On 05/19/16 04:02, Ni, Ruiyu wrote: > Laszlo, > All are good except: can you use EfiCreateProtocolNotifyEvent() > exposed by UefiLib?
I am aware of that function, but I dislike it. The reason I dislike it is that (in my opinion) its internal error handling is inferior. For the return values of gBS->CreateEvent() and gBS->RegisterProtocolNotify(), is only uses ASSERT_EFI_ERROR(), and to the return value of gBS->SignalEvent(), it doesn't apply any check. I think the error handling in my code below is superior. CreateEvent() can legitimately fail with EFI_OUT_OF_RESOURCES. So can RegisterProtocolNotify(). I wondered before how the error handling could be fixed in EfiCreateProtocolNotifyEvent(). One problem I see is that it returns an EFI_EVENT object, not an EFI_STATUS one. Given that EFI_EVENT is just a typedef for VOID*, we could return a NULL if something fails. However, in the library class header file, such a return value is not permitted: @return The notification event that was created. This means that the ASSERT_EFI_ERROR() macro invocations in the function body actually conform to the specification: namely, EfiCreateProtocolNotifyEvent() is never supposed to fail (and I guess all of its callers rely on this). Too bad that this function specification doesn't actually reflect reality. (See the above EFI_OUT_OF_RESOURCES failure modes for CreateEvent() and RegisterProtocolNotify().) Which is, I guess, my ultimate reason for never using this utility function, and always open-coding CreateEvent() + RegisterProtocolNotify() + SignalEvent() with proper error checking (using an assert for SignalEvent(), which really can't fail, according to the UEFI spec). Thanks Laszlo >> -----Original Message----- >> From: edk2-devel [mailto:[email protected]] On Behalf Of >> Laszlo Ersek >> Sent: Thursday, May 19, 2016 6:13 AM >> To: edk2-devel-01 <[email protected]> >> Cc: Ni, Ruiyu <[email protected]>; Justen, Jordan L >> <[email protected]> >> Subject: [edk2] [PATCH] OvmfPkg: prevent 64-bit MMIO BAR degradation if >> there is no CSM >> >> According to edk2 commit >> >> "MdeModulePkg/PciBus: do not improperly degrade resource" >> >> and to the EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL definition in the >> Platform Init 1.4a specification, a platform can provide such a protocol >> in order to influence the PCI resource allocation performed by the PCI Bus >> driver. >> >> In particular it is possible instruct the PCI Bus driver, with a >> "wildcard" hint, to allocate the 64-bit MMIO BARs of a device in 64-bit >> address space, regardless of whether the device features an option ROM. >> >> (By default, the PCI Bus driver considers an option ROM reason enough for >> allocating the 64-bit MMIO BARs in 32-bit address space. It cannot know if >> BDS will launch a legacy boot option, and under legacy boot, a legacy BIOS >> binary from a combined option ROM could be dispatched, and fail to access >> MMIO BARs in 64-bit address space.) >> >> In platform code we can ascertain whether a CSM is present or not. If not, >> then legacy BIOS binaries in option ROMs can't be dispatched, hence the >> BAR degradation is detrimental, and we should prevent it. This is expected >> to conserve the 32-bit address space for 32-bit MMIO BARs. >> >> The driver added in this patch could be simplified based on the following >> facts: >> >> - In the Ia32 build, the 64-bit MMIO aperture is always zero-size, hence >> the driver will exit immediately. Therefore the driver could be omitted >> from the Ia32 