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| 1 | +# Copyright 2025 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| 2 | +# SPDX-License-Identifier: Apache-2.0 |
| 3 | +"""Tests for the virtio-pmem device.""" |
| 4 | + |
| 5 | +import json |
| 6 | +import os |
| 7 | + |
| 8 | +import host_tools.drive as drive_tools |
| 9 | + |
| 10 | +ALIGNMENT = 2 << 20 |
| 11 | + |
| 12 | + |
| 13 | +def align(size: int) -> int: |
| 14 | + """ |
| 15 | + Align the value to ALIGNMENT |
| 16 | + """ |
| 17 | + return (size + ALIGNMENT - 1) & ~(ALIGNMENT - 1) |
| 18 | + |
| 19 | + |
| 20 | +def check_pmem_exist(vm, index, root, read_only, size, extension): |
| 21 | + """ |
| 22 | + Check the pmem exist with correct parameters |
| 23 | + """ |
| 24 | + vm.ssh.check_output(f"ls /dev/pmem{index}") |
| 25 | + |
| 26 | + if root: |
| 27 | + _, stdout, _ = vm.ssh.check_output("mount") |
| 28 | + if read_only: |
| 29 | + assert f"/dev/pmem0 on / type {extension} (ro" in stdout |
| 30 | + else: |
| 31 | + assert f"/dev/pmem0 on / type {extension} (rw" in stdout |
| 32 | + |
| 33 | + _, stdout, _ = vm.ssh.check_output("lsblk -J") |
| 34 | + |
| 35 | + j = json.loads(stdout) |
| 36 | + blocks = j["blockdevices"] |
| 37 | + for block in blocks: |
| 38 | + if block["name"] == f"pmem{index}": |
| 39 | + assert block["size"][-1] == "M" |
| 40 | + block_size_mb = int(block["size"][:-1]) |
| 41 | + assert int(block_size_mb << 20) == size |
| 42 | + if root: |
| 43 | + assert "/" in block["mountpoints"] |
| 44 | + return |
| 45 | + assert False |
| 46 | + |
| 47 | + |
| 48 | +def test_pmem_add(uvm_plain_any, microvm_factory): |
| 49 | + """ |
| 50 | + Test addition of pmem devices to the VM and |
| 51 | + writes persistance |
| 52 | + """ |
| 53 | + |
| 54 | + vm = uvm_plain_any |
| 55 | + vm.spawn() |
| 56 | + vm.basic_config(add_root_device=True) |
| 57 | + vm.add_net_iface() |
| 58 | + |
| 59 | + # Pmem should work with non 2MB aligned files as well |
| 60 | + pmem_size_mb_1 = 1 |
| 61 | + fs_1 = drive_tools.FilesystemFile( |
| 62 | + os.path.join(vm.fsfiles, "scratch_1"), size=pmem_size_mb_1 |
| 63 | + ) |
| 64 | + pmem_size_mb_2 = 2 |
| 65 | + fs_2 = drive_tools.FilesystemFile( |
| 66 | + os.path.join(vm.fsfiles, "scratch_2"), size=pmem_size_mb_2 |
| 67 | + ) |
| 68 | + vm.add_pmem("pmem_1", fs_1.path, False, False) |
| 69 | + vm.add_pmem("pmem_2", fs_2.path, False, True) |
| 70 | + vm.start() |
| 71 | + |
| 72 | + # Both 1MB and 2MB block will show as 2MB because of |
| 73 | + # the aligment |
| 74 | + check_pmem_exist(vm, 0, False, False, align(pmem_size_mb_1 << 20), "ext4") |
| 75 | + check_pmem_exist(vm, 1, False, True, align(pmem_size_mb_2 << 20), "ext4") |
| 76 | + |
| 77 | + # Write something to the pmem0 to see that it is indeed saved to |
| 78 | + # underlying file when VM shots down |
| 79 | + test_string = "testing pmem persistance" |
| 80 | + vm.ssh.check_output("mkdir /tmp/mnt") |
| 81 | + vm.ssh.check_output("mount /dev/pmem0 -o dax=always /tmp/mnt") |
| 82 | + vm.ssh.check_output(f'echo "{test_string}" > /tmp/mnt/test') |
| 83 | + |
| 84 | + snapshot = vm.snapshot_full() |
| 85 | + # Killing or rebooting an old VM will make OS to flush writes to the underlying file |
| 86 | + vm.kill() |
| 87 | + |
| 88 | + restored_vm = microvm_factory.build_from_snapshot(snapshot) |
| 89 | + check_pmem_exist(restored_vm, 0, False, False, align(pmem_size_mb_1 << 20), "ext4") |
| 90 | + check_pmem_exist(restored_vm, 1, False, True, align(pmem_size_mb_2 << 20), "ext4") |
| 91 | + |
| 92 | + # The /tmp/mnt and the mount still persist after snapshot restore. |
| 93 | + # Since we used `dax=always` during mounting there is no data in guest page |
| 94 | + # cache, so the read happens directly from pmem device |
| 95 | + _, stdout, _ = restored_vm.ssh.check_output("cat /tmp/mnt/test") |
| 96 | + assert stdout.strip() == test_string |
| 97 | + |
| 98 | + |
| 99 | +def test_pmem_add_as_root_rw(uvm_plain_any, rootfs_rw, microvm_factory): |
| 100 | + """ |
| 101 | + Test addition of a single root pmem device in read-write mode |
| 102 | + """ |
| 103 | + |
| 104 | + vm = uvm_plain_any |
| 105 | + vm.memory_monitor = None |
| 106 | + vm.monitors = [] |
| 107 | + vm.spawn() |
| 108 | + vm.basic_config(add_root_device=False) |
| 109 | + vm.add_net_iface() |
| 110 | + |
| 111 | + rootfs_size = os.path.getsize(rootfs_rw) |
| 112 | + vm.add_pmem("pmem", rootfs_rw, True, False) |
| 113 | + vm.start() |
| 114 | + |
| 115 | + check_pmem_exist(vm, 0, True, False, align(rootfs_size), "ext4") |
| 116 | + |
| 117 | + snapshot = vm.snapshot_full() |
| 118 | + restored_vm = microvm_factory.build_from_snapshot(snapshot) |
| 119 | + check_pmem_exist(restored_vm, 0, True, False, align(rootfs_size), "ext4") |
| 120 | + |
| 121 | + |
| 122 | +def test_pmem_add_as_root_ro(uvm_plain_any, rootfs, microvm_factory): |
| 123 | + """ |
| 124 | + Test addition of a single root pmem device in read-only mode |
| 125 | + """ |
| 126 | + |
| 127 | + vm = uvm_plain_any |
| 128 | + vm.memory_monitor = None |
| 129 | + vm.monitors = [] |
| 130 | + vm.spawn() |
| 131 | + vm.basic_config(add_root_device=False) |
| 132 | + vm.add_net_iface() |
| 133 | + |
| 134 | + rootfs_size = os.path.getsize(rootfs) |
| 135 | + vm.add_pmem("pmem", rootfs, True, True) |
| 136 | + vm.start() |
| 137 | + |
| 138 | + check_pmem_exist(vm, 0, True, True, align(rootfs_size), "squashfs") |
| 139 | + |
| 140 | + snapshot = vm.snapshot_full() |
| 141 | + restored_vm = microvm_factory.build_from_snapshot(snapshot) |
| 142 | + check_pmem_exist(restored_vm, 0, True, True, align(rootfs_size), "squashfs") |
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