[PATCH v2 5/5] tests/functional: add vdpa-blk blockdev-mirror test

[Stefan Hajnoczi <stefanha@redhat.com>]

Add a test case that reproduces
https://issues.redhat.com/browse/RHEL-88175.

When the mirror blockjob completes, it replaces the original vdpa-blk
blockdev node with a new vdpa-blk blockdev. This will only work if the
BlockRAMRegistrar populates memory mappings (see the previous commit).

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/functional/x86_64/meson.build           |   1 +
 .../functional/x86_64/test_vdpa_blk_mirror.py | 118 ++++++++++++++++++
 2 files changed, 119 insertions(+)
 create mode 100755 tests/functional/x86_64/test_vdpa_blk_mirror.py

diff --git a/tests/functional/x86_64/meson.build b/tests/functional/x86_64/meson.build
index f78eec5e6c..dfe0e00190 100644
--- a/tests/functional/x86_64/meson.build
+++ b/tests/functional/x86_64/meson.build
@@ -33,6 +33,7 @@ tests_x86_64_system_thorough = [
   'replay',
   'reverse_debug',
   'tuxrun',
+  'vdpa_blk_mirror',
   'vfio_user_client',
   'virtio_balloon',
   'virtio_gpu',
diff --git a/tests/functional/x86_64/test_vdpa_blk_mirror.py b/tests/functional/x86_64/test_vdpa_blk_mirror.py
new file mode 100755
index 0000000000..7d52836920
--- /dev/null
+++ b/tests/functional/x86_64/test_vdpa_blk_mirror.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright Red Hat, Inc.
+#
+# vdpa-blk mirror blockjob tests
+
+
+import glob
+import os
+import subprocess
+from qemu_test import LinuxKernelTest, Asset
+from qemu_test import exec_command_and_wait_for_pattern
+
+
+def run(cmd: str) -> None:
+    '''
+    Run a shell command without capturing stdout/stderr and raise
+    subprocess.CalledProcessError on failure.
+    '''
+    subprocess.check_call(cmd, shell=True,
+                          stdout=subprocess.DEVNULL,
+                          stderr=subprocess.DEVNULL)
+
+
+class VdpaBlk(LinuxKernelTest):
+
+    KERNEL_COMMAND_LINE = 'printk.time=0 console=ttyS0 rd.rescue'
+    ASSET_KERNEL = Asset(
+        ('https://archives.fedoraproject.org/pub/archive/fedora/linux/releases'
+         '/31/Server/x86_64/os/images/pxeboot/vmlinuz'),
+        'd4738d03dbbe083ca610d0821d0a8f1488bebbdccef54ce33e3adb35fda00129')
+    ASSET_INITRD = Asset(
+        ('https://archives.fedoraproject.org/pub/archive/fedora/linux/releases'
+         '/31/Server/x86_64/os/images/pxeboot/initrd.img'),
+        '277cd6c7adf77c7e63d73bbb2cded8ef9e2d3a2f100000e92ff1f8396513cd8b')
+    VDPA_DEV_1 = f'vdpa-{os.getpid()}-1'
+    VDPA_DEV_2 = f'vdpa-{os.getpid()}-2'
+
+    def setUp(self) -> None:
+        def create_vdpa_dev(name):
+            '''
+            Create a new vdpasim_blk device and return its vhost_vdpa device
+            path.
+            '''
+            run(f'sudo -n vdpa dev add mgmtdev vdpasim_blk name {name}')
+            sysfs_vhost_vdpa_dev_dir = \
+                glob.glob(f'/sys/bus/vdpa/devices/{name}/vhost-vdpa-*')[0]
+            vhost_dev_basename = os.path.basename(sysfs_vhost_vdpa_dev_dir)
+            vhost_dev_path = f'/dev/{vhost_dev_basename}'
+            run(f'sudo -n chown {os.getuid()}:{os.getgid()} {vhost_dev_path}')
+            return vhost_dev_path
+
+        try:
+            run('sudo -n modprobe vhost_vdpa')
+            run('sudo -n modprobe vdpa_sim_blk')
+
+            self.vhost_dev_1_path = create_vdpa_dev(self.VDPA_DEV_1)
+            self.vhost_dev_2_path = create_vdpa_dev(self.VDPA_DEV_2)
+        except subprocess.CalledProcessError:
+            self.skipTest('Failed to set up vdpa_blk device')
+
+        super().setUp()
+
+    def tearDown(self) -> None:
+        super().tearDown()
+
+        try:
+            run(f'sudo -n vdpa dev del {self.VDPA_DEV_2}')
+            run(f'sudo -n vdpa dev del {self.VDPA_DEV_1}')
+            run('sudo -n modprobe --remove vdpa_sim_blk')
+            run('sudo -n modprobe --remove vhost_vdpa')
+        except subprocess.CalledProcessError:
+            pass # ignore failures
+
+    def test_mirror(self) -> None:
+        '''
+        Check that I/O works after a mirror blockjob pivots. See
+        https://issues.redhat.com/browse/RHEL-88175.
+        '''
+        kernel_path = self.ASSET_KERNEL.fetch()
+        initrd_path = self.ASSET_INITRD.fetch()
+
+        self.vm.add_args('-m', '1G')
+        self.vm.add_args('-object', 'memory-backend-memfd,id=mem,size=1G')
+        self.vm.add_args('-machine', 'pc,accel=kvm:tcg,memory-backend=mem')
+        self.vm.add_args('-append', self.KERNEL_COMMAND_LINE)
+        self.vm.add_args('-blockdev',
+            'virtio-blk-vhost-vdpa,node-name=vdpa-blk-0,' +
+            f'path={self.vhost_dev_1_path},cache.direct=on')
+        self.vm.add_args('-device', 'virtio-blk-pci,drive=vdpa-blk-0')
+
+        self.launch_kernel(kernel_path, initrd_path,
+                           wait_for='# ')
+
+        self.vm.cmd('blockdev-add',
+                    driver='virtio-blk-vhost-vdpa',
+                    node_name='vdpa-blk-1',
+                    path=self.vhost_dev_2_path,
+                    cache={'direct': True})
+        self.vm.cmd('blockdev-mirror',
+                    device='vdpa-blk-0',
+                    job_id='mirror0',
+                    target='vdpa-blk-1',
+                    sync='full',
+                    target_is_zero=True)
+        self.vm.event_wait('BLOCK_JOB_READY')
+        self.vm.cmd('block-job-complete',
+                    device='mirror0')
+
+        exec_command_and_wait_for_pattern(self,
+            'dd if=/dev/vda of=/dev/null iflag=direct bs=4k count=1',
+            '4096 bytes (4.1 kB, 4.0 KiB) copied')
+
+
+if __name__ == '__main__':
+    LinuxKernelTest.main()
-- 
2.51.0