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Niklas Schnelle
dc287e4c91
Since commit25f39d3dcb("s390/pci: Ignore RID for isolated VFs") PFs which are not initially configured but in standby are considered isolated. That is they create only a single function PCI domain. Due to the PCI domains being created on discovery, this means that even if they are configured later on, sibling PFs and their child VFs will not be added to their PCI domain breaking SR-IOV expectations. The reason the referenced commit ignored standby PFs for the creation of multi-function PCI subhierarchies, was to work around a PCI domain renumbering scenario on reboot. The renumbering would occur after removing a previously in standby PF, whose domain number is used for its configured sibling PFs and their child VFs, but which itself remained in standby. When this is followed by a reboot, the sibling PF is used instead to determine the PCI domain number of it and its child VFs. In principle it is not possible to know which standby PFs will be configured later and which may be removed. The PCI domain and root bus are pre-requisites for hotplug slots so the decision of which functions belong to which domain can not be postponed. With the renumbering occurring only in rare circumstances and being generally benign, accept it as an oddity and fix SR-IOV for initially standby PFs simply by allowing them to create PCI domains. Cc: stable@vger.kernel.org Reviewed-by: Gerd Bayer <gbayer@linux.ibm.com> Fixes:25f39d3dcb("s390/pci: Ignore RID for isolated VFs") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.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 reStructuredText 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.