The initial implementation of PCI/MSI interrupt domains in the hierarchical interrupt domain model used a shortcut by providing a global PCI/MSI domain.
This works because the PCI/MSI[X] hardware is standardized and uniform, but it violates the basic design principle of hierarchical interrupt domains: Each hardware block involved in the interrupt delivery chain should have a separate interrupt domain. For PCI/MSI[X], the interrupt controller is per PCI device and not a global made-up entity. Unsurprisingly, the shortcut turned out to have downsides as it does not allow dynamic allocation of interrupt vectors after initialization and it prevents supporting IMS on PCI. For further details, see: https://lore.kernel.org/lkml/20221111120501.026511...@linutronix.de/ The solution is implementing per device MSI domains, this means the entities which provide global PCI/MSI domain so far have to implement MSI parent domain functionality instead. This series: - Untangle XIVE driver from Powernv and Pseries drivers - Convert the Powernv and Pseries drivers to implement MSI parent domain functionality Nam Cao (3): powerpc/xive: Untangle xive from child interrupt controller drivers powerpc/powernv/pci: Switch to use msi_create_parent_irq_domain() powerpc/pseries/msi: Switch to msi_create_parent_irq_domain() arch/powerpc/include/asm/pci-bridge.h | 2 - arch/powerpc/include/asm/xive.h | 1 - arch/powerpc/platforms/powernv/Kconfig | 1 + arch/powerpc/platforms/powernv/pci-ioda.c | 96 ++++++----------- arch/powerpc/platforms/pseries/Kconfig | 1 + arch/powerpc/platforms/pseries/msi.c | 124 ++++++++-------------- arch/powerpc/sysdev/xive/common.c | 63 ++++++----- 7 files changed, 113 insertions(+), 175 deletions(-) -- 2.39.5
