The TotalVFs register in the SR-IOV capability is the hardware limit on the
number of VFs.  A PF driver can limit the number of VFs further with
pci_sriov_set_totalvfs().  When the PF driver is removed, reset any VF
limit that was imposed by the driver because that limit may not apply to
other drivers.

Before 8d85a7a4f2c9 ("PCI/IOV: Allow PF drivers to limit total_VFs to 0"),
pci_sriov_set_totalvfs(pdev, 0) meant "we can enable TotalVFs virtual
functions", and the nfp driver used that to remove the VF limit when the
driver unloads.

8d85a7a4f2c9 broke that because instead of removing the VF limit,
pci_sriov_set_totalvfs(pdev, 0) actually sets the limit to zero, and that
limit persists even if another driver is loaded.

We could fix that by making the nfp driver reset the limit when it unloads,
but it seems more robust to do it in the PCI core instead of relying on the
driver.

The regression scenario is:

  nfp_pci_probe (driver 1)
  ...
  nfp_pci_remove
    pci_sriov_set_totalvfs(pf->pdev, 0)   # limits VFs to 0

  ...
  nfp_pci_probe (driver 2)
    nfp_rtsym_read_le("nfd_vf_cfg_max_vfs")
    # no VF limit from firmware

Now driver 2 is broken because the VF limit is still 0 from driver 1.

Fixes: 8d85a7a4f2c9 ("PCI/IOV: Allow PF drivers to limit total_VFs to 0")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
[bhelgaas: changelog, rename functions]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Some SR-IOV PF drivers implement .sriov_configure(), which allows
user-space to enable VFs by writing the desired number of VFs to the sysfs
"sriov_numvfs" file (see sriov_numvfs_store()).

The PCI core limits the number of VFs to the TotalVFs advertised by the
device in its SR-IOV capability.  The PF driver can limit the number of VFs
to even fewer (it may have pre-allocated data structures or knowledge of
device limitations) by calling pci_sriov_set_totalvfs(), but previously it
could not limit the VFs to 0.

Change pci_sriov_get_totalvfs() so it always respects the VF limit imposed
by the PF driver, even if the limit is 0.

This sequence:

  pci_sriov_set_totalvfs(dev, 0);
  x = pci_sriov_get_totalvfs(dev);

previously set "x" to TotalVFs from the SR-IOV capability.  Now it will set
"x" to 0.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
[bhelgaas: split to separate patch]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

SR-IOV (Single Root I/O Virtualization) is an optional PCIe capability (see
PCIe r4.0, sec 9).  A PCIe Function with the SR-IOV capability is referred
to as a PF (Physical Function).  If SR-IOV is enabled on the PF, several
VFs (Virtual Functions) may be created.  The VFs can be individually
assigned to virtual machines, which allows them to share a single hardware
device while being isolated from each other.

Some SR-IOV devices have resources such as queues and interrupts that must
be set up in the PF before enabling the VFs, so they require a PF driver to
do that.

Other SR-IOV devices don't require any PF setup before enabling VFs.  Add a
pci_sriov_configure_simple() interface so PF drivers for such devices can
use it without repeating the VF-enabling code.

Tested-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
[bhelgaas: changelog, comment]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Rose <gvrose8192@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>:wq

  - probe for device reset support during enumeration instead of runtime
    (Bjorn Helgaas)

  - add ACS quirk for Ampere (née APM) root ports (Feng Kan)

  - add function 1 DMA alias quirk for Marvell 88SE9220 (Thomas
    Vincent-Cross)

  - protect device restore with device lock (Sinan Kaya)

  - handle failure of FLR gracefully (Sinan Kaya)

  - handle CRS (config retry status) after device resets (Sinan Kaya)

  - skip various config reads for SR-IOV VFs as an optimization (KarimAllah
    Ahmed)

* pci/virtualization:
  PCI/IOV: Add missing prototypes for powerpc pcibios interfaces
  PCI/IOV: Use VF0 cached config registers for other VFs
  PCI/IOV: Skip BAR sizing for VFs
  PCI/IOV: Skip INTx config reads for VFs
  PCI: Wait for device to become ready after secondary bus reset
  PCI: Add a return type for pci_reset_bridge_secondary_bus()
  PCI: Wait for device to become ready after a power management reset
  PCI: Rename pci_flr_wait() to pci_dev_wait() and make it generic
  PCI: Handle FLR failure and allow other reset types
  PCI: Protect restore with device lock to be consistent
  PCI: Add function 1 DMA alias quirk for Marvell 88SE9220
  PCI: Add ACS quirk for Ampere root ports
  PCI: Remove redundant probes for device reset support
  PCI: Probe for device reset support during enumeration

Conflicts:
	include/linux/pci.h

Cache some config data from VF0 and use it for all other VFs instead of
reading it from the config space of each VF.  We assume these items are the
same across all associated VFs:

   Revision ID
   Class Code
   Subsystem Vendor ID
   Subsystem ID

This is an optimization when enabling SR-IOV on a device with many VFs.

