Migration Pull request

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Merge remote-tracking branch 'remotes/juanquintela/tags/migration-pull-request' into staging

Migration Pull request

# gpg: Signature made Wed 05 Jun 2019 12:52:06 BST
# gpg:                using RSA key 1899FF8EDEBF58CCEE034B82F487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>" [full]
# gpg:                 aka "Juan Quintela <quintela@trasno.org>" [full]
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* remotes/juanquintela/tags/migration-pull-request:
  migratioin/ram: leave RAMBlock->bmap blank on allocating
  migration-test: Add a test for fd protocol
  migration: Fix fd protocol for incoming defer
  migration/ram.c: multifd_send_state->count is not really used
  migration/ram.c: MultiFDSendParams.sem_sync is not really used

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

migration/fd.c

@@ -52,12 +52,14 @@ static gboolean fd_accept_incoming_migration(QIOChannel *ioc,
     return G_SOURCE_REMOVE;
 }
 
-void fd_start_incoming_migration(const char *infd, Error **errp)
+void fd_start_incoming_migration(const char *fdname, Error **errp)
 {
     QIOChannel *ioc;
-    int fd;
+    int fd = monitor_fd_param(cur_mon, fdname, errp);
+    if (fd == -1) {
+        return;
+    }
 
-    fd = strtol(infd, NULL, 0);
     trace_migration_fd_incoming(fd);
 
     ioc = qio_channel_new_fd(fd, errp);

migration/fd.h

@@ -16,7 +16,7 @@
 
 #ifndef QEMU_MIGRATION_FD_H
 #define QEMU_MIGRATION_FD_H
-void fd_start_incoming_migration(const char *path, Error **errp);
+void fd_start_incoming_migration(const char *fdname, Error **errp);
 
 void fd_start_outgoing_migration(MigrationState *s, const char *fdname,
                                  Error **errp);

migration/ram.c

@@ -661,8 +661,6 @@ typedef struct {
     uint64_t num_packets;
     /* pages sent through this channel */
     uint64_t num_pages;
-    /* syncs main thread and channels */
-    QemuSemaphore sem_sync;
 }  MultiFDSendParams;
 
 typedef struct {
@@ -894,8 +892,6 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
 
 struct {
     MultiFDSendParams *params;
-    /* number of created threads */
-    int count;
     /* array of pages to sent */
     MultiFDPages_t *pages;
     /* syncs main thread and channels */
@@ -1027,7 +1023,6 @@ void multifd_save_cleanup(void)
         p->c = NULL;
         qemu_mutex_destroy(&p->mutex);
         qemu_sem_destroy(&p->sem);
-        qemu_sem_destroy(&p->sem_sync);
         g_free(p->name);
         p->name = NULL;
         multifd_pages_clear(p->pages);
@@ -1174,8 +1169,6 @@ static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque)
         p->running = true;
         qemu_thread_create(&p->thread, p->name, multifd_send_thread, p,
                            QEMU_THREAD_JOINABLE);
-
-        atomic_inc(&multifd_send_state->count);
     }
 }
 
@@ -1191,7 +1184,6 @@ int multifd_save_setup(void)
     thread_count = migrate_multifd_channels();
     multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
     multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
-    atomic_set(&multifd_send_state->count, 0);
     multifd_send_state->pages = multifd_pages_init(page_count);
     qemu_sem_init(&multifd_send_state->sem_sync, 0);
     qemu_sem_init(&multifd_send_state->channels_ready, 0);
@@ -1201,7 +1193,6 @@ int multifd_save_setup(void)
 
         qemu_mutex_init(&p->mutex);
         qemu_sem_init(&p->sem, 0);
-        qemu_sem_init(&p->sem_sync, 0);
         p->quit = false;
         p->pending_job = 0;
         p->id = i;
@@ -3182,11 +3173,11 @@ static int ram_state_init(RAMState **rsp)
     QSIMPLEQ_INIT(&(*rsp)->src_page_requests);
 
     /*
-     * Count the total number of pages used by ram blocks not including any
-     * gaps due to alignment or unplugs.
+     * This must match with the initial values of dirty bitmap.
+     * Currently we initialize the dirty bitmap to all zeros so
+     * here the total dirty page count is zero.
      */
-    (*rsp)->migration_dirty_pages = ram_bytes_total() >> TARGET_PAGE_BITS;
-
+    (*rsp)->migration_dirty_pages = 0;
     ram_state_reset(*rsp);
 
