kernel/linux.git/drivers/pci/setup-res.c, branch v6.12.91

PCI: Update saved_config_space upon resource assignment

2026-05-14T13:29:25+00:00

commit 909f7bf9b080c10df3c3b38533906dbf09ff1d8b upstream. Bernd reports passthrough failure of a Digital Devices Cine S2 V6 DVB adapter plugged into an ASRock X570S PG Riptide board with BIOS version P5.41 (09/07/2023): ddbridge 0000:05:00.0: detected Digital Devices Cine S2 V6 DVB adapter ddbridge 0000:05:00.0: cannot read registers ddbridge 0000:05:00.0: fail BIOS assigns an incorrect BAR to the DVB adapter which doesn't fit into the upstream bridge window. The kernel corrects the BAR assignment: pci 0000:07:00.0: BAR 0 [mem 0xfffffffffc500000-0xfffffffffc50ffff 64bit]: can't claim; no compatible bridge window pci 0000:07:00.0: BAR 0 [mem 0xfc500000-0xfc50ffff 64bit]: assigned Correction of the BAR assignment happens in an x86-specific fs_initcall, pcibios_assign_resources(), after device enumeration in a subsys_initcall. This order was introduced at the behest of Linus in 2004: https://git.kernel.org/tglx/history/c/a06a30144bbc No other architecture performs such a late BAR correction. Bernd bisected the issue to commit a2f1e22390ac ("PCI/ERR: Ensure error recoverability at all times"), but it only occurs in the absence of commit 4d4c10f763d7 ("PCI: Explicitly put devices into D0 when initializing"). This combination exists in stable kernel v6.12.70, but not in mainline, hence Bernd cannot reproduce the issue with mainline. Since a2f1e22390ac, config space is saved on enumeration, prior to BAR correction. Upon passthrough, the corrected BAR is overwritten with the incorrect saved value by: vfio_pci_core_register_device() vfio_pci_set_power_state() pci_restore_state() But only if the device's current_state is PCI_UNKNOWN, as it was prior to commit 4d4c10f763d7. Since the commit, it is PCI_D0, which changes the behavior of vfio_pci_set_power_state() to no longer restore the state without saving it first. Alexandre is reporting the same issue as Bernd, but in his case, mainline is affected as well. The difference is that on Alexandre's system, the host kernel binds a driver to the device which is unbound prior to passthrough, whereas on Bernd's system no driver gets bound by the host kernel. Unbinding sets current_state to PCI_UNKNOWN in pci_device_remove(), so when vfio-pci is subsequently bound to the device, pci_restore_state() is once again called without invoking pci_save_state() first. To robustly fix the issue, always update saved_config_space upon resource assignment. Reported-by: Bernd Schumacher Closes: https://lore.kernel.org/r/acfZrlP0Ua_5D3U4@eldamar.lan/ Reported-by: Alexandre N. Closes: https://lore.kernel.org/r/dd3c3358-de0f-4a56-9c81-04aceaab4058@mailo.com/ Fixes: a2f1e22390ac ("PCI/ERR: Ensure error recoverability at all times") Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Tested-by: Bernd Schumacher Tested-by: Alexandre N. Cc: stable@vger.kernel.org # v6.12+ Link: https://patch.msgid.link/febc3f354e0c1f5a9f5b3ee9ffddaa44caccf651.1776268054.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman

PCI: Use resource names in PCI log messages

2023-12-15T23:28:42+00:00

Use the pci_resource_name() to get the name of the resource and use it while printing log messages. [bhelgaas: rename to match struct resource * names, also use names in other BAR messages] Link: https://lore.kernel.org/r/20211106112606.192563-3-puranjay12@gmail.com Signed-off-by: Puranjay Mohan Signed-off-by: Bjorn Helgaas

PCI: Fix printk field formatting

2023-08-25T13:15:08+00:00

Previously we used "%#08x" to print a 32-bit value. This fills an 8-character field with "0x...", but of course many 32-bit values require a 10-character field "0x12345678" for this format. Fix the formats to avoid confusion. Link: https://lore.kernel.org/r/20230824193712.542167-5-helgaas@kernel.org Signed-off-by: Bjorn Helgaas Reviewed-by: Ilpo Järvinen

PCI: Introduce pci_dev_for_each_resource()

2023-04-04T15:43:52+00:00

Instead of open-coding it everywhere introduce a tiny helper that can be used to iterate over each resource of a PCI device, and convert the most obvious users into it. While at it drop doubled empty line before pdev_sort_resources(). No functional changes intended. Suggested-by: Andy Shevchenko Link: https://lore.kernel.org/r/20230330162434.35055-4-andriy.shevchenko@linux.intel.com Signed-off-by: Mika Westerberg Signed-off-by: Andy Shevchenko Signed-off-by: Bjorn Helgaas Reviewed-by: Krzysztof Wilczyński