build. >> >> - In the Ia32X64 and X64 builds, the driver could be omitted if CSM_ENABLE >> was defined (because in that case the degradation would be justified). >> On the other hand, if CSM_ENABLE was undefined, then the driver could be >> included, and it could provide the hint unconditionally (without looking >> for the Legacy BIOS protocol). >> >> These short-cuts are not taken because they would increase the differences >> between the OVMF DSC/FDF files. If we can manage without extreme >> complexity, we should use dynamic logic (vs. build time configuration), >> plus keep conditional compilation to a minimum. >> >> Cc: Jordan Justen <[email protected]> >> Cc: Ruiyu Ni <[email protected]> >> Contributed-under: TianoCore Contribution Agreement 1.0 >> Signed-off-by: Laszlo Ersek <[email protected]> >> --- >> >> Notes: >> This patch will make a difference only when Ray's patch at >> <http://thread.gmane.org/gmane.comp.bios.edk2.devel/12290/focus=12292> >> is committed. >> >> OvmfPkg/OvmfPkgIa32.dsc | >> 1 + >> OvmfPkg/OvmfPkgIa32X64.dsc | >> 1 + >> OvmfPkg/OvmfPkgX64.dsc | >> 1 + >> OvmfPkg/OvmfPkgIa32.fdf | >> 1 + >> OvmfPkg/OvmfPkgIa32X64.fdf | >> 1 + >> OvmfPkg/OvmfPkgX64.fdf | >> 1 + >> OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf | >> 50 +++ >> OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c | >> 353 ++++++++++++++++++++ >> 8 files changed, 409 insertions(+) >> >> diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc >> index 45569f2875b5..1becb65cd878 100644 >> --- a/OvmfPkg/OvmfPkgIa32.dsc >> +++ b/OvmfPkg/OvmfPkgIa32.dsc >> @@ -552,6 +552,7 @@ [Components] >> UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf >> UefiCpuPkg/CpuDxe/CpuDxe.inf >> PcAtChipsetPkg/8254TimerDxe/8254Timer.inf >> + OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf { >> <LibraryClasses> >> PciHostBridgeLib|OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf >> diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc >> index 05ff1c914455..3d838cdcb125 100644 >> --- a/OvmfPkg/OvmfPkgIa32X64.dsc >> +++ b/OvmfPkg/OvmfPkgIa32X64.dsc >> @@ -561,6 +561,7 @@ [Components.X64] >> UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf >> UefiCpuPkg/CpuDxe/CpuDxe.inf >> PcAtChipsetPkg/8254TimerDxe/8254Timer.inf >> + OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf { >> <LibraryClasses> >> PciHostBridgeLib|OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf >> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc >> index 54d4413f11f6..16d58bad7865 100644 >> --- a/OvmfPkg/OvmfPkgX64.dsc >> +++ b/OvmfPkg/OvmfPkgX64.dsc >> @@ -559,6 +559,7 @@ [Components] >> UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf >> UefiCpuPkg/CpuDxe/CpuDxe.inf >> PcAtChipsetPkg/8254TimerDxe/8254Timer.inf >> + OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf { >> <LibraryClasses> >> PciHostBridgeLib|OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf >> diff --git a/OvmfPkg/OvmfPkgIa32.fdf b/OvmfPkg/OvmfPkgIa32.fdf >> index 594e84fd713b..8ab1633f832a 100644 >> --- a/OvmfPkg/OvmfPkgIa32.fdf >> +++ b/OvmfPkg/OvmfPkgIa32.fdf >> @@ -207,6 +207,7 @@ [FV.DXEFV] >> INF UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf >> INF UefiCpuPkg/CpuDxe/CpuDxe.inf >> INF PcAtChipsetPkg/8254TimerDxe/8254Timer.inf >> +INF >> OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> INF MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf >> INF MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf >> INF PcAtChipsetPkg/KbcResetDxe/Reset.inf >> diff --git a/OvmfPkg/OvmfPkgIa32X64.fdf