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91fa127794
Add a simple sysfs interface to Resizable BAR support, largely for the purposes of assigning such devices to a VM through VFIO. Resizable BARs present a difficult feature to expose to a VM through emulation, as resizing a BAR is done on the host. It can fail, and often does, but we have no means via emulation of a PCIe REBAR capability to handle the error cases. A vfio-pci specific ioctl interface is also cumbersome as there are often multiple devices within the same bridge aperture and handling them is a challenge. In the interface proposed here, expanding a BAR potentially requires such devices to be soft-removed during the resize operation and rescanned after, in order for all the necessary resources to be released. A pci-sysfs interface is also more universal than a vfio specific interface. Please see the ABI documentation update for usage. Link: https://lore.kernel.org/r/166336088796.3597940.14973499936692558556.stgit@omen Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Christian König <christian.koenig@amd.com> Cc: Krzysztof Wilczyński <kw@linux.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.