When setting new_id of a PCI device driver using sysfs a lockdep splat
occurs. This is because new_id_store() builds a temporary pci_dev for
pci_match_device(), which calls device_match_driver_override().  That
depends on the driver_override.lock added by cb3d1049f4ea ("driver core:
generalize driver_override in struct device").

The new driver_override.lock was not initialized in the temporary pci_dev,
resulting in this lockdep splat.

Initialize the temporary pci_dev to fix this.

Repro:

  Build with CONFIG_LOCKDEP=y, boot with QEMU, and add a new ID:

  # echo "8086 10f5" > /sys/bus/pci/drivers/e1000e/new_id

  INFO: trying to register non-static key.
  The code is fine but needs lockdep annotation, or maybe
  you didn't initialize this object before use?
  turning off the locking correctness validator.
  CPU: 2 UID: 0 PID: 177 Comm: liveupdate-iomm Not tainted 7.0.0+ #9 PREEMPT(full)
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x5d/0x80
   register_lock_class+0x77e/0x790
   lock_acquire+0xbf/0x2e0
   pci_match_device+0x24/0x180
   new_id_store+0x189/0x1d0
   kernfs_fop_write_iter+0x14f/0x210
   vfs_write+0x263/0x5e0
   ksys_write+0x79/0xf0
   do_syscall_64+0x117/0xf80

Fixes: 10a4206a2401 ("PCI: use generic driver_override infrastructure")
Fixes: 8895d3bcb8ba ("PCI: Fail new_id for vendor/device values already built into driver")
Signed-off-by: Samiullah Khawaja <skhawaja@google.com>
[bhelgaas: add commit log details and repro, trim backtrace]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/20260505234327.716630-1-skhawaja@google.com

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 <bernd@bschu.de>
Closes: https://lore.kernel.org/r/acfZrlP0Ua_5D3U4@eldamar.lan/
Reported-by: Alexandre N. <an.tech@mailo.com>
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 <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Bernd Schumacher <bernd@bschu.de>
Tested-by: Alexandre N. <an.tech@mailo.com>
Cc: stable@vger.kernel.org # v6.12+
Link: https://patch.msgid.link/febc3f354e0c1f5a9f5b3ee9ffddaa44caccf651.1776268054.git.lukas@wunner.de

If a bus has hotplug slots that implement the slot's reset_slot callback,
it is not safe to do the non-slot specific bus reset, so don't fallback to
it. If a slot reset does fail, the subsequent bus reset will attempt a 2nd
link reset on top of previous and fail to handle the hotplug events.

Fixes: 8238cb69c01fe ("PCI: Make reset_subordinate hotplug safe")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20260421150644.3543733-1-kbusch@meta.com

Pull LoongArch updates from Huacai Chen:

 - Adjust build infrastructure for 32BIT/64BIT

 - Add HIGHMEM (PKMAP and FIX_KMAP) support

 - Show and handle CPU vulnerabilites correctly

 - Batch the icache maintenance for jump_label

 - Add more atomic instructions support for BPF JIT

 - Add more features (e.g. fsession) support for BPF trampoline

 - Some bug fixes and other small changes

* tag 'loongarch-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (21 commits)
  selftests/bpf: Enable CAN_USE_LOAD_ACQ_STORE_REL for LoongArch
  LoongArch: BPF: Add fsession support for trampolines
  LoongArch: BPF: Introduce emit_store_stack_imm64() helper
  LoongArch: BPF: Support up to 12 function arguments for trampoline
  LoongArch: BPF: Support small struct arguments for trampoline
  LoongArch: BPF: Open code and remove invoke_bpf_mod_ret()
  LoongArch: BPF: Support load-acquire and store-release instructions
  LoongArch: BPF: Support 8 and 16 bit read-modify-write instructions
  LoongArch: BPF: Add the default case in emit_atomic() and rename it
  LoongArch: Define instruction formats for AM{SWAP/ADD}.{B/H} and DBAR
  LoongArch: Batch the icache maintenance for jump_label
  LoongArch: Add flush_icache_all()/local_flush_icache_all()
  LoongArch: Add spectre boundry for syscall dispatch table
  LoongArch: Show CPU vulnerabilites correctly
  LoongArch: Make arch_irq_work_has_interrupt() true only if IPI HW exist
  LoongArch: Use get_random_canary() for stack canary init
  LoongArch: Improve the logging of disabling KASLR
  LoongArch: Align FPU register state to 32 bytes
  LoongArch: Handle CONFIG_32BIT in syscall_get_arch()
  LoongArch: Add HIGHMEM (PKMAP and FIX_KMAP) support
  ...

Pull PCMCIA updates from Dominik Brodowski:
 "A number of minor PCMCIA bugfixes and cleanups, and a patch removing
  obsolete host controller drivers"

* tag 'pcmcia-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux:
  pcmcia: remove obsolete host controller drivers
  pcmcia: Convert to use less arguments in pci_bus_for_each_resource()
  PCMCIA: Fix garbled log messages for KERN_CONT

Pull s390 updates from Vasily Gorbik:

 - Add support for CONFIG_PAGE_TABLE_CHECK and enable it in
   debug_defconfig. s390 can only tell user from kernel PTEs via the mm,
   so mm_struct is now passed into pxx_user_accessible_page() callbacks

 - Expose the PCI function UID as an arch-specific slot attribute in
   sysfs so a function can be identified by its user-defined id while
   still in standby. Introduces a generic ARCH_PCI_SLOT_GROUPS hook in
   drivers/pci/slot.c

 - Refresh s390 PCI documentation to reflect current behavior and cover
   previously undocumented sysfs attributes

 - zcrypt device driver cleanup series: consistent field types, clearer
   variable naming, a kernel-doc warning fix, and a comment explaining
   the intentional synchronize_rcu() in pkey_handler_register()

 - Provide an s390 arch_raw_cpu_ptr() that avoids the detour via
   get_lowcore() using alternatives, shrinking defconfig by ~27 kB

 - Guard identity-base randomization with kaslr_enabled() so nokaslr
   keeps the identity mapping at 0 even with RANDOMIZE_IDENTITY_BASE=y

 - Build S390_MODULES_SANITY_TEST as a module only by requiring KUNIT &&
   m, since built-in would not exercise module loading

 - Remove the permanently commented-out HMCDRV_DEV_CLASS create_class()
   code in the hmcdrv driver

 - Drop stale ident_map_size extern conflicting with asm/page.h

* tag 's390-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/zcrypt: Fix warning about wrong kernel doc comment
  PCI: s390: Expose the UID as an arch specific PCI slot attribute
  docs: s390/pci: Improve and update PCI documentation
  s390/pkey: Add comment about synchronize_rcu() to pkey base
  s390/hmcdrv: Remove commented out code
  s390/zcrypt: Slight rework on the agent_id field
  s390/zcrypt: Explicitly use a card variable in _zcrypt_send_cprb
  s390/zcrypt: Rework MKVP fields and handling
  s390/zcrypt: Make apfs a real unsigned int field
  s390/zcrypt: Rework domain processing within zcrypt device driver
  s390/zcrypt: Move inline function rng_type6cprb_msgx from header to code
  s390/percpu: Provide arch_raw_cpu_ptr()
  s390: Enable page table check for debug_defconfig
  s390/pgtable: Add s390 support for page table check
  s390/pgtable: Use set_pmd_bit() to invalidate PMD entry
  mm/page_table_check: Pass mm_struct to pxx_user_accessible_page()
  s390/boot: Respect kaslr_enabled() for identity randomization
  s390/Kconfig: Make modules sanity test a module-only option
  s390/setup: Drop stale ident_map_size declaration

Pull Hyper-V updates from Wei Liu:

 - Fix cross-compilation for hv tools (Aditya Garg)

 - Fix vmemmap_shift exceeding MAX_FOLIO_ORDER in mshv_vtl (Naman Jain)

 - Limit channel interrupt scan to relid high water mark (Michael
   Kelley)

