Merge remote-tracking branch 'remotes/juanquintela/tags/migration/20161014' into staging

migration/next for 20161014

# gpg: Signature made Fri 14 Oct 2016 16:24:13 BST
# gpg:                using RSA key 0xF487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg:                 aka "Juan Quintela <quintela@trasno.org>"
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* remotes/juanquintela/tags/migration/20161014:
  docs/xbzrle: correction
  migrate: move max-bandwidth and downtime-limit to migrate_set_parameter
  migration: Fix seg with missing port
  migration/postcopy: Explicitly disallow huge pages
  RAMBlocks: Store page size
  Postcopy vs xbzrle: Don't send xbzrle pages once in postcopy [for 2.8]
  migrate: Fix bounds check for migration parameters in migration.c
  migrate: Use boxed qapi for migrate-set-parameters
  migrate: Share common MigrationParameters struct
  migrate: Fix cpu-throttle-increment regression in HMP
  migration/rdma: Don't flag an error when we've been told about one
  migration: Make failed migration load set file error
  migration/rdma: Pass qemu_file errors across link
  migration: Report values for comparisons
  migration: report an error giving the failed field

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

15 files changed, 281 insertions, 182 deletions

diff --git a/docs/qmp-commands.txt b/docs/qmp-commands.txt
index 7f652e01e5..3220fb1075 100644
--- a/docs/qmp-commands.txt
+++ b/docs/qmp-commands.txt
@@ -2910,7 +2910,9 @@ Set migration parameters
                           throttled for auto-converge (json-int)
 - "cpu-throttle-increment": set throttle increasing percentage for
                             auto-converge (json-int)
-
+- "max-bandwidth": set maximum speed for migrations (in bytes/sec) (json-int)
+- "downtime-limit": set maximum tolerated downtime (in milliseconds) for
+                    migrations (json-int)
 Arguments:
 
 Example:
@@ -2931,7 +2933,10 @@ Query current migration parameters
                                     throttled (json-int)
          - "cpu-throttle-increment" : throttle increasing percentage for
                                       auto-converge (json-int)
-
+         - "max-bandwidth" : maximium migration speed in bytes per second
+                             (json-int)
+         - "downtime-limit" : maximum tolerated downtime of migration in
+                              milliseconds (json-int)
 Arguments:
 
 Example:
@@ -2943,7 +2948,9 @@ Example:
          "cpu-throttle-increment": 10,
          "compress-threads": 8,
          "compress-level": 1,
-         "cpu-throttle-initial": 20
+         "cpu-throttle-initial": 20,
+         "max-bandwidth": 33554432,
+         "downtime-limit": 300
       }
    }
 
diff --git a/docs/xbzrle.txt b/docs/xbzrle.txt
index 52c8511a4c..c0a7dfd44c 100644
--- a/docs/xbzrle.txt
+++ b/docs/xbzrle.txt
@@ -42,7 +42,7 @@ nzrun = length byte...
 length = uleb128 encoded integer
 
 On the sender side XBZRLE is used as a compact delta encoding of page updates,
-retrieving the old page content from the cache (default size of 512 MB). The
+retrieving the old page content from the cache (default size of 64MB). The
 receiving side uses the existing page's content and XBZRLE to decode the new
 page's content.
 
@@ -73,7 +73,7 @@ e9 07 0f 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 03 01 67 01 01 69
 
 Cache update strategy
 =====================
-Keeping the hot pages in the cache is effective for decreased cache
+Keeping the hot pages in the cache is effective for decreasing cache
 misses. XBZRLE uses a counter as the age of each page. The counter will
 increase after each ram dirty bitmap sync. When a cache conflict is
 detected, XBZRLE will only evict pages in the cache that are older than
diff --git a/exec.c b/exec.c
index 374c364dff..e63c5a1bd4 100644
--- a/exec.c
+++ b/exec.c
@@ -1199,7 +1199,6 @@ static void *file_ram_alloc(RAMBlock *block,
     char *c;
     void *area = MAP_FAILED;
     int fd = -1;
-    int64_t page_size;
 
     if (kvm_enabled() && !kvm_has_sync_mmu()) {
         error_setg(errp,
@@ -1254,17 +1253,17 @@ static void *file_ram_alloc(RAMBlock *block,
          */
     }
 
-    page_size = qemu_fd_getpagesize(fd);
-    block->mr->align = MAX(page_size, QEMU_VMALLOC_ALIGN);
+    block->page_size = qemu_fd_getpagesize(fd);
+    block->mr->align = MAX(block->page_size, QEMU_VMALLOC_ALIGN);
 
-    if (memory < page_size) {
+    if (memory < block->page_size) {
         error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to "
-                   "or larger than page size 0x%" PRIx64,
-                   memory, page_size);
+                   "or larger than page size 0x%zx",
+                   memory, block->page_size);
         goto error;
     }
 
