Merge remote-tracking branch 'remotes/juanquintela/tags/migration/20150707' into staging

migration/next for 20150707

# gpg: Signature made Tue Jul  7 13:56:30 2015 BST using RSA key ID 5872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg:                 aka "Juan Quintela <quintela@trasno.org>"

* remotes/juanquintela/tags/migration/20150707: (28 commits)
  migration: extend migration_bitmap
  migration: protect migration_bitmap
  check_section_footers: Check the correct section_id
  migration: Add migration events on target side
  migration: Make events a capability
  migration: create migration event
  migration: No need to call trace_migrate_set_state()
  migration: Use always helper to set state
  migration: ensure we start in NONE state
  migration: Use cmpxchg correctly
  migration: Add configuration section
  vmstate: Create optional sections
  global_state: Make section optional
  migration: create new section to store global state
  runstate: migration allows more transitions now
  runstate: Add runstate store
  Fix older machine type compatibility on power with section footers
  Fail more cleanly in mismatched RAM cases
  Sanity check RDMA remote data
  Sort destination RAMBlocks to be the same as the source
  ...

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

1 files changed, 134 insertions, 46 deletions

diff --git a/migration/savevm.c b/migration/savevm.c
index 9e0e286..86735fc 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -246,11 +246,55 @@ typedef struct SaveStateEntry {
 typedef struct SaveState {
     QTAILQ_HEAD(, SaveStateEntry) handlers;
     int global_section_id;
+    bool skip_configuration;
+    uint32_t len;
+    const char *name;
 } SaveState;
 
 static SaveState savevm_state = {
     .handlers = QTAILQ_HEAD_INITIALIZER(savevm_state.handlers),
     .global_section_id = 0,
+    .skip_configuration = false,
+};
+
+void savevm_skip_configuration(void)
+{
+    savevm_state.skip_configuration = true;
+}
+
+
+static void configuration_pre_save(void *opaque)
+{
+    SaveState *state = opaque;
+    const char *current_name = MACHINE_GET_CLASS(current_machine)->name;
+
+    state->len = strlen(current_name);
+    state->name = current_name;
+}
+
+static int configuration_post_load(void *opaque, int version_id)
+{
+    SaveState *state = opaque;
+    const char *current_name = MACHINE_GET_CLASS(current_machine)->name;
+
+    if (strncmp(state->name, current_name, state->len) != 0) {
+        error_report("Machine type received is '%s' and local is '%s'",
+                     state->name, current_name);
+        return -EINVAL;
+    }
+    return 0;
+}
+
+static const VMStateDescription vmstate_configuration = {
+    .name = "configuration",
+    .version_id = 1,
+    .post_load = configuration_post_load,
+    .pre_save = configuration_pre_save,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(len, SaveState),
+        VMSTATE_VBUFFER_ALLOC_UINT32(name, SaveState, 0, NULL, 0, len),
+        VMSTATE_END_OF_LIST()
+    },
 };
 
 static void dump_vmstate_vmsd(FILE *out_file,
@@ -653,41 +697,6 @@ static void save_section_footer(QEMUFile *f, SaveStateEntry *se)
     }
 }
 
-/*
- * Read a footer off the wire and check that it matches the expected section
- *
- * Returns: true if the footer was good
- *          false if there is a problem (and calls error_report to say why)
- */
-static bool check_section_footer(QEMUFile *f, SaveStateEntry *se)
-{
-    uint8_t read_mark;
-    uint32_t read_section_id;
-
-    if (skip_section_footers) {
-        /* No footer to check */
-        return true;
-    }
-
-    read_mark = qemu_get_byte(f);
-
-    if (read_mark != QEMU_VM_SECTION_FOOTER) {
-        error_report("Missing section footer for %s", se->idstr);
-        return false;
-    }
-
-    read_section_id = qemu_get_be32(f);
-    if (read_section_id != se->section_id) {
-        error_report("Mismatched section id in footer for %s -"
-                     " read 0x%x expected 0x%x",
-                     se->idstr, read_section_id, se->section_id);
-        return false;
-    }
-
-    /* All good */
-    return true;
-}
-
 bool qemu_savevm_state_blocked(Error **errp)
 {
     SaveStateEntry *se;
@@ -723,6 +732,11 @@ void qemu_savevm_state_begin(QEMUFile *f,
         se->ops->set_params(params, se->opaque);
     }
 
