Re: [PATCH V2 1/5] ara virt interface of perf to support kvm guestos statistics collection in guest os

From: Avi Kivity
Date: Tue Jun 22 2010 - 05:54:28 EST


On 06/22/2010 12:46 PM, Peter Zijlstra wrote:

Avi's suggestion of using virtual MSRs makes a ton of sense for this
though, and it makes it possible to switch direct access on/off for the
cases where direct access is possible, and go emulated when it isn't.
/me has no clue what virtual MSRs are,

MSRs that are not defined by the hardware, but instead by the hypervisor.

but yeah, that sounds about
right. Anyway, the generic case is full trap and emulate get that
working first, then try and be smart and avoid some traps.

I doubt we can avoid traps for the paravirt PMU since the counter indexes will not match.

When emulating the hardware PMU we can be clever at times and allow RDPMC not to trap.

--
error compiling committee.c: too many arguments to function

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