Migration (and HMP and virtiofs) pull 2020-06-17

Migration:
    HMP/migration and test changes from Mao Zhongyi
    multifd fix from Laurent Vivier
 HMP
    qom-set partial reversion/change from David Hildenbrand
       now you need -j to pass json format, but it's regained the
       old 100M type format.
   Memory leak fix from Pan Nengyuan
 
 Virtiofs
   fchmod seccomp fix from Max Reitz
 
 Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20200617a' into staging

Migration (and HMP and virtiofs) pull 2020-06-17

Migration:
   HMP/migration and test changes from Mao Zhongyi
   multifd fix from Laurent Vivier
HMP
   qom-set partial reversion/change from David Hildenbrand
      now you need -j to pass json format, but it's regained the
      old 100M type format.
  Memory leak fix from Pan Nengyuan

Virtiofs
  fchmod seccomp fix from Max Reitz

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

# gpg: Signature made Wed 17 Jun 2020 19:34:58 BST
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20200617a:
  migration: fix multifd_send_pages() next channel
  docs/xbzrle: update 'cache miss rate' and 'encoding rate' to docs
  monitor/hmp-cmds: improvements for the 'info migrate'
  monitor/hmp-cmds: add 'goto end' to reduce duplicate code.
  monitor/hmp-cmds: delete redundant Error check before invoke hmp_handle_error()
  monitor/hmp-cmds: don't silently output when running 'migrate_set_downtime' fails
  monitor/hmp-cmds: add units for migrate_parameters
  tests/migration: fix unreachable path in stress test
  tests/migration: mem leak fix
  hmp: Make json format optional for qom-set
  qom-hmp-cmds: fix a memleak in hmp_qom_get
  virtiofsd: Whitelist fchmod

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

docs/xbzrle.txt

@@ -112,10 +112,12 @@ is recommended.
     cache size: H bytes
     xbzrle transferred: I kbytes
     xbzrle pages: J pages
-    xbzrle cache miss: K
+    xbzrle cache miss: K pages
-    xbzrle overflow: L
+    xbzrle cache miss rate: L
+    xbzrle encoding rate: M
+    xbzrle overflow: N
 
-xbzrle cache-miss: the number of cache misses to date - high cache-miss rate
+xbzrle cache miss: the number of cache misses to date - high cache-miss rate
 indicates that the cache size is set too low.
 xbzrle overflow: the number of overflows in the decoding which where the delta
 could not be compressed. This can happen if the changes in the pages are too

hmp-commands.hx

@@ -1806,9 +1806,10 @@ ERST
 
     {
         .name       = "qom-set",
-        .args_type  = "path:s,property:s,value:S",
+        .args_type  = "json:-j,path:s,property:s,value:S",
-        .params     = "path property value",
+        .params     = "[-j] path property value",
-        .help       = "set QOM property",
+        .help       = "set QOM property.\n\t\t\t"
+                      "-j: the value is specified in json format.",
         .cmd        = hmp_qom_set,
         .flags      = "p",
     },

migration/multifd.c

@@ -415,6 +415,12 @@ static int multifd_send_pages(QEMUFile *f)
     }
 
     qemu_sem_wait(&multifd_send_state->channels_ready);
+    /*
+     * next_channel can remain from a previous migration that was
+     * using more channels, so ensure it doesn't overflow if the
+     * limit is lower now.
+     */
+    next_channel %= migrate_multifd_channels();
     for (i = next_channel;; i = (i + 1) % migrate_multifd_channels()) {
         p = &multifd_send_state->params[i];
 

