From 02b9a8343ffce442195ae8569b4a35424242e67e Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Sat, 28 Apr 2018 23:23:10 +0200 Subject: OvmfPkg: introduce PciCapPciIoLib Add a library class, and a UEFI_DRIVER lib instance, that are layered on top of PciCapLib, and allow clients to plug an EFI_PCI_IO_PROTOCOL backend into PciCapLib, for config space access. (Side note: Although the UEFI spec says that EFI_PCI_IO_PROTOCOL_CONFIG() returns EFI_UNSUPPORTED if "[t]he address range specified by Offset, Width, and Count is not valid for the PCI configuration header of the PCI controller", this patch doesn't directly document the EFI_UNSUPPORTED error code, for ProtoDevTransferConfig() and its callers ProtoDevReadConfig() and ProtoDevWriteConfig(). Instead, the patch refers to "unspecified error codes". The reason is that in edk2, the PciIoConfigRead() and PciIoConfigWrite() functions [1] can also return EFI_INVALID_PARAMETER for the above situation. Namely, PciIoConfigRead() and PciIoConfigWrite() first call PciIoVerifyConfigAccess(), which indeed produces the standard EFI_UNSUPPORTED error code, if the device's config space is exceeded. However, if PciIoVerifyConfigAccess() passes, and we reach RootBridgeIoPciRead() and RootBridgeIoPciWrite() [2], then RootBridgeIoCheckParameter() can still fail, e.g. if the root bridge doesn't support extended config space (see commit 014b472053ae3). For all kinds of Limit violations in IO, MMIO, and config space, RootBridgeIoCheckParameter() returns EFI_INVALID_PARAMETER, not EFI_UNSUPPORTED. That error code is then propagated up to, and out of, PciIoConfigRead() and PciIoConfigWrite(). [1] MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c [2] MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c ) Cc: Ard Biesheuvel Cc: Jordan Justen Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek Reviewed-by: Ard Biesheuvel --- OvmfPkg/OvmfPkg.dec | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'OvmfPkg/OvmfPkg.dec') diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec index fbec1cfe4a..dc5597db41 100644 --- a/OvmfPkg/OvmfPkg.dec +++ b/OvmfPkg/OvmfPkg.dec @@ -35,6 +35,11 @@ # config space. PciCapLib|Include/Library/PciCapLib.h + ## @libraryclass Layered on top of PciCapLib, allows clients to plug an + # EFI_PCI_IO_PROTOCOL backend into PciCapLib, for config + # space access. + PciCapPciIoLib|Include/Library/PciCapPciIoLib.h + ## @libraryclass Layered on top of PciCapLib, allows clients to plug a # PciSegmentLib backend into PciCapLib, for config space # access. -- cgit v1.2.3