vfio/pci: Support dynamic MSI-X

pci_msix_alloc_irq_at() enables an individual MSI-X interrupt to be
allocated after MSI-X enabling.

Use dynamic MSI-X (if supported by the device) to allocate an int

vfio/pci: Support dynamic MSI-X

pci_msix_alloc_irq_at() enables an individual MSI-X interrupt to be
allocated after MSI-X enabling.

Use dynamic MSI-X (if supported by the device) to allocate an interrupt
after MSI-X is enabled. An MSI-X interrupt is dynamically allocated at
the time a valid eventfd is assigned. This is different behavior from
a range provided during MSI-X enabling where interrupts are allocated
for the entire range whether a valid eventfd is provided for each
interrupt or not.

The PCI-MSIX API requires that some number of irqs are allocated for
an initial set of vectors when enabling MSI-X on the device. When
dynamic MSIX allocation is not supported, the vector table, and thus
the allocated irq set can only be resized by disabling and re-enabling
MSI-X with a different range. In that case the irq allocation is
essentially a cache for configuring vectors within the previously
allocated vector range. When dynamic MSI-X allocation is supported,
the API still requires some initial set of irqs to be allocated, but
also supports allocating and freeing specific irq vectors both
within and beyond the initially allocated range.

For consistency between modes, as well as to reduce latency and improve
reliability of allocations, and also simplicity, this implementation
only releases irqs via pci_free_irq_vectors() when either the interrupt
mode changes or the device is released.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/lkml/20230403211841.0e206b67.alex.williamson@redhat.com/
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/956c47057ae9fd45591feaa82e9ae20929889249.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/pci: Update stale comment

In preparation for surrounding code change it is helpful to
ensure that existing comments are accurate.

Remove inaccurate comment about direct access and update
the r

vfio/pci: Update stale comment

In preparation for surrounding code change it is helpful to
ensure that existing comments are accurate.

Remove inaccurate comment about direct access and update
the rest of the comment to reflect the purpose of writing
the cached MSI message to the device.

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/lkml/20230330164050.0069e2a5.alex.williamson@redhat.com/
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/5b605ce7dcdab5a5dfef19cec4d73ae2fdad3ae1.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/pci: Remove interrupt context counter

struct vfio_pci_core_device::num_ctx counts how many interrupt
contexts have been allocated. When all interrupt contexts are
allocated simultaneously num_c

vfio/pci: Remove interrupt context counter

struct vfio_pci_core_device::num_ctx counts how many interrupt
contexts have been allocated. When all interrupt contexts are
allocated simultaneously num_ctx provides the upper bound of all
vectors that can be used as indices into the interrupt context
array.

With the upcoming support for dynamic MSI-X the number of
interrupt contexts does not necessarily span the range of allocated
interrupts. Consequently, num_ctx is no longer a trusted upper bound
for valid indices.

Stop using num_ctx to determine if a provided vector is valid. Use
the existence of allocated interrupt.

This changes behavior on the error path when user space provides
an invalid vector range. Behavior changes from early exit without
any modifications to possible modifications to valid vectors within
the invalid range. This is acceptable considering that an invalid
range is not a valid scenario, see link to discussion.

The checks that ensure that user space provides a range of vectors
that is valid for the device are untouched.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/lkml/20230316155646.07ae266f.alex.williamson@redhat.com/
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/e27d350f02a65b8cbacd409b4321f5ce35b3186d.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/pci: Use xarray for interrupt context storage

Interrupt context is statically allocated at the time interrupts
are allocated. Following allocation, the context is managed by
directly accessing

vfio/pci: Use xarray for interrupt context storage

Interrupt context is statically allocated at the time interrupts
are allocated. Following allocation, the context is managed by
directly accessing the elements of the array using the vector
as index. The storage is released when interrupts are disabled.

It is possible to dynamically allocate a single MSI-X interrupt
after MSI-X is enabled. A dynamic storage for interrupt context
is needed to support this. Replace the interrupt context array with an
xarray (similar to what the core uses as store for MSI descriptors)
that can support the dynamic expansion while maintaining the
custom that uses the vector as index.

With a dynamic storage it is no longer required to pre-allocate
interrupt contexts at the time the interrupts are allocated.
MSI and MSI-X interrupt contexts are only used when interrupts are
enabled. Their allocation can thus be delayed until interrupt enabling.
Only enabled interrupts will have associated interrupt contexts.
Whether an interrupt has been allocated (a Linux irq number exists
for it) becomes the criteria for whether an interrupt can be enabled.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/lkml/20230404122444.59e36a99.alex.williamson@redhat.com/
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/40e235f38d427aff79ae35eda0ced42502aa0937.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/pci: Move to single error path

Enabling and disabling of an interrupt involves several steps
that can fail. Cleanup after failure is done when the error
is encountered, resulting in some repeti

vfio/pci: Move to single error path

Enabling and disabling of an interrupt involves several steps
that can fail. Cleanup after failure is done when the error
is encountered, resulting in some repetitive code.