PCI: Sanitise firmware BAR assignments behind a PCI-PCI bridge

2022-09-21T22:52:47+00:00

When pci_assign_resource() is unable to assign resources to a BAR, it uses pci_revert_fw_address() to fall back to a firmware assignment (if any). Previously pci_revert_fw_address() assumed all addresses could reach the device, but this is not true if the device is below a bridge that only forwards addresses within its windows. This problem was observed on a Tyan Tomcat IV S1564D system where the BIOS did not assign valid addresses to several bridges and USB devices: pci 0000:00:11.0: PCI-to-PCIe bridge to [bus 01-ff] pci 0000:00:11.0: bridge window [io 0xe000-0xefff] pci 0000:01:00.0: PCIe Upstream Port to [bus 02-ff] pci 0000:01:00.0: bridge window [io 0x0000-0x0fff] # unreachable pci 0000:02:02.0: PCIe Downstream Port to [bus 05-ff] pci 0000:02:02.0: bridge window [io 0x0000-0x0fff] # unreachable pci 0000:05:00.0: PCIe-to-PCI bridge to [bus 06-ff] pci 0000:05:00.0: bridge window [io 0x0000-0x0fff] # unreachable pci 0000:06:08.0: USB UHCI 1.1 pci 0000:06:08.0: BAR 4: [io 0xfce0-0xfcff] # unreachable pci 0000:06:08.1: USB UHCI 1.1 pci 0000:06:08.1: BAR 4: [io 0xfce0-0xfcff] # unreachable pci 0000:06:08.0: can't claim BAR 4 [io 0xfce0-0xfcff]: no compatible bridge window pci 0000:06:08.1: can't claim BAR 4 [io 0xfce0-0xfcff]: no compatible bridge window During the first pass of assigning unassigned resources, there was not enough I/O space available, so we couldn't assign the 06:08.0 BAR and reverted to the firmware assignment (still unreachable). Reverting the 06:08.1 assignment failed because it conflicted with 06:08.0: pci 0000:00:11.0: bridge window [io 0xe000-0xefff] pci 0000:01:00.0: no space for bridge window [io size 0x2000] pci 0000:02:02.0: no space for bridge window [io size 0x1000] pci 0000:05:00.0: no space for bridge window [io size 0x1000] pci 0000:06:08.0: BAR 4: no space for [io size 0x0020] pci 0000:06:08.0: BAR 4: trying firmware assignment [io 0xfce0-0xfcff] pci 0000:06:08.1: BAR 4: no space for [io size 0x0020] pci 0000:06:08.1: BAR 4: trying firmware assignment [io 0xfce0-0xfcff] pci 0000:06:08.1: BAR 4: [io 0xfce0-0xfcff] conflicts with 0000:06:08.0 [io 0xfce0-0xfcff] A subsequent pass assigned valid bridge windows and a valid 06:08.1 BAR, but left the 06:08.0 BAR alone, so the UHCI device was still unusable: pci 0000:00:11.0: bridge window [io 0xe000-0xefff] released pci 0000:00:11.0: bridge window [io 0x1000-0x2fff] # reassigned pci 0000:01:00.0: bridge window [io 0x1000-0x2fff] # reassigned pci 0000:02:02.0: bridge window [io 0x2000-0x2fff] # reassigned pci 0000:05:00.0: bridge window [io 0x2000-0x2fff] # reassigned pci 0000:06:08.0: BAR 4: assigned [io 0xfce0-0xfcff] # left alone pci 0000:06:08.1: BAR 4: assigned [io 0x2000-0x201f] ... uhci_hcd 0000:06:08.0: host system error, PCI problems? uhci_hcd 0000:06:08.0: host controller process error, something bad happened! uhci_hcd 0000:06:08.0: host controller halted, very bad! uhci_hcd 0000:06:08.0: HCRESET not completed yet! uhci_hcd 0000:06:08.0: HC died; cleaning up If the address assigned by firmware is not reachable because it's not within upstream bridge windows, fail instead of assigning the unusable address from firmware. [bhelgaas: commit log, use pci_upstream_bridge()] Link: https://bugzilla.kernel.org/show_bug.cgi?id=16263 Link: https://lore.kernel.org/r/alpine.DEB.2.21.2203012338460.46819@angie.orcam.me.uk Link: https://lore.kernel.org/r/alpine.DEB.2.21.2209211921250.29493@angie.orcam.me.uk Fixes: 58c84eda0756 ("PCI: fall back to original BIOS BAR addresses") Signed-off-by: Maciej W. Rozycki Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v2.6.35+

