8 files changed, 77 insertions, 4 deletions

diff --git a/docs/replay.txt b/docs/replay.txt
index ce97c3f72f..f4619a62a3 100644
--- a/docs/replay.txt
+++ b/docs/replay.txt
@@ -67,6 +67,7 @@ Modifications of qemu include:
  * network filter for recording and replaying the packets
  * block driver for making block layer deterministic
  * serial port input record and replay
+ * recording of random numbers obtained from the external sources
 
 Locking and thread synchronisation
 ----------------------------------
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index 8df517298c..5471bb514d 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -117,6 +117,13 @@ int64_t replay_read_clock(ReplayClockKind kind);
             ? replay_save_clock((clock), (value), cpu_get_icount_raw_locked()) \
         : (value))
 
+/* Processing data from random generators */
+
+/* Saves the values from the random number generator */
+void replay_save_random(int ret, void *buf, size_t len);
+/* Loads the saved values for the random number generator */
+int replay_read_random(void *buf, size_t len);
+
 /* Events */
 
 /*! Called when qemu shutdown is requested. */
diff --git a/replay/Makefile.objs b/replay/Makefile.objs
index cee6539a23..939be964a9 100644
--- a/replay/Makefile.objs
+++ b/replay/Makefile.objs
@@ -6,4 +6,5 @@ common-obj-y += replay-input.o
 common-obj-y += replay-char.o
 common-obj-y += replay-snapshot.o
 common-obj-y += replay-net.o
-common-obj-y += replay-audio.o
\ No newline at end of file
+common-obj-y += replay-audio.o
+common-obj-y += replay-random.o
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 55fca1ac6b..33ac551e78 100644
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -34,6 +34,8 @@ enum ReplayEvents {
     EVENT_AUDIO_OUT,
     /* for audio in event */
     EVENT_AUDIO_IN,
+    /* for random number generator */
+    EVENT_RANDOM,
     /* for clock read/writes */
     /* some of greater codes are reserved for clocks */
     EVENT_CLOCK,
diff --git a/replay/replay-random.c b/replay/replay-random.c
new file mode 100644
index 0000000000..afc7a0fccc
--- /dev/null
+++ b/replay/replay-random.c
@@ -0,0 +1,44 @@
+/*
+ * replay-random.c
+ *
+ * Copyright (c) 2010-2020 Institute for System Programming
+ *                         of the Russian Academy of Sciences.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "sysemu/replay.h"
+#include "replay-internal.h"
+
+void replay_save_random(int ret, void *buf, size_t len)
+{
+    g_assert(replay_mutex_locked());
+
+    replay_save_instructions();
+    replay_put_event(EVENT_RANDOM);
+    replay_put_dword(ret);
+    replay_put_array(buf, len);
+}
+
+int replay_read_random(void *buf, size_t len)
+{
+    int ret = 0;
+    g_assert(replay_mutex_locked());
+
+    replay_account_executed_instructions();
+    if (replay_next_event_is(EVENT_RANDOM)) {
+        size_t buf_size = 0;
+        ret = replay_get_dword();
+        replay_get_array(buf, &buf_size);
+        replay_finish_event();
+        g_assert(buf_size == len);
+    } else {
+        error_report("Missing random event in the replay log");
+        exit(1);
+    }
+    return ret;
+}
diff --git a/replay/replay.c b/replay/replay.c
index 5cc25bd2f8..706c7b4f4b 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -22,7 +22,7 @@
 
 /* Current version of the replay mechanism.
    Increase it when file format changes. */
-#define REPLAY_VERSION              0xe02008
+#define REPLAY_VERSION              0xe02009
 /* Size of replay log header */
 #define HEADER_SIZE                 (sizeof(uint32_t) + sizeof(uint64_t))
 
diff --git a/stubs/replay.c b/stubs/replay.c
index 10b3925e2f..5974ec1f50 100644
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -79,3 +79,12 @@ void replay_mutex_lock(void)
 void replay_mutex_unlock(void)
 {
 }
+
+void replay_save_random(int ret, void *buf, size_t len)
+{
+}
+
+int replay_read_random(void *buf, size_t len)
+{
+    return 0;
+}
diff --git a/util/guest-random.c b/util/guest-random.c
index 9453968bd7..086115bd67 100644
--- a/util/guest-random.c
+++ b/util/guest-random.c
@@ -14,6 +14,7 @@
 #include "qapi/error.h"
 #include "qemu/guest-random.h"
 #include "crypto/random.h"
+#include "sysemu/replay.h"
 
 
 static __thread GRand *thread_rand;
@@ -44,13 +45,21 @@ static int glib_random_bytes(void *buf, size_t len)
 
 int qemu_guest_getrandom(void *buf, size_t len, Error **errp)
 {
+    int ret;
+    if (replay_mode == REPLAY_MODE_PLAY) {
+        return replay_read_random(buf, len);
+    }
     if (unlikely(deterministic)) {
         /* Deterministic implementation using Glib's Mersenne Twister.  */
-        return glib_random_bytes(buf, len);
+        ret = glib_random_bytes(buf, len);
     } else {
         /* Non-deterministic implementation using crypto routines.  */
-        return qcrypto_random_bytes(buf, len, errp);
+        ret = qcrypto_random_bytes(buf, len, errp);
+    }
+    if (replay_mode == REPLAY_MODE_RECORD) {
+        replay_save_random(ret, buf, len);
     }
+    return ret;
 }
 
 void qemu_guest_getrandom_nofail(void *buf, size_t len)