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Subject: Re: [patch V2 27/46] x86/xen: Rework MSI teardown
To:     Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>
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References: <20200826111628.794979401@linutronix.de>
 <20200826112333.326841410@linutronix.de>
From:   =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= <jgross@suse.com>
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Date:   Thu, 27 Aug 2020 09:46:22 +0200
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On 26.08.20 13:16, Thomas Gleixner wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
> 
> X86 cannot store the irq domain pointer in struct device without breaking
> XEN because the irq domain pointer takes precedence over arch_*_msi_irqs()
> fallbacks.
> 
> XENs MSI teardown relies on default_teardown_msi_irqs() which invokes
> arch_teardown_msi_irq(). default_teardown_msi_irqs() is a trivial iterator
> over the msi entries associated to a device.
> 
> Implement this loop in xen_teardown_msi_irqs() to prepare for removal of
> the fallbacks for X86.
> 
> This is a preparatory step to wrap XEN MSI alloc/free into a irq domain
> which in turn allows to store the irq domain pointer in struct device and
> to use the irq domain functions directly.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen