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Re: [Xen-devel] Timer going backwards and Unable to handle kernel NULLpo

To: Jan Beulich <jbeulich@xxxxxxxxxx>, Ian Pratt <Ian.Pratt@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Timer going backwards and Unable to handle kernel NULLpointer
From: Keir Fraser <keir@xxxxxxxxxxxxx>
Date: Wed, 30 May 2007 18:31:04 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, Robert Hulme <rob@xxxxxxxxxxxx>
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On 30/5/07 17:25, "Keir Fraser" <keir@xxxxxxxxxxxxx> wrote:

> How about if we add support for ACPI PM timer as platform clock source?
> Should be easy, any ACPI system will most likely provide it, and it should
> be much better to use than the PIT (even a 24-bit PM timer should only wrap
> every 5 seconds). We'll have to prevent dom0 monkeying with the timer:
> either disallow accesses, or emulate the register.

I've now done this in c/s 15189:2d7d33ac982. Works okay on my test box and
is now available from the staging tree. I didn't implement anything to stop
dom0 clobbering the timer register, as we don't currently do so for cyclone
or hpet time sources either. We can add it if it turns out to be a problem.

 -- Keir

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