There is currently almost no coverage for the dump-guest-memory QMP command beyond the test-hmp smoke test. Add a qtest that runs on a bare machine (no guest OS) and checks:
- query-dump-guest-memory-capability always advertises 'elf'; - an ELF dump is produced and starts with the ELF magic; - a non-raw kdump dump is emitted in makedumpfile flattened format; - a raw kdump dump starts with the on-disk KDUMP header; - an unknown protocol is rejected without killing the VM, and dumping still works afterwards. Signed-off-by: Denis V. Lunev <[email protected]> --- MAINTAINERS | 1 + tests/qtest/dump-test.c | 188 ++++++++++++++++++++++++++++++++++++++++ tests/qtest/meson.build | 1 + 3 files changed, 190 insertions(+) create mode 100644 tests/qtest/dump-test.c diff --git a/MAINTAINERS b/MAINTAINERS index 93df53d87f..f82412443c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3291,6 +3291,7 @@ F: scripts/dump-guest-memory.py F: stubs/dump.c F: docs/specs/vmcoreinfo.rst F: tests/qtest/vmcoreinfo-test.c +F: tests/qtest/dump-test.c Error reporting M: Markus Armbruster <[email protected]> diff --git a/tests/qtest/dump-test.c b/tests/qtest/dump-test.c new file mode 100644 index 0000000000..eb188c9ccb --- /dev/null +++ b/tests/qtest/dump-test.c @@ -0,0 +1,188 @@ +/* + * QTest testcase for dump-guest-memory + * + * Generic coverage for the dump-guest-memory QMP command and the + * query-dump-guest-memory-capability reporting, exercised on a bare + * machine (no guest OS required). + * + * Copyright (c) 2026 Virtuozzo International GmbH + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "libqtest.h" +#include "qobject/qdict.h" +#include "qobject/qlist.h" +#include "qobject/qstring.h" +#include "qemu/bswap.h" +#include "elf.h" + +#define KDUMP_RAW_MAGIC "KDUMP " +#define KDUMP_FLAT_MAGIC "makedumpfile" + +static QTestState *dump_test_start(void) +{ + return qtest_initf("-machine q35 -accel qtest -m 16"); +} + +static void assert_file_magic(const char *path, const char *magic, size_t len) +{ + g_autofree char *buf = g_malloc0(len); + FILE *f = fopen(path, "rb"); + + g_assert_nonnull(f); + g_assert_cmpint(fread(buf, 1, len, f), ==, len); + fclose(f); + g_assert_cmpint(memcmp(buf, magic, len), ==, 0); +} + +/* validate that the file is a sane x86 ELF core, not just the leading magic */ +static void assert_valid_elf_core(const char *path) +{ + unsigned char e[64]; + FILE *f = fopen(path, "rb"); + uint16_t e_type, e_machine, e_phnum; + + g_assert_nonnull(f); + g_assert_cmpint(fread(e, 1, sizeof(e), f), ==, sizeof(e)); + fclose(f); + + g_assert_cmpint(memcmp(e, ELFMAG, SELFMAG), ==, 0); + + /* e_type and e_machine sit at the same offset for ELF32 and ELF64 */ + e_type = lduw_le_p(e + 16); + e_machine = lduw_le_p(e + 18); + g_assert_cmpint(e_type, ==, ET_CORE); + g_assert(e_machine == EM_386 || e_machine == EM_X86_64); + + /* e_phnum lives at a class-dependent offset */ + if (e[EI_CLASS] == ELFCLASS64) { + e_phnum = lduw_le_p(e + 56); + } else { + e_phnum = lduw_le_p(e + 44); + } + g_assert_cmpint(e_phnum, >, 0); +} + +/* dump-guest-memory to a fresh temp file; returns the path (caller frees) */ +static char *do_dump(QTestState *qts, const char *format) +{ + g_autofree char *tmp = NULL; + g_autofree char *proto = NULL; + GError *err = NULL; + int fd; + + fd = g_file_open_tmp("dump-test-XXXXXX", &tmp, &err); + g_assert_no_error(err); + close(fd); + proto = g_strdup_printf("file:%s", tmp); + + if (format) { + qtest_qmp_assert_success(qts, + "{ 