-    memory = ROUND_UP(memory, page_size);
+    memory = ROUND_UP(memory, block->page_size);
 
     /*
      * ftruncate is not supported by hugetlbfs in older
@@ -1419,6 +1418,11 @@ void qemu_ram_unset_idstr(RAMBlock *block)
     }
 }
 
+size_t qemu_ram_pagesize(RAMBlock *rb)
+{
+    return rb->page_size;
+}
+
 static int memory_try_enable_merging(void *addr, size_t len)
 {
     if (!machine_mem_merge(current_machine)) {
@@ -1658,6 +1662,7 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
     new_block->max_length = max_size;
     assert(max_size >= size);
     new_block->fd = -1;
+    new_block->page_size = getpagesize();
     new_block->host = host;
     if (host) {
         new_block->flags |= RAM_PREALLOC;
diff --git a/hmp.c b/hmp.c
index 42bef84ed5..80f7f1fefb 100644
--- a/hmp.c
+++ b/hmp.c
@@ -284,27 +284,40 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
 
     if (params) {
         monitor_printf(mon, "parameters:");
+        assert(params->has_compress_level);
         monitor_printf(mon, " %s: %" PRId64,
             MigrationParameter_lookup[MIGRATION_PARAMETER_COMPRESS_LEVEL],
             params->compress_level);
+        assert(params->has_compress_threads);
         monitor_printf(mon, " %s: %" PRId64,
             MigrationParameter_lookup[MIGRATION_PARAMETER_COMPRESS_THREADS],
             params->compress_threads);
+        assert(params->has_decompress_threads);
         monitor_printf(mon, " %s: %" PRId64,
             MigrationParameter_lookup[MIGRATION_PARAMETER_DECOMPRESS_THREADS],
             params->decompress_threads);
+        assert(params->has_cpu_throttle_initial);
         monitor_printf(mon, " %s: %" PRId64,
             MigrationParameter_lookup[MIGRATION_PARAMETER_CPU_THROTTLE_INITIAL],
             params->cpu_throttle_initial);
+        assert(params->has_cpu_throttle_increment);
         monitor_printf(mon, " %s: %" PRId64,
             MigrationParameter_lookup[MIGRATION_PARAMETER_CPU_THROTTLE_INCREMENT],
             params->cpu_throttle_increment);
         monitor_printf(mon, " %s: '%s'",
             MigrationParameter_lookup[MIGRATION_PARAMETER_TLS_CREDS],
-            params->tls_creds ? : "");
+            params->has_tls_creds ? params->tls_creds : "");
         monitor_printf(mon, " %s: '%s'",
             MigrationParameter_lookup[MIGRATION_PARAMETER_TLS_HOSTNAME],
-            params->tls_hostname ? : "");
+            params->has_tls_hostname ? params->tls_hostname : "");
+        assert(params->has_max_bandwidth);
+        monitor_printf(mon, " %s: %" PRId64 " bytes/second",
+            MigrationParameter_lookup[MIGRATION_PARAMETER_MAX_BANDWIDTH],
+            params->max_bandwidth);
+        assert(params->has_downtime_limit);
+        monitor_printf(mon, " %s: %" PRId64 " milliseconds",
+            MigrationParameter_lookup[MIGRATION_PARAMETER_DOWNTIME_LIMIT],
+            params->downtime_limit);
         monitor_printf(mon, "\n");
     }
 
@@ -1260,6 +1273,7 @@ void hmp_migrate_incoming(Monitor *mon, const QDict *qdict)
     hmp_handle_error(mon, &err);
 }
 
+/* Kept for backwards compatibility */
 void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict)
 {
     double value = qdict_get_double(qdict, "value");
@@ -1278,6 +1292,7 @@ void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict)
     }
 }
 
+/* Kept for backwards compatibility */
 void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict)
 {
     int64_t value = qdict_get_int(qdict, "value");
@@ -1318,45 +1333,58 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
 {
     const char *param = qdict_get_str(qdict, "parameter");
     const char *valuestr = qdict_get_str(qdict, "value");
+    int64_t valuebw = 0;
     long valueint = 0;
+    char *endp;
     Error *err = NULL;
-    bool has_compress_level = false;
-    bool has_compress_threads = false;
-    bool has_decompress_threads = false;
-    bool has_cpu_throttle_initial = false;
-    bool has_cpu_throttle_increment = false;
-    bool has_tls_creds = false;
-    bool has_tls_hostname = false;
     bool use_int_value = false;
     int i;
 
