Initialize the system from system and linux-user arguments.
Propagate deterministic seeds when creating new cpu threads.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
include/qemu/random.h | 58 +++++++++++++++++++++++++++++++++
include/qom/cpu.h | 1 +
cpus.c | 9 +++++
linux-user/main.c | 9 ++---
linux-user/syscall.c | 3 ++
util/random.c | 76 +++++++++++++++++++++++++++++++++++++++++++
vl.c | 4 +++
qemu-options.hx | 10 ++++++
util/Makefile.objs | 1 +
9 files changed, 164 insertions(+), 7 deletions(-)
create mode 100644 include/qemu/random.h
create mode 100644 util/random.c
diff --git a/include/qemu/random.h b/include/qemu/random.h
new file mode 100644
index 0000000000..9d88008288
--- /dev/null
+++ b/include/qemu/random.h
@@ -0,0 +1,58 @@
+/*
+ * QEMU random functions
+ *
+ * Copyright 2019 Linaro, Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#ifndef QEMU_RANDOM_H
+#define QEMU_RANDOM_H
+
+/**
+ * qemu_seedrandom_main(const char *optarg, Error **errp)
+ * @optarg: a non-NULL pointer to a C string
+ * @errp: an Error handler
+ *
+ * The @optarg value is that which accompanies the -seed argument.
+ * This forces qemu_getrandom into deterministic mode.
+ */
+