Re: [PATCH v2 2/2] iotests: test NBD+TLS+iothread

[Eric Blake]

Adding a bit of self-review (in case you want to amend this before
pushing, instead of waiting for me to get back online),

On Fri, May 17, 2024 at 09:50:15PM GMT, Eric Blake wrote:
> Prevent regressions when using NBD with TLS in the presence of
> iothreads, adding coverage the fix to qio channels made in the
> previous patch.
> 
> CC: qemu-stable@nongnu.org
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  tests/qemu-iotests/tests/nbd-tls-iothread     | 170 ++++++++++++++++++
>  tests/qemu-iotests/tests/nbd-tls-iothread.out |  54 ++++++
>  2 files changed, 224 insertions(+)
>  create mode 100755 tests/qemu-iotests/tests/nbd-tls-iothread
>  create mode 100644 tests/qemu-iotests/tests/nbd-tls-iothread.out
> 
> diff --git a/tests/qemu-iotests/tests/nbd-tls-iothread 
> b/tests/qemu-iotests/tests/nbd-tls-iothread
> new file mode 100755
> index 00000000000..a737224a90e
> --- /dev/null
> +++ b/tests/qemu-iotests/tests/nbd-tls-iothread
> @@ -0,0 +1,170 @@
> +#!/usr/bin/env bash
> +# group: rw quick
> +#
> +# Test of NBD+TLS+iothread
> +#
> +# Copyright (C) 2024 Red Hat, Inc.
> +#
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 2 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +#
> +
> +# creator
> +owner=eblake@redhat.com
> +
> +seq=`basename $0`
> +echo "QA output created by $seq"
> +
> +status=1    # failure is the default!
> +
> +_cleanup()
> +{
> +    _cleanup_qemu
> +    _cleanup_test_img
> +    rm -f "$dst_image"
> +    tls_x509_cleanup
> +}
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +# get standard environment, filters and checks
> +cd ..
> +. ./common.rc
> +. ./common.filter
> +. ./common.qemu
> +. ./common.tls
> +. ./common.nbd
> +
> +_supported_fmt qcow2  # Hardcoded to qcow2 command line and QMP below
> +_supported_proto file
> +_require_command QEMU_NBD

This line can probably be dropped.  I originally included it thinking
I might reuse common.nbd's nbd_server_start_tcp_socket to pick an
unused port via a throwaway qemu-nbd, then kill the qemu-nbd process
before starting up the two qemu processes.  But in the end, using ss
to probe a port's use seems a bit more elegant than a throwaway
qemu-nbd process, although it may make CI testing harder by dragging
in another dependency that is less universal.

> +
> +# pick_unused_port
> +# Copied from nbdkit/tests/functions.sh.in with compatible 2-clause BSD 
> license

I'm not sure if I have to include the license text verbatim in this
file, and/or have this function moved to a helper utility file.  The
original source file that I borrowed pick_unused_port from has:

# Copyright Red Hat
#
# 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 Red Hat 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 RED HAT 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 RED HAT 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.


> +#
> +# Picks and returns an "unused" port, setting the global variable
> +# $port.
> +#
> +# This is inherently racy, but we need it because qemu does not currently
> +# permit NBD+TLS over a Unix domain socket
> +pick_unused_port ()
> +{
> +    if ! (ss --version) >/dev/null 2>&1; then
> +        _notrun "ss utility required, skipped this test"
> +    fi
> +
> +    # Start at a random port to make it less likely that two parallel
> +    # tests will conflict.
> +    port=$(( 50000 + (RANDOM%15000) ))
> +    while ss -ltn | grep -sqE ":$port\b"; do
> +        ((port++))
> +        if [ $port -eq 65000 ]; then port=50000; fi

Also, common.nbd only probes:
    for ((port = 10809; port <= 10909; port++))
and nbdkit's choice of starting with a random offset is interesting.

> +    done
> +    echo picked unused port

I'm not sure if there is any easy way to make an iotest output the
unfiltered text for debugging...

