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A PCI bridge may reside on a bus with other devices as well. The resource distribution code does not take this into account and therefore it expands the bridge resource windows too much, not leaving space for the other devices (or functions of a multifunction device). This leads to an issue that Jonathan reported when running QEMU with the following topology (QEMU parameters): -device pcie-root-port,port=0,id=root_port13,chassis=0,slot=2 \ -device x3130-upstream,id=sw1,bus=root_port13,multifunction=on \ -device e1000,bus=root_port13,addr=0.1 \ -device xio3130-downstream,id=fun1,bus=sw1,chassis=0,slot=3 \ -device e1000,bus=fun1 The first e1000 NIC here is another function in the switch upstream port. This leads to following errors: pci 0000:00:04.0: bridge window [mem 0x10200000-0x103fffff] to [bus 02-04] pci 0000:02:00.0: bridge window [mem 0x10200000-0x103fffff] to [bus 03-04] pci 0000:02:00.1: BAR 0: failed to assign [mem size 0x00020000] e1000 0000:02:00.1: can't ioremap BAR 0: [??? 0x00000000 flags 0x0] Fix this by taking into account bridge windows, device BARs and SR-IOV PF BARs on the bus (PF BARs include space for VF BARS so only account PF BARs), including the ones belonging to bridges themselves if it has any. Link: https://lore.kernel.org/linux-pci/20221014124553.0000696f@huawei.com/ Link: https://lore.kernel.org/linux-pci/6053736d-1923-41e7-def9-7585ce1772d9@ixsystems.com/ Link: https://lore.kernel.org/r/20230131092405.29121-3-mika.westerberg@linux.intel.com Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reported-by: Alexander Motin <mav@ixsystems.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>