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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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.