/// <summary>
/// Maps a given range of pages to the specified CPU virtual address.
/// </summary>
/// <remarks>
/// All addresses and sizes must be page aligned.
/// </remarks>
/// <param name="pa">CPU virtual address to map into</param>
/// <param name="va">GPU virtual address to be mapped</param>
/// <param name="size">Size in bytes of the mapping</param>
public void Map(ulong pa, ulong va, ulong size)
{
lock (_pageTable)
{
MemoryUnmapped?.Invoke(this, new UnmapEventArgs(va, size));
for (ulong offset = 0; offset < size; offset += PageSize)
{
SetPte(va + offset, pa + offset);
}
}
}
/// <summary>
/// Frees memory that was previously allocated by a map or reserved.
/// </summary>
/// <param name="va">GPU virtual address to free</param>
/// <param name="size">Size in bytes of the region being freed</param>
public void Free(ulong va, ulong size)
{
lock (_pageTable)
{
// Event handlers are not expected to be thread safe.
MemoryUnmapped?.Invoke(this, new UnmapEventArgs(va, size));
for (ulong offset = 0; offset < size; offset += PageSize)
{
SetPte(va + offset, PteUnmapped);
}
}
}
/// <summary>
/// Reserves memory at a fixed GPU memory location.
/// This prevents the reserved region from being used for memory allocation for map.
/// </summary>
/// <param name="va">GPU virtual address to reserve</param>
/// <param name="size">Size in bytes of the reservation</param>
/// <returns>GPU virtual address of the reservation, or an all ones mask in case of failure</returns>
public ulong ReserveFixed(ulong va, ulong size)
{
lock (_pageTable)
{
MemoryUnmapped?.Invoke(this, new UnmapEventArgs(va, size));
for (ulong offset = 0; offset < size; offset += PageSize)
{
if (IsPageInUse(va + offset))
{
return(PteUnmapped);
}
}
for (ulong offset = 0; offset < size; offset += PageSize)
{
SetPte(va + offset, PteReserved);
}
}
return(va);
}
