kernel/linux.git/drivers/pci/hotplug, branch v6.1.124

PCI: cpqphp: Fix PCIBIOS_* return value confusion

2024-12-14T18:53:44+00:00

[ Upstream commit e2226dbc4a4919d9c8bd9293299b532090bdf020 ] Code in and related to PCI_RefinedAccessConfig() has three types of return type confusion: - PCI_RefinedAccessConfig() tests pci_bus_read_config_dword() return value against -1. - PCI_RefinedAccessConfig() returns both -1 and PCIBIOS_* return codes. - Callers of PCI_RefinedAccessConfig() only test for -1. Make PCI_RefinedAccessConfig() return PCIBIOS_* codes consistently and adapt callers accordingly. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Link: https://lore.kernel.org/r/20241022091140.3504-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Signed-off-by: Sasha Levin

PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads

2024-12-14T18:53:44+00:00

[ Upstream commit 87d5403378cccc557af9e02a8a2c8587ad8b7e9a ] Use PCI_POSSIBLE_ERROR() to check the response we get when we read data from hardware. This unifies PCI error response checking and makes error checks consistent and easier to find. Link: https://lore.kernel.org/r/20240806065050.28725-1-412574090@163.com Signed-off-by: weiyufeng Signed-off-by: Bjorn Helgaas Stable-dep-of: e2226dbc4a49 ("PCI: cpqphp: Fix PCIBIOS_* return value confusion") Signed-off-by: Sasha Levin

pci/hotplug/pnv_php: Fix hotplug driver crash on Powernv

2024-09-12T09:10:23+00:00

[ Upstream commit 335e35b748527f0c06ded9eebb65387f60647fda ] The hotplug driver for powerpc (pci/hotplug/pnv_php.c) causes a kernel crash when we try to hot-unplug/disable the PCIe switch/bridge from the PHB. The crash occurs because although the MSI data structure has been released during disable/hot-unplug path and it has been assigned with NULL, still during unregistration the code was again trying to explicitly disable the MSI which causes the NULL pointer dereference and kernel crash. The patch fixes the check during unregistration path to prevent invoking pci_disable_msi/msix() since its data structure is already freed. Reported-by: Timothy Pearson Closes: https://lore.kernel.org/all/1981605666.2142272.1703742465927.JavaMail.zimbra@raptorengineeringinc.com/ Acked-by: Bjorn Helgaas Tested-by: Shawn Anastasio Signed-off-by: Krishna Kumar Signed-off-by: Michael Ellerman Link: https://msgid.link/20240701074513.94873-2-krishnak@linux.ibm.com Signed-off-by: Sasha Levin

Revert "PCI: acpiphp: Reassign resources on bridge if necessary"

2023-12-20T16:00:20+00:00

commit 5df12742b7e3aae2594a30a9d14d5d6e9e7699f4 upstream. This reverts commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 and the subsequent fix to it: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") 40613da52b13 fixed a problem where hot-adding a device with large BARs failed if the bridge windows programmed by firmware were not large enough. cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") fixed a problem with 40613da52b13: an ACPI hot-add of a device on a PCI root bus (common in the virt world) or firmware sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron 7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs. Unfortunately the combination of 40613da52b13 and cc22522fd55e caused other problems: - Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails sometimes. - Dongli reported a similar problem with hot-add of SCSI disks. - Jonathan reported a console freeze during boot on bare metal due to an error in radeon GPU initialization. Revert both patches to avoid adding these problems. This means we will again see the problems with hot-adding devices with large BARs and the NULL pointer dereferences and suspend/resume issues that 40613da52b13 and cc22522fd55e were intended to fix. Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") Fixes: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus") Reported-by: Fiona Ebner Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@proxmox.com Reported-by: Dongli Zhang Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@oracle.com Reported-by: Jonathan Woithe Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au Signed-off-by: Bjorn Helgaas Acked-by: Michael S. Tsirkin Acked-by: Igor Mammedov Cc: Signed-off-by: Greg Kroah-Hartman

PCI: pciehp: Use RMW accessors for changing LNKCTL

2023-09-13T07:42:46+00:00

[ Upstream commit 5f75f96c61039151c193775d776fde42477eace1 ] As hotplug is not the only driver touching LNKCTL, use the RMW capability accessor which handles concurrent changes correctly. Suggested-by: Lukas Wunner Fixes: 7f822999e12a ("PCI: pciehp: Add Disable/enable link functions") Link: https://lore.kernel.org/r/20230717120503.15276-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Acked-by: "Rafael J. Wysocki" Signed-off-by: Sasha Levin

PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus

2023-08-30T14:11:09+00:00

commit cc22522fd55e257c86d340ae9aedc122e705a435 upstream. 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") changed acpiphp hotplug to use pci_assign_unassigned_bridge_resources() which depends on bridge being available, however enable_slot() can be called without bridge associated: 1. Legitimate case of hotplug on root bus (widely used in virt world) 2. A (misbehaving) firmware, that sends ACPI Bus Check notifications to non existing root ports (Dell Inspiron 7352/0W6WV0), which end up at enable_slot(..., bridge = 0) where bus has no bridge assigned to it. acpihp doesn't know that it's a bridge, and bus specific 'PCI subsystem' can't augment ACPI context with bridge information since the PCI device to get this data from is/was not available. Issue is easy to reproduce with QEMU's 'pc' machine, which supports PCI hotplug on hostbridge slots. To reproduce, boot kernel at commit 40613da52b13 in VM started with following CLI (assuming guest root fs is installed on sda1 partition): # qemu-system-x86_64 -M pc -m 1G -enable-kvm -cpu host \ -monitor stdio -serial file:serial.log \ -kernel arch/x86/boot/bzImage \ -append "root=/dev/sda1 console=ttyS0" \ guest_disk.img Once guest OS is fully booted at qemu prompt: (qemu) device_add e1000 (check serial.log) it will cause NULL pointer dereference at: void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge) { struct pci_bus *parent = bridge->subordinate; BUG: kernel NULL pointer dereference, address: 0000000000000018 ? pci_assign_unassigned_bridge_resources+0x1f/0x260 enable_slot+0x21f/0x3e0 acpiphp_hotplug_notify+0x13d/0x260 acpi_device_hotplug+0xbc/0x540 acpi_hotplug_work_fn+0x15/0x20 process_one_work+0x1f7/0x370 worker_thread+0x45/0x3b0 The issue was discovered on Dell Inspiron 7352/0W6WV0 laptop with following sequence: 1. Suspend to RAM 2. Wake up with the same backtrace being observed: 3. 2nd suspend to RAM attempt makes laptop freeze Fix it by using __pci_bus_assign_resources() instead of pci_assign_unassigned_bridge_resources() as we used to do, but only in case when bus doesn't have a bridge associated (to cover for the case of ACPI event on hostbridge or non existing root port). That lets us keep hotplug on root bus working like it used to and at the same time keeps resource reassignment usable on root ports (and other 1st level bridges) that was fixed by 40613da52b13. Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary") Link: https://lore.kernel.org/r/20230726123518.2361181-2-imammedo@redhat.com Reported-by: Woody Suwalski Tested-by: Woody Suwalski Tested-by: Michal Koutný Link: https://lore.kernel.org/r/11fc981c-af49-ce64-6b43-3e282728bd1a@gmail.com Signed-off-by: Igor Mammedov Signed-off-by: Bjorn Helgaas Acked-by: Rafael J. Wysocki Acked-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

PCI: acpiphp: Reassign resources on bridge if necessary

2023-08-30T14:10:58+00:00

[ Upstream commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 ] When using ACPI PCI hotplug, hotplugging a device with large BARs may fail if bridge windows programmed by firmware are not large enough. Reproducer: $ qemu-kvm -monitor stdio -M q35 -m 4G \ -global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=on \ -device id=rp1,pcie-root-port,bus=pcie.0,chassis=4 \ disk_image wait till linux guest boots, then hotplug device: (qemu) device_add qxl,bus=rp1 hotplug on guest side fails with: pci 0000:01:00.0: [1b36:0100] type 00 class 0x038000 pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x03ffffff] pci 0000:01:00.0: reg 0x14: [mem 0x00000000-0x03ffffff] pci 0000:01:00.0: reg 0x18: [mem 0x00000000-0x00001fff] pci 0000:01:00.0: reg 0x1c: [io 0x0000-0x001f] pci 0000:01:00.0: BAR 0: no space for [mem size 0x04000000] pci 0000:01:00.0: BAR 0: failed to assign [mem size 0x04000000] pci 0000:01:00.0: BAR 1: no space for [mem size 0x04000000] pci 0000:01:00.0: BAR 1: failed to assign [mem size 0x04000000] pci 0000:01:00.0: BAR 2: assigned [mem 0xfe800000-0xfe801fff] pci 0000:01:00.0: BAR 3: assigned [io 0x1000-0x101f] qxl 0000:01:00.0: enabling device (0000 -> 0003) Unable to create vram_mapping qxl: probe of 0000:01:00.0 failed with error -12 However when using native PCIe hotplug '-global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off' it works fine, since kernel attempts to reassign unused resources. Use the same machinery as native PCIe hotplug to (re)assign resources. Link: https://lore.kernel.org/r/20230424191557.2464760-1-imammedo@redhat.com Signed-off-by: Igor Mammedov Signed-off-by: Bjorn Helgaas Acked-by: Michael S. Tsirkin Acked-by: Rafael J. Wysocki Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin

PCI: pciehp: Cancel bringup sequence if card is not present

2023-07-19T14:21:35+00:00

[ Upstream commit e8afd0d9fccc27c8ad263db5cf5952cfcf72d6fe ] If a PCIe hotplug slot has an Attention Button, the normal hot-add flow is: - Slot is empty and slot power is off - User inserts card in slot and presses Attention Button - OS blinks Power Indicator for 5 seconds - After 5 seconds, OS turns on Power Indicator, turns on slot power, and enumerates the device Previously, if a user pressed the Attention Button on an *empty* slot, pciehp logged the following messages and blinked the Power Indicator until a second button press: [0.000] pciehp: Button press: will power on in 5 sec [0.001] # Power Indicator starts blinking [5.001] # 5 second timeout; slot is empty, so we should cancel the request to power on and turn off Power Indicator [7.000] # Power Indicator still blinking [8.000] # possible card insertion [9.000] pciehp: Button press: canceling request to power on The first button press incorrectly left the slot in BLINKINGON_STATE, so the second was interpreted as a "cancel power on" event regardless of whether a card was present. If the slot is empty, turn off the Power Indicator and return from BLINKINGON_STATE to OFF_STATE after 5 seconds, effectively canceling the request to power on. Putting the slot in OFF_STATE also means the second button press will correctly request a slot power on if the slot is occupied. [bhelgaas: commit log] Link: https://lore.kernel.org/r/20230512021518.336460-1-clementwei90@163.com Fixes: d331710ea78f ("PCI: pciehp: Become resilient to missed events") Suggested-by: Lukas Wunner Signed-off-by: Rongguang Wei Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner Signed-off-by: Sasha Levin

