/** @file
A simple DXE_DRIVER that causes the PCI Bus UEFI_DRIVER to allocate 64-bit
MMIO BARs above 4 GB, regardless of option ROM availability, conserving 32-bit
MMIO aperture for 32-bit BARs.
Copyright (C) 2016, Red Hat, Inc.
Copyright (c) 2017, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
//
// The protocol interface this driver produces.
//
STATIC EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL
mIncompatiblePciDeviceSupport;
//
// Configuration template for the CheckDevice() protocol member function.
//
// Refer to Table 20 "ACPI 2.0 & 3.0 QWORD Address Space Descriptor Usage" in
// the Platform Init 1.4a Spec, Volume 5.
//
// This structure is interpreted by the UpdatePciInfo() function in the edk2
// PCI Bus UEFI_DRIVER.
//
// This structure looks like:
// AddressDesc-1 + AddressDesc-2 + ... + AddressDesc-n + EndDesc
//
STATIC CONST EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR mMmio64Configuration = {
ACPI_ADDRESS_SPACE_DESCRIPTOR, // Desc
(UINT16)( // Len
sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
OFFSET_OF (
EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
ResType
)
),
ACPI_ADDRESS_SPACE_TYPE_MEM, // ResType
0, // GenFlag
0, // SpecificFlag
64, // AddrSpaceGranularity:
// aperture selection hint
// for BAR allocation
0, // AddrRangeMin
0, // AddrRangeMax:
// no special alignment
// for affected BARs
MAX_UINT64, // AddrTranslationOffset:
// hint covers all
// eligible BARs
0 // AddrLen:
// use probed BAR size
};
//
// mOptionRomConfiguration is present only in Td guest.
// Host VMM can inject option ROM which is untrusted in Td guest,
// so PCI option ROM needs to be ignored.
// According to "Table 20. ACPI 2.0 & 3.0 QWORD Address Space Descriptor Usage"
// PI spec 1.7, type-specific flags can be set to 0 when
// Address Translation Offset == 6 to skip device option ROM.
//
STATIC CONST EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR mOptionRomConfiguration = {
ACPI_ADDRESS_SPACE_DESCRIPTOR, // Desc
(UINT16)( // Len
sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
OFFSET_OF (
EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
ResType
)
),
ACPI_ADDRESS_SPACE_TYPE_MEM, // ResType
0, // GenFlag
0, // Disable option roms SpecificFlag
64, // AddrSpaceGranularity:
// aperture selection hint
// for BAR allocation
MAX_UINT64, // AddrRangeMin
MAX_UINT64, // AddrRangeMax:
// no special alignment
// for affected BARs
6, // AddrTranslationOffset:
// hint covers all
// eligible BARs
0 // AddrLen:
// use probed BAR size
};
STATIC CONST EFI_ACPI_END_TAG_DESCRIPTOR mEndDesc = {
ACPI_END_TAG_DESCRIPTOR, // Desc
0 // Checksum: to be ignored
};
/**
Returns a list of ACPI resource descriptors that detail the special resource
configuration requirements for an incompatible PCI device.
Prior to bus enumeration, the PCI bus driver will look for the presence of
the EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL. Only one instance of this
protocol can be present in the system. For each PCI device that the PCI bus
driver discovers, the PCI bus driver calls this function with the device's
vendor ID, device ID, revision ID, subsystem vendor ID, and subsystem device
ID. If the VendorId, DeviceId, RevisionId, SubsystemVendorId, or
SubsystemDeviceId value is set to (UINTN)-1, that field will be ignored. The
ID values that are not (UINTN)-1 will be used to identify the current device.
This function will only return EFI_SUCCESS. However, if the device is an
incompatible PCI device, a list of ACPI resource descriptors will be returned
in Configuration. Otherwise, NULL will be returned in Configuration instead.
The PCI bus driver does not need to allocate memory for Configuration.
However, it is the PCI bus driver's responsibility to free it. The PCI bus
driver then can configure this device with the information that is derived
from this list of resource nodes, rather than the result of BAR probing.
Only the following two resource descriptor types from the ACPI Specification
may be used to describe the incompatible PCI device resource requirements:
- QWORD Address Space Descriptor (ACPI 2.0, section 6.4.3.5.1; also ACPI 3.0)
- End Tag (ACPI 2.0, section 6.4.2.8; also ACPI 3.0)
The QWORD Address Space Descriptor can describe memory, I/O, and bus number
ranges for dynamic or fixed resources. The configuration of a PCI root bridge
is described with one or more QWORD Address Space Descriptors, followed by an
End Tag. See the ACPI Specification for details on the field values.
