tests/qtest/dump: cover win-dmp availability via vmcoreinfo
win-dmp becomes available only once the guest exposes a Windows dump header through vmcoreinfo. Forge exactly such a note (an ELF note header followed by a WinDumpHeader64 carrying the PAGE/DU64 signatures, the layout a Windows guest with the QEMU vmcoreinfo writer produces), place it in guest RAM, point the vmcoreinfo device at it via fw_cfg, and check that win-dmp flips from unavailable to available. This exercises win_dump_available()'s positive path without a real Windows guest. It only covers availability reporting; the actual win-dmp generation (create_win_dump()) needs real Windows kernel structures and is not exercised here. The test is registered only on x86_64 with a vmcoreinfo device present. Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20260619101834.228432-8-den@openvz.org>
Denis V. Lunev committed
Jun 19, 2026 at 12:18 UTC
49854252fc9f22f21f6c6a307e141309bcd54fc6
1 file changed
+94
tests/qtest/dump-test.c
+94
@@ -12,10 +12,15 @@
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#include "qemu/osdep.h"
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#include "libqtest.h"
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+#include "libqos/libqos-pc.h"
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+#include "libqos/fw_cfg.h"
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#include "qobject/qdict.h"
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#include "qobject/qlist.h"
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#include "qobject/qstring.h"
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#include "qemu/bswap.h"
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+#include "qemu/win_dump_defs.h"
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+#include "standard-headers/linux/qemu_fw_cfg.h"
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+#include "hw/misc/vmcoreinfo.h"
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#include "elf.h"
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#define KDUMP_RAW_MAGIC "KDUMP "
@@ -215,6 +220,90 @@ static void test_dump_win_dmp_unavailable(void)
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qtest_quit(qts);
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}
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+static bool capability_has_format(QTestState *qts, const char *want)
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+{
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+ QDict *resp, *ret;
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+ QList *formats;
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+ QListEntry *e;
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+ bool found = false;
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+
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+ resp = qtest_qmp(qts,
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+ "{ 'execute': 'query-dump-guest-memory-capability' }");
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+ g_assert(qdict_haskey(resp, "return"));
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+ ret = qdict_get_qdict(resp, "return");
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+ formats = qdict_get_qlist(ret, "formats");
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+ g_assert_nonnull(formats);
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+
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+ QLIST_FOREACH_ENTRY(formats, e) {
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+ QString *qs = qobject_to(QString, qlist_entry_obj(e));
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+
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+ if (g_str_equal(qstring_get_str(qs), want)) {
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+ found = true;
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+ }
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+ }
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+ qobject_unref(resp);
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+ return found;
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+}
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+
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+/*
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+ * win-dmp becomes available only once the guest exposes a Windows dump
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+ * header through vmcoreinfo. Forge exactly such a note -- the layout a
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+ * Windows guest with the QEMU vmcoreinfo writer produces: a fixed-size ELF
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+ * note header followed by a WinDumpHeader64 carrying the PAGE/DU64
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+ * signatures -- place it in guest RAM, point the vmcoreinfo device at it
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+ * via fw_cfg, and check that win-dmp flips from unavailable to available.
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+ *
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+ * This only covers availability *reporting*; the actual win-dmp generation
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+ * (create_win_dump()) needs real Windows kernel structures and is not
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+ * exercised here.
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+ */
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+static void test_dump_win_dmp_available(void)
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+{
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+ const uint64_t paddr = 0x800000; /* 8 MiB, inside guest RAM */
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+ size_t notesz = VMCOREINFO_WIN_DUMP_NOTE_SIZE64;
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+ g_autofree uint8_t *note = g_malloc0(notesz);
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+ Elf64_Nhdr *nhdr = (Elf64_Nhdr *)note;
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+ WinDumpHeader64 *hdr;
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+ FWCfgVMCoreInfo info;
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+ QFWCFG *fw_cfg;
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+ QOSState *qs;
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+
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+ /* the WinDumpHeader64 must sit right after the fixed ELF note header */
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+ g_assert_cmpint(sizeof(WinDumpHeader64) % 4, ==, 0);
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+
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+ nhdr->n_namesz = cpu_to_le32(sizeof("VMCOREINFO")); /* 11 -> padded 12 */
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+ nhdr->n_descsz = cpu_to_le32(sizeof(WinDumpHeader64));
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+ nhdr->n_type = 0;
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+ memcpy(note + sizeof(Elf64_Nhdr), "VMCOREINFO", sizeof("VMCOREINFO") - 1);
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+
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+ hdr = (WinDumpHeader64 *)(note + VMCOREINFO_ELF_NOTE_HDR_SIZE);
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+ memcpy(hdr->Signature, "PAGE", sizeof(hdr->Signature));
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+ memcpy(hdr->ValidDump, "DU64", sizeof(hdr->ValidDump));
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+
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+ qs = qtest_pc_boot("-device vmcoreinfo -m 16");
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+ fw_cfg = pc_fw_cfg_init(qs->qts);
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+
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+ /* with no guest note yet, win-dmp must not be advertised */
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+ g_assert_false(capability_has_format(qs->qts, "win-dmp"));
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+
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+ /* place the forged note in guest RAM and point vmcoreinfo at it */
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+ qtest_memwrite(qs->qts, paddr, note, notesz);
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+
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+ memset(&info, 0, sizeof(info));
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+ info.host_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF);
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+ info.guest_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF);
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+ info.size = cpu_to_le32(notesz);
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+ info.paddr = cpu_to_le64(paddr);
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+ qfw_cfg_write_file(fw_cfg, qs, FW_CFG_VMCOREINFO_FILENAME,
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+ &info, sizeof(info));
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+
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+ /* now win-dmp must be reported as available */
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+ g_assert_true(capability_has_format(qs->qts, "win-dmp"));
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+
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+ pc_fw_cfg_uninit(fw_cfg);
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+ qtest_shutdown(qs);
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+}
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+
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int main(int argc, char **argv)
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{
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const char *arch = qtest_get_arch();
@@ -231,6 +320,11 @@ int main(int argc, char **argv)
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if (g_str_equal(arch, "x86_64")) {
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qtest_add_func("/dump/win-dmp-unavailable",
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test_dump_win_dmp_unavailable);
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+
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+ if (qtest_has_device("vmcoreinfo")) {
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+ qtest_add_func("/dump/win-dmp-available",
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+ test_dump_win_dmp_available);
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+ }
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}
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return g_test_run();