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Date: Thu, 11 Sep 2014 14:08:34 +0100
From: David Vrabel <david.vrabel@citrix.com>
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To: Yijing Wang <wangyijing@huawei.com>, David Vrabel
 <david.vrabel@citrix.com>, Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [Xen-devel] [PATCH v1 04/21] x86/xen/MSI: Eliminate
 arch_msix_mask_irq() and arch_msi_mask_irq()
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On 11/09/14 02:22, Yijing Wang wrote:
> On 2014/9/10 20:36, David Vrabel wrote:
>> On 05/09/14 11:09, Yijing Wang wrote:
>>> Commit 0e4ccb150 added two __weak arch functions arch_msix_mask_irq()
>>> and arch_msi_mask_irq() to fix a bug found when running xen in x86.
>>> Introduced these two funcntions make MSI code complex. And mask/unmask
>>> is the irq actions related to interrupt controller, should not use
>>> weak arch functions to override mask/unmask interfaces. This patch
>>> reverted commit 0e4ccb150 and export struct irq_chip msi_chip, modify
>>> msi_chip->irq_mask/irq_unmask() in xen init functions to fix this
>>> bug for simplicity. Also this is preparation for using struct
>>> msi_chip instead of weak arch MSI functions in all platforms.
>>
>> Acked-by: David Vrabel <david.vrabel@citrix.com>
>>
>> But I wonder if it would be better the Xen subsystem to provide its own
>> struct irq_chip instead of adjusting the fields in the generic x86 one.
> 
> Thanks! Currently, Xen and the bare x86 system only have the different irq_chip->irq_mask/irq_unmask.
> So I chose to override the two ops of bare x86 irq_chip in xen. Konrad Rzeszutek Wilk has been tested it
> ok in his platform, so I think we could use its own irq_chip for xen later if the difference become large.

This sounds reasonable.

David