@param[in] This Pointer to the
EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL
instance.
@param[in] VendorId A unique ID to identify the manufacturer of
the PCI device. See the Conventional PCI
Specification 3.0 for details.
@param[in] DeviceId A unique ID to identify the particular PCI
device. See the Conventional PCI
Specification 3.0 for details.
@param[in] RevisionId A PCI device-specific revision identifier.
See the Conventional PCI Specification 3.0
for details.
@param[in] SubsystemVendorId Specifies the subsystem vendor ID. See the
Conventional PCI Specification 3.0 for
details.
@param[in] SubsystemDeviceId Specifies the subsystem device ID. See the
Conventional PCI Specification 3.0 for
details.
@param[out] Configuration A list of ACPI resource descriptors that
detail the configuration requirement.
@retval EFI_SUCCESS The function always returns EFI_SUCCESS.
**/
STATIC
EFI_STATUS
EFIAPI
CheckDevice (
IN EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL *This,
IN UINTN VendorId,
IN UINTN DeviceId,
IN UINTN RevisionId,
IN UINTN SubsystemVendorId,
IN UINTN SubsystemDeviceId,
OUT VOID **Configuration
)
{
UINTN Length;
UINT8 *Ptr;
//
// Unlike the general description of this protocol member suggests, there is
// nothing incompatible about the PCI devices that we'll match here. We'll
// match all PCI devices, and generate exactly one QWORD Address Space
// Descriptor for each. That descriptor will instruct the PCI Bus UEFI_DRIVER
// not to degrade 64-bit MMIO BARs for the device, even if a PCI option ROM
// BAR is present on the device.
//
// The concern captured in the PCI Bus UEFI_DRIVER is that a legacy BIOS boot
// (via a CSM) could dispatch a legacy option ROM on the device, which might
// have trouble with MMIO BARs that have been allocated outside of the 32-bit
// address space. But, we don't support legacy option ROMs at all, thus this
// problem cannot arise.
//
// This member function is mis-specified actually: it is supposed to allocate
// memory, but as specified, it could not return an error status. Thankfully,
// the edk2 PCI Bus UEFI_DRIVER actually handles error codes; see the
// UpdatePciInfo() function.
//
Length = sizeof mMmio64Configuration + sizeof mEndDesc;
//
// In Td guest OptionRom is not allowed.
//
if (CcProbe ()) {
Length += sizeof mOptionRomConfiguration;
}
*Configuration = AllocateZeroPool (Length);
if (*Configuration == NULL) {
DEBUG ((
DEBUG_WARN,
"%a: 64-bit MMIO BARs may be degraded for PCI 0x%04x:0x%04x (rev %d)\n",
__func__,
(UINT32)VendorId,
(UINT32)DeviceId,
(UINT8)RevisionId
));
return EFI_OUT_OF_RESOURCES;
}
Ptr = (UINT8 *)(UINTN)*Configuration;
CopyMem (Ptr, &mMmio64Configuration, sizeof mMmio64Configuration);
Length = sizeof mMmio64Configuration;
if (CcProbe ()) {
CopyMem (Ptr + Length, &mOptionRomConfiguration, sizeof mOptionRomConfiguration);
Length += sizeof mOptionRomConfiguration;
}
CopyMem (Ptr + Length, &mEndDesc, sizeof mEndDesc);
return EFI_SUCCESS;
}
/**
Entry point for this driver.
@param[in] ImageHandle Image handle of this driver.
@param[in] SystemTable Pointer to SystemTable.
@retval EFI_SUCESS Driver has loaded successfully.
@retval EFI_UNSUPPORTED PCI resource allocation has been disabled.
@retval EFI_UNSUPPORTED There is no 64-bit PCI MMIO aperture.
@return Error codes from lower level functions.
**/
EFI_STATUS
EFIAPI
DriverInitialize (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
//
// If there is no 64-bit PCI MMIO aperture, then 64-bit MMIO BARs have to be
// allocated under 4 GB unconditionally.
//
if (PcdGet64 (PcdPciMmio64Size) == 0) {
return EFI_UNSUPPORTED;
}
mIncompatiblePciDeviceSupport.CheckDevice = CheckDevice;
Status = gBS->InstallMultipleProtocolInterfaces (
&ImageHandle,
&gEfiIncompatiblePciDeviceSupportProtocolGuid,
&mIncompatiblePciDeviceSupport,
NULL
);
return Status;
}