     return 0;
@@ -3201,8 +3192,16 @@ static void ram_list_init_bitmaps(void)
     if (ram_bytes_total()) {
         RAMBLOCK_FOREACH_NOT_IGNORED(block) {
             pages = block->max_length >> TARGET_PAGE_BITS;
+            /*
+             * The initial dirty bitmap for migration must be set with all
+             * ones to make sure we'll migrate every guest RAM page to
+             * destination.
+             * Here we didn't set RAMBlock.bmap simply because it is already
+             * set in ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] in
+             * ram_block_add, and that's where we'll sync the dirty bitmaps.
+             * Here setting RAMBlock.bmap would be fine too but not necessary.
+             */
             block->bmap = bitmap_new(pages);
-            bitmap_set(block->bmap, 0, pages);
             if (migrate_postcopy_ram()) {
                 block->unsentmap = bitmap_new(pages);
                 bitmap_set(block->unsentmap, 0, pages);

tests/libqtest.c

@@ -32,6 +32,7 @@
 
 #define MAX_IRQ 256
 #define SOCKET_TIMEOUT 50
+#define SOCKET_MAX_FDS 16
 
 QTestState *global_qtest;
 
@@ -391,6 +392,40 @@ static void GCC_FMT_ATTR(2, 3) qtest_sendf(QTestState *s, const char *fmt, ...)
     va_end(ap);
 }
 
+/* Sends a message and file descriptors to the socket.
+ * It's needed for qmp-commands like getfd/add-fd */
+static void socket_send_fds(int socket_fd, int *fds, size_t fds_num,
+                            const char *buf, size_t buf_size)
+{
+    ssize_t ret;
+    struct msghdr msg = { 0 };
+    char control[CMSG_SPACE(sizeof(int) * SOCKET_MAX_FDS)] = { 0 };
+    size_t fdsize = sizeof(int) * fds_num;
+    struct cmsghdr *cmsg;
+    struct iovec iov = { .iov_base = (char *)buf, .iov_len = buf_size };
+
+    msg.msg_iov = &iov;
+    msg.msg_iovlen = 1;
+
+    if (fds && fds_num > 0) {
+        g_assert_cmpuint(fds_num, <, SOCKET_MAX_FDS);
+
+        msg.msg_control = control;
+        msg.msg_controllen = CMSG_SPACE(fdsize);
+
+        cmsg = CMSG_FIRSTHDR(&msg);
+        cmsg->cmsg_len = CMSG_LEN(fdsize);
+        cmsg->cmsg_level = SOL_SOCKET;
+        cmsg->cmsg_type = SCM_RIGHTS;
+        memcpy(CMSG_DATA(cmsg), fds, fdsize);
+    }
+
+    do {
+        ret = sendmsg(socket_fd, &msg, 0);
+    } while (ret < 0 && errno == EINTR);
+    g_assert_cmpint(ret, >, 0);
+}
+
 static GString *qtest_recv_line(QTestState *s)
 {
     GString *line;
@@ -545,7 +580,8 @@ QDict *qtest_qmp_receive(QTestState *s)
  * in the case that they choose to discard all replies up until
  * a particular EVENT is received.
  */
-void qmp_fd_vsend(int fd, const char *fmt, va_list ap)
+void qmp_fd_vsend_fds(int fd, int *fds, size_t fds_num,
+                      const char *fmt, va_list ap)
 {
     QObject *qobj;
 
@@ -569,25 +605,49 @@ void qmp_fd_vsend(int fd, const char *fmt, va_list ap)
             fprintf(stderr, "%s", str);
         }
         /* Send QMP request */
-        socket_send(fd, str, qstring_get_length(qstr));
+        if (fds && fds_num > 0) {
+            socket_send_fds(fd, fds, fds_num, str, qstring_get_length(qstr));
+        } else {
+            socket_send(fd, str, qstring_get_length(qstr));
+        }
 
         qobject_unref(qstr);
         qobject_unref(qobj);
     }
 }
 
+void qmp_fd_vsend(int fd, const char *fmt, va_list ap)
+{
+    qmp_fd_vsend_fds(fd, NULL, 0, fmt, ap);
+}
+
+void qtest_qmp_vsend_fds(QTestState *s, int *fds, size_t fds_num,
+                         const char *fmt, va_list ap)
+{
+    qmp_fd_vsend_fds(s->qmp_fd, fds, fds_num, fmt, ap);
+}
+
 void qtest_qmp_vsend(QTestState *s, const char *fmt, va_list ap)
 {
-    qmp_fd_vsend(s->qmp_fd, fmt, ap);
+    qmp_fd_vsend_fds(s->qmp_fd, NULL, 0, fmt, ap);
 }
 
 QDict *qmp_fdv(int fd, const char *fmt, va_list ap)
 {
-    qmp_fd_vsend(fd, fmt, ap);
+    qmp_fd_vsend_fds(fd, NULL, 0, fmt, ap);
 
     return qmp_fd_receive(fd);
 }
 
+QDict *qtest_vqmp_fds(QTestState *s, int *fds, size_t fds_num,
+                      const char *fmt, va_list ap)
+{
+    qtest_qmp_vsend_fds(s, fds, fds_num, fmt, ap);
+
+    /* Receive reply */
+    return qtest_qmp_receive(s);
+}
+
 QDict *qtest_vqmp(QTestState *s, const char *fmt, va_list ap)
 {
     qtest_qmp_vsend(s, fmt, ap);
@@ -616,6 +676,18 @@ void qmp_fd_send(int fd, const char *fmt, ...)
     va_end(ap);
 }
 