monitor/hmp-cmds.c

@@ -299,7 +299,7 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
                        info->xbzrle_cache->bytes >> 10);
         monitor_printf(mon, "xbzrle pages: %" PRIu64 " pages\n",
                        info->xbzrle_cache->pages);
-        monitor_printf(mon, "xbzrle cache miss: %" PRIu64 "\n",
+        monitor_printf(mon, "xbzrle cache miss: %" PRIu64 " pages\n",
                        info->xbzrle_cache->cache_miss);
         monitor_printf(mon, "xbzrle cache miss rate: %0.2f\n",
                        info->xbzrle_cache->cache_miss_rate);
@@ -316,8 +316,8 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
                        info->compression->busy);
         monitor_printf(mon, "compression busy rate: %0.2f\n",
                        info->compression->busy_rate);
-        monitor_printf(mon, "compressed size: %" PRIu64 "\n",
+        monitor_printf(mon, "compressed size: %" PRIu64 " kbytes\n",
-                       info->compression->compressed_size);
+                       info->compression->compressed_size >> 10);
         monitor_printf(mon, "compression rate: %0.2f\n",
                        info->compression->compression_rate);
     }
@@ -443,11 +443,11 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
             MigrationParameter_str(MIGRATION_PARAMETER_MAX_BANDWIDTH),
             params->max_bandwidth);
         assert(params->has_downtime_limit);
-        monitor_printf(mon, "%s: %" PRIu64 " milliseconds\n",
+        monitor_printf(mon, "%s: %" PRIu64 " ms\n",
             MigrationParameter_str(MIGRATION_PARAMETER_DOWNTIME_LIMIT),
             params->downtime_limit);
         assert(params->has_x_checkpoint_delay);
-        monitor_printf(mon, "%s: %u\n",
+        monitor_printf(mon, "%s: %u ms\n",
             MigrationParameter_str(MIGRATION_PARAMETER_X_CHECKPOINT_DELAY),
             params->x_checkpoint_delay);
         assert(params->has_block_incremental);
@@ -460,7 +460,7 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, "%s: %s\n",
             MigrationParameter_str(MIGRATION_PARAMETER_MULTIFD_COMPRESSION),
             MultiFDCompression_str(params->multifd_compression));
-        monitor_printf(mon, "%s: %" PRIu64 "\n",
+        monitor_printf(mon, "%s: %" PRIu64 " bytes\n",
             MigrationParameter_str(MIGRATION_PARAMETER_XBZRLE_CACHE_SIZE),
             params->xbzrle_cache_size);
         monitor_printf(mon, "%s: %" PRIu64 "\n",
@@ -1189,8 +1189,11 @@ void hmp_migrate_pause(Monitor *mon, const QDict *qdict)
 /* Kept for backwards compatibility */
 void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict)
 {
+    Error *err = NULL;
+
     double value = qdict_get_double(qdict, "value");
-    qmp_migrate_set_downtime(value, NULL);
+    qmp_migrate_set_downtime(value, &err);
+    hmp_handle_error(mon, err);
 }
 
 void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict)
@@ -1499,8 +1502,7 @@ void hmp_change(Monitor *mon, const QDict *qdict)
                                 read_only,
                                 BLOCKDEV_CHANGE_READ_ONLY_MODE_RETAIN, &err);
             if (err) {
-                hmp_handle_error(mon, err);
+                goto end;
-                return;
             }
         }
 
@@ -1509,6 +1511,7 @@ void hmp_change(Monitor *mon, const QDict *qdict)
                                    &err);
     }
 
+end:
     hmp_handle_error(mon, err);
 }
 
@@ -1627,16 +1630,15 @@ void hmp_object_add(Monitor *mon, const QDict *qdict)
 
     opts = qemu_opts_from_qdict(qemu_find_opts("object"), qdict, &err);
     if (err) {
-        hmp_handle_error(mon, err);
+        goto end;
-        return;
     }
 
     obj = user_creatable_add_opts(opts, &err);
     qemu_opts_del(opts);
 
-    if (err) {
+end:
-        hmp_handle_error(mon, err);
+    hmp_handle_error(mon, err);
-    }
+
     if (obj) {
         object_unref(obj);
     }

qom/qom-hmp-cmds.c

@@ -44,15 +44,27 @@ void hmp_qom_list(Monitor *mon, const QDict *qdict)
 
 void hmp_qom_set(Monitor *mon, const QDict *qdict)
 {
+    const bool json = qdict_get_try_bool(qdict, "json", false);
     const char *path = qdict_get_str(qdict, "path");
     const char *property = qdict_get_str(qdict, "property");
     const char *value = qdict_get_str(qdict, "value");
     Error *err = NULL;
-    QObject *obj;
 