> +}
> +
> +tls_x509_init
> +
> +size=1G
> +DST_IMG="$TEST_DIR/dst.qcow2"
> +
> +echo
> +echo "== preparing TLS creds and spare port =="
> +
> +pick_unused_port
> +tls_x509_create_root_ca "ca1"
> +tls_x509_create_server "ca1" "server1"
> +tls_x509_create_client "ca1" "client1"
> +tls_obj_base=tls-creds-x509,id=tls0,verify-peer=true,dir="${tls_dir}"
> +
> +echo
> +echo "== preparing image =="
> +
> +_make_test_img $size
> +$QEMU_IMG create -f qcow2 "$DST_IMG" $size
> +
> +echo
> +echo === Starting Src QEMU ===
> +echo
> +
> +_launch_qemu -machine q35 \
> +    -object iothread,id=iothread0 \
> +    -object "${tls_obj_base}"/client1,endpoint=client \
> +    -device '{"driver":"pcie-root-port", "id":"root0", "multifunction":true,
> +              "bus":"pcie.0"}' \
> +    -device '{"driver":"virtio-scsi-pci", "id":"virtio_scsi_pci0",
> +              "bus":"root0", "iothread":"iothread0"}' \
> +    -device '{"driver":"scsi-hd", "id":"image1", "drive":"drive_image1",
> +              "bus":"virtio_scsi_pci0.0"}' \
> +    -blockdev '{"driver":"file", "cache":{"direct":true, "no-flush":false},
> +                "filename":"'"$TEST_IMG"'", "node-name":"drive_sys1"}' \
> +    -blockdev '{"driver":"qcow2", "node-name":"drive_image1",
> +                "file":"drive_sys1"}'
> +h1=$QEMU_HANDLE
> +_send_qemu_cmd $h1 '{"execute": "qmp_capabilities"}' 'return'
> +
> +echo
> +echo === Starting Dst VM2 ===
> +echo
> +
> +_launch_qemu -machine q35 \
> +    -object iothread,id=iothread0 \
> +    -object "${tls_obj_base}"/server1,endpoint=server \
> +    -device '{"driver":"pcie-root-port", "id":"root0", "multifunction":true,
> +              "bus":"pcie.0"}' \
> +    -device '{"driver":"virtio-scsi-pci", "id":"virtio_scsi_pci0",
> +              "bus":"root0", "iothread":"iothread0"}' \
> +    -device '{"driver":"scsi-hd", "id":"image1", "drive":"drive_image1",
> +              "bus":"virtio_scsi_pci0.0"}' \
> +    -blockdev '{"driver":"file", "cache":{"direct":true, "no-flush":false},
> +                "filename":"'"$DST_IMG"'", "node-name":"drive_sys1"}' \
> +    -blockdev '{"driver":"qcow2", "node-name":"drive_image1",
> +                "file":"drive_sys1"}' \
> +    -incoming defer
> +h2=$QEMU_HANDLE
> +_send_qemu_cmd $h2 '{"execute": "qmp_capabilities"}' 'return'
> +
> +echo
> +echo === Dst VM: Enable NBD server for incoming storage migration ===
> +echo
> +
> +_send_qemu_cmd $h2 '{"execute": "nbd-server-start", "arguments":
> +    {"addr": {"type": "inet", "data": {"host": "127.0.0.1", "port": 
> "'$port'"}},
> +              "tls-creds": "tls0"}}' '{"return": {}}' | sed 
> "s/\"$port\"/PORT/g"

...while still having only filtered text in the .out file to avoid
spurious mismatch due to the intentional non-determinism in the port
picked.