+QDict *qtest_qmp_fds(QTestState *s, int *fds, size_t fds_num,
+                     const char *fmt, ...)
+{
+    va_list ap;
+    QDict *response;
+
+    va_start(ap, fmt);
+    response = qtest_vqmp_fds(s, fds, fds_num, fmt, ap);
+    va_end(ap);
+    return response;
+}
+
 QDict *qtest_qmp(QTestState *s, const char *fmt, ...)
 {
     va_list ap;

tests/libqtest.h

@@ -84,6 +84,21 @@ QTestState *qtest_init_with_serial(const char *extra_args, int *sock_fd);
  */
 void qtest_quit(QTestState *s);
 
+/**
+ * qtest_qmp_fds:
+ * @s: #QTestState instance to operate on.
+ * @fds: array of file descriptors
+ * @fds_num: number of elements in @fds
+ * @fmt...: QMP message to send to qemu, formatted like
+ * qobject_from_jsonf_nofail().  See parse_escape() for what's
+ * supported after '%'.
+ *
+ * Sends a QMP message to QEMU with fds and returns the response.
+ */
+QDict *qtest_qmp_fds(QTestState *s, int *fds, size_t fds_num,
+                     const char *fmt, ...)
+    GCC_FMT_ATTR(4, 5);
+
 /**
  * qtest_qmp:
  * @s: #QTestState instance to operate on.
@@ -120,7 +135,23 @@ void qtest_qmp_send_raw(QTestState *s, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
 
 /**
- * qtest_qmpv:
+ * qtest_vqmp_fds:
+ * @s: #QTestState instance to operate on.
+ * @fds: array of file descriptors
+ * @fds_num: number of elements in @fds
+ * @fmt: QMP message to send to QEMU, formatted like
+ * qobject_from_jsonf_nofail().  See parse_escape() for what's
+ * supported after '%'.
+ * @ap: QMP message arguments
+ *
+ * Sends a QMP message to QEMU with fds and returns the response.
+ */
+QDict *qtest_vqmp_fds(QTestState *s, int *fds, size_t fds_num,
+                      const char *fmt, va_list ap)
+    GCC_FMT_ATTR(4, 0);
+
+/**
+ * qtest_vqmp:
  * @s: #QTestState instance to operate on.
  * @fmt: QMP message to send to QEMU, formatted like
  * qobject_from_jsonf_nofail().  See parse_escape() for what's
@@ -132,6 +163,22 @@ void qtest_qmp_send_raw(QTestState *s, const char *fmt, ...)
 QDict *qtest_vqmp(QTestState *s, const char *fmt, va_list ap)
     GCC_FMT_ATTR(2, 0);
 
+/**
+ * qtest_qmp_vsend_fds:
+ * @s: #QTestState instance to operate on.
+ * @fds: array of file descriptors
+ * @fds_num: number of elements in @fds
+ * @fmt: QMP message to send to QEMU, formatted like
+ * qobject_from_jsonf_nofail().  See parse_escape() for what's
+ * supported after '%'.
+ * @ap: QMP message arguments
+ *
+ * Sends a QMP message to QEMU and leaves the response in the stream.
+ */
+void qtest_qmp_vsend_fds(QTestState *s, int *fds, size_t fds_num,
+                         const char *fmt, va_list ap)
+    GCC_FMT_ATTR(4, 0);
+
 /**
  * qtest_qmp_vsend:
  * @s: #QTestState instance to operate on.
@@ -888,6 +935,8 @@ static inline int64_t clock_step(int64_t step)
 }
 
 QDict *qmp_fd_receive(int fd);
+void qmp_fd_vsend_fds(int fd, int *fds, size_t fds_num,
+                      const char *fmt, va_list ap) GCC_FMT_ATTR(4, 0);
 void qmp_fd_vsend(int fd, const char *fmt, va_list ap) GCC_FMT_ATTR(2, 0);
 void qmp_fd_send(int fd, const char *fmt, ...) GCC_FMT_ATTR(2, 3);
 void qmp_fd_send_raw(int fd, const char *fmt, ...) GCC_FMT_ATTR(2, 3);

tests/migration-test.c

@@ -174,6 +174,21 @@ static void stop_cb(void *opaque, const char *name, QDict *data)
     }
 }
 
