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From: Nam Cao <namcao@linutronix.de>
To: Madhavan Srinivasan <maddy@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>,
	Gautam Menghani <gautam@linux.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Cc: Nam Cao <namcao@linutronix.de>
Subject: [PATCH v2 0/3] powerpc: Cleanup and convert to MSI parent domain
Date: Mon, 11 Aug 2025 11:28:53 +0200	[thread overview]
Message-ID: <cover.1754903590.git.namcao@linutronix.de> (raw)

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/20221111120501.026511281@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

v2: Fix up boot issue with NVMe

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      | 132 ++++++++--------------
 arch/powerpc/sysdev/xive/common.c         |  63 +++++------
 7 files changed, 117 insertions(+), 179 deletions(-)

-- 
2.39.5



             reply	other threads:[~2025-08-11  9:29 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-11  9:28 Nam Cao [this message]
2025-08-11  9:28 ` [PATCH v2 1/3] powerpc/xive: Untangle xive from child interrupt controller drivers Nam Cao
2025-10-07  3:24   ` Ritesh Harjani
2025-10-07  5:24     ` Nam Cao
2025-10-07 15:08       ` Nam Cao
2025-08-11  9:28 ` [PATCH v2 2/3] powerpc/powernv/pci: Switch to use msi_create_parent_irq_domain() Nam Cao
2025-08-11  9:28 ` [PATCH v2 3/3] powerpc/pseries/msi: Switch to msi_create_parent_irq_domain() Nam Cao
2025-09-03 14:07 ` [PATCH v2 0/3] powerpc: Cleanup and convert to MSI parent domain Thomas Gleixner
2025-09-06 11:48   ` Madhavan Srinivasan
2025-09-12  3:56 ` Madhavan Srinivasan

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