     for (i = 0; i < MIGRATION_PARAMETER__MAX; i++) {
         if (strcmp(param, MigrationParameter_lookup[i]) == 0) {
+            MigrationParameters p = { 0 };
             switch (i) {
             case MIGRATION_PARAMETER_COMPRESS_LEVEL:
-                has_compress_level = true;
+                p.has_compress_level = true;
                 use_int_value = true;
                 break;
             case MIGRATION_PARAMETER_COMPRESS_THREADS:
-                has_compress_threads = true;
+                p.has_compress_threads = true;
                 use_int_value = true;
                 break;
             case MIGRATION_PARAMETER_DECOMPRESS_THREADS:
-                has_decompress_threads = true;
+                p.has_decompress_threads = true;
                 use_int_value = true;
                 break;
             case MIGRATION_PARAMETER_CPU_THROTTLE_INITIAL:
-                has_cpu_throttle_initial = true;
+                p.has_cpu_throttle_initial = true;
                 use_int_value = true;
                 break;
             case MIGRATION_PARAMETER_CPU_THROTTLE_INCREMENT:
-                has_cpu_throttle_increment = true;
+                p.has_cpu_throttle_increment = true;
+                use_int_value = true;
                 break;
             case MIGRATION_PARAMETER_TLS_CREDS:
-                has_tls_creds = true;
+                p.has_tls_creds = true;
+                p.tls_creds = (char *) valuestr;
                 break;
             case MIGRATION_PARAMETER_TLS_HOSTNAME:
-                has_tls_hostname = true;
+                p.has_tls_hostname = true;
+                p.tls_hostname = (char *) valuestr;
+                break;
+            case MIGRATION_PARAMETER_MAX_BANDWIDTH:
+                p.has_max_bandwidth = true;
+                valuebw = qemu_strtosz(valuestr, &endp);
+                if (valuebw < 0 || (size_t)valuebw != valuebw
+                    || *endp != '\0') {
+                    error_setg(&err, "Invalid size %s", valuestr);
+                    goto cleanup;
+                }
+                p.max_bandwidth = valuebw;
+                break;
+            case MIGRATION_PARAMETER_DOWNTIME_LIMIT:
+                p.has_downtime_limit = true;
+                use_int_value = true;
                 break;
             }
 
@@ -1366,16 +1394,17 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
                                valuestr);
                     goto cleanup;
                 }
+                /* Set all integers; only one has_FOO will be set, and
+                 * the code ignores the remaining values */
+                p.compress_level = valueint;
+                p.compress_threads = valueint;
+                p.decompress_threads = valueint;
+                p.cpu_throttle_initial = valueint;
+                p.cpu_throttle_increment = valueint;
+                p.downtime_limit = valueint;
             }
 
-            qmp_migrate_set_parameters(has_compress_level, valueint,
-                                       has_compress_threads, valueint,
-                                       has_decompress_threads, valueint,
-                                       has_cpu_throttle_initial, valueint,
-                                       has_cpu_throttle_increment, valueint,
-                                       has_tls_creds, valuestr,
-                                       has_tls_hostname, valuestr,
-                                       &err);
+            qmp_migrate_set_parameters(&p, &err);
             break;
         }
     }
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 869ba41b0c..cffdc130e6 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -63,6 +63,7 @@ RAMBlock *qemu_ram_block_from_host(void *ptr, bool round_offset,
 void qemu_ram_set_idstr(RAMBlock *block, const char *name, DeviceState *dev);
 void qemu_ram_unset_idstr(RAMBlock *block);
 const char *qemu_ram_get_idstr(RAMBlock *rb);
+size_t qemu_ram_pagesize(RAMBlock *block);
 
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
                             int len, int is_write);
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 2a9465da11..54d7108a9e 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -36,6 +36,7 @@ struct RAMBlock {
     /* RCU-enabled, writes protected by the ramlist lock */
     QLIST_ENTRY(RAMBlock) next;
     int fd;
+    size_t page_size;
 };
 
 static inline bool offset_in_ramblock(RAMBlock *b, ram_addr_t offset)
diff --git a/include/migration/migration.h b/include/migration/migration.h
index d4acc72b85..2791b90c00 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -129,7 +129,6 @@ struct MigrationSrcPageRequest {
 
 struct MigrationState
 {
-    int64_t bandwidth_limit;
     size_t bytes_xfer;
     size_t xfer_limit;
     QemuThread thread;
diff --git a/migration/migration.c b/migration/migration.c
index 955d5ee38c..4d417b76cf 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -44,6 +44,10 @@
 #define BUFFER_DELAY     100
 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
 
+/* Time in milliseconds we are allowed to stop the source,
+ * for sending the last part */
+#define DEFAULT_MIGRATE_SET_DOWNTIME 300
+
 /* Default compression thread count */
 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
 /* Default decompression thread count, usually decompression is at
@@ -80,7 +84,6 @@ MigrationState *migrate_get_current(void)
     static bool once;
     static MigrationState current_migration = {
         .state = MIGRATION_STATUS_NONE,
-        .bandwidth_limit = MAX_THROTTLE,
         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
         .mbps = -1,
         .parameters = {
@@ -89,6 +92,8 @@ MigrationState *migrate_get_current(void)
             .decompress_threads = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
             .cpu_throttle_initial = DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL,
             .cpu_throttle_increment = DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT,
+            .max_bandwidth = MAX_THROTTLE,
+            .downtime_limit = DEFAULT_MIGRATE_SET_DOWNTIME,
         },
     };
 
