diff --git a/client/tests/kvm/tests/cpu_set.py b/client/tests/kvm/tests/cpu_set.py
new file mode 100644
index 0000000..72213f6
--- /dev/null
+++ b/client/tests/kvm/tests/cpu_set.py
@@ -0,0 +1,92 @@
+import os, logging, re
+from autotest_lib.client.common_lib import error
+from autotest_lib.client.bin import utils
+import kvm_subprocess, kvm_utils, kvm_test_utils
+
+def run_cpu_set(test, params, env):
+    """
+    Runs CPU set test:
+
+    1) Pick up a living guest
+    2) Send the monitor command cpu_set [n cpus]
+    3) Verify if guest has the additional CPU showing up under
+        /sys/devices/system/cpu
+    4) Try to bring it online by writing 1 to the 'online' file inside that dir
+    5) Run the CPU Hotplug test suite shipped with autotest inside guest
+
+    @param test: kvm test object.
+    @param params: Dictionary with test parameters.
+    @param env: Dictionary with the test environment.
+    """
+    vm = kvm_test_utils.get_living_vm(env, params.get("main_vm"))
+    session = kvm_test_utils.wait_for_login(vm)
+
+    n_cpus_add = int(params.get("n_cpus_add", 1))
+    current_cpus = int(params.get("smp", 1))
+    total_cpus = current_cpus + n_cpus_add
+    # As of today (01-21-2010) it is unlikely that we're going to raise the
+    # number of processors of a VM to anywhere near 100, but still, it's good
+    # to put some boundaries to the test
+    if total_cpus > 100:
+        raise error.TestError("Unsupported number of total CPUs: %s. "
+                              "Please choose a smaller number." % total_cpus)
+
+    dmesg_before = session.get_command_output("dmesg -c")
+
+    logging.info("Adding %d CPUs to guest" % n_cpus_add)
+    (ret, output) = vm.send_monitor_cmd("cpu_set %s online" % total_cpus)
+    if ret != 0:
+        raise error.TestFail("Failed to add CPUs to guest: %s" % output)
+
+    dmesg_after = session.get_command_output("dmesg -c")
+
+    logging.debug("Guest dmesg output after CPU add:\n%s" % dmesg_after)
+
+    # Verify whether the new cpus are showing up on /sys
+    n_cmd = 'find /sys/devices/system/cpu/cpu[0-99] -maxdepth 0 -type d | wc -l'
+    try:
+        cpus_after_addition = int(session.get_command_output(n_cmd))
+    except ValueError:
+        raise error.TestFail("Unable to get CPU count after CPU addition "
+                             "(Guest dead?)")
+
+    if cpus_after_addition != total_cpus:
+        raise error.TestFail("%s CPUs are showing up under "
+                             "/sys/devices/system/cpu, was expecting %s" %
+                             (cpus_after_addition, total_cpus))
+
+    r_cmd = 'find /sys/devices/system/cpu/cpu[0-99]/online -maxdepth 0 -type f'
+    online_files = session.get_command_output(r_cmd).split().sort()
+
+    if not online_files:
+        raise error.TestFail("Could not find CPUs that can be "
+                             "enabled/disabled on guest")
+
+    for online_file in online_files:
+        cpu_regexp = re.compile("cpu(\d+)", re.IGNORECASE)
+        cpu_id = cpu_regexp.findall(online_file)[0]
+        try:
+            online_status = int(session.get_command_output("cat %s" %
+                                                           online_file))
+        except ValueError:
+            raise error.TestFail("Unable to get online status from CPU %s "
+                                 "(Guest dead?)" % cpu_id)
+        if online_status == 0:
+            logging.debug("CPU %s offline, bringing it online" % cpu_id)
+            rc = session.get_command_status("echo 1 > %s" % online_file)
+            if rc != 0:
+                raise error.TestError("Error bringing guest CPU %s online" %
+                                      cpu_id)
+
+    # Now that all CPUs were onlined, let's execute the
+    # autotest CPU Hotplug test
+    timeout = int(params.get("cpu_hotplug_timeout"))
+    test_name = "cpu_hotplug"
+    control_path = os.path.join(test.bindir, "autotest_control",
+                                "cpu_hotplug.control")
+    outputdir = test.outputdir
+
+    logging.info("Executing CPU hotplug autotest on guest")
+    kvm_test_utils.run_autotest(vm, session, control_path, timeout, test_name,
+                                outputdir)
+
diff --git a/client/tests/kvm/tests_base.cfg.sample b/client/tests/kvm/tests_base.cfg.sample
index b00ed9e..07b394a 100644
--- a/client/tests/kvm/tests_base.cfg.sample
+++ b/client/tests/kvm/tests_base.cfg.sample
@@ -287,6 +287,11 @@ variants:
         kill_vm = yes
         kill_vm_gracefully = no
 
+    - cpu_set:
+        type = cpu_set
+        cpu_hotplug_timeout = 600
+        n_cpus_add = 1
+
     - system_reset: install setup unattended_install
         type = boot
         reboot_method = system_reset
