[PATCH v3] powerpc/pci: unmap legacy INTx interrupts when a PHB is removed

[Cédric Le Goater]

On 9/23/20 9:40 AM, Cédric Le Goater wrote:
> 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.
> 
> To solve this problem, we introduce a PPC platform specific
> pcibios_remove_bus() routine which clears all interrupt mappings when
> the bus is removed. This also clears the associated page table entries
> of the ESB pages when using XIVE.
> 
> For this purpose, we record the logical interrupt numbers of the
> mapped interrupt under the PHB structure and let pcibios_remove_bus()
> do the clean up.
> 
> Since some PCI adapters, like GPUs, use the "interrupt-map" property
> to describe interrupt mappings other than the legacy INTx interrupts,
> we can not restrict the size of the mapping array to PCI_NUM_INTX. The
> number of interrupt mappings is computed from the "interrupt-map"
> property and the mapping array is allocated accordingly.
> 
> Cc: "Oliver O'Halloran" <oohall at gmail.com>
> Cc: Alexey Kardashevskiy <aik at ozlabs.ru>
> Reviewed-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> Signed-off-by: Cédric Le Goater <clg at kaod.org>
> ---
> 
>  Changes in v3 :
> 
>  - NULLified 'irq_map' in pci_irq_map_dispose()


Forge that. I am going to move the kfree() in the routine freeing the 
PCI controller structure.

Thanks,

C.