Re: [PATCH 2/3] powerpc/pci: unmap legacy INTx interrupts of passthrough IO adapters
From: Cédric Le Goater <clg@kaod.org>
Date: 2020-05-27 12:29:36
From: Cédric Le Goater <clg@kaod.org>
Date: 2020-05-27 12:29:36
Hello Michael, On 4/29/20 9:51 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, pHyp, expects the guest OS to have cleared 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. INTx interrupt numbers need special care because Linux maps the interrupts automatically in the Linux interrupt number space if they are presented in the device tree node describing the IO adapter. These interrupts are not un-mapped automatically and in case of an hot-plug adapter, the PCI hot-plug layer needs to handle the cleanup to make sure that all the page table entries of the XIVE ESB pages are cleared.
It seems this patch needs more digging to make sure we are handling the IRQ unmapping in the correct PCI handler. Could you please keep it back for the moment ? Thanks, C.