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450be4960a
When a passthrough IO adapter is removed from a pseries machine using hash MMU and the XIVE interrupt mode, the POWER hypervisor expects the guest OS to clear all page table entries related to the adapter. If some are still present, the RTAS call which isolates the PCI slot returns error 9001 "valid outstanding translations" and the removal of the IO adapter fails. This is because when the PHBs are scanned, Linux maps automatically the INTx interrupts in the Linux interrupt number space but these are never removed. This problem can be fixed by adding the corresponding unmap operation when the device is removed. There's no pcibios_* hook for the remove case, but the same effect can be achieved using a bus notifier. Because INTx are shared among PHBs (and potentially across the system), this adds tracking of virq to unmap them only when the last user is gone. [aik: added refcounter] Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Tested-by: Cédric Le Goater <clg@kaod.org> Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201202005222.5477-1-aik@ozlabs.ru
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.