Currently we allocate IO BARs bottom-up in the EfiPciHostBridgeAllocateResources phase of the enumeration.
> GCD:AddIoSpace(Base=0000000000000000,Length=0000000000010000) > GcdIoType = I/O > Status = Success > GCDIoType Range > ========== ================================= > I/O 0000000000000000-000000000000FFFF Because the IO aperture is based at zero, the first allocation happens to get the zero address. However, a zero address for a PCI BAR is considered unmapped; see eg.: - <http://www.pcisig.com/reflector/msg00459.html>, - the (new_addr == 0) part in QEMU, pci_bar_address() [hw/pci/pci.c]: new_addr = pci_get_long(d->config + bar) & ~(size - 1); last_addr = new_addr + size - 1; /* Check if 32 bit BAR wraps around explicitly. * TODO: make priorities correct and remove this work around. */ if (last_addr <= new_addr || new_addr == 0 || last_addr >= UINT32_MAX) { return PCI_BAR_UNMAPPED; } We can avoid this problem by allocating top-down in the IO aperture. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek <[email protected]> --- ArmPlatformPkg/ArmVirtualizationPkg/PciHostBridgeDxe/PciHostBridge.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/ArmPlatformPkg/ArmVirtualizationPkg/PciHostBridgeDxe/PciHostBridge.c b/ArmPlatformPkg/ArmVirtualizationPkg/PciHostBridgeDxe/PciHostBridge.c index 973735a..635ecaa 100644 --- a/ArmPlatformPkg/ArmVirtualizationPkg/PciHostBridgeDxe/PciHostBridge.c +++ b/ArmPlatformPkg/ArmVirtualizationPkg/PciHostBridgeDxe/PciHostBridge.c @@ -382,8 +382,9 @@ NotifyPhase( BitsOfAlignment = 0; } + BaseAddress = mResAperture[0][0].IoLimit; Status = gDS->AllocateIoSpace ( - EfiGcdAllocateAnySearchBottomUp, + EfiGcdAllocateMaxAddressSearchTopDown, EfiGcdIoTypeIo, BitsOfAlignment, AddrLen, -- 1.8.3.1 ------------------------------------------------------------------------------ Dive into the World of Parallel Programming. The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ edk2-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/edk2-devel
