Hello Rich,
Could you tell me how can I tell it works?  I only find some message from boot debug logs.

"    
    -cpu host,+kvmclock \
    ...
    kvm-clock: Using msrs 4b564d01 and 4b564d00
    kvm-clock: cpu 0, msr 0:1c247c1, boot clock
    kvm-clock: cpu 0, msr 0:22167c1, primary cpu clock
    [    0.381003] Switching to clocksource kvm-clock
"
Is it enough?

(In reply to bfan from comment #1)
> Hello Rich,
> Could you tell me how can I tell it works?

https://rwmj.wordpress.com/2010/10/15/kvm-pvclock/#content

> I only find some message from
> boot debug logs.
> 
> "    
>     -cpu host,+kvmclock \
>     ...
>     kvm-clock: Using msrs 4b564d01 and 4b564d00
>     kvm-clock: cpu 0, msr 0:1c247c1, boot clock
>     kvm-clock: cpu 0, msr 0:22167c1, primary cpu clock
>     [    0.381003] Switching to clocksource kvm-clock
> "
> Is it enough?

This is sufficient to verify the bug fix IMHO.

Verify this bug according to #comment 2
libguestfs-1.20.11-2.el6.x86_64

[root@dhcp-9-42 home]# guestfish -x -v -N fs > boot.log 2>&1
[root@dhcp-9-42 home]# cat boot.log | grep -Ei "kvmclock|kvm-clock"
    -cpu host,+kvmclock \
kvm-clock: Using msrs 4b564d01 and 4b564d00
kvm-clock: cpu 0, msr 0:1c247c1, boot clock
kvm-clock: cpu 0, msr 0:22167c1, primary cpu clock
[    0.153354] Switching to clocksource kvm-clock

So change the status to verified

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2013-1536.html