 - Export hv_vmbus_exists() and use it in pci-hyperv (Dexuan Cui)

 - Fix cleanup and shutdown issues for MSHV (Jork Loeser)

 - Introduce more tracing support for MSHV (Stanislav Kinsburskii)

* tag 'hyperv-next-signed-20260421' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Skip LP/VP creation on kexec
  x86/hyperv: move stimer cleanup to hv_machine_shutdown()
  Drivers: hv: vmbus: fix hyperv_cpuhp_online variable shadowing
  mshv: Add tracepoint for GPA intercept handling
  mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER
  tools: hv: Fix cross-compilation
  Drivers: hv: vmbus: Export hv_vmbus_exists() and use it in pci-hyperv
  mshv: Introduce tracing support
  Drivers: hv: vmbus: Limit channel interrupt scan to relid high water mark

Adjust build infrastructure (Kconfig, Makefile and ld scripts) to let
us enable both 32BIT/64BIT kernel build.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Pull pci updates from Bjorn Helgaas:
 "Enumeration:

   - Allow TLP Processing Hints to be enabled for RCiEPs (George Abraham
     P)

   - Enable AtomicOps only if we know the Root Port supports them (Gerd
     Bayer)

   - Don't enable AtomicOps for RCiEPs since none of them need Atomic
     Ops and we can't tell whether the Root Complex would support them
     (Gerd Bayer)

   - Leave Precision Time Measurement disabled until a driver enables it
     to avoid PCIe errors (Mika Westerberg)

   - Make pci_set_vga_state() fail if bridge doesn't support VGA
     routing, i.e., PCI_BRIDGE_CTL_VGA is not writable, and return
     errors to vga_get() callers including userspace via
     /dev/vga_arbiter (Simon Richter)

   - Validate max-link-speed from DT in j721e, brcmstb, mediatek-gen3,
     rzg3s drivers (where the actual controller constraints are known),
     and remove validation from the generic OF DT accessor (Hans Zhang)

   - Remove pc110pad driver (no longer useful after 486 CPU support
     removed) and no_pci_devices() (pc110pad was the last user) (Dmitry
     Torokhov, Heiner Kallweit)

  Resource management:

   - Prevent assigning space to unimplemented bridge windows; previously
     we mistakenly assumed prefetchable window existed and assigned
     space and put a BAR there (Ahmed Naseef)

   - Avoid shrinking bridge windows to fit in the initial Root Port
     window; fixes one problem with devices with large BARs connected
     via switches, e.g., Thunderbolt (Ilpo Järvinen)

   - Pass full extent of empty space, not just the aligned space, to
     resource_alignf callback so free space before the requested
     alignment can be used (Ilpo Järvinen)

   - Place small resources before larger ones for better utilization of
     address space (Ilpo Järvinen)

   - Fix alignment calculation for resource size larger than align,
     e.g., bridge windows larger than the 1MB required alignment (Ilpo
     Järvinen)

  Reset:

   - Update slot handling so all ARI functions are treated as being in
     the same slot. They're all reset by Secondary Bus Reset, but
     previously drivers of ARI functions that appeared to be on a
     non-zero device weren't notified and fatal hardware errors could
     result (Keith Busch)

   - Make sysfs reset_subordinate hotplug safe to avoid spurious hotplug
     events (Keith Busch)

   - Hide Secondary Bus Reset ('bus') from sysfs reset_methods if masked
     by CXL because it has no effect (Vidya Sagar)

   - Avoid FLR for AMD NPU device, where it causes the device to hang
     (Lizhi Hou)

  Error handling:

   - Clear only error bits in PCIe Device Status to avoid accidentally
     clearing Emergency Power Reduction Detected (Shuai Xue)

   - Check for AER errors even in devices without drivers (Lukas Wunner)

   - Initialize ratelimit info so DPC and EDR paths log AER error
     information (Kuppuswamy Sathyanarayanan)

  Power control:

   - Add UPD720201/UPD720202 USB 3.0 xHCI Host Controller .compatible so
     generic pwrctrl driver can control it (Neil Armstrong)