+    if (!savevm_state.skip_configuration) {
+        qemu_put_byte(f, QEMU_VM_CONFIGURATION);
+        vmstate_save_state(f, &vmstate_configuration, &savevm_state, 0);
+    }
+
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
         if (!se->ops || !se->ops->save_live_setup) {
             continue;
@@ -836,6 +850,11 @@ void qemu_savevm_state_complete(QEMUFile *f)
         if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
             continue;
         }
+        if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
+            trace_savevm_section_skip(se->idstr, se->section_id);
+            continue;
+        }
+
         trace_savevm_section_start(se->idstr, se->section_id);
 
         json_start_object(vmdesc, NULL);
@@ -949,6 +968,9 @@ static int qemu_save_device_state(QEMUFile *f)
         if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
             continue;
         }
+        if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
+            continue;
+        }
 
         save_section_header(f, se, QEMU_VM_SECTION_FULL);
 
@@ -989,6 +1011,41 @@ struct LoadStateEntry {
     int version_id;
 };
 
+/*
+ * Read a footer off the wire and check that it matches the expected section
+ *
+ * Returns: true if the footer was good
+ *          false if there is a problem (and calls error_report to say why)
+ */
+static bool check_section_footer(QEMUFile *f, LoadStateEntry *le)
+{
+    uint8_t read_mark;
+    uint32_t read_section_id;
+
+    if (skip_section_footers) {
+        /* No footer to check */
+        return true;
+    }
+
+    read_mark = qemu_get_byte(f);
+
+    if (read_mark != QEMU_VM_SECTION_FOOTER) {
+        error_report("Missing section footer for %s", le->se->idstr);
+        return false;
+    }
+
+    read_section_id = qemu_get_be32(f);
+    if (read_section_id != le->section_id) {
+        error_report("Mismatched section id in footer for %s -"
+                     " read 0x%x expected 0x%x",
+                     le->se->idstr, read_section_id, le->section_id);
+        return false;
+    }
+
+    /* All good */
+    return true;
+}
+
 void loadvm_free_handlers(MigrationIncomingState *mis)
 {
     LoadStateEntry *le, *new_le;
@@ -1029,6 +1086,18 @@ int qemu_loadvm_state(QEMUFile *f)
         return -ENOTSUP;
     }
 
+    if (!savevm_state.skip_configuration) {
+        if (qemu_get_byte(f) != QEMU_VM_CONFIGURATION) {
+            error_report("Configuration section missing");
+            return -EINVAL;
+        }
+        ret = vmstate_load_state(f, &vmstate_configuration, &savevm_state, 0);
+
+        if (ret) {
+            return ret;
+        }
+    }
+
     while ((section_type = qemu_get_byte(f)) != QEMU_VM_EOF) {
         uint32_t instance_id, version_id, section_id;
         SaveStateEntry *se;
@@ -1082,7 +1151,7 @@ int qemu_loadvm_state(QEMUFile *f)
                              " device '%s'", instance_id, idstr);
                 goto out;
             }
-            if (!check_section_footer(f, le->se)) {
+            if (!check_section_footer(f, le)) {
                 ret = -EINVAL;
                 goto out;
             }
@@ -1109,7 +1178,7 @@ int qemu_loadvm_state(QEMUFile *f)
                              section_id, le->se->idstr);
                 goto out;
             }
-            if (!check_section_footer(f, le->se)) {
+            if (!check_section_footer(f, le)) {
                 ret = -EINVAL;
                 goto out;
             }
@@ -1127,16 +1196,35 @@ int qemu_loadvm_state(QEMUFile *f)
      * Try to read in the VMDESC section as well, so that dumping tools that
      * intercept our migration stream have the chance to see it.
      */
-    if (qemu_get_byte(f) == QEMU_VM_VMDESCRIPTION) {
-        uint32_t size = qemu_get_be32(f);
-        uint8_t *buf = g_malloc(0x1000);
-
-        while (size > 0) {
-            uint32_t read_chunk = MIN(size, 0x1000);
-            qemu_get_buffer(f, buf, read_chunk);
-            size -= read_chunk;
+
+    /* We've got to be careful; if we don't read the data and just shut the fd
+     * then the sender can error if we close while it's still sending.
+     * We also mustn't read data that isn't there; some transports (RDMA)
+     * will stall waiting for that data when the source has already closed.
+     */
+    if (should_send_vmdesc()) {
+        uint8_t *buf;
+        uint32_t size;
+        section_type = qemu_get_byte(f);
+
+        if (section_type != QEMU_VM_VMDESCRIPTION) {
+            error_report("Expected vmdescription section, but got %d",
+                         section_type);
+            /*
+             * It doesn't seem worth failing at this point since
+             * we apparently have an otherwise valid VM state
+             */
+        } else {
+            buf = g_malloc(0x1000);
+            size = qemu_get_be32(f);
+
+            while (size > 0) {
+                uint32_t read_chunk = MIN(size, 0x1000);
+                qemu_get_buffer(f, buf, read_chunk);
+                size -= read_chunk;
+            }
+            g_free(buf);
         }
-        g_free(buf);
     }
 
     cpu_synchronize_all_post_init();