@@ -517,17 +522,6 @@ void migrate_send_rp_pong(MigrationIncomingState *mis,
     migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
 }
 
-/* amount of nanoseconds we are willing to wait for migration to be down.
- * the choice of nanoseconds is because it is the maximum resolution that
- * get_clock() can achieve. It is an internal measure. All user-visible
- * units must be in seconds */
-static uint64_t max_downtime = 300000000;
-
-uint64_t migrate_max_downtime(void)
-{
-    return max_downtime;
-}
-
 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
 {
     MigrationCapabilityStatusList *head = NULL;
@@ -559,13 +553,24 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
     MigrationState *s = migrate_get_current();
 
     params = g_malloc0(sizeof(*params));
+    params->has_compress_level = true;
     params->compress_level = s->parameters.compress_level;
+    params->has_compress_threads = true;
     params->compress_threads = s->parameters.compress_threads;
+    params->has_decompress_threads = true;
     params->decompress_threads = s->parameters.decompress_threads;
+    params->has_cpu_throttle_initial = true;
     params->cpu_throttle_initial = s->parameters.cpu_throttle_initial;
+    params->has_cpu_throttle_increment = true;
     params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
+    params->has_tls_creds = !!s->parameters.tls_creds;
     params->tls_creds = g_strdup(s->parameters.tls_creds);
+    params->has_tls_hostname = !!s->parameters.tls_hostname;
     params->tls_hostname = g_strdup(s->parameters.tls_hostname);
+    params->has_max_bandwidth = true;
+    params->max_bandwidth = s->parameters.max_bandwidth;
+    params->has_downtime_limit = true;
+    params->downtime_limit = s->parameters.downtime_limit;
 
     return params;
 }
@@ -759,78 +764,92 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
     }
 }
 
-void qmp_migrate_set_parameters(bool has_compress_level,
-                                int64_t compress_level,
-                                bool has_compress_threads,
-                                int64_t compress_threads,
-                                bool has_decompress_threads,
-                                int64_t decompress_threads,
-                                bool has_cpu_throttle_initial,
-                                int64_t cpu_throttle_initial,
-                                bool has_cpu_throttle_increment,
-                                int64_t cpu_throttle_increment,
-                                bool has_tls_creds,
-                                const char *tls_creds,
-                                bool has_tls_hostname,
-                                const char *tls_hostname,
-                                Error **errp)
+void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
 {
     MigrationState *s = migrate_get_current();
 
-    if (has_compress_level && (compress_level < 0 || compress_level > 9)) {
+    if (params->has_compress_level &&
+        (params->compress_level < 0 || params->compress_level > 9)) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level",
                    "is invalid, it should be in the range of 0 to 9");
         return;
     }
-    if (has_compress_threads &&
-            (compress_threads < 1 || compress_threads > 255)) {
+    if (params->has_compress_threads &&
+        (params->compress_threads < 1 || params->compress_threads > 255)) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
                    "compress_threads",
                    "is invalid, it should be in the range of 1 to 255");
         return;
     }
-    if (has_decompress_threads &&
-            (decompress_threads < 1 || decompress_threads > 255)) {
+    if (params->has_decompress_threads &&
+        (params->decompress_threads < 1 || params->decompress_threads > 255)) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
                    "decompress_threads",
                    "is invalid, it should be in the range of 1 to 255");
         return;
     }
-    if (has_cpu_throttle_initial &&
-            (cpu_throttle_initial < 1 || cpu_throttle_initial > 99)) {
+    if (params->has_cpu_throttle_initial &&
+        (params->cpu_throttle_initial < 1 ||
+         params->cpu_throttle_initial > 99)) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
                    "cpu_throttle_initial",
                    "an integer in the range of 1 to 99");
+        return;
     }
-    if (has_cpu_throttle_increment &&
-            (cpu_throttle_increment < 1 || cpu_throttle_increment > 99)) {
+    if (params->has_cpu_throttle_increment &&
+        (params->cpu_throttle_increment < 1 ||
+         params->cpu_throttle_increment > 99)) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
                    "cpu_throttle_increment",
                    "an integer in the range of 1 to 99");
+        return;
+    }
+    if (params->has_max_bandwidth &&
+        (params->max_bandwidth < 0 || params->max_bandwidth > SIZE_MAX)) {
+        error_setg(errp, "Parameter 'max_bandwidth' expects an integer in the"
+                         " range of 0 to %zu bytes/second", SIZE_MAX);
+        return;
+    }
+    if (params->has_downtime_limit &&
+        (params->downtime_limit < 0 || params->downtime_limit > 2000000)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   "downtime_limit",
+                   "an integer in the range of 0 to 2000000 milliseconds");
+        return;
     }
 
