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* [PATCH 0/1] x86/hyperv: MSI parent domain conversion
@ 2025-06-26 14:47 Nam Cao
  2025-06-26 14:47 ` [PATCH 1/1] x86/hyperv: Switch to msi_create_parent_irq_domain() Nam Cao
  0 siblings, 1 reply; 4+ messages in thread
From: Nam Cao @ 2025-06-26 14:47 UTC (permalink / raw)
  To: K . Y . Srinivasan, Marc Zyngier, Haiyang Zhang, Wei Liu,
	Dexuan Cui, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	Dave Hansen, x86, H . Peter Anvin, linux-hyperv, linux-kernel
  Cc: Nam Cao

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 converts the x86 hyperv driver to implement MSI parent domain.

 arch/x86/hyperv/irqdomain.c | 107 ++++++++++++++++++++++++------------
 drivers/hv/Kconfig          |   1 +
 2 files changed, 73 insertions(+), 35 deletions(-)

-- 
2.39.5


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2025-06-28 15:19 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2025-06-26 14:47 [PATCH 0/1] x86/hyperv: MSI parent domain conversion Nam Cao
2025-06-26 14:47 ` [PATCH 1/1] x86/hyperv: Switch to msi_create_parent_irq_domain() Nam Cao
2025-06-27 21:03   ` kernel test robot
2025-06-28 15:18   ` kernel test robot

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