages == 1)
{
ulong tag = (ulong)(write ? ManagedPtBits.WriteTracked : ManagedPtBits.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, precise: false, exemptId);
return;
}
else if (state == 0)
{
ThrowInvalidMemoryRegionException($"Not mapped: va=0x{va:X16}, size=0x{size:X16}");
}
}
else
{
ulong pageEnd = pageStart + (ulong)pages;
GetPageBlockRange(pageStart, pageEnd, out ulong startMask, out ulong endMask, out int pageIndex, out int pageEndIndex);
ulong mask = startMask;
ulong anyTrackingTag = (ulong)ManagedPtBits.WriteTrackedReplicated;
while (pageIndex <= pageEndIndex)
{
if (pageIndex == pageEndIndex)
{
mask &= endMask;
}
ref ulong pageRef = ref _pageBitmap[pageIndex++];
ulong pte = Volatile.Read(ref pageRef);
ulong mappedMask = mask & BlockMappedMask;
ulong mappedPte = pte | (pte >> 1);
if ((mappedPte & mappedMask) != mappedMask)
{
ThrowInvalidMemoryRegionException($"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, precise: false, exemptId);
break;
}
}
mask = ulong.MaxValue;
}
}
}
/// <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>
public readonly 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>
public readonly 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 static void ThrowInvalidMemoryRegionException(string message) => throw new InvalidMemoryRegionException(message);
}
}