kernel/drivers/pci/hotplug/acpiphp_glue.c, branch linux-6.5.y

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

2023-08-08T19:30:00Z

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

PCI: acpiphp: Reassign resources on bridge if necessary

2023-05-24T16:53:41Z

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

PCI: acpiphp: Avoid setting is_hotplug_bridge for PCIe Upstream Ports

2022-11-22T19:27:28Z

It is reported that on some systems pciehp binds to an Upstream Port and attempts to operate it which causes devices below the Port to disappear from the bus. This happens because acpiphp sets dev->is_hotplug_bridge for that Port (after receiving a Device Check notification on it from the platform firmware via ACPI) during the enumeration of PCI devices. get_port_device_capability() sees that dev->is_hotplug_bridge is set and adds PCIE_PORT_SERVICE_HP to Port services, which allows pciehp to bind to the Port in question. Even though this particular problem can be addressed by making the portdrv_core checks more robust, it also causes power management to work differently on the affected systems which generally is not desirable (PCIe Ports with dev->is_hotplug_bridge set have to pass additional tests to be allowed to go into the D3hot/cold power states which affects runtime PM of devices below these Ports). For this reason, amend check_hotplug_bridge() with a PCIe type check to prevent it from setting dev->is_hotplug_bridge for Upstream Ports. Suggested-by: Lukas Wunner Link: https://lore.kernel.org/r/2262230.ElGaqSPkdT@kreacher Reported-by: Rodrigo Vivi Tested-by: Rodrigo Vivi Signed-off-by: Rafael J. Wysocki Signed-off-by: Bjorn Helgaas Reviewed-by: Rodrigo Vivi Reviewed-by: Lukas Wunner

PCI/ACPI: Replace acpi_bus_get_device() with acpi_fetch_acpi_dev()

2022-02-04T23:10:44Z

Replace acpi_bus_get_device() that is going to be dropped with acpi_fetch_acpi_dev(). No intentional functional impact. Link: https://lore.kernel.org/r/11930209.O9o76ZdvQC@kreacher Signed-off-by: Rafael J. Wysocki Signed-off-by: Bjorn Helgaas Reviewed-by: Mika Westerberg

PCI: Correct misspelled and remove duplicated words

2021-10-08T22:14:04Z

Correct a number of misspelled words and remove any words that were duplicated in the PCI tree. No change to functionality intended. Link: https://lore.kernel.org/r/20211006233827.147328-1-kw@linux.com Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas

ACPI / hotplug / PCI: Fix reference count leak in enable_slot()

2021-04-08T16:04:18Z

In enable_slot(), if pci_get_slot() returns NULL, we clear the SLOT_ENABLED flag. When pci_get_slot() finds a device, it increments the device's reference count. In this case, we did not call pci_dev_put() to decrement the reference count, so the memory of the device (struct pci_dev type) will eventually leak. Call pci_dev_put() to decrement its reference count when pci_get_slot() returns a PCI device. Link: https://lore.kernel.org/r/b411af88-5049-a1c6-83ac-d104a1f429be@huawei.com Signed-off-by: Feilong Lin Signed-off-by: Zhiqiang Liu Signed-off-by: Bjorn Helgaas Reviewed-by: Rafael J. Wysocki

PCI: hotplug: ACPI: Fix context refcounting in acpiphp_grab_context()

2020-06-26T17:42:34Z

If context is not NULL in acpiphp_grab_context(), but the is_going_away flag is set for the device's parent, the reference counter of the context needs to be decremented before returning NULL or the context will never be freed, so make that happen. Fixes: edf5bf34d408 ("ACPI / dock: Use callback pointers from devices' ACPI hotplug contexts") Reported-by: Vasily Averin Cc: 3.15+ # 3.15+ Signed-off-by: Rafael J. Wysocki

ACPI: hotplug: PCI: Use the new acpi_evaluate_reg() helper

2020-05-09T09:40:25Z

Use the new acpi_evaluate_reg() helper in the acpiphp_glue.c code. Acked-by: Bjorn Helgaas Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI / hotplug / PCI: Allocate resources directly under the non-hotplug bridge

2019-11-13T23:01:59Z

Valerio and others reported that commit 84c8b58ed3ad ("ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug") prevents some recent LG and HP laptops from booting with endless loop of: ACPI Error: No handler or method for GPE 08, disabling event (20190215/evgpe-835) ACPI Error: No handler or method for GPE 09, disabling event (20190215/evgpe-835) ACPI Error: No handler or method for GPE 0A, disabling event (20190215/evgpe-835) ... What seems to happen is that during boot, after the initial PCI enumeration when EC is enabled the platform triggers ACPI Notify() to one of the root ports. The root port itself looks like this: pci 0000:00:1b.0: PCI bridge to [bus 02-3a] pci 0000:00:1b.0: bridge window [mem 0xc4000000-0xda0fffff] pci 0000:00:1b.0: bridge window [mem 0x80000000-0xa1ffffff 64bit pref] The BIOS has configured the root port so that it does not have I/O bridge window. Now when the ACPI Notify() is triggered ACPI hotplug handler calls acpiphp_native_scan_bridge() for each non-hotplug bridge (as this system is using native PCIe hotplug) and pci_assign_unassigned_bridge_resources() to allocate resources. The device connected to the root port is a PCIe switch (Thunderbolt controller) with two hotplug downstream ports. Because of the hotplug ports __pci_bus_size_bridges() tries to add "additional I/O" of 256 bytes to each (DEFAULT_HOTPLUG_IO_SIZE). This gets further aligned to 4k as that's the minimum I/O window size so each hotplug port gets 4k I/O window and the same happens for the root port (which is also hotplug port). This means 3 * 4k = 12k I/O window. Because of this pci_assign_unassigned_bridge_resources() ends up opening a I/O bridge window for the root port at first available I/O address which seems to be in range 0x1000 - 0x3fff. Normally this range is used for ACPI stuff such as GPE bits (below is part of /proc/ioports): 1800-1803 : ACPI PM1a_EVT_BLK 1804-1805 : ACPI PM1a_CNT_BLK 1808-180b : ACPI PM_TMR 1810-1815 : ACPI CPU throttle 1850-1850 : ACPI PM2_CNT_BLK 1854-1857 : pnp 00:05 1860-187f : ACPI GPE0_BLK However, when the ACPI Notify() happened this range was not yet reserved for ACPI/PNP (that happens later) so PCI gets it. It then starts writing to this range and accidentally stomps over GPE bits among other things causing the endless stream of messages about missing GPE handler. This problem does not happen if "pci=hpiosize=0" is passed in the kernel command line. The reason is that then the kernel does not try to allocate the additional 256 bytes for each hotplug port. Fix this by allocating resources directly below the non-hotplug bridges where a new device may appear as a result of ACPI Notify(). This avoids the hotplug bridges and prevents opening the additional I/O window. Fixes: 84c8b58ed3ad ("ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug") Link: https://bugzilla.kernel.org/show_bug.cgi?id=203617 Link: https://lore.kernel.org/r/20191030150545.19885-1-mika.westerberg@linux.intel.com Reported-by: Valerio Passini Signed-off-by: Mika Westerberg Signed-off-by: Bjorn Helgaas Reviewed-by: Rafael J. Wysocki Cc: stable@vger.kernel.org

Update email address

2018-09-30T02:47:48Z

Redirect some older email addresses that are in the git logs. Signed-off-by: Matthew Wilcox