IopGetMaxValidSectionSizeDown

UINT64 __stdcall IopGetMaxValidSectionSizeDown(UINT64 StartPage, UINT64 NumberOfPages){
  unsigned int v2; 
  unsigned int v3; 

  v2 = NumberOfPages;
  v3 = 0;
  if( StartPage < (unsigned int)NumberOfPages )
    v2 = StartPage;
  if( v2 )
  {
    do
    {
      if( !MmIsAddressValidEx(StartPage - v3) )
        break;
      ++v3;
    }
    while( v3 < v2 );
  }
  return v3;
}

Referenced by:

KeCapturePersistentThreadState