Support for dynamic contexts will introduce more steps during
interrupt enabling and disabling.

Transition to centralized exit path in preparation for dynamic
contexts to eliminate duplicate error handling code.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/72dddae8aa710ce522a74130120733af61cffe4d.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/pci: Prepare for dynamic interrupt context storage

Interrupt context storage is statically allocated at the time
interrupts are allocated. Following allocation, the interrupt
context is managed

vfio/pci: Prepare for dynamic interrupt context storage

Interrupt context storage is statically allocated at the time
interrupts are allocated. Following allocation, the interrupt
context is managed by directly accessing the elements of the
array using the vector as index.

It is possible to allocate additional MSI-X vectors after
MSI-X has been enabled. Dynamic storage of interrupt context
is needed to support adding new MSI-X vectors after initial
allocation.

Replace direct access of array elements with pointers to the
array elements. Doing so reduces impact of moving to a new data
structure. Move interactions with the array to helpers to
mostly contain changes needed to transition to a dynamic
data structure.

No functional change intended.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/eab289693c8325ede9aba99380f8b8d5143980a4.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/pci: Remove negative check on unsigned vector

User space provides the vector as an unsigned int that is checked
early for validity (vfio_set_irqs_validate_and_prepare()).

A later negative chec

vfio/pci: Remove negative check on unsigned vector

User space provides the vector as an unsigned int that is checked
early for validity (vfio_set_irqs_validate_and_prepare()).

A later negative check of the provided vector is not necessary.

Remove the negative check and ensure the type used
for the vector is consistent as an unsigned int.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/28521e1b0b091849952b0ecb8c118729fc8cdc4f.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/pci: Consolidate irq cleanup on MSI/MSI-X disable

vfio_msi_disable() releases all previously allocated state
associated with each interrupt before disabling MSI/MSI-X.

vfio_msi_disable() itera

vfio/pci: Consolidate irq cleanup on MSI/MSI-X disable

vfio_msi_disable() releases all previously allocated state
associated with each interrupt before disabling MSI/MSI-X.

vfio_msi_disable() iterates twice over the interrupt state:
first directly with a for loop to do virqfd cleanup, followed
by another for loop within vfio_msi_set_block() that removes
the interrupt handler and its associated state using
vfio_msi_set_vector_signal().

Simplify interrupt cleanup by iterating over allocated interrupts
once.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/837acb8cbe86a258a50da05e56a1f17c1a19abbe.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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Merge branch 'next' into for-linus

Prepare input updates for 6.4 merge window.

Merge branch 'for-6.4/amd-sfh' into for-linus

- assorted functional fixes for amd-sfh driver (Basavaraj Natikar)

Merge drm/drm-next into drm-intel-gt-next

Need to pull in commit from drm-next (earlier in drm-intel-next):

1eca0778f4b3 ("drm/i915: add struct i915_dsm to wrap dsm members together")

In order to

Merge drm/drm-next into drm-intel-gt-next

Need to pull in commit from drm-next (earlier in drm-intel-next):

1eca0778f4b3 ("drm/i915: add struct i915_dsm to wrap dsm members together")

In order to merge following patch to drm-intel-gt-next:

https://patchwork.freedesktop.org/patch/530942/?series=114925&rev=6

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

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Merge drm/drm-next into drm-intel-next

Catch up with 6.3-rc cycle...

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge remote-tracking branch 'drm/drm-next' into msm-next

Merge drm-next into msm-next to pick up external clk and PM dependencies
for improved a6xx GPU reset sequence.

Signed-off-by: Rob Clark <ro

Merge remote-tracking branch 'drm/drm-next' into msm-next

Merge drm-next into msm-next to pick up external clk and PM dependencies
for improved a6xx GPU reset sequence.

Signed-off-by: Rob Clark <robdclark@chromium.org>

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Merge tag 'v6.3-rc2' into next

Merge with mainline to get of_property_present() and other newer APIs.

