audk/OvmfPkg/Library/PciHostBridgeUtilityLib/PciHostBridgeUtilityLib.c

819 lines
24 KiB
C

/** @file
Provide common utility functions to PciHostBridgeLib instances in
ArmVirtPkg and OvmfPkg.
Copyright (C) 2016, Red Hat, Inc.
Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2020, Huawei Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <IndustryStandard/Acpi10.h>
#include <IndustryStandard/Pci.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/DevicePathLib.h>
#include <Library/HardwareInfoLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/PciHostBridgeUtilityLib.h>
#include <Library/PciLib.h>
#include <Library/QemuFwCfgLib.h>
#include <Protocol/PciHostBridgeResourceAllocation.h>
#pragma pack(1)
typedef struct {
ACPI_HID_DEVICE_PATH AcpiDevicePath;
EFI_DEVICE_PATH_PROTOCOL EndDevicePath;
} OVMF_PCI_ROOT_BRIDGE_DEVICE_PATH;
#pragma pack ()
GLOBAL_REMOVE_IF_UNREFERENCED
CHAR16 *mPciHostBridgeUtilityLibAcpiAddressSpaceTypeStr[] = {
L"Mem", L"I/O", L"Bus"
};
STATIC
CONST
OVMF_PCI_ROOT_BRIDGE_DEVICE_PATH mRootBridgeDevicePathTemplate = {
{
{
ACPI_DEVICE_PATH,
ACPI_DP,
{
(UINT8)(sizeof (ACPI_HID_DEVICE_PATH)),
(UINT8)((sizeof (ACPI_HID_DEVICE_PATH)) >> 8)
}
},
EISA_PNP_ID (0x0A03), // HID
0 // UID
},
{
END_DEVICE_PATH_TYPE,
END_ENTIRE_DEVICE_PATH_SUBTYPE,
{
END_DEVICE_PATH_LENGTH,
0
}
}
};
/**
Utility function to initialize a PCI_ROOT_BRIDGE structure.
@param[in] Supports Supported attributes.
@param[in] Attributes Initial attributes.
@param[in] AllocAttributes Allocation attributes.
@param[in] DmaAbove4G DMA above 4GB memory.
@param[in] NoExtendedConfigSpace No Extended Config Space.
@param[in] RootBusNumber The bus number to store in RootBus.
@param[in] MaxSubBusNumber The inclusive maximum bus number that can
be assigned to any subordinate bus found
behind any PCI bridge hanging off this
root bus.
The caller is repsonsible for ensuring
that RootBusNumber <= MaxSubBusNumber. If
RootBusNumber equals MaxSubBusNumber, then
the root bus has no room for subordinate
buses.
@param[in] Io IO aperture.
@param[in] Mem MMIO aperture.
@param[in] MemAbove4G MMIO aperture above 4G.
@param[in] PMem Prefetchable MMIO aperture.
@param[in] PMemAbove4G Prefetchable MMIO aperture above 4G.
@param[out] RootBus The PCI_ROOT_BRIDGE structure (allocated
by the caller) that should be filled in by
this function.
@retval EFI_SUCCESS Initialization successful. A device path
consisting of an ACPI device path node,
with UID = RootBusNumber, has been
allocated and linked into RootBus.
@retval EFI_OUT_OF_RESOURCES Memory allocation failed.
**/
EFI_STATUS
EFIAPI
PciHostBridgeUtilityInitRootBridge (
IN UINT64 Supports,
IN UINT64 Attributes,
IN UINT64 AllocAttributes,
IN BOOLEAN DmaAbove4G,
IN BOOLEAN NoExtendedConfigSpace,
IN UINT8 RootBusNumber,
IN UINT8 MaxSubBusNumber,
IN PCI_ROOT_BRIDGE_APERTURE *Io,
IN PCI_ROOT_BRIDGE_APERTURE *Mem,
IN PCI_ROOT_BRIDGE_APERTURE *MemAbove4G,
IN PCI_ROOT_BRIDGE_APERTURE *PMem,
IN PCI_ROOT_BRIDGE_APERTURE *PMemAbove4G,
OUT PCI_ROOT_BRIDGE *RootBus
)
{
OVMF_PCI_ROOT_BRIDGE_DEVICE_PATH *DevicePath;
//
// Be safe if other fields are added to PCI_ROOT_BRIDGE later.
