[GIT PULL 7/8] tests/qtest/dump: cover win-dmp availability via vmcoreinfo

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

From: "Denis V. Lunev" <den@openvz.org>

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>
---
 tests/qtest/dump-test.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)

diff --git a/tests/qtest/dump-test.c b/tests/qtest/dump-test.c
index 6afaa2c2ea4..30c95a35285 100644
--- a/tests/qtest/dump-test.c
+++ b/tests/qtest/dump-test.c
@@ -12,10 +12,15 @@
 
 #include "qemu/osdep.h"
 #include "libqtest.h"
+#include "libqos/libqos-pc.h"
+#include "libqos/fw_cfg.h"
 #include "qobject/qdict.h"
 #include "qobject/qlist.h"
 #include "qobject/qstring.h"
 #include "qemu/bswap.h"
+#include "qemu/win_dump_defs.h"
+#include "standard-headers/linux/qemu_fw_cfg.h"
+#include "hw/misc/vmcoreinfo.h"
 #include "elf.h"
 
 #define KDUMP_RAW_MAGIC     "KDUMP   "
@@ -215,6 +220,90 @@ static void test_dump_win_dmp_unavailable(void)
     qtest_quit(qts);
 }
 
+static bool capability_has_format(QTestState *qts, const char *want)
+{
+    QDict *resp, *ret;
+    QList *formats;
+    QListEntry *e;
+    bool found = 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), want)) {
+            found = true;
+        }
+    }
+    qobject_unref(resp);
+    return found;
+}
+
+/*
+ * win-dmp becomes available only once the guest exposes a Windows dump
+ * header through vmcoreinfo. Forge exactly such a note -- the layout a
+ * Windows guest with the QEMU vmcoreinfo writer produces: a fixed-size ELF
+ * note header followed by a WinDumpHeader64 carrying the PAGE/DU64
+ * signatures -- 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 only covers availability *reporting*; the actual win-dmp generation
+ * (create_win_dump()) needs real Windows kernel structures and is not
+ * exercised here.
+ */
+static void test_dump_win_dmp_available(void)
+{
+    const uint64_t paddr = 0x800000; /* 8 MiB, inside guest RAM */
+    size_t notesz = VMCOREINFO_WIN_DUMP_NOTE_SIZE64;
+    g_autofree uint8_t *note = g_malloc0(notesz);
+    Elf64_Nhdr *nhdr = (Elf64_Nhdr *)note;
+    WinDumpHeader64 *hdr;
+    FWCfgVMCoreInfo info;
+    QFWCFG *fw_cfg;
+    QOSState *qs;
+
+    /* the WinDumpHeader64 must sit right after the fixed ELF note header */
+    g_assert_cmpint(sizeof(WinDumpHeader64) % 4, ==, 0);
+
+    nhdr->n_namesz = cpu_to_le32(sizeof("VMCOREINFO")); /* 11 -> padded 12 */
+    nhdr->n_descsz = cpu_to_le32(sizeof(WinDumpHeader64));
+    nhdr->n_type = 0;
+    memcpy(note + sizeof(Elf64_Nhdr), "VMCOREINFO", sizeof("VMCOREINFO") - 1);
+
+    hdr = (WinDumpHeader64 *)(note + VMCOREINFO_ELF_NOTE_HDR_SIZE);
+    memcpy(hdr->Signature, "PAGE", sizeof(hdr->Signature));
+    memcpy(hdr->ValidDump, "DU64", sizeof(hdr->ValidDump));
+
+    qs = qtest_pc_boot("-device vmcoreinfo -m 16");
+    fw_cfg = pc_fw_cfg_init(qs->qts);
+
+    /* with no guest note yet, win-dmp must not be advertised */
+    g_assert_false(capability_has_format(qs->qts, "win-dmp"));
+
+    /* place the forged note in guest RAM and point vmcoreinfo at it */
+    qtest_memwrite(qs->qts, paddr, note, notesz);
+
+    memset(&info, 0, sizeof(info));
+    info.host_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF);
+    info.guest_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF);
+    info.size = cpu_to_le32(notesz);
+    info.paddr = cpu_to_le64(paddr);
+    qfw_cfg_write_file(fw_cfg, qs, FW_CFG_VMCOREINFO_FILENAME,
+                       &info, sizeof(info));
+
+    /* now win-dmp must be reported as available */
+    g_assert_true(capability_has_format(qs->qts, "win-dmp"));
+
+    pc_fw_cfg_uninit(fw_cfg);
+    qtest_shutdown(qs);
+}
+
 int main(int argc, char **argv)
 {
     const char *arch = qtest_get_arch();
@@ -231,6 +320,11 @@ int main(int argc, char **argv)
     if (g_str_equal(arch, "x86_64")) {
         qtest_add_func("/dump/win-dmp-unavailable",
                        test_dump_win_dmp_unavailable);
+
+        if (qtest_has_device("vmcoreinfo")) {
+            qtest_add_func("/dump/win-dmp-available",
+                           test_dump_win_dmp_available);
+        }
     }
 
     return g_test_run();

-- 
2.54.0