-    if (has_compress_level) {
-        s->parameters.compress_level = compress_level;
+    if (params->has_compress_level) {
+        s->parameters.compress_level = params->compress_level;
     }
-    if (has_compress_threads) {
-        s->parameters.compress_threads = compress_threads;
+    if (params->has_compress_threads) {
+        s->parameters.compress_threads = params->compress_threads;
     }
-    if (has_decompress_threads) {
-        s->parameters.decompress_threads = decompress_threads;
+    if (params->has_decompress_threads) {
+        s->parameters.decompress_threads = params->decompress_threads;
     }
-    if (has_cpu_throttle_initial) {
-        s->parameters.cpu_throttle_initial = cpu_throttle_initial;
+    if (params->has_cpu_throttle_initial) {
+        s->parameters.cpu_throttle_initial = params->cpu_throttle_initial;
     }
-    if (has_cpu_throttle_increment) {
-        s->parameters.cpu_throttle_increment = cpu_throttle_increment;
+    if (params->has_cpu_throttle_increment) {
+        s->parameters.cpu_throttle_increment = params->cpu_throttle_increment;
     }
-    if (has_tls_creds) {
+    if (params->has_tls_creds) {
         g_free(s->parameters.tls_creds);
-        s->parameters.tls_creds = g_strdup(tls_creds);
+        s->parameters.tls_creds = g_strdup(params->tls_creds);
     }
-    if (has_tls_hostname) {
+    if (params->has_tls_hostname) {
         g_free(s->parameters.tls_hostname);
-        s->parameters.tls_hostname = g_strdup(tls_hostname);
+        s->parameters.tls_hostname = g_strdup(params->tls_hostname);
+    }
+    if (params->has_max_bandwidth) {
+        s->parameters.max_bandwidth = params->max_bandwidth;
+        if (s->to_dst_file) {
+            qemu_file_set_rate_limit(s->to_dst_file,
+                                s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
+        }
+    }
+    if (params->has_downtime_limit) {
+        s->parameters.downtime_limit = params->downtime_limit;
     }
 }
 
@@ -1165,28 +1184,25 @@ int64_t qmp_query_migrate_cache_size(Error **errp)
 
 void qmp_migrate_set_speed(int64_t value, Error **errp)
 {
-    MigrationState *s;
-
-    if (value < 0) {
-        value = 0;
-    }
-    if (value > SIZE_MAX) {
-        value = SIZE_MAX;
-    }
+    MigrationParameters p = {
+        .has_max_bandwidth = true,
+        .max_bandwidth = value,
+    };
 
-    s = migrate_get_current();
-    s->bandwidth_limit = value;
-    if (s->to_dst_file) {
-        qemu_file_set_rate_limit(s->to_dst_file,
-                                 s->bandwidth_limit / XFER_LIMIT_RATIO);
-    }
+    qmp_migrate_set_parameters(&p, errp);
 }
 
 void qmp_migrate_set_downtime(double value, Error **errp)
 {
-    value *= 1e9;
-    value = MAX(0, MIN(UINT64_MAX, value));
-    max_downtime = (uint64_t)value;
+    value *= 1000; /* Convert to milliseconds */
+    value = MAX(0, MIN(INT64_MAX, value));
+
+    MigrationParameters p = {
+        .has_downtime_limit = true,
+        .downtime_limit = value,
+    };
+
+    qmp_migrate_set_parameters(&p, errp);
 }
 
 bool migrate_postcopy_ram(void)
@@ -1793,7 +1809,7 @@ static void *migration_thread(void *opaque)
                                          initial_bytes;
             uint64_t time_spent = current_time - initial_time;
             double bandwidth = (double)transferred_bytes / time_spent;
-            max_size = bandwidth * migrate_max_downtime() / 1000000;
+            max_size = bandwidth * s->parameters.downtime_limit;
 
             s->mbps = (((double) transferred_bytes * 8.0) /
                     ((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
@@ -1852,13 +1868,12 @@ static void *migration_thread(void *opaque)
 
 void migrate_fd_connect(MigrationState *s)
 {
-    /* This is a best 1st approximation. ns to ms */
-    s->expected_downtime = max_downtime/1000000;
+    s->expected_downtime = s->parameters.downtime_limit;
     s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
 
     qemu_file_set_blocking(s->to_dst_file, true);
     qemu_file_set_rate_limit(s->to_dst_file,
-                             s->bandwidth_limit / XFER_LIMIT_RATIO);
+                             s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
 
     /* Notify before starting migration thread */
     notifier_list_notify(&migration_state_notifiers, s);
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 9b0477835f..a40dddbaf6 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -85,6 +85,24 @@ static bool ufd_version_check(int ufd)
 }
 