//
ZeroMem (RootBus, sizeof *RootBus);
RootBus->Segment = 0;
RootBus->Supports = Supports;
RootBus->Attributes = Attributes;
RootBus->DmaAbove4G = DmaAbove4G;
RootBus->AllocationAttributes = AllocAttributes;
RootBus->Bus.Base = RootBusNumber;
RootBus->Bus.Limit = MaxSubBusNumber;
CopyMem (&RootBus->Io, Io, sizeof (*Io));
CopyMem (&RootBus->Mem, Mem, sizeof (*Mem));
CopyMem (&RootBus->MemAbove4G, MemAbove4G, sizeof (*MemAbove4G));
CopyMem (&RootBus->PMem, PMem, sizeof (*PMem));
CopyMem (&RootBus->PMemAbove4G, PMemAbove4G, sizeof (*PMemAbove4G));
RootBus->NoExtendedConfigSpace = NoExtendedConfigSpace;
DevicePath = AllocateCopyPool (
sizeof mRootBridgeDevicePathTemplate,
&mRootBridgeDevicePathTemplate
);
if (DevicePath == NULL) {
DEBUG ((DEBUG_ERROR, "%a: %r\n", __FUNCTION__, EFI_OUT_OF_RESOURCES));
return EFI_OUT_OF_RESOURCES;
}
DevicePath->AcpiDevicePath.UID = RootBusNumber;
RootBus->DevicePath = (EFI_DEVICE_PATH_PROTOCOL *)DevicePath;
DEBUG ((
DEBUG_INFO,
"%a: populated root bus %d, with room for %d subordinate bus(es)\n",
__FUNCTION__,
RootBusNumber,
MaxSubBusNumber - RootBusNumber
));
return EFI_SUCCESS;
}
/**
Utility function to uninitialize a PCI_ROOT_BRIDGE structure set up with
PciHostBridgeUtilityInitRootBridge().
@param[in] RootBus The PCI_ROOT_BRIDGE structure, allocated by the caller and
initialized with PciHostBridgeUtilityInitRootBridge(),
that should be uninitialized. This function doesn't free
RootBus.
**/
VOID
EFIAPI
PciHostBridgeUtilityUninitRootBridge (
IN PCI_ROOT_BRIDGE *RootBus
)
{
FreePool (RootBus->DevicePath);
}
/**
Utility function to scan PCI root bridges and create instances for those
that are found not empty. Populate their resources from the default
provided parameters and return all the root bridge instances in an array.
@param[out] Count The number of root bridge instances.
@param[in] Attributes Initial attributes.
@param[in] AllocAttributes Allocation attributes.
@param[in] DmaAbove4G DMA above 4GB memory.
@param[in] NoExtendedConfigSpace No Extended Config Space.
@param[in] BusMin Minimum Bus number, inclusive.
@param[in] BusMax Maximum Bus number, inclusive.
@param[in] Io IO aperture.
@param[in] Mem MMIO aperture.
@param[in] MemAbove4G MMIO aperture above 4G.
@param[in] PMem Prefetchable MMIO aperture.
@param[in] PMemAbove4G Prefetchable MMIO aperture above 4G.
@return All the root bridge instances in an array.
