PCI/ATS: Add pci_pri_supported() to check device or associated PF

For SR-IOV, the PF PRI is shared between the PF and any associated VFs, and
the PRI Capability is allowed for PFs but not for VFs. Searching for the
PRI Capability on a VF always fails, even if its associated PF supports
PRI.

Add pci_pri_supported() to check whether device or its associated PF
supports PRI.

[bhelgaas: commit log, avoid "!!"]
Fixes: b16d0cb9e2fc ("iommu/vt-d: Always enable PASID/PRI PCI capabilities before ATS")
Link: https://lore.kernel.org/r/1595543849-19692-1-git-send-email-ashok.raj@intel.com
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Cc: stable@vger.kernel.org # v4.4+

PCI/ATS: Only enable ATS for trusted devices

Add pci_ats_supported(), which checks whether a device has an ATS
capability, and whether it is trusted. A device is untrusted if it is
plugged into an external-facing port such as Thunderbolt and could be
spoofing an existing device to exploit weaknesses in the IOMMU
configuration. PCIe ATS is one such weaknesses since it allows
endpoints to cache IOMMU translations and emit transactions with
'Translated' Address Type (10b) that partially bypass the IOMMU
translation.

The SMMUv3 and VT-d IOMMU drivers already disallow ATS and transactions
with 'Translated' Address Type for untrusted devices. Add the check to
pci_enable_ats() to let other drivers (AMD IOMMU for now) benefit from
it.

By checking ats_cap, the pci_ats_supported() helper also returns whether
ATS was globally disabled with pci=noats, and could later include more
things, for example whether the whole PCIe hierarchy down to the
endpoint supports ATS.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20200520152201.3309416-2-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>

PCI/ATS: Add PASID stubs

The SMMUv3 driver, which may be built without CONFIG_PCI, will soon gain
PASID support. Partially revert commit c6e9aefbf9db ("PCI/ATS: Remove
unused PRI and PASID stubs") to re-introduce the PASID stubs, and avoid
adding more #ifdefs to the SMMU driver.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>

PCI/ATS: Make pci_restore_pri_state(), pci_restore_pasid_state() private

These interfaces:

void pci_restore_pri_state(struct pci_dev *pdev);
void pci_restore_pasid_state(struct pci_dev *pdev);

are only used in drivers/pci and do not need to be seen by the rest of the
kernel. Most them to drivers/pci/pci.h so they're private to the PCI
subsystem.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>

PCI/ATS: Remove unused PRI and PASID stubs

The following functions are only used by amd_iommu.c and intel-iommu.c
(when CONFIG_INTEL_IOMMU_SVM is enabled). CONFIG_PCI_PRI and
CONFIG_PCI_PASID are always defined in those cases, so there's no need for
the stubs.

pci_enable_pri()
pci_disable_pri()
pci_reset_pri()
pci_prg_resp_pasid_required()
pci_enable_pasid()
pci_disable_pasid()

Remove the unused stubs.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>

PCI/ATS: Consolidate ATS declarations in linux/pci-ats.h

Move ATS function prototypes from include/linux/pci.h to
include/linux/pci-ats.h as the ATS, PRI, and PASID interfaces are related
and are used only by the IOMMU drivers. This effectively reverts
ff9bee895c4d ("PCI: Move ATS declarations to linux/pci.h so they're all
together").

Also, remove surplus forward declaration of struct pci_ats from
include/linux/pci.h, as it is no longer needed, since struct pci_ats was
embedded directly into struct pci_dev by d544d75ac96a ("PCI: Embed ATS info
directly into struct pci_dev").

No functional changes intended.

Link: https://lore.kernel.org/r/20190914213032.22314-1-kw@linux.com
Signed-off-by: Krzysztof Wilczynski <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI/ATS: Move pci_prg_resp_pasid_required() to CONFIG_PCI_PRI

pci_prg_resp_pasid_required() returns the value of the "PRG Response PASID
Required" bit from the PRI capability, but the interface was previously
defined under #ifdef CONFIG_PCI_PASID.

Move it from CONFIG_PCI_PASID to CONFIG_PCI_PRI so it's with the other
PRI-related things.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>

PCI/ATS: Add inline to pci_prg_resp_pasid_required()

Fix unused function warning when compiled with CONFIG_PCI_PASID
disabled.

Fixes: e5567f5f6762 ("PCI/ATS: Add pci_prg_resp_pasid_required() interface.")
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

PCI/ATS: Add pci_prg_resp_pasid_required() interface.

Return the PRG Response PASID Required bit in the Page Request
Status Register.