 /*
+ * Check for things that postcopy won't support; returns 0 if the block
+ * is fine.
+ */
+static int check_range(const char *block_name, void *host_addr,
+                      ram_addr_t offset, ram_addr_t length, void *opaque)
+{
+    RAMBlock *rb = qemu_ram_block_by_name(block_name);
+
+    if (qemu_ram_pagesize(rb) > getpagesize()) {
+        error_report("Postcopy doesn't support large page sizes yet (%s)",
+                     block_name);
+        return -E2BIG;
+    }
+
+    return 0;
+}
+
+/*
  * Note: This has the side effect of munlock'ing all of RAM, that's
  * normally fine since if the postcopy succeeds it gets turned back on at the
  * end.
@@ -104,6 +122,12 @@ bool postcopy_ram_supported_by_host(void)
         goto out;
     }
 
+    /* Check for anything about the RAMBlocks we don't support */
+    if (qemu_ram_foreach_block(check_range, NULL)) {
+        /* check_range will have printed its own error */
+        goto out;
+    }
+
     ufd = syscall(__NR_userfaultfd, O_CLOEXEC);
     if (ufd == -1) {
         error_report("%s: userfaultfd not available: %s", __func__,
diff --git a/migration/ram.c b/migration/ram.c
index c8ec9f268f..bc6154fe34 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -771,7 +771,9 @@ static int ram_save_page(QEMUFile *f, PageSearchStatus *pss,
              * page would be stale
              */
             xbzrle_cache_zero_page(current_addr);
-        } else if (!ram_bulk_stage && migrate_use_xbzrle()) {
+        } else if (!ram_bulk_stage &&
+                   !migration_in_postcopy(migrate_get_current()) &&
+                   migrate_use_xbzrle()) {
             pages = save_xbzrle_page(f, &p, current_addr, block,
                                      offset, last_stage, bytes_transferred);
             if (!last_stage) {
diff --git a/migration/rdma.c b/migration/rdma.c
index 88bdb64457..674ccab12e 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -350,6 +350,7 @@ typedef struct RDMAContext {
      */
     int error_state;
     int error_reported;
+    int received_error;
 
     /*
      * Description of ram blocks used throughout the code.
@@ -1676,6 +1677,9 @@ static int qemu_rdma_exchange_get_response(RDMAContext *rdma,
                 ", but got: %s (%d), length: %d",
                 control_desc[expecting], expecting,
                 control_desc[head->type], head->type, head->len);
+        if (head->type == RDMA_CONTROL_ERROR) {
+            rdma->received_error = true;
+        }
         return -EIO;
     }
     if (head->len > RDMA_CONTROL_MAX_BUFFER - sizeof(*head)) {
@@ -2202,7 +2206,7 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
     int ret, idx;
 
     if (rdma->cm_id && rdma->connected) {
-        if (rdma->error_state) {
+        if (rdma->error_state && !rdma->received_error) {
             RDMAControlHeader head = { .len = 0,
                                        .type = RDMA_CONTROL_ERROR,
                                        .repeat = 1,
@@ -2804,6 +2808,9 @@ static int qio_channel_rdma_close(QIOChannel *ioc,
     QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(ioc);
     trace_qemu_rdma_close();
     if (rioc->rdma) {
+        if (!rioc->rdma->error_state) {
+            rioc->rdma->error_state = qemu_file_get_error(rioc->file);
+        }
         qemu_rdma_cleanup(rioc->rdma);
         g_free(rioc->rdma);
         rioc->rdma = NULL;
diff --git a/migration/savevm.c b/migration/savevm.c
index 33a2911ec2..a831ec2d67 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1828,40 +1828,45 @@ qemu_loadvm_section_part_end(QEMUFile *f, MigrationIncomingState *mis)
 static int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis)
 {
     uint8_t section_type;
-    int ret;
+    int ret = 0;
 
     while ((section_type = qemu_get_byte(f)) != QEMU_VM_EOF) {
-
+        ret = 0;
         trace_qemu_loadvm_state_section(section_type);
         switch (section_type) {
         case QEMU_VM_SECTION_START:
         case QEMU_VM_SECTION_FULL:
             ret = qemu_loadvm_section_start_full(f, mis);
             if (ret < 0) {
-                return ret;
+                goto out;
             }
             break;
         case QEMU_VM_SECTION_PART:
         case QEMU_VM_SECTION_END:
             ret = qemu_loadvm_section_part_end(f, mis);
             if (ret < 0) {
-                return ret;
+                goto out;
             }
             break;
         case QEMU_VM_COMMAND:
             ret = loadvm_process_command(f);
             trace_qemu_loadvm_state_section_command(ret);
             if ((ret < 0) || (ret & LOADVM_QUIT)) {
-                return ret;
+                goto out;
             }
             break;
         default:
             error_report("Unknown savevm section type %d", section_type);
-            return -EINVAL;
+            ret = -EINVAL;
+            goto out;
         }
     }
 