  Hotplug:

   - Set LED_HW_PLUGGABLE for NPEM hotplug-capable ports so LED core
     doesn't complain when setting brightness fails because the endpoint
     is gone (Richard Cheng)

  Peer-to-peer DMA:

   - Allow wildcards in list of host bridges that support peer-to-peer
     DMA between hierarchy domains and add all Google SoCs (Jacob
     Moroni)

  Endpoint framework:

   - Advertise dynamic inbound mapping support in pci-epf-test and
     update host pci_endpoint_test to skip doorbell testing if not
     advertised by endpoint (Koichiro Den)

   - Return 0, not remaining timeout, when MHI eDMA ops complete so
     mhi_ep_ring_add_element() doesn't interpret non-zero as failure
     (Daniel Hodges)

   - Remove vntb and ntb duplicate resource teardown that leads to oops
     when .allow_link() fails or .drop_link() is called (Koichiro Den)

   - Disable vntb delayed work before clearing BAR mappings and
     doorbells to avoid oops caused by doing the work after resources
     have been torn down (Koichiro Den)

   - Add a way to describe reserved subregions within BARs, e.g.,
     platform-owned fixed register windows, and use it for the RK3588
     BAR4 DMA ctrl window (Koichiro Den)

   - Add BAR_DISABLED for BARs that will never be available to an EPF
     driver, and change some BAR_RESERVED annotations to BAR_DISABLED
     (Niklas Cassel)

   - Add NTB .get_dma_dev() callback for cases where DMA API requires a
     different device, e.g., vNTB devices (Koichiro Den)

   - Add reserved region types for MSI-X Table and PBA so Endpoint
     controllers can them as describe hardware-owned regions in a
     BAR_RESERVED BAR (Manikanta Maddireddy)

   - Make Tegra194/234 BAR0 programmable and remove 1MB size limit
     (Manikanta Maddireddy)

   - Expose Tegra BAR2 (MSI-X) and BAR4 (DMA) as 64-bit BAR_RESERVED
     (Manikanta Maddireddy)

   - Add Tegra194 and Tegra234 device table entries to pci_endpoint_test
     (Manikanta Maddireddy)

   - Skip the BAR subrange selftest if there are not enough inbound
     window resources to run the test (Christian Bruel)

  New native PCIe controller drivers:

   - Add DT binding and driver for Andes QiLai SoC PCIe host controller
     (Randolph Lin)

   - Add DT binding and driver for ESWIN PCIe Root Complex (Senchuan
     Zhang)

  Baikal T-1 PCIe controller driver:

   - Remove driver since it never quite became usable (Andy Shevchenko)

  Cadence PCIe controller driver:

   - Implement byte/word config reads with dword (32-bit) reads because
     some Cadence controllers don't support sub-dword accesses (Aksh
     Garg)

  CIX Sky1 PCIe controller driver:

   - Add 'power-domains' to DT binding for SCMI power domain (Gary Yang)

  Freescale i.MX6 PCIe controller driver:

   - Add i.MX94 and i.MX943 to fsl,imx6q-pcie-ep DT binding (Richard
     Zhu)

   - Delay instead of polling for L2/L3 Ready after PME_Turn_off when
     suspending i.MX6SX because LTSSM registers are inaccessible
     (Richard Zhu)

   - Separate PERST# assertion (for resetting endpoints) from core reset
     (for resetting the RC itself) to prepare for new DTs with PERST#
     GPIO in per-Root Port nodes (Sherry Sun)

   - Retain Root Port MSI capability on i.MX7D, i.MX8MM, and i.MX8MQ so
     MSI from downstream devices will work (Richard Zhu)

   - Fix i.MX95 reference clock source selection when internal refclk is
     used (Franz Schnyder)

  Freescale Layerscape PCIe controller driver:

   - Allow building as a removable module (Sascha Hauer)

  MediaTek PCIe Gen3 controller driver:

   - Use dev_err_probe() to simplify error paths and make deferred probe
     messages visible in /sys/kernel/debug/devices_deferred (Chen-Yu
     Tsai)

