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RE: [Xen-devel] [PATCH] new hvm platform vhpet enable parameter

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] new hvm platform vhpet enable parameter
From: "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx>
Date: Thu, 7 Feb 2008 11:29:32 -0700
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> HPET is also advertised in the ACPI tables which would need 
> to be gated.

Could you point me in the right direction?  I see that a Linux
hvm kernel still prints a line indicating it has discovered
an HPET in the ACPI tables, but I couldn't find anything in
hvm code that would turn that off, and I just want to turn off
HPET per guest, not for Xen and all guests.

> Should be called vhpet not hpet as the 'v' is rather redundant.

OK, will fix

> Why would we want to do the same for pmtimer? Is it inaccurate?

If Linux were using it as a timekeeping source, I think it would
be (per earlier post by Dave Winchell), but on second look once
HPET is disabled, Linux discovers pmtimer but still uses PIT/TSC
based timekeeping.  So an equivalent pmtimer patch might be
needed for some future version of Linux but I guess we won't worry
about that now.

> From: Samuel Thibault [mailto:samuel.thibault@xxxxxxxxxxxxx]
> > This patch applies against and was tested with xen-3.1-testing.
> Mmm, that's a bit old, maybe you should check it against 3.2

Will do.  3.1 is my daily test/dev environment so I started there.


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