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[Xen-devel] Re: [PATCH] [PVOPS] dom0 sync xen wallclock

To: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Subject: [Xen-devel] Re: [PATCH] [PVOPS] dom0 sync xen wallclock
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Fri, 19 Feb 2010 15:05:04 -0800
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>
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On 02/19/2010 01:10 AM, Ian Campbell wrote:
Unfortunately there is an existing large installed base of guests which
use the dependent wallclock mode since it is the default in oldstyle Xen
kernels.

Sure. I'm not suggesting that we remove the existing hypercall. I just don't think we should extend it or encourage its use.

     * HVM domains similarly get an emulated CMOS implemented in qemu
Isn't this currently emulated within the hypervisor using the wallclock
time within Xen? I assume that it was pulled into the h/v for a specific
reason? I'm not sure what reason though, the emulated RTC doesn't seem
especially performance critical...

It is?  I wonder why we bothered adding a pvop for it then...

    J

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