PCI: Work around Intel I210 ROM BAR overlap defect

2022-01-11T15:33:10+00:00

Per PCIe r5, sec 7.5.1.2.4, a device must not claim accesses to its Expansion ROM unless both the Memory Space Enable and the Expansion ROM Enable bit are set. But apparently some Intel I210 NICs don't work correctly if the ROM BAR overlaps another BAR, even if the Expansion ROM is disabled. Michael reported that on a Kontron SMARC-sAL28 ARM64 system with U-Boot v2021.01-rc3, the ROM BAR overlaps BAR 3, and networking doesn't work at all: BAR 0: 0x40000000 (32-bit, non-prefetchable) [size=1M] BAR 3: 0x40200000 (32-bit, non-prefetchable) [size=16K] ROM: 0x40200000 (disabled) [size=1M] NETDEV WATCHDOG: enP2p1s0 (igb): transmit queue 0 timed out Hardware name: Kontron SMARC-sAL28 (Single PHY) on SMARC Eval 2.0 carrier (DT) igb 0002:01:00.0 enP2p1s0: Reset adapter Previously, pci_std_update_resource() wrote the assigned ROM address to the BAR only when the ROM was enabled. This meant that the I210 ROM BAR could be left with an address assigned by firmware, which might overlap with other BARs. Quirk these I210 devices so pci_std_update_resource() always writes the assigned address to the ROM BAR, whether or not the ROM is enabled. Link: https://lore.kernel.org/r/20211223163754.GA1267351@bhelgaas Link: https://lore.kernel.org/r/20201230185317.30915-1-michael@walle.cc Link: https://bugzilla.kernel.org/show_bug.cgi?id=211105 Reported-by: Michael Walle Tested-by: Michael Walle Signed-off-by: Bjorn Helgaas

PCI: Decline to resize resources if boot config must be preserved

2021-01-12T22:39:52+00:00

The _DSM #5 method in the ACPI host bridge object tells us whether the OS must preserve the resource assignments done by firmware. If this is the case, we should not permit drivers to resize BARs on the fly. Make pci_resize_resource() take this into account. Link: https://lore.kernel.org/r/20210109095353.13417-1-ardb@kernel.org Signed-off-by: Ard Biesheuvel Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v5.4+

PCI: Replace lkml.org, spinics, gmane with lore.kernel.org

2020-06-30T18:05:16+00:00

The lkml.org, spinics.net, and gmane.org archives are not very reliable and, in some cases, not even easily accessible. Replace links to them with links to lore.kernel.org, the archives hosted by kernel.org. I found the gmane items via the Wayback Machine archive at https://web.archive.org/. Signed-off-by: Bjorn Helgaas

PCI: Allow pci_resize_resource() for devices on root bus

2020-05-01T17:28:35+00:00

When resizing a BAR, pci_reassign_bridge_resources() is invoked to bring the bridge windows of parent bridges in line with the new BAR assignment. This assumes the device whose BAR is being resized lives on a subordinate bus, but this is not necessarily the case. A device may live on the root bus, in which case dev->bus->self is NULL, and passing a NULL pci_dev pointer to pci_reassign_bridge_resources() will cause it to crash. So let's make the call to pci_reassign_bridge_resources() conditional on whether dev->bus->self is non-NULL in the first place. Fixes: 8bb705e3e79d84e7 ("PCI: Add pci_resize_resource() for resizing BARs") Link: https://lore.kernel.org/r/20200421162256.26887-1-ardb@kernel.org Signed-off-by: Ard Biesheuvel Signed-off-by: Bjorn Helgaas Reviewed-by: Christian König

PCI: Remove messages about reassigning resources

2018-04-11T13:46:50+00:00

When reassigning device resources to increase their alignment, e.g., because of a "pci=resource_alignment=" kernel parameter or because the platform aligns resources to its page size, we previously emitted messages like this: pci 0000:00:00.0: Disabling memory decoding and releasing memory resources pci 0000:00:00.0: disabling bridge mem windows These messages don't convey any useful information, so remove them. Fixes: 38274637699 ("powerpc/powernv: Override pcibios_default_alignment() to force PCI devices to be page aligned") Signed-off-by: Desnes A. Nunes do Rosario [bhelgaas: changelog] Signed-off-by: Bjorn Helgaas