-    return 0;
+out:
+    if (ret < 0) {
+        qemu_file_set_error(f, ret);
+    }
+    return ret;
 }
 
 int qemu_loadvm_state(QEMUFile *f)
diff --git a/migration/socket.c b/migration/socket.c
index 00de1fe127..a21c0c5c35 100644
--- a/migration/socket.c
+++ b/migration/socket.c
@@ -112,8 +112,12 @@ void tcp_start_outgoing_migration(MigrationState *s,
                                   const char *host_port,
                                   Error **errp)
 {
-    SocketAddress *saddr = tcp_build_address(host_port, errp);
-    socket_start_outgoing_migration(s, saddr, errp);
+    Error *err = NULL;
+    SocketAddress *saddr = tcp_build_address(host_port, &err);
+    if (!err) {
+        socket_start_outgoing_migration(s, saddr, &err);
+    }
+    error_propagate(errp, err);
 }
 
 void unix_start_outgoing_migration(MigrationState *s,
@@ -174,8 +178,12 @@ static void socket_start_incoming_migration(SocketAddress *saddr,
 
 void tcp_start_incoming_migration(const char *host_port, Error **errp)
 {
-    SocketAddress *saddr = tcp_build_address(host_port, errp);
-    socket_start_incoming_migration(saddr, errp);
+    Error *err = NULL;
+    SocketAddress *saddr = tcp_build_address(host_port, &err);
+    if (!err) {
+        socket_start_incoming_migration(saddr, &err);
+    }
+    error_propagate(errp, err);
 }
 
 void unix_start_incoming_migration(const char *path, Error **errp)
diff --git a/migration/vmstate.c b/migration/vmstate.c
index fc29acf74d..0bc9f35ef8 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -130,6 +130,8 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
                 }
                 if (ret < 0) {
                     qemu_file_set_error(f, ret);
+                    error_report("Failed to load %s:%s", vmsd->name,
+                                 field->name);
                     trace_vmstate_load_field_error(field->name, ret);
                     return ret;
                 }
@@ -555,6 +557,7 @@ static int get_int32_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%" PRIx32 " != %" PRIx32, *v, v2);
     return -EINVAL;
 }
 
@@ -578,6 +581,9 @@ static int get_int32_le(QEMUFile *f, void *pv, size_t size)
         *cur = loaded;
         return 0;
     }
+    error_report("Invalid value %" PRId32
+                 " expecting positive value <= %" PRId32,
+                 loaded, *cur);
     return -EINVAL;
 }
 
@@ -683,6 +689,7 @@ static int get_uint32_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%" PRIx32 " != %" PRIx32, *v, v2);
     return -EINVAL;
 }
 
@@ -725,6 +732,7 @@ static int get_uint64_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%" PRIx64 " != %" PRIx64, *v, v2);
     return -EINVAL;
 }
 
@@ -746,6 +754,7 @@ static int get_uint8_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%x != %x", *v, v2);
     return -EINVAL;
 }
 
@@ -767,6 +776,7 @@ static int get_uint16_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%x != %x", *v, v2);
     return -EINVAL;
 }
 
diff --git a/qapi-schema.json b/qapi-schema.json
index 9e47b47cc7..ded1179f06 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -658,101 +658,85 @@
 #                hostname must be provided so that the server's x509
 #                certificate identity can be validated. (Since 2.7)
 #
+# @max-bandwidth: to set maximum speed for migration. maximum speed in
+#                 bytes per second. (Since 2.8)
+#
+# @downtime-limit: set maximum tolerated downtime for migration. maximum
+#                  downtime in milliseconds (Since 2.8)
+#
 # Since: 2.4
 ##
 { 'enum': 'MigrationParameter',
   'data': ['compress-level', 'compress-threads', 'decompress-threads',
            'cpu-throttle-initial', 'cpu-throttle-increment',
-           'tls-creds', 'tls-hostname'] }
+           'tls-creds', 'tls-hostname', 'max-bandwidth',
+           'downtime-limit'] }
 
