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From:   Thomas Gleixner <tglx@linutronix.de>
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Subject: Re: [PATCH RFC v2 02/18] irq/dev-msi: Add support for a new DEV_MSI irq domain
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Date:   Tue, 11 Aug 2020 11:53:31 +0200
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Thomas Gleixner <tglx@linutronix.de> writes:

CC+: XEN folks

> Thomas Gleixner <tglx@linutronix.de> writes:
>> The infrastructure itself is not more than a thin wrapper around the
>> existing msi domain infrastructure and might even share code with
>> platform-msi.
>
> And the annoying fact that you need XEN support which opens another can
> of worms...

which needs some real cleanup first.

x86 still does not associate the irq domain to devices at device
discovery time, i.e. the device::msi_domain pointer is never populated.

So to support this new fangled device MSI stuff we'd need yet more
x86/xen specific arch_*msi_irqs() indirection and hackery, which is not
going to happen.

The right thing to do is to convert XEN MSI support over to proper irq
domains. This allows to populate device::msi_domain which makes a lot of
things simpler and also more consistent.

Thanks,

        tglx