b/OvmfPkg/OvmfPkgIa32X64.fdf >> index 36a8f7e279c3..85fead07e957 100644 >> --- a/OvmfPkg/OvmfPkgIa32X64.fdf >> +++ b/OvmfPkg/OvmfPkgIa32X64.fdf >> @@ -207,6 +207,7 @@ [FV.DXEFV] >> INF UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf >> INF UefiCpuPkg/CpuDxe/CpuDxe.inf >> INF PcAtChipsetPkg/8254TimerDxe/8254Timer.inf >> +INF >> OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> INF MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf >> INF MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf >> INF PcAtChipsetPkg/KbcResetDxe/Reset.inf >> diff --git a/OvmfPkg/OvmfPkgX64.fdf b/OvmfPkg/OvmfPkgX64.fdf >> index 4b1fa944ad1b..dd5ea30662d6 100644 >> --- a/OvmfPkg/OvmfPkgX64.fdf >> +++ b/OvmfPkg/OvmfPkgX64.fdf >> @@ -207,6 +207,7 @@ [FV.DXEFV] >> INF UefiCpuPkg/CpuIo2Dxe/CpuIo2Dxe.inf >> INF UefiCpuPkg/CpuDxe/CpuDxe.inf >> INF PcAtChipsetPkg/8254TimerDxe/8254Timer.inf >> +INF >> OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> INF MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf >> INF MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf >> INF PcAtChipsetPkg/KbcResetDxe/Reset.inf >> diff --git >> a/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> b/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> new file mode 100644 >> index 000000000000..883e45c17436 >> --- /dev/null >> +++ >> b/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf >> @@ -0,0 +1,50 @@ >> +## @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 (as long as a >> CSM >> +# is not present), conserving 32-bit MMIO aperture for 32-bit BARs. >> +# >> +# Copyright (C) 2016, Red Hat, Inc. >> +# >> +# This program and the accompanying materials are licensed and made >> available >> +# under the terms and conditions of the BSD License which accompanies this >> +# distribution. The full text of the license may be found at >> +# http://opensource.org/licenses/bsd-license.php >> +# >> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, >> WITHOUT >> +# WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. >> +## >> + >> +[Defines] >> + INF_VERSION = 0x00010005 >> + BASE_NAME = IncompatiblePciDeviceSupportDxe >> + FILE_GUID = F6697AC4-A776-4EE1-B643-1FEFF2B615BB >> + MODULE_TYPE = DXE_DRIVER >> + VERSION_STRING = 1.0 >> + ENTRY_POINT = DriverInitialize >> + >> +[Sources] >> + IncompatiblePciDeviceSupport.c >> + >> +[Packages] >> + IntelFrameworkPkg/IntelFrameworkPkg.dec >> + MdeModulePkg/MdeModulePkg.dec >> + MdePkg/MdePkg.dec >> + OvmfPkg/OvmfPkg.dec >> + >> +[LibraryClasses] >> + DebugLib >> + MemoryAllocationLib >> + PcdLib >> + UefiBootServicesTableLib >> + UefiDriverEntryPoint >> + >> +[Protocols] >> + gEfiIncompatiblePciDeviceSupportProtocolGuid ## SOMETIMES_PRODUCES >> + gEfiLegacyBiosProtocolGuid ## NOTIFY >> + >> +[Pcd] >> + gEfiMdeModulePkgTokenSpaceGuid.PcdPciDisableBusEnumeration ## CONSUMES >> + gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size ## CONSUMES >> + >> +[Depex] >> + TRUE >> diff --git >> a/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c >> b/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c >> new file mode 100644 >> index 000000000000..b6ff12842c21 >> --- /dev/null >> +++ b/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c >> @@ -0,0 +1,353 @@ >> +/** @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 (as long as a >> CSM >> + is not present), conserving 32-bit MMIO aperture for 32-bit BARs. >> + >> + Copyright (C) 2016, Red Hat, Inc. >> + >> + This program and the accompanying materials are licensed