From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <jbeulich@novell.com>
Subject: Re: irq_guest_eoi_timer interaction with MSI
Date: Tue, 25 Nov 2008 10:12:05 +0000
Message-ID: <492BDD85.76E4.0078.0@novell.com>
References: <492AE5B6.76E4.0078.0@novell.com>
	<C5508EB7.295BA%keir.fraser@eu.citrix.com>
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>>> Keir Fraser <keir.fraser@eu.citrix.com> 24.11.08 18:02 >>>
>Setting the need-a-hypercall bit looks racey. Don't you need to set the =
bit,
>then check the guest didn't unmask meanwhile?

What would the action be in that case? Try send_guest_pirq() a second
time, and not arm the timer (along with clearing all the bits again) if =
one
of the guests is now able to accept it? Would seem too complicated to me
(the more that then the HVM case would need to be taken care of
explicitly), given that all we try to avoid is a 1ms gap in delivering the
next event. But it would be doable of course.

Jan