**/
STATIC
PCI_ROOT_BRIDGE *
PciHostBridgeUtilityGetRootBridgesBusScan (
OUT UINTN *Count,
IN UINT64 Attributes,
IN UINT64 AllocationAttributes,
IN BOOLEAN DmaAbove4G,
IN BOOLEAN NoExtendedConfigSpace,
IN UINTN BusMin,
IN UINTN BusMax,
IN PCI_ROOT_BRIDGE_APERTURE *Io,
IN PCI_ROOT_BRIDGE_APERTURE *Mem,
IN PCI_ROOT_BRIDGE_APERTURE *MemAbove4G,
IN PCI_ROOT_BRIDGE_APERTURE *PMem,
IN PCI_ROOT_BRIDGE_APERTURE *PMemAbove4G
)
{
EFI_STATUS Status;
FIRMWARE_CONFIG_ITEM FwCfgItem;
UINTN FwCfgSize;
UINT64 ExtraRootBridges;
PCI_ROOT_BRIDGE *Bridges;
UINTN Initialized;
UINTN LastRootBridgeNumber;
UINTN RootBridgeNumber;
if ((BusMin > BusMax) || (BusMax > PCI_MAX_BUS)) {
DEBUG ((
DEBUG_ERROR,
"%a: invalid bus range with BusMin %Lu and BusMax "
"%Lu\n",
__FUNCTION__,
(UINT64)BusMin,
(UINT64)BusMax
));
return NULL;
}
//
// QEMU provides the number of extra root buses, shortening the exhaustive
// search below. If there is no hint, the feature is missing.
//
Status = QemuFwCfgFindFile ("etc/extra-pci-roots", &FwCfgItem, &FwCfgSize);
if (EFI_ERROR (Status) || (FwCfgSize != sizeof ExtraRootBridges)) {
ExtraRootBridges = 0;
} else {
QemuFwCfgSelectItem (FwCfgItem);
QemuFwCfgReadBytes (FwCfgSize, &ExtraRootBridges);
//
// Validate the number of extra root bridges. As BusMax is inclusive, the
// max bus count is (BusMax - BusMin + 1). From that, the "main" root bus
// is always a given, so the max count for the "extra" root bridges is one
// less, i.e. (BusMax - BusMin). If the QEMU hint exceeds that, we have
// invalid behavior.
//
if (ExtraRootBridges > BusMax - BusMin) {
DEBUG ((
DEBUG_ERROR,
"%a: invalid count of extra root buses (%Lu) "
"reported by QEMU\n",
__FUNCTION__,
ExtraRootBridges
));
return NULL;
}
DEBUG ((
DEBUG_INFO,
"%a: %Lu extra root buses reported by QEMU\n",
__FUNCTION__,
ExtraRootBridges
));
}
//
// Allocate the "main" root bridge, and any extra root bridges.
//
Bridges = AllocatePool ((1 + (UINTN)ExtraRootBridges) * sizeof *Bridges);
if (Bridges == NULL) {
DEBUG ((DEBUG_ERROR, "%a: %r\n", __FUNCTION__, EFI_OUT_OF_RESOURCES));
return NULL;
}
Initialized = 0;
//
// The "main" root bus is always there.
//
LastRootBridgeNumber = BusMin;
//
// Scan all other root buses. If function 0 of any device on a bus returns a
// VendorId register value different from all-bits-one, then that bus is
// alive.
//
for (RootBridgeNumber = BusMin + 1;
RootBridgeNumber <= BusMax && Initialized < ExtraRootBridges;
++RootBridgeNumber)
{
UINTN Device;
for (Device = 0; Device <= PCI_MAX_DEVICE; ++Device) {
if (PciRead16 (
PCI_LIB_ADDRESS (
RootBridgeNumber,
Device,
0,
PCI_VENDOR_ID_OFFSET
)
) != MAX_UINT16)
{
break;
}
}
if (Device <= PCI_MAX_DEVICE) {
//
// Found the next root bus. We can now install the *previous* one,
// because now we know how big a bus number range *that* one has, for any
// subordinate buses that might exist behind PCI bridges hanging off it.
//
Status = PciHostBridgeUtilityInitRootBridge (
Attributes,
Attributes,
AllocationAttributes,
DmaAbove4G,
NoExtendedConfigSpace,
(UINT8)LastRootBridgeNumber,
(UINT8)(RootBridgeNumber - 1),
Io,
Mem,
MemAbove4G,
PMem,
PMemAbove4G,
&Bridges[Initialized]
);
if (EFI_ERROR (Status)) {
goto FreeBridges;
}
++Initialized;
LastRootBridgeNumber = RootBridgeNumber;
}
}
//
// Install the last root bus (which might be the only, ie. main, root bus, if
// we've found no extra root buses).