and made >> available >> + under the terms and conditions of the BSD License which accompanies this >> + distribution. The full text of the license may be found at >> + http://opensource.org/licenses/bsd-license.php >> + >> + THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, >> WITHOUT >> + WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. >> +**/ >> + >> +#include <IndustryStandard/Acpi10.h> >> +#include <IndustryStandard/Pci22.h> >> + >> +#include <Library/DebugLib.h> >> +#include <Library/MemoryAllocationLib.h> >> +#include <Library/PcdLib.h> >> +#include <Library/UefiBootServicesTableLib.h> >> + >> +#include <Protocol/IncompatiblePciDeviceSupport.h> >> +#include <Protocol/LegacyBios.h> >> + >> +// >> +// The Legacy BIOS protocol has been located. >> +// >> +STATIC BOOLEAN mLegacyBiosInstalled; >> + >> +// >> +// 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. >> +// >> +#pragma pack (1) >> +typedef struct { >> + EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR AddressSpaceDesc; >> + EFI_ACPI_END_TAG_DESCRIPTOR EndDesc; >> +} MMIO64_PREFERENCE; >> +#pragma pack () >> + >> +STATIC CONST MMIO64_PREFERENCE mConfiguration = { >> + // >> + // AddressSpaceDesc >> + // >> + { >> + 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 >> + PCI_ACPI_UNUSED, // GenFlag >> + PCI_ACPI_UNUSED, // SpecificFlag >> + 64, // AddrSpaceGranularity: >> + // aperture selection >> hint >> + // for BAR allocation >> + PCI_ACPI_UNUSED, // AddrRangeMin >> + PCI_BAR_OLD_ALIGN, // AddrRangeMax: >> + // no special alignment >> + // for affected BARs >> + PCI_BAR_ALL, // AddrTranslationOffset: >> + // hint covers all >> + // eligible BARs >> + PCI_BAR_NOCHANGE // AddrLen: >> + // use probed BAR size >> + }, >> + // >> + // EndDesc >> + // >> + { >> + ACPI_END_TAG_DESCRIPTOR, // Desc >> + 0 // Checksum: to be >> ignored >> + } >> +}; >> + >> +// >> +// The CheckDevice() member function has been called. >> +// >> +STATIC BOOLEAN mCheckDeviceCalled; >> + >> + >> +/** >> + Notification callback for Legacy BIOS protocol installation. >> + >> + @param[in] Event Event whose notification function is being invoked. >> + >> + @param[in] Context The pointer to the notification function's context, >> which >> + is implementation-dependent. >> +**/ >> +STATIC >> +VOID >> +EFIAPI >> +LegacyBiosInstalled ( >> + IN EFI_EVENT Event, >> + IN VOID *Context >> + ) >> +{ >> + EFI_STATUS Status; >> + EFI_LEGACY_BIOS_PROTOCOL *LegacyBios; >> + >> + ASSERT (!mCheckDeviceCalled); >> + >> + Status = gBS->LocateProtocol (&gEfiLegacyBiosProtocolGuid, >> + NULL /* Registration */, (VOID **)&LegacyBios); >> + if (EFI_ERROR (Status)) { >> + return; >> + } >> + >> + mLegacyBiosInstalled = TRUE; >> + >> + // >> + // Close the event and deregister this callback. >> + // >> + Status = gBS->CloseEvent (Event); >> + ASSERT_EFI_ERROR (Status); >> +} >> + >> + >> +/** >> + 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 >> + ) >> +{ >> + mCheckDeviceCalled = TRUE; >> + >> + // >> + // 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, if we don't support legacy option ROMs at all, then >> + // this problem cannot arise. >> + // >> + if (mLegacyBiosInstalled) { >> + // >> + // Don't interfere with resource degradation. >> + // >> + *Configuration = NULL; >> + return EFI_SUCCESS; >> + } >> + >> + // >> + // 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. >> + // >> + *Configuration = AllocateCopyPool (sizeof mConfiguration, >> &mConfiguration); >> + if (*Configuration == NULL) { >> + DEBUG ((EFI_D_WARN, >> + "%a: 64-bit MMIO BARs may be degraded for PCI 0x%04x:0x%04x (rev >> %d)\n", >> + __FUNCTION__, (UINT32)VendorId, (UINT32)DeviceId, (UINT8)RevisionId)); >> + return EFI_OUT_OF_RESOURCES; >> + } >> + 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; >> + EFI_EVENT Event; >> + VOID *Registration; >> + >> + // >> + // If the PCI Bus driver is not supposed to allocate resources, then it >> makes >> + // no sense to install a protocol that influences the resource allocation. >> + // >> + // Similarly, if there is no 64-bit PCI MMIO aperture, then 64-bit MMIO >> BARs >> + // have to be allocated under 4 GB unconditionally. >> + // >> + if (PcdGetBool (PcdPciDisableBusEnumeration) || >> + PcdGet64 (PcdPciMmio64Size) == 0) { >> + return EFI_UNSUPPORTED; >> + } >> + >> + // >> + // Otherwise, create a protocol notify to see if a CSM is present. (With >> the >> + // CSM absent, the PCI Bus driver won't have to worry about allocating >> 64-bit >> + // MMIO BARs in the 32-bit MMIO aperture, for the sake of a legacy BIOS.) >> + // >> + // If the Legacy BIOS Protocol is present at the time of this driver >> starting >> + // up, we can mark immediately that the PCI Bus driver should perform the >> + // usual 64-bit MMIO BAR degradation. >> + // >> + // Otherwise, if the Legacy BIOS Protocol is absent at startup, it may be >> + // installed later. However, if it doesn't show up until the first >> + // EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL.CheckDevice() call from >> the >> + // PCI Bus driver, then it never will: >> + // >> + // 1. The following drivers are dispatched in some unspecified order: >> + // - PCI Host Bridge DXE_DRIVER, >> + // - PCI Bus UEFI_DRIVER, >> + // - this DXE_DRIVER, >> + // - Legacy BIOS DXE_DRIVER. >> + // >> + // 2. The DXE_CORE enters BDS. >> + // >> + // 3. The platform BDS connects the PCI Root Bridge IO instances >> (produced by >> + // the PCI Host Bridge DXE_DRIVER). >> + // >> + // 4. The PCI Bus UEFI_DRIVER enumerates resources and calls into this >> + // DXE_DRIVER (CheckDevice()). >> + // >> + // 5. This driver remembers if EFI_LEGACY_BIOS_PROTOCOL has been installed >> + // sometime during step 1 (produced by the Legacy BIOS DXE_DRIVER). >> + // >> + // For breaking this order, the Legacy BIOS DXE_DRIVER would have to >> install >> + // its protocol after the firmware enters BDS, which cannot happen. >> + // >> + Status = gBS->CreateEvent (EVT_NOTIFY_SIGNAL, TPL_CALLBACK, >> + LegacyBiosInstalled, NULL /* Context */, &Event); >> + if (EFI_ERROR (Status)) { >> + return Status; >> + } >> + >> + Status = gBS->RegisterProtocolNotify (&gEfiLegacyBiosProtocolGuid, Event, >> + &Registration); >> + if (EFI_ERROR (Status)) { >> + goto CloseEvent; >> + } >> + >> + Status = gBS->SignalEvent (Event); >> + ASSERT_EFI_ERROR (Status); >> + >> + mIncompatiblePciDeviceSupport.CheckDevice = CheckDevice; >> + Status = gBS->InstallMultipleProtocolInterfaces (&ImageHandle, >> + &gEfiIncompatiblePciDeviceSupportProtocolGuid, >> + &mIncompatiblePciDeviceSupport, NULL); >> + if (EFI_ERROR (Status)) { >> + goto CloseEvent; >> + } >> + >> + return EFI_SUCCESS; >> + >> +CloseEvent: >> + if (!mLegacyBiosInstalled) { >> + EFI_STATUS CloseStatus; >> + >> + CloseStatus = gBS->CloseEvent (Event); >> + ASSERT_EFI_ERROR (CloseStatus); >> + } >> + >> + return Status; >> +} >> -- >> 1.8.3.1 >> >> _______________________________________________ >> edk2-devel mailing list >> [email protected] >> https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