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
[bhelgaas: changelog, simplify comments, remove unused "device", test
CONFIG_PCI_IOV instead of CONFIG_PCI_ATS, rename functions]
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>

Remove pointless comments that tell us the file name, remove blank line
comments, follow multi-line comment conventions.  No functional change
intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Pull PCI updates from Bjorn Helgaas:

 - skip AER driver error recovery callbacks for correctable errors
   reported via ACPI APEI, as we already do for errors reported via the
   native path (Tyler Baicar)

 - fix DPC shared interrupt handling (Alex Williamson)

 - print full DPC interrupt number (Keith Busch)

 - enable DPC only if AER is available (Keith Busch)

 - simplify DPC code (Bjorn Helgaas)

 - calculate ASPM L1 substate parameter instead of hardcoding it (Bjorn
   Helgaas)

 - enable Latency Tolerance Reporting for ASPM L1 substates (Bjorn
   Helgaas)

 - move ASPM internal interfaces out of public header (Bjorn Helgaas)

 - allow hot-removal of VGA devices (Mika Westerberg)

 - speed up unplug and shutdown by assuming Thunderbolt controllers
   don't support Command Completed events (Lukas Wunner)

 - add AtomicOps support for GPU and Infiniband drivers (Felix Kuehling,
   Jay Cornwall)

 - expose "ari_enabled" in sysfs to help NIC naming (Stuart Hayes)

 - clean up PCI DMA interface usage (Christoph Hellwig)

 - remove PCI pool API (replaced with DMA pool) (Romain Perier)

 - deprecate pci_get_bus_and_slot(), which assumed PCI domain 0 (Sinan
   Kaya)

 - move DT PCI code from drivers/of/ to drivers/pci/ (Rob Herring)

 - add PCI-specific wrappers for dev_info(), etc (Frederick Lawler)

 - remove warnings on sysfs mmap failure (Bjorn Helgaas)

 - quiet ROM validation messages (Alex Deucher)

 - remove redundant memory alloc failure messages (Markus Elfring)

 - fill in types for compile-time VGA and other I/O port resources
   (Bjorn Helgaas)

 - make "pci=pcie_scan_all" work for Root Ports as well as Downstream
   Ports to help AmigaOne X1000 (Bjorn Helgaas)

 - add SPDX tags to all PCI files (Bjorn Helgaas)

 - quirk Marvell 9128 DMA aliases (Alex Williamson)

 - quirk broken INTx disable on Ceton InfiniTV4 (Bjorn Helgaas)

 - fix CONFIG_PCI=n build by adding dummy pci_irqd_intx_xlate() (Niklas
   Cassel)

 - use DMA API to get MSI address for DesignWare IP (Niklas Cassel)

 - fix endpoint-mode DMA mask configuration (Kishon Vijay Abraham I)

 - fix ARTPEC-6 incorrect IS_ERR() usage (Wei Yongjun)

 - add support for ARTPEC-7 SoC (Niklas Cassel)

 - add endpoint-mode support for ARTPEC (Niklas Cassel)

 - add Cadence PCIe host and endpoint controller driver (Cyrille
   Pitchen)

 - handle multiple INTx status bits being set in dra7xx (Vignesh R)

 - translate dra7xx hwirq range to fix INTD handling (Vignesh R)

 - remove deprecated Exynos PHY initialization code (Jaehoon Chung)

 - fix MSI erratum workaround for HiSilicon Hip06/Hip07 (Dongdong Liu)

 - fix NULL pointer dereference in iProc BCMA driver (Ray Jui)

 - fix Keystone interrupt-controller-node lookup (Johan Hovold)

 - constify qcom driver structures (Julia Lawall)

 - rework Tegra config space mapping to increase space available for
   endpoints (Vidya Sagar)

 - simplify Tegra driver by using bus->sysdata (Manikanta Maddireddy)

 - remove PCI_REASSIGN_ALL_BUS usage on Tegra (Manikanta Maddireddy)

 - add support for Global Fabric Manager Server (GFMS) event to
   Microsemi Switchtec switch driver (Logan Gunthorpe)

 - add IDs for Switchtec PSX 24xG3 and PSX 48xG3 (Kelvin Cao)

* tag 'pci-v4.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (140 commits)
  PCI: cadence: Add EndPoint Controller driver for Cadence PCIe controller
  dt-bindings: PCI: cadence: Add DT bindings for Cadence PCIe endpoint controller
  PCI: endpoint: Fix EPF device name to support multi-function devices
  PCI: endpoint: Add the function number as argument to EPC ops
  PCI: cadence: Add host driver for Cadence PCIe controller
  dt-bindings: PCI: cadence: Add DT bindings for Cadence PCIe host controller
  PCI: Add vendor ID for Cadence
  PCI: Add generic function to probe PCI host controllers
  PCI: generic: fix missing call of pci_free_resource_list()
  PCI: OF: Add generic function to parse and allocate PCI resources
  PCI: Regroup all PCI related entries into drivers/pci/Makefile
  PCI/DPC: Reformat DPC register definitions
  PCI/DPC: Add and use DPC Status register field definitions
  PCI/DPC: Squash dpc_rp_pio_get_info() into dpc_process_rp_pio_error()
  PCI/DPC: Remove unnecessary RP PIO register structs
  PCI/DPC: Push dpc->rp_pio_status assignment into dpc_rp_pio_get_info()
  PCI/DPC: Squash dpc_rp_pio_print_error() into dpc_rp_pio_get_info()
  PCI/DPC: Make RP PIO log size check more generic
  PCI/DPC: Rename local "status" to "dpc_status"
  PCI/DPC: Squash dpc_rp_pio_print_tlp_header() into dpc_rp_pio_print_error()
  ...

* pci/spdx:
  PCI: Add SPDX GPL-2.0+ to replace implicit GPL v2 or later statement
  PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate
  PCI: Add SPDX GPL-2.0 to replace COPYING boilerplate
  PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate
  PCI: Add SPDX GPL-2.0 when no license was specified

b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to
files with no license") added SPDX GPL-2.0 to several PCI files that
previously contained no license information.

Add SPDX GPL-2.0 to all other PCI files that did not contain any license
information and hence were under the default GPL version 2 license of the
kernel.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add PCI-specific dev_printk() wrappers and use them to simplify the code
slightly.  No functional change intended.

Signed-off-by: Frederick Lawler <fred@fredlawl.com>
[bhelgaas: squash into one patch]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>