diff --git a/tests/qtest/acpi-bits/bits-tests/meson.build b/tests/qtest/acpi-bits/bits-tests/meson.build
index 3056731a53..06bca75d99 100644
--- a/tests/qtest/acpi-bits/bits-tests/meson.build
+++ b/tests/qtest/acpi-bits/bits-tests/meson.build
@@ -1,4 +1,4 @@
-test_files = ['smbios.py', 'testacpi.py', 'testcpuid.py']
+test_files = ['smbios.py', 'smilatency.py', 'testacpi.py', 'testcpuid.py']
 
 copytestfiles = custom_target('copy test files',
   input : test_files,
diff --git a/tests/qtest/acpi-bits/bits-tests/smilatency.py b/tests/qtest/acpi-bits/bits-tests/smilatency.py
new file mode 100644
index 0000000000..fb1b7228e3
--- /dev/null
+++ b/tests/qtest/acpi-bits/bits-tests/smilatency.py
@@ -0,0 +1,102 @@
+# Copyright (c) 2015, Intel Corporation
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+#     * Redistributions of source code must retain the above copyright notice,
+#       this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above copyright notice,
+#       this list of conditions and the following disclaimer in the documentation
+#       and/or other materials provided with the distribution.
+#     * Neither the name of Intel Corporation nor the names of its contributors
+#       may be used to endorse or promote products derived from this software
+#       without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""SMI latency test."""
+
+import bits
+from collections import namedtuple
+import testsuite
+import time
+import usb
+
+def register_tests():
+    testsuite.add_test("SMI latency test", smi_latency);
+    testsuite.add_test("SMI latency test with USB disabled via BIOS handoff", test_with_usb_disabled, runall=False);
+
+def smi_latency():
+    MSR_SMI_COUNT = 0x34
+
+    print "Warning: touching the keyboard can affect the results of this test."
+
+    tsc_per_sec = bits.tsc_per_sec()
+    tsc_per_usec = tsc_per_sec / (1000 * 1000)
+    bins = [long(tsc_per_usec * 10**i) for i in range(9)]
+    bin_descs = [
+        "0     < t <=   1us",
+        "1us   < t <=  10us",
+        "10us  < t <= 100us",
+        "100us < t <=   1ms",
+        "1ms   < t <=  10ms",
+        "10ms  < t <= 100ms",
+        "100ms < t <=   1s ",
+        "1s    < t <=  10s ",
+        "10s   < t <= 100s ",
+        "100s  < t         ",
+    ]
+
+    print "Starting test. Wait here, I will be back in 15 seconds."
+    (max_latency, smi_count_delta, bins) = bits.smi_latency(long(15 * tsc_per_sec), bins)
+    BinType = namedtuple('BinType', ("max", "total", "count", "times"))
+    bins = [BinType(*b) for b in bins]
+
+    testsuite.test("SMI latency < 150us to minimize risk of OS timeouts", max_latency / tsc_per_usec <= 150)
+    if not testsuite.show_detail():
+        return
+
+    for bin, desc in zip(bins, bin_descs):
+        if bin.count == 0:
+            continue
+        testsuite.print_detail("{}; average = {}; count = {}".format(desc, bits.format_tsc(bin.total/bin.count), bin.count))
+        deltas = (bits.format_tsc(t2 - t1) for t1,t2 in zip(bin.times, bin.times[1:]))
+        testsuite.print_detail(" Times between first few observations: {}".format(" ".join("{:>6}".format(delta) for delta in deltas)))
+
+    if smi_count_delta is not None:
+        testsuite.print_detail("{} SMI detected using MSR_SMI_COUNT (MSR {:#x})".format(smi_count_delta, MSR_SMI_COUNT))
+
+    testsuite.print_detail("Summary of impact: observed maximum latency = {}".format(bits.format_tsc(max_latency)))
+
+def test_with_usb_disabled():
+    if usb.handoff_to_os():
+        smi_latency()
+
+def average_io_smi(port, value, count):
+    def f():
+        tsc_start = bits.rdtsc()
+        bits.outb(port, value)
+        return bits.rdtsc() - tsc_start
+    counts = [f() for i in range(count)]
+    return sum(counts)/len(counts)
+
+def time_io_smi(port=0xb2, value=0, count=1000):
+    count_for_estimate = 10
+    start = time.time()
+    average_io_smi(port, value, count_for_estimate)
+    avg10 = time.time() - start
+    estimate = avg10 * count/count_for_estimate
+    if estimate > 1:
+        print "Running test, estimated time: {}s".format(int(estimate))
+    average = average_io_smi(port, value, count)
+    print "Average of {} SMIs (via outb, port={:#x}, value={:#x}): {}".format(count, port, value, bits.format_tsc(average))