'execute': 'dump-guest-memory'," + " 'arguments': { 'paging': false, 'protocol': %s," + " 'format': %s } }", proto, format); + } else { + qtest_qmp_assert_success(qts, + "{ 'execute': 'dump-guest-memory'," + " 'arguments': { 'paging': false, 'protocol': %s } }", proto); + } + + return g_steal_pointer(&tmp); +} + +/* query-dump-guest-memory-capability must always advertise at least 'elf' */ +static void test_query_capability(void) +{ + QTestState *qts = dump_test_start(); + QDict *resp, *ret; + QList *formats; + QListEntry *e; + bool has_elf = false; + + resp = qtest_qmp(qts, + "{ 'execute': 'query-dump-guest-memory-capability' }"); + g_assert(qdict_haskey(resp, "return")); + ret = qdict_get_qdict(resp, "return"); + formats = qdict_get_qlist(ret, "formats"); + g_assert_nonnull(formats); + + QLIST_FOREACH_ENTRY(formats, e) { + QString *qs = qobject_to(QString, qlist_entry_obj(e)); + + if (g_str_equal(qstring_get_str(qs), "elf")) { + has_elf = true; + } + } + g_assert_true(has_elf); + + qobject_unref(resp); + qtest_quit(qts); +} + +static void test_dump_elf(void) +{ + QTestState *qts = dump_test_start(); + g_autofree char *path = do_dump(qts, NULL); + + assert_valid_elf_core(path); + unlink(path); + qtest_quit(qts); +} + +/* non-raw kdump is emitted in makedumpfile flattened format */ +static void test_dump_kdump_zlib(void) +{ + QTestState *qts = dump_test_start(); + g_autofree char *path = do_dump(qts, "kdump-zlib"); + + assert_file_magic(path, KDUMP_FLAT_MAGIC, strlen(KDUMP_FLAT_MAGIC)); + unlink(path); + qtest_quit(qts); +} + +/* raw kdump starts with the on-disk KDUMP header */ +static void test_dump_kdump_raw_zlib(void) +{ + QTestState *qts = dump_test_start(); + g_autofree char *path = do_dump(qts, "kdump-raw-zlib"); + + assert_file_magic(path, KDUMP_RAW_MAGIC, strlen(KDUMP_RAW_MAGIC)); + unlink(path); + qtest_quit(qts); +} + +/* an unknown protocol must be rejected, not crash the VM */ +static void test_dump_invalid_protocol(void) +{ + QTestState *qts = dump_test_start(); + g_autofree char *path = NULL; + QDict *resp; + + resp = qtest_qmp(qts, + "{ 'execute': 'dump-guest-memory'," + " 'arguments': { 'paging': false, 'protocol': 'bogus:/x' } }"); + g_assert(qdict_haskey(resp, "error")); + qobject_unref(resp); + + /* VM is still alive and dumping still works afterwards */ + path = do_dump(qts, NULL); + assert_valid_elf_core(path); + unlink(path); + + qtest_quit(qts); +} + +int main(int argc, char **argv) +{ + g_test_init(&argc, &argv, NULL); + + qtest_add_func("/dump/query-capability", test_query_capability); + qtest_add_func("/dump/elf", test_dump_elf); + qtest_add_func("/dump/kdump-zlib", test_dump_kdump_zlib); + qtest_add_func("/dump/kdump-raw-zlib", test_dump_kdump_raw_zlib); + qtest_add_func("/dump/invalid-protocol", test_dump_invalid_protocol); + + return g_test_run(); +} diff --git a/tests/qtest/meson.build b/tests/qtest/meson.build index 4897325d84..e5266bc1eb 100644 --- a/tests/qtest/meson.build +++ b/tests/qtest/meson.build @@ -59,6 +59,7 @@ qtests_i386 = \ (config_all_devices.has_key('CONFIG_FDC_ISA') ? ['fdc-test'] : []) + \ (config_all_devices.has_key('CONFIG_I440FX') ? ['fw_cfg-test'] : []) + \ (config_all_devices.has_key('CONFIG_FW_CFG_DMA') ? ['vmcoreinfo-test'] : []) + \ + ['dump-test'] + \ (config_all_devices.has_key('CONFIG_I440FX') ? ['i440fx-test'] : []) + \ (config_all_devices.has_key('CONFIG_I440FX') ? ['ide-test'] : []) + \ (config_all_devices.has_key('CONFIG_I440FX') ? ['numa-test'] : []) + \ -- 2.53.0