PCI: pciehp: Fix AB-BA deadlock between reset_lock and device_lock

2023-05-11T14:02:59+00:00

commit f5eff5591b8f9c5effd25c92c758a127765f74c1 upstream. In 2013, commits 2e35afaefe64 ("PCI: pciehp: Add reset_slot() method") 608c388122c7 ("PCI: Add slot reset option to pci_dev_reset()") amended PCIe hotplug to mask Presence Detect Changed events during a Secondary Bus Reset. The reset thus no longer causes gratuitous slot bringdown and bringup. However the commits neglected to serialize reset with code paths reading slot registers. For instance, a slot bringup due to an earlier hotplug event may see the Presence Detect State bit cleared during a concurrent Secondary Bus Reset. In 2018, commit 5b3f7b7d062b ("PCI: pciehp: Avoid slot access during reset") retrofitted the missing locking. It introduced a reset_lock which serializes a Secondary Bus Reset with other parts of pciehp. Unfortunately the locking turns out to be overzealous: reset_lock is held for the entire enumeration and de-enumeration of hotplugged devices, including driver binding and unbinding. Driver binding and unbinding acquires device_lock while the reset_lock of the ancestral hotplug port is held. A concurrent Secondary Bus Reset acquires the ancestral reset_lock while already holding the device_lock. The asymmetric locking order in the two code paths can lead to AB-BA deadlocks. Michael Haeuptle reports such deadlocks on simultaneous hot-removal and vfio release (the latter implies a Secondary Bus Reset): pciehp_ist() # down_read(reset_lock) pciehp_handle_presence_or_link_change() pciehp_disable_slot() __pciehp_disable_slot() remove_board() pciehp_unconfigure_device() pci_stop_and_remove_bus_device() pci_stop_bus_device() pci_stop_dev() device_release_driver() device_release_driver_internal() __device_driver_lock() # device_lock() SYS_munmap() vfio_device_fops_release() vfio_device_group_close() vfio_device_close() vfio_device_last_close() vfio_pci_core_close_device() vfio_pci_core_disable() # device_lock() __pci_reset_function_locked() pci_reset_bus_function() pci_dev_reset_slot_function() pci_reset_hotplug_slot() pciehp_reset_slot() # down_write(reset_lock) Ian May reports the same deadlock on simultaneous hot-removal and an AER-induced Secondary Bus Reset: aer_recover_work_func() pcie_do_recovery() aer_root_reset() pci_bus_error_reset() pci_slot_reset() pci_slot_lock() # device_lock() pci_reset_hotplug_slot() pciehp_reset_slot() # down_write(reset_lock) Fix by releasing the reset_lock during driver binding and unbinding, thereby splitting and shrinking the critical section. Driver binding and unbinding is protected by the device_lock() and thus serialized with a Secondary Bus Reset. There's no need to additionally protect it with the reset_lock. However, pciehp does not bind and unbind devices directly, but rather invokes PCI core functions which also perform certain enumeration and de-enumeration steps. The reset_lock's purpose is to protect slot registers, not enumeration and de-enumeration of hotplugged devices. That would arguably be the job of the PCI core, not the PCIe hotplug driver. After all, an AER-induced Secondary Bus Reset may as well happen during boot-time enumeration of the PCI hierarchy and there's no locking to prevent that either. Exempting *de-enumeration* from the reset_lock is relatively harmless: A concurrent Secondary Bus Reset may foil config space accesses such as PME interrupt disablement. But if the device is physically gone, those accesses are pointless anyway. If the device is physically present and only logically removed through an Attention Button press or the sysfs "power" attribute, PME interrupts as well as DMA cannot come through because pciehp_unconfigure_device() disables INTx and Bus Master bits. That's still protected by the reset_lock in the present commit. Exempting *enumeration* from the reset_lock also has limited impact: The exempted call to pci_bus_add_device() may perform device accesses through pcibios_bus_add_device() and pci_fixup_device() which are now no longer protected from a concurrent Secondary Bus Reset. Otherwise there should be no impact. In essence, the present commit seeks to fix the AB-BA deadlocks while still retaining a best-effort reset protection for enumeration and de-enumeration of hotplugged devices -- until a general solution is implemented in the PCI core. Link: https://lore.kernel.org/linux-pci/CS1PR8401MB0728FC6FDAB8A35C22BD90EC95F10@CS1PR8401MB0728.NAMPRD84.PROD.OUTLOOK.COM Link: https://lore.kernel.org/linux-pci/20200615143250.438252-1-ian.may@canonical.com Link: https://lore.kernel.org/linux-pci/ce878dab-c0c4-5bd0-a725-9805a075682d@amd.com Link: https://lore.kernel.org/linux-pci/ed831249-384a-6d35-0831-70af191e9bce@huawei.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=215590 Fixes: 5b3f7b7d062b ("PCI: pciehp: Avoid slot access during reset") Link: https://lore.kernel.org/r/fef2b2e9edf245c049a8c5b94743c0f74ff5008a.1681191902.git.lukas@wunner.de Reported-by: Michael Haeuptle Reported-by: Ian May Reported-by: Andrey Grodzovsky Reported-by: Rahul Kumar Reported-by: Jialin Zhang Tested-by: Anatoli Antonovitch Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v4.19+ Cc: Dan Stein Cc: Ashok Raj Cc: Alex Michon Cc: Xiongfeng Wang Cc: Alex Williamson Cc: Mika Westerberg Cc: Sathyanarayanan Kuppuswamy Signed-off-by: Greg Kroah-Hartman

PCI: pciehp: Add Qualcomm quirk for Command Completed erratum

2023-03-11T12:55:40+00:00

[ Upstream commit 82b34b0800af8c9fc9988c290cdc813e0ca0df31 ] The Qualcomm PCI bridge device (Device ID 0x010e) found in chipsets such as SC8280XP used in Lenovo Thinkpad X13s, does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. This results in timeouts like below during boot and resume from suspend: pcieport 0002:00:00.0: pciehp: Timeout on hotplug command 0x03c0 (issued 2020 msec ago) ... pcieport 0002:00:00.0: pciehp: Timeout on hotplug command 0x13f1 (issued 107724 msec ago) Add the device to the Command Completed quirk to mark commands "completed" immediately unless they change the "Control" bits. Link: https://lore.kernel.org/r/20230213144922.89982-1-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Signed-off-by: Sasha Levin