From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Desfossez <ju@klipix.org>
Subject: Accessing host TSC from a guest kernel
Date: Thu, 23 Sep 2010 22:49:43 -0400
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Hello,

I'd like to access the host TSC from the inside of a guest kernel and I
don't really know if it's possible.

I'm working with kvm_clock and I have been playing with the
pvclock_vcpu_time_info structure, but I'm not sure if I'm in the right
direction.

So could you tell me if there is an efficient way to access to access
the host TSC (or at least the TSC_OFFSET) from a module inside a guest
kernel ?

I did it with an hypercall, but it's for tracing purpose and doing an
hypercall every time I want to record an event, is way too costly.

Thanks,

Julien