   - Power off device if setup fails (Chen-Yu Tsai)

   - Integrate new pwrctrl API to enable power control for WiFi/BT
     adapters on mainboard or in PCIe or M.2 slots (Chen-Yu Tsai)

  NVIDIA Tegra194 PCIe controller driver:

   - Poll less aggressively and non-atomically for PME_TO_Ack during
     transition to L2 (Vidya Sagar)

   - Disable LTSSM after transition to Detect on surprise link down to
     stop toggling between Polling and Detect (Manikanta Maddireddy)

   - Don't force the device into the D0 state before L2 when suspending
     or shutting down the controller (Vidya Sagar)

   - Disable PERST# IRQ only in Endpoint mode because it's not
     registered in Root Port mode (Manikanta Maddireddy)

   - Handle 'nvidia,refclk-select' as optional (Vidya Sagar)

   - Disable direct speed change in Endpoint mode so link speed change
     is controlled by the host (Vidya Sagar)

   - Set LTR values before link up to avoid bogus LTR messages with 0
     latency (Vidya Sagar)

   - Allow system suspend when the Endpoint link is down (Vidya Sagar)

   - Use DWC IP core version, not Tegra custom values, to avoid DWC core
     version check warnings (Manikanta Maddireddy)

   - Apply ECRC workaround to devices based on DesignWare 5.00a as well
     as 4.90a (Manikanta Maddireddy)

   - Disable PM Substate L1.2 in Endpoint mode to work around Tegra234
     erratum (Vidya Sagar)

   - Delay post-PERST# cleanup until core is powered on to avoid CBB
     timeout (Manikanta Maddireddy)

   - Assert CLKREQ# so switches that forward it to their downstream side
     can bring up those links successfully (Vidya Sagar)

   - Calibrate pipe to UPHY for Endpoint mode to reset stale PLL state
     from any previous bad link state (Vidya Sagar)

   - Remove IRQF_ONESHOT flag from Endpoint interrupt registration so
     DMA driver and Endpoint controller driver can share the interrupt
     line (Vidya Sagar)

   - Enable DMA interrupt to support DMA in both Root Port and Endpoint
     modes (Vidya Sagar)

   - Enable hardware link retraining after link goes down in Endpoint
     mode (Vidya Sagar)

   - Add DT binding and driver support for core clock monitoring (Vidya
     Sagar)

  Qualcomm PCIe controller driver:

   - Advertise 'Hot-Plug Capable' and set 'No Command Completed Support'
     since Qcom Root Ports support hotplug events like DL_Up/Down and
     can accept writes to Slot Control without delays between writes
     (Krishna Chaitanya Chundru)

  Renesas R-Car PCIe controller driver:

   - Mark Endpoint BAR0 and BAR2 as Resizable (Koichiro Den)

   - Reduce EPC BAR alignment requirement to 4K (Koichiro Den)

  Renesas RZ/G3S PCIe controller driver:

   - Add RZ/G3E to DT binding and to driver (John Madieu)

   - Assert (not deassert) resets in probe error path (John Madieu)

   - Assert resets in suspend path in reverse order they were deasserted
     during probe (John Madieu)

   - Rework inbound window algorithm to prevent mapping more than
     intended region and enforce alignment on size, to prepare for
     RZ/G3E support (John Madieu)

  Rockchip DesignWare PCIe controller driver:

   - Add tracepoints for PCIe controller LTSSM transitions and link rate
     changes (Shawn Lin)

   - Trace LTSSM events collected by the dw-rockchip debug FIFO (Shawn
     Lin)

  SOPHGO PCIe controller driver:

   - Disable ASPM L0s and L1 on Sophgo 2042 PCIe Root Ports that
     advertise support for them (Yao Zi)

  Synopsys DesignWare PCIe controller driver:

   - Continue with system suspend even if an Endpoint doesn't respond
     with PME_TO_Ack message (Manivannan Sadhasivam)

   - Set Endpoint MSI-X Table Size in the correct function of a
     multi-function device when configuring MSI-X, not in Function 0
     (Aksh Garg)