 #
 # @migrate-set-parameters
 #
-# Set the following migration parameters
-#
-# @compress-level: compression level
-#
-# @compress-threads: compression thread count
-#
-# @decompress-threads: decompression thread count
-#
-# @cpu-throttle-initial: Initial percentage of time guest cpus are throttled
-#                        when migration auto-converge is activated. The
-#                        default value is 20. (Since 2.7)
-#
-# @cpu-throttle-increment: throttle percentage increase each time
-#                          auto-converge detects that migration is not making
-#                          progress. The default value is 10. (Since 2.7)
-#
-# @tls-creds: ID of the 'tls-creds' object that provides credentials for
-#             establishing a TLS connection over the migration data channel.
-#             On the outgoing side of the migration, the credentials must
-#             be for a 'client' endpoint, while for the incoming side the
-#             credentials must be for a 'server' endpoint. Setting this
-#             will enable TLS for all migrations. The default is unset,
-#             resulting in unsecured migration at the QEMU level. (Since 2.7)
-#
-# @tls-hostname: hostname of the target host for the migration. This is
-#                required when using x509 based TLS credentials and the
-#                migration URI does not already include a hostname. For
-#                example if using fd: or exec: based migration, the
-#                hostname must be provided so that the server's x509
-#                certificate identity can be validated. (Since 2.7)
+# Set various migration parameters.  See MigrationParameters for details.
 #
 # Since: 2.4
 ##
-{ 'command': 'migrate-set-parameters',
-  'data': { '*compress-level': 'int',
-            '*compress-threads': 'int',
-            '*decompress-threads': 'int',
-            '*cpu-throttle-initial': 'int',
-            '*cpu-throttle-increment': 'int',
-            '*tls-creds': 'str',
-            '*tls-hostname': 'str'} }
+{ 'command': 'migrate-set-parameters', 'boxed': true,
+  'data': 'MigrationParameters' }
 
 #
 # @MigrationParameters
 #
-# @compress-level: compression level
+# Optional members can be omitted on input ('migrate-set-parameters')
+# but most members will always be present on output
+# ('query-migrate-parameters'), with the exception of tls-creds and
+# tls-hostname.
 #
-# @compress-threads: compression thread count
+# @compress-level: #optional compression level
 #
-# @decompress-threads: decompression thread count
+# @compress-threads: #optional compression thread count
 #
-# @cpu-throttle-initial: Initial percentage of time guest cpus are throttled
-#                        when migration auto-converge is activated. The
-#                        default value is 20. (Since 2.7)
+# @decompress-threads: #optional decompression thread count
 #
-# @cpu-throttle-increment: throttle percentage increase each time
+# @cpu-throttle-initial: #optional Initial percentage of time guest cpus are
+#                        throttledwhen migration auto-converge is activated.
+#                        The default value is 20. (Since 2.7)
+#
+# @cpu-throttle-increment: #optional throttle percentage increase each time
 #                          auto-converge detects that migration is not making
 #                          progress. The default value is 10. (Since 2.7)
 #
-# @tls-creds: ID of the 'tls-creds' object that provides credentials for
-#             establishing a TLS connection over the migration data channel.
-#             On the outgoing side of the migration, the credentials must
-#             be for a 'client' endpoint, while for the incoming side the
+# @tls-creds: #optional ID of the 'tls-creds' object that provides credentials
+#             for establishing a TLS connection over the migration data
+#             channel. On the outgoing side of the migration, the credentials
+#             must be for a 'client' endpoint, while for the incoming side the
 #             credentials must be for a 'server' endpoint. Setting this
 #             will enable TLS for all migrations. The default is unset,
 #             resulting in unsecured migration at the QEMU level. (Since 2.7)
 #
-# @tls-hostname: hostname of the target host for the migration. This is
-#                required when using x509 based TLS credentials and the
+# @tls-hostname: #optional hostname of the target host for the migration. This
+#                is required when using x509 based TLS credentials and the
 #                migration URI does not already include a hostname. For
 #                example if using fd: or exec: based migration, the
 #                hostname must be provided so that the server's x509
 #                certificate identity can be validated. (Since 2.7)
 #
+# @max-bandwidth: to set maximum speed for migration. maximum speed in
+#                 bytes per second. (Since 2.8)
+#
+# @downtime-limit: set maximum tolerated downtime for migration. maximum
+#                  downtime in milliseconds (Since 2.8)
+#
 # Since: 2.4
 ##
 { 'struct': 'MigrationParameters',
-  'data': { 'compress-level': 'int',
-            'compress-threads': 'int',
-            'decompress-threads': 'int',
-            'cpu-throttle-initial': 'int',
-            'cpu-throttle-increment': 'int',
-            'tls-creds': 'str',
-            'tls-hostname': 'str'} }
-
+  'data': { '*compress-level': 'int',
+            '*compress-threads': 'int',
+            '*decompress-threads': 'int',
+            '*cpu-throttle-initial': 'int',
+            '*cpu-throttle-increment': 'int',
+            '*tls-creds': 'str',
+            '*tls-hostname': 'str',
+            '*max-bandwidth': 'int',
+            '*downtime-limit': 'int'} }
 ##
 # @query-migrate-parameters
 #
@@ -1834,6 +1818,8 @@
 #
 # Returns: nothing on success
 #
+# Notes: This command is deprecated in favor of 'migrate-set-parameters'
+#
 # Since: 0.14.0
 ##
 { 'command': 'migrate_set_downtime', 'data': {'value': 'number'} }
@@ -1847,7 +1833,7 @@
 #
 # Returns: nothing on success
 #
-# Notes: A value lesser than zero will be automatically round up to zero.
+# Notes: This command is deprecated in favor of 'migrate-set-parameters'
 #
 # Since: 0.14.0
 ##