+/*
+ * Events can get in the way of responses we are actually waiting for.
+ */
+GCC_FMT_ATTR(3, 4)
+static QDict *wait_command_fd(QTestState *who, int fd, const char *command, ...)
+{
+    va_list ap;
+
+    va_start(ap, command);
+    qtest_qmp_vsend_fds(who, &fd, 1, command, ap);
+    va_end(ap);
+
+    return qtest_qmp_receive_success(who, stop_cb, NULL);
+}
+
 /*
  * Events can get in the way of responses we are actually waiting for.
  */
@@ -480,6 +495,7 @@ static void migrate(QTestState *who, const char *uri, const char *fmt, ...)
     qdict_put_str(args, "uri", uri);
 
     rsp = qmp("{ 'execute': 'migrate', 'arguments': %p}", args);
+
     g_assert(qdict_haskey(rsp, "return"));
     qobject_unref(rsp);
 }
@@ -1027,6 +1043,90 @@ static void test_precopy_tcp(void)
     g_free(uri);
 }
 
+static void test_migrate_fd_proto(void)
+{
+    QTestState *from, *to;
+    int ret;
+    int pair[2];
+    QDict *rsp;
+    const char *error_desc;
+
+    if (test_migrate_start(&from, &to, "defer", false, false)) {
+        return;
+    }
+
+    /*
+     * We want to pick a speed slow enough that the test completes
+     * quickly, but that it doesn't complete precopy even on a slow
+     * machine, so also set the downtime.
+     */
+    /* 1 ms should make it not converge */
+    migrate_set_parameter(from, "downtime-limit", 1);
+    /* 1GB/s */
+    migrate_set_parameter(from, "max-bandwidth", 1000000000);
+
+    /* Wait for the first serial output from the source */
+    wait_for_serial("src_serial");
+
+    /* Create two connected sockets for migration */
+    ret = socketpair(PF_LOCAL, SOCK_STREAM, 0, pair);
+    g_assert_cmpint(ret, ==, 0);
+
+    /* Send the 1st socket to the target */
+    rsp = wait_command_fd(to, pair[0],
+                          "{ 'execute': 'getfd',"
+                          "  'arguments': { 'fdname': 'fd-mig' }}");
+    qobject_unref(rsp);
+    close(pair[0]);
+
+    /* Start incoming migration from the 1st socket */
+    rsp = wait_command(to, "{ 'execute': 'migrate-incoming',"
+                           "  'arguments': { 'uri': 'fd:fd-mig' }}");
+    qobject_unref(rsp);
+
+    /* Send the 2nd socket to the target */
+    rsp = wait_command_fd(from, pair[1],
+                          "{ 'execute': 'getfd',"
+                          "  'arguments': { 'fdname': 'fd-mig' }}");
+    qobject_unref(rsp);
+    close(pair[1]);
+
+    /* Start migration to the 2nd socket*/
+    migrate(from, "fd:fd-mig", "{}");
+
+    wait_for_migration_pass(from);
+
+    /* 300ms should converge */
+    migrate_set_parameter(from, "downtime-limit", 300);
+
+    if (!got_stop) {
+        qtest_qmp_eventwait(from, "STOP");
+    }
+    qtest_qmp_eventwait(to, "RESUME");
+
+    /* Test closing fds */
+    /* We assume, that QEMU removes named fd from its list,
+     * so this should fail */
+    rsp = qtest_qmp(from, "{ 'execute': 'closefd',"
+                          "  'arguments': { 'fdname': 'fd-mig' }}");
+    g_assert_true(qdict_haskey(rsp, "error"));
+    error_desc = qdict_get_str(qdict_get_qdict(rsp, "error"), "desc");
+    g_assert_cmpstr(error_desc, ==, "File descriptor named 'fd-mig' not found");
+    qobject_unref(rsp);
+
+    rsp = qtest_qmp(to, "{ 'execute': 'closefd',"
+                        "  'arguments': { 'fdname': 'fd-mig' }}");
+    g_assert_true(qdict_haskey(rsp, "error"));
+    error_desc = qdict_get_str(qdict_get_qdict(rsp, "error"), "desc");
+    g_assert_cmpstr(error_desc, ==, "File descriptor named 'fd-mig' not found");
+    qobject_unref(rsp);
+
+    /* Complete migration */
+    wait_for_serial("dest_serial");
+    wait_for_migration_complete(from);
+    test_migrate_end(from, to, true);
+}
+
 int main(int argc, char **argv)
 {
     char template[] = "/tmp/migration-test-XXXXXX";
@@ -1081,6 +1181,7 @@ int main(int argc, char **argv)
     qtest_add_func("/migration/precopy/tcp", test_precopy_tcp);
     /* qtest_add_func("/migration/ignore_shared", test_ignore_shared); */
     qtest_add_func("/migration/xbzrle/unix", test_xbzrle_unix);
+    qtest_add_func("/migration/fd_proto", test_migrate_fd_proto);
 
     ret = g_test_run();