-    obj = qobject_from_json(value, &err);
+    if (!json) {
-    if (err == NULL) {
+        Object *obj = object_resolve_path(path, NULL);
-        qmp_qom_set(path, property, obj, &err);
+
+        if (!obj) {
+            error_set(&err, ERROR_CLASS_DEVICE_NOT_FOUND,
+                      "Device '%s' not found", path);
+        } else {
+            object_property_parse(obj, value, property, &err);
+        }
+    } else {
+        QObject *obj = qobject_from_json(value, &err);
+
+        if (!err) {
+            qmp_qom_set(path, property, obj, &err);
+        }
     }
 
     hmp_handle_error(mon, err);
@@ -71,6 +83,7 @@ void hmp_qom_get(Monitor *mon, const QDict *qdict)
         qobject_unref(str);
     }
 
+    qobject_unref(obj);
     hmp_handle_error(mon, err);
 }
 

tests/migration/stress.c

@@ -167,29 +167,17 @@ static unsigned long long now(void)
     return (tv.tv_sec * 1000ull) + (tv.tv_usec / 1000ull);
 }
 
-static int stressone(unsigned long long ramsizeMB)
+static void stressone(unsigned long long ramsizeMB)
 {
     size_t pagesPerMB = 1024 * 1024 / PAGE_SIZE;
-    char *ram = malloc(ramsizeMB * 1024 * 1024);
+    g_autofree char *ram = g_malloc(ramsizeMB * 1024 * 1024);
     char *ramptr;
     size_t i, j, k;
-    char *data = malloc(PAGE_SIZE);
+    g_autofree char *data = g_malloc(PAGE_SIZE);
     char *dataptr;
     size_t nMB = 0;
     unsigned long long before, after;
 
-    if (!ram) {
-        fprintf(stderr, "%s (%05d): ERROR: cannot allocate %llu MB of RAM: %s\n",
-                argv0, gettid(), ramsizeMB, strerror(errno));
-        return -1;
-    }
-    if (!data) {
-        fprintf(stderr, "%s (%d): ERROR: cannot allocate %d bytes of RAM: %s\n",
-                argv0, gettid(), PAGE_SIZE, strerror(errno));
-        free(ram);
-        return -1;
-    }
-
     /* We don't care about initial state, but we do want
      * to fault it all into RAM, otherwise the first iter
      * of the loop below will be quite slow. We can't use
@@ -198,9 +186,7 @@ static int stressone(unsigned long long ramsizeMB)
     memset(ram, 0xfe, ramsizeMB * 1024 * 1024);
 
     if (random_bytes(data, PAGE_SIZE) < 0) {
-        free(ram);
+        return;
-        free(data);
-        return -1;
     }
 
     before = now();
@@ -227,9 +213,6 @@ static int stressone(unsigned long long ramsizeMB)
             }
         }
     }
-
-    free(data);
-    free(ram);
 }
 
 
@@ -242,7 +225,7 @@ static void *stressthread(void *arg)
     return NULL;
 }
 
-static int stress(unsigned long long ramsizeGB, int ncpus)
+static void stress(unsigned long long ramsizeGB, int ncpus)
 {
     size_t i;
     unsigned long long ramsizeMB = ramsizeGB * 1024 / ncpus;
@@ -255,8 +238,6 @@ static int stress(unsigned long long ramsizeGB, int ncpus)
     }
 
     stressone(ramsizeMB);
-
-    return 0;
 }
 
 
@@ -352,8 +333,7 @@ int main(int argc, char **argv)
     fprintf(stdout, "%s (%05d): INFO: RAM %llu GiB across %d CPUs\n",
             argv0, gettid(), ramsizeGB, ncpus);
 
-    if (stress(ramsizeGB, ncpus) < 0)
+    stress(ramsizeGB, ncpus);
-        exit_failure();
 
-    exit_success();
+    exit_failure();
 }

tools/virtiofsd/seccomp.c

@@ -42,6 +42,7 @@ static const int syscall_whitelist[] = {
     SCMP_SYS(exit_group),
     SCMP_SYS(fallocate),
     SCMP_SYS(fchdir),
+    SCMP_SYS(fchmod),
     SCMP_SYS(fchmodat),
     SCMP_SYS(fchownat),
     SCMP_SYS(fcntl),