Mika Westerberg bf1ab09d2c PCI: Take other bus devices into account when distributing resources
[ Upstream commit 9db0b9b6a1 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-11 13:55:38 +01:00
2023-03-11 13:55:35 +01:00
2022-09-28 09:02:20 +02:00
2022-09-28 09:02:20 +02:00
2023-03-11 11:03:45 +01:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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