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[Xen-devel] Re: the irq_enter in do_IRQ

To: "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>
Subject: [Xen-devel] Re: the irq_enter in do_IRQ
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Sat, 18 Sep 2010 08:59:36 +0100
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On 18/09/2010 03:22, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> wrote:

> Hi, Keir, in do_IRQ,  why do we call the irq_enter only in __do_IRQ_guest and
> the action->handler(), instead of the whole flow of do_IRQ?
> I asked this because we noticed a bug that the map/unmap_domain_page() is
> called in a interrupt handler's ack() method, which is not guarded by
> irq_enter(), thus the "ASSERT(!in_irq())" in map/unmap_domain_page() is not
> work expected to guard this calling.

Okay, xen-unstable:22175 fixes do_IRQ() to be better covered by
irq_enter()/irq_exit(). Xen-unstable:22177 fixes
map_domain_page()/unmap_domain_page() to be IRQ safe.

If these work okay for you then they are candidates for backport for 4.0.2.

 -- Keir

> Thanks
> --jyh

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