//
Status = PciHostBridgeUtilityInitRootBridge (
Attributes,
Attributes,
AllocationAttributes,
DmaAbove4G,
NoExtendedConfigSpace,
(UINT8)LastRootBridgeNumber,
(UINT8)BusMax,
Io,
Mem,
MemAbove4G,
PMem,
PMemAbove4G,
&Bridges[Initialized]
);
if (EFI_ERROR (Status)) {
goto FreeBridges;
}
++Initialized;
*Count = Initialized;
return Bridges;
FreeBridges:
while (Initialized > 0) {
--Initialized;
PciHostBridgeUtilityUninitRootBridge (&Bridges[Initialized]);
}
FreePool (Bridges);
return NULL;
}
/**
Utility function to read root bridges information from host-provided fw-cfg
file and return them in an array.
@param[out] Count The number of root bridge instances.
@return All the root bridge instances in an array parsed from
host-provided fw-cfg file (hardware-info).
**/
STATIC
PCI_ROOT_BRIDGE *
PciHostBridgeUtilityGetRootBridgesHostProvided (
OUT UINTN *Count
)
{
EFI_STATUS Status;
FIRMWARE_CONFIG_ITEM FwCfgItem;
UINTN FwCfgSize;
PCI_ROOT_BRIDGE *Bridges;
UINTN Initialized;
UINTN LastRootBridgeNumber;
UINTN RootBridgeNumber;
UINTN PciHostBridgeCount;
UINT8 *HardwareInfoBlob;
LIST_ENTRY HwInfoList;
LIST_ENTRY *HwLink;
HARDWARE_INFO *HwInfo;
UINT64 Attributes;
UINT64 AllocationAttributes;
BOOLEAN DmaAbove4G;
BOOLEAN NoExtendedConfigSpace;
BOOLEAN CombineMemPMem;
PCI_ROOT_BRIDGE_APERTURE Io;
PCI_ROOT_BRIDGE_APERTURE Mem;
PCI_ROOT_BRIDGE_APERTURE MemAbove4G;
PCI_ROOT_BRIDGE_APERTURE PMem;
PCI_ROOT_BRIDGE_APERTURE PMemAbove4G;
//
// Initialize the Hardware Info list head to start with an empty but valid
// list head.
//
InitializeListHead (&HwInfoList);
HardwareInfoBlob = NULL;
Initialized = 0;
Bridges = NULL;
PciHostBridgeCount = 0;
//
// Hypervisor can provide the specifications (resources) for one or more
// PCI host bridges. Such information comes through fw-cfg as part of
// the hardware-info file.
//
Status = QemuFwCfgFindFile ("etc/hardware-info", &FwCfgItem, &FwCfgSize);
if (EFI_ERROR (Status)) {
return NULL;
}
HardwareInfoBlob = AllocatePool (FwCfgSize);
if (HardwareInfoBlob == NULL) {
DEBUG ((
DEBUG_ERROR,
"%a: Failed to allocate memory for hardware resources info\n",
__FUNCTION__
));
return NULL;
}
QemuFwCfgSelectItem (FwCfgItem);
QemuFwCfgReadBytes (FwCfgSize, HardwareInfoBlob);
//
// Create the list of hardware info devices filtering for PCI host
// bridges
//
Status = CreateHardwareInfoList (
HardwareInfoBlob,
FwCfgSize,
HardwareInfoTypeHostBridge,
&HwInfoList
);
if (EFI_ERROR (Status)) {
DEBUG ((
DEBUG_ERROR,
"%a: Failed to create hardware info list to retrieve host "
"bridges information from fw-cfg\n",
__FUNCTION__
));
goto FreeBridges;
}
PciHostBridgeCount = GetHardwareInfoCountByType (
&HwInfoList,
HardwareInfoTypeHostBridge,
sizeof (HOST_BRIDGE_INFO)
);
if (PciHostBridgeCount == 0) {
goto FreeBridges;
}
DEBUG ((
DEBUG_INFO,
"%a: Host provided description for %Lu root bridges\n",
__FUNCTION__,
PciHostBridgeCount
));
//
// Allocate the root bridges
//
Bridges = AllocatePool (((UINTN)PciHostBridgeCount) * sizeof *Bridges);
if (Bridges == NULL) {
DEBUG ((DEBUG_ERROR, "%a: %r\n", __FUNCTION__, EFI_OUT_OF_RESOURCES));
goto FreeBridges;
}
//
// If Host Bridges' specification was obtained from fw-cfg, the list
// contains information to populate all root bridges in the system
// including resources and attributes.
//
HwLink = GetFirstHardwareInfoByType (
&HwInfoList,
HardwareInfoTypeHostBridge,
sizeof (HOST_BRIDGE_INFO)
);
while (!EndOfHardwareInfoList (&HwInfoList, HwLink)) {
HwInfo = HARDWARE_INFO_FROM_LINK (HwLink);
Status = HardwareInfoPciHostBridgeGet (
HwInfo->Data.PciHostBridge,
(UINTN)HwInfo->Header.Size,
&RootBridgeNumber,
&LastRootBridgeNumber,
&Attributes,
&DmaAbove4G,
&NoExtendedConfigSpace,
&CombineMemPMem,
&Io,
&Mem,
&MemAbove4G,
&PMem,
&PMemAbove4G,
NULL
);
if (EFI_ERROR (Status)) {
goto FreeBridges;
}
if ((RootBridgeNumber > LastRootBridgeNumber) || (LastRootBridgeNumber > PCI_MAX_BUS)) {
DEBUG ((
DEBUG_ERROR,
"%a: invalid bus range with BusMin %Lu and BusMax "
"%Lu\n",
__FUNCTION__,
(UINT64)RootBridgeNumber,
(UINT64)LastRootBridgeNumber
));
goto FreeBridges;
}
AllocationAttributes = 0;
if (CombineMemPMem) {
AllocationAttributes |= EFI_PCI_HOST_BRIDGE_COMBINE_MEM_PMEM;
}
if ((MemAbove4G.Limit > MemAbove4G.Base) ||
(PMemAbove4G.Limit > PMemAbove4G.Base))
{
AllocationAttributes |= EFI_PCI_HOST_BRIDGE_MEM64_DECODE;
}
Status = PciHostBridgeUtilityInitRootBridge (
Attributes,
Attributes,
AllocationAttributes,
DmaAbove4G,
NoExtendedConfigSpace,
(UINT8)RootBridgeNumber,
(UINT8)LastRootBridgeNumber,
&Io,
&Mem,
&MemAbove4G,
&PMem,
&PMemAbove4G,
&Bridges[Initialized]
);
if (EFI_ERROR (Status)) {
goto FreeBridges;
}
++Initialized;
HwLink = GetNextHardwareInfoByType (
&HwInfoList,
HwLink,
HardwareInfoTypeHostBridge,
sizeof (HOST_BRIDGE_INFO)
);
}
*Count = Initialized;
//
// If resources were allocated for host bridges info, release them
//
if (HardwareInfoBlob) {
FreePool (HardwareInfoBlob);
}
FreeHardwareInfoList (&HwInfoList);
return Bridges;
FreeBridges:
while (Initialized > 0) {
--Initialized;
PciHostBridgeUtilityUninitRootBridge (&Bridges[Initialized]);
}
if (Bridges) {
FreePool (Bridges);
}
if (HardwareInfoBlob) {
FreePool (HardwareInfoBlob);
}
FreeHardwareInfoList (&HwInfoList);
return NULL;
}
/**
Utility function to return all the root bridge instances in an array.
@param[out] Count The number of root bridge instances.
@param[in] Attributes Initial attributes.
@param[in] AllocAttributes Allocation attributes.
@param[in] DmaAbove4G DMA above 4GB memory.
@param[in] NoExtendedConfigSpace No Extended Config Space.
@param[in] BusMin Minimum Bus number, inclusive.
@param[in] BusMax Maximum Bus number, inclusive.
@param[in] Io IO aperture.
@param[in] Mem MMIO aperture.
@param[in] MemAbove4G MMIO aperture above 4G.
@param[in] PMem Prefetchable MMIO aperture.
@param[in] PMemAbove4G Prefetchable MMIO aperture above 4G.
@return All the root bridge instances in an array.
**/
PCI_ROOT_BRIDGE *
EFIAPI
PciHostBridgeUtilityGetRootBridges (
OUT UINTN *Count,
IN UINT64 Attributes,
IN UINT64 AllocationAttributes,
IN BOOLEAN DmaAbove4G,
IN BOOLEAN NoExtendedConfigSpace,
IN UINTN BusMin,
IN UINTN BusMax,
IN PCI_ROOT_BRIDGE_APERTURE *Io,
IN PCI_ROOT_BRIDGE_APERTURE *Mem,
IN PCI_ROOT_BRIDGE_APERTURE *MemAbove4G,
IN PCI_ROOT_BRIDGE_APERTURE *PMem,
IN PCI_ROOT_BRIDGE_APERTURE *PMemAbove4G
)
{
PCI_ROOT_BRIDGE *Bridges;
*Count = 0;
//
// First attempt to get the host provided descriptions of the Root Bridges
// if available.
//
Bridges = PciHostBridgeUtilityGetRootBridgesHostProvided (Count);
//
// If host did not provide Root Bridge information, scan the buses and
// auto populate them with default resources.
//
if (Bridges == NULL) {
Bridges = PciHostBridgeUtilityGetRootBridgesBusScan (
Count,
Attributes,
AllocationAttributes,
DmaAbove4G,
NoExtendedConfigSpace,
BusMin,
BusMax,
Io,
Mem,
MemAbove4G,
PMem,
PMemAbove4G
);
}
return Bridges;
}
/**
Utility function to free root bridge instances array from
PciHostBridgeUtilityGetRootBridges().
@param[in] Bridges The root bridge instances array.
@param[in] Count The count of the array.
**/
VOID
EFIAPI
PciHostBridgeUtilityFreeRootBridges (
IN PCI_ROOT_BRIDGE *Bridges,
IN UINTN Count
)
{
if ((Bridges == NULL) && (Count == 0)) {
return;
}
ASSERT (Bridges != NULL && Count > 0);
do {
--Count;
PciHostBridgeUtilityUninitRootBridge (&Bridges[Count]);
} while (Count > 0);
FreePool (Bridges);
}
/**
Utility function to inform the platform that the resource conflict happens.
@param[in] Configuration Pointer to PCI I/O and PCI memory resource
descriptors. The Configuration contains the
resources for all the root bridges. The resource
for each root bridge is terminated with END
descriptor and an additional END is appended
indicating the end of the entire resources. The
resource descriptor field values follow the
description in
EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL
.SubmitResources().
**/
VOID
EFIAPI
PciHostBridgeUtilityResourceConflict (
IN VOID *Configuration
)
{
EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *Descriptor;
UINTN RootBridgeIndex;
DEBUG ((DEBUG_ERROR, "PciHostBridge: Resource conflict happens!\n"));
RootBridgeIndex = 0;
Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *)Configuration;
while (Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR) {
DEBUG ((DEBUG_ERROR, "RootBridge[%d]:\n", RootBridgeIndex++));
for ( ; Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR; Descriptor++) {
ASSERT (
Descriptor->ResType <
ARRAY_SIZE (mPciHostBridgeUtilityLibAcpiAddressSpaceTypeStr)
);
DEBUG ((
DEBUG_ERROR,
" %s: Length/Alignment = 0x%lx / 0x%lx\n",
mPciHostBridgeUtilityLibAcpiAddressSpaceTypeStr[Descriptor->ResType],
Descriptor->AddrLen,
Descriptor->AddrRangeMax
));
if (Descriptor->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM) {
DEBUG ((
DEBUG_ERROR,
" Granularity/SpecificFlag = %ld / %02x%s\n",
Descriptor->AddrSpaceGranularity,
Descriptor->SpecificFlag,
((Descriptor->SpecificFlag &
EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE
) != 0) ? L" (Prefetchable)" : L""
));
}
}
//
// Skip the END descriptor for root bridge
//
ASSERT (Descriptor->Desc == ACPI_END_TAG_DESCRIPTOR);
Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *)(
(EFI_ACPI_END_TAG_DESCRIPTOR *)Descriptor + 1
);
}
}