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Re: [Xen-devel] Real-time support

To: "Ky Srinivasan" <ksrinivasan@xxxxxxxxxx>
Subject: Re: [Xen-devel] Real-time support
From: "Geoffrey Lefebvre" <geoffrey@xxxxxxxxx>
Date: Fri, 11 May 2007 10:53:20 -0700
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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One way to deal with the problem you mention here is to have the guest OS have 
the smarts to (a) check for preemption conditions that may arise because a 
higher priority thread in the guest is runnable and (b) re-issue the hypercall 
that was only partially completed.

Hi,

Yes i agree.  Preempting the hypercall and returning an indication of
forward progress to the guest as is currently done with multicall, etc
should work. I misunderstood Ian Pratt's earlier suggestion. I thought
his idea was to preempt the hypercall and keep preemption state inside
the hypervisor. My mistake :).

cheers,

Geoffrey

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