   - Set Max Link Width and Max Link Speed for all functions of a
     multi-function device, not just Function 0 (Aksh Garg)

   - Expose PCIe event counters in groups 5-7 in debugfs (Hans Zhang)

  Miscellaneous:

   - Warn only once about invalid ACS kernel parameter format (Richard
     Cheng)

   - Suppress FW_BUG warning when writing sysfs 'numa_node' with the
     current value (Li RongQing)

   - Drop redundant 'depends on PCI' from Kconfig (Julian Braha)"

* tag 'pci-v7.1-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (165 commits)
  PCI/P2PDMA: Add Google SoCs to the P2P DMA host bridge list
  PCI/P2PDMA: Allow wildcard Device IDs in host bridge list
  PCI: sg2042: Avoid L0s and L1 on Sophgo 2042 PCIe Root Ports
  PCI: cadence: Add flags for disabling ASPM capability for broken Root Ports
  PCI: tegra194: Add core monitor clock support
  dt-bindings: PCI: tegra194: Add monitor clock support
  PCI: tegra194: Enable hardware hot reset mode in Endpoint mode
  PCI: tegra194: Enable DMA interrupt
  PCI: tegra194: Remove IRQF_ONESHOT flag during Endpoint interrupt registration
  PCI: tegra194: Calibrate pipe to UPHY for Endpoint mode
  PCI: tegra194: Assert CLKREQ# explicitly by default
  PCI: tegra194: Fix CBB timeout caused by DBI access before core power-on
  PCI: tegra194: Disable L1.2 capability of Tegra234 EP
  PCI: dwc: Apply ECRC workaround to DesignWare 5.00a as well
  PCI: tegra194: Use DWC IP core version
  PCI: tegra194: Free up Endpoint resources during remove()
  PCI: tegra194: Allow system suspend when the Endpoint link is not up
  PCI: tegra194: Set LTR message request before PCIe link up in Endpoint mode
  PCI: tegra194: Disable direct speed change for Endpoint mode
  PCI: tegra194: Use devm_gpiod_get_optional() to parse "nvidia,refclk-select"
  ...

With commit f84b21da3624 ("PCI: hv: Don't load the driver for baremetal root partition"),
the bare metal Linux root partition won't use the pci-hyperv driver, but
when a Linux VM runs on the Linux root partition, pci-hyperv's module_init
function init_hv_pci_drv() can still run, e.g. in the case of
CONFIG_PCI_HYPERV=y, even if the VMBus driver is not used in such a VM
(i.e. the hv_vmbus driver's init function returns -ENODEV due to
vmbus_root_device being NULL).

In such a Linux VM, init_hv_pci_drv() runs with a side effect: the 3
hvpci_block_ops callbacks are set to functions that depend on hv_vmbus.

Later, when the MLX driver in such a VM invokes the callbacks, e.g. in
drivers/net/ethernet/mellanox/mlx5/core/lib/hv.c:
mlx5_hv_register_invalidate(), hvpci_block_ops.reg_blk_invalidate() is
hv_register_block_invalidate() rather than a NULL function pointer, and
hv_register_block_invalidate() assumes that it can find a struct
hv_pcibus_device from pdev->bus->sysdata, which is false in such a VM.

Consequently, hv_register_block_invalidate() -> get_pcichild_wslot() ->
spin_lock_irqsave() may hang since it can be accessing an invalid
spinlock pointer.

Fix the issue by exporting hv_vmbus_exists() and using it in pci-hyperv:

    hv_root_partition() is true and hv_nested is false ==>
	hv_vmbus_exists() is false.

    hv_root_partition() is true and hv_nested is true ==>
	hv_vmbus_exists() is true.

    hv_root_partition() is false ==> hv_vmbus_exists() is true.

While at it, rename vmbus_exists() to hv_vmbus_exists() to follow the
convention that all public functions have the hv_ prefix; also change
the return value's type from int to bool to make the code more readable;
also move the two pr_info() calls.

Reported-by: Mukesh Rathor <mrathor@linux.microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>