As per PCIe spec r4.0, sec 10.5.2.3, if this bit is Set, the device
expects a PASID TLP Prefix on PRG Response Messages when the
corresponding Page Requests had a PASID TLP Prefix. If Clear, the device
does not expect PASID TLP Prefixes on any PRG Response Message, and the
device behavior is undefined if the device receives a PRG Response Message
with a PASID TLP Prefix. Also the device behavior is undefined if this
bit is Set and the device receives a PRG Response Message with no PASID TLP
Prefix when the corresponding Page Requests had a PASID TLP Prefix.

This function will be used by drivers like IOMMU, if it is required to
check the status of the PRG Response PASID Required bit before enabling
the PASID support of the device.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PCI: Restore PRI and PASID state after Function-Level Reset

After a Function-Level Reset, PCI states need to be restored. Save PASID
features and PRI reqs cached.

[bhelgaas: search for capability only if PRI/PASID were enabled]
Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jean-Phillipe Brucker <jean-philippe.brucker@arm.com>
Cc: David Woodhouse <dwmw2@infradead.org>

PCI: Move ATS declarations to linux/pci.h so they're all together

Move ATS declarations to linux/pci.h so they're all in one place.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>

PCI: Embed ATS info directly into struct pci_dev

The pci_ats struct is small and will get smaller, so I don't think it's
worth allocating it separately from the pci_dev struct.

Embed the ATS fields directly into struct pci_dev.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>

PCI: Allocate ATS struct during enumeration

Previously, we allocated pci_ats structures when an IOMMU driver called
pci_enable_ats(). An SR-IOV VF shares the STU setting with its PF, so when
enabling ATS on the VF, we allocated a pci_ats struct for the PF if it
didn't already have one. We held the sriov->lock to serialize threads
concurrently enabling ATS on several VFS so only one would allocate the PF
pci_ats.

Gregor reported a deadlock here:

pci_enable_sriov
sriov_enable
virtfn_add
mutex_lock(dev->sriov->lock) # acquire sriov->lock
pci_device_add
device_add
BUS_NOTIFY_ADD_DEVICE notifier chain
iommu_bus_notifier
amd_iommu_add_device # iommu_ops.add_device
init_iommu_group
iommu_group_get_for_dev
iommu_group_add_device
__iommu_attach_device
amd_iommu_attach_device # iommu_ops.attach_device
attach_device
pci_enable_ats
mutex_lock(dev->sriov->lock) # deadlock

There's no reason to delay allocating the pci_ats struct, and if we
allocate it for each device at enumeration-time, there's no need for
locking in pci_enable_ats().

Allocate pci_ats struct during enumeration, when we initialize other
capabilities.

Note that this implementation requires ATS to be enabled on the PF first,
before on any of the VFs because the PF controls the STU for all the VFs.

Link: http://permalink.gmane.org/gmane.linux.kernel.iommu/9433
Reported-by: Gregor Dick <gdick@solarflare.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>

PCI: Removed unused parts of Page Request Interface support

My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.

This reverts parts of c320b976d783 ("PCI: Add implementation for PRI
capability"), removing these interfaces:

pci_pri_enabled()
pci_pri_stopped()
pci_pri_status()

[bhelgaas: split to separate patch]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Joerg Roedel <joro@8bytes.org>

PCI: Remove "extern" from function declarations

We had an inconsistent mix of using and omitting the "extern" keyword
on function declarations in header files. This removes them all.

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

PCI: Fix compile errors with PCI_ATS and !PCI_IOV

The ats and sroiv members of 'struct pci_dev' are required
for the ATS code already, even without IOV support compiled
in. So depend on ATS here. This is fine with PCI_IOV too
because it selects PCI_ATS. Also the prototypes for ATS
need to be available for PCI_ATS.

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: Add support for PASID capability

Devices supporting Process Address Space Identifiers
(PASIDs) can use an IOMMU to access multiple IO address
spaces at the same time. A PCIe device indicates support for
this feature by implementing the PASID capability. This
patch adds support for the capability to the Linux kernel.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: Add implementation for PRI capability

Implement the necessary functions to handle PRI capabilities
on PCIe devices. With PRI devices behind an IOMMU can signal
page fault conditions to software and recover from such
faults.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: Move ATS implementation into own file

ATS does not depend on IOV support, so move the code into
its own file. This file will also include support for the
PRI and PASID capabilities later.
Also give ATS its own Kconfig variable to allow selecting it
without IOV support.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: Move ATS declarations in seperate header file

This patch moves the relevant declarations from the local
header file in drivers/pci to a more accessible locations so
that it can be used by the AMD IOMMU driver too.
The file is named pci-ats.h because support for the PCI PRI
capability will also be added there in a later patch-set.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>