Merge drm/drm-fixes into drm-misc-fixes

Backmerging to get latest upstream.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-misc-next

Backmerging to get v6.3-rc1 and sync with the other DRM trees.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge remote-tracking branch 'acme/perf-tools' into perf-tools-next

To pick up perf-tools fixes just merged upstream.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge tag 'vfio-v6.3-rc1' of https://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

- Remove redundant resource check in vfio-platform (Angus Chen)

- Use GFP_KERNEL_ACCOU

Merge tag 'vfio-v6.3-rc1' of https://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

- Remove redundant resource check in vfio-platform (Angus Chen)

- Use GFP_KERNEL_ACCOUNT for persistent userspace allocations, allowing
removal of arbitrary kernel limits in favor of cgroup control (Yishai
Hadas)

- mdev tidy-ups, including removing the module-only build restriction
for sample drivers, Kconfig changes to select mdev support,
documentation movement to keep sample driver usage instructions with
sample drivers rather than with API docs, remove references to
out-of-tree drivers in docs (Christoph Hellwig)

- Fix collateral breakages from mdev Kconfig changes (Arnd Bergmann)

- Make mlx5 migration support match device support, improve source and
target flows to improve pre-copy support and reduce downtime (Yishai
Hadas)

- Convert additional mdev sysfs case to use sysfs_emit() (Bo Liu)

- Resolve copy-paste error in mdev mbochs sample driver Kconfig (Ye
Xingchen)

- Avoid propagating missing reset error in vfio-platform if reset
requirement is relaxed by module option (Tomasz Duszynski)

- Range size fixes in mlx5 variant driver for missed last byte and
stricter range calculation (Yishai Hadas)

- Fixes to suspended vaddr support and locked_vm accounting, excluding
mdev configurations from the former due to potential to indefinitely
block kernel threads, fix underflow and restore locked_vm on new mm
(Steve Sistare)

- Update outdated vfio documentation due to new IOMMUFD interfaces in
recent kernels (Yi Liu)

- Resolve deadlock between group_lock and kvm_lock, finally (Matthew
Rosato)

- Fix NULL pointer in group initialization error path with IOMMUFD (Yan
Zhao)

* tag 'vfio-v6.3-rc1' of https://github.com/awilliam/linux-vfio: (32 commits)
vfio: Fix NULL pointer dereference caused by uninitialized group->iommufd
docs: vfio: Update vfio.rst per latest interfaces
vfio: Update the kdoc for vfio_device_ops
vfio/mlx5: Fix range size calculation upon tracker creation
vfio: no need to pass kvm pointer during device open
vfio: fix deadlock between group lock and kvm lock
vfio: revert "iommu driver notify callback"
vfio/type1: revert "implement notify callback"
vfio/type1: revert "block on invalid vaddr"
vfio/type1: restore locked_vm
vfio/type1: track locked_vm per dma
vfio/type1: prevent underflow of locked_vm via exec()
vfio/type1: exclude mdevs from VFIO_UPDATE_VADDR
vfio: platform: ignore missing reset if disabled at module init
vfio/mlx5: Improve the target side flow to reduce downtime
vfio/mlx5: Improve the source side flow upon pre_copy
vfio/mlx5: Check whether VF is migratable
samples: fix the prompt about SAMPLE_VFIO_MDEV_MBOCHS
vfio/mdev: Use sysfs_emit() to instead of sprintf()
vfio-mdev: add back CONFIG_VFIO dependency
...

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vfio: Use GFP_KERNEL_ACCOUNT for userspace persistent allocations

Use GFP_KERNEL_ACCOUNT for userspace persistent allocations.

The GFP_KERNEL_ACCOUNT option lets the memory allocator know that this

vfio: Use GFP_KERNEL_ACCOUNT for userspace persistent allocations

Use GFP_KERNEL_ACCOUNT for userspace persistent allocations.

The GFP_KERNEL_ACCOUNT option lets the memory allocator know that this
is untrusted allocation triggered from userspace and should be a subject
of kmem accounting, and as such it is controlled by the cgroup
mechanism.

The way to find the relevant allocations was for example to look at the
close_device function and trace back all the kfrees to their
allocations.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230108154427.32609-4-yishaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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Merge branch 'main' into zstd-linus

Merge branch 'for-6.2/apple' into for-linus

- new quirks for select Apple keyboards (Kerem Karabay, Aditya Garg)

Merge branch 'next' into for-linus

Prepare input updates for 6.2 merge window.

Merge branch 'rework/console-list-lock' into for-linus

Merge drm/drm-next into drm-misc-next-fixes

Backmerging to update drm-misc-next-fixes for the final phase
of the release cycle.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-intel-next

Catch up on 6.1-rc cycle in order to solve the intel_backlight
conflict on linux-next.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>