> +_send_qemu_cmd $h2 '{"execute": "block-export-add", "arguments":
> +    {"node-name": "drive_image1", "type": "nbd", "writable": true,
> +      "id": "drive_image1"}}' '{"return": {}}'
> +
> +echo
> +echo === Src VM: Mirror to dst NBD for outgoing storage migration ===
> +echo
> +
> +_send_qemu_cmd $h1 '{"execute": "blockdev-add", "arguments":
> +    {"node-name": "mirror", "driver": "nbd",
> +     "server": {"type": "inet", "host": "127.0.0.1", "port": "'$port'"},
> +     "export": "drive_image1", "tls-creds": "tls0",
> +     "tls-hostname": "127.0.0.1"}}' '{"return": {}}' | sed 
> "s/\"$port\"/PORT/g"
> +_send_qemu_cmd $h1 '{"execute": "blockdev-mirror", "arguments":
> +    {"sync": "full", "device": "drive_image1", "target": "mirror",
> +     "job-id": "drive_image1_53"}}' '{"return": {}}'
> +_timed_wait_for $h1 '"ready"'
> +
> +echo
> +echo === Cleaning up ===
> +echo
> +
> +_send_qemu_cmd $h1 '{"execute":"quit"}' ''
> +_send_qemu_cmd $h2 '{"execute":"quit"}' ''

Since the bug was exposed by this point, I didn't bother to do a clean
shutdown of the mirror job or NBD export.  As is, testing that we shut
down cleanly despite abandoning a job is probably not a bad idea.

> +
> +echo "*** done"
> +rm -f $seq.full
> +status=0
> diff --git a/tests/qemu-iotests/tests/nbd-tls-iothread.out 
> b/tests/qemu-iotests/tests/nbd-tls-iothread.out
> new file mode 100644
> index 00000000000..b5e12dcbe7a
> --- /dev/null
> +++ b/tests/qemu-iotests/tests/nbd-tls-iothread.out
> @@ -0,0 +1,54 @@
> +QA output created by nbd-tls-iothread
> +
> +== preparing TLS creds and spare port ==
> +picked unused port
> +Generating a self signed certificate...
> +Generating a signed certificate...
> +Generating a signed certificate...
> +
> +== preparing image ==
> +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1073741824
> +Formatting 
> '/home/eblake/qemu/build/tests/qemu-iotests/scratch/qcow2-file-nbd-tls-iothread/dst.qcow2',
>  fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib 
> size=1073741824 lazy_refcounts=off refcount_bits=16
> +
> +=== Starting Src QEMU ===
> +
> +{"execute": "qmp_capabilities"}
> +{"return": {}}
> +
> +=== Starting Dst VM2 ===
> +
> +{"execute": "qmp_capabilities"}
> +{"return": {}}
> +
> +=== Dst VM: Enable NBD server for incoming storage migration ===
> +
> +{"execute": "nbd-server-start", "arguments":
> +    {"addr": {"type": "inet", "data": {"host": "127.0.0.1", "port": PORT}},
> +              "tls-creds": "tls0"}}
> +{"return": {}}
> +{"execute": "block-export-add", "arguments":
> +    {"node-name": "drive_image1", "type": "nbd", "writable": true,
> +      "id": "drive_image1"}}
> +{"return": {}}
> +
> +=== Src VM: Mirror to dst NBD for outgoing storage migration ===
> +
> +{"execute": "blockdev-add", "arguments":
> +    {"node-name": "mirror", "driver": "nbd",
> +     "server": {"type": "inet", "host": "127.0.0.1", "port": PORT},
> +     "export": "drive_image1", "tls-creds": "tls0",
> +     "tls-hostname": "127.0.0.1"}}
> +{"return": {}}
> +{"execute": "blockdev-mirror", "arguments":
> +    {"sync": "full", "device": "drive_image1", "target": "mirror",
> +     "job-id": "drive_image1_53"}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": 
> "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "drive_image1_53"}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": 
> "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "drive_image1_53"}}
> +{"return": {}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": 
> "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "drive_image1_53"}}
> +
> +=== Cleaning up ===
> +
> +{"execute":"quit"}
> +{"execute":"quit"}
> +*** done
> -- 
> 2.45.0
> 
> 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization:  qemu.org | libguestfs.org