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# Copyright (c) 2015, Intel Corporation
# All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause
# 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.
# This script runs only from the biosbits VM.
"""SMI latency test."""
import bits
from collections import namedtuple
import testsuite
import time
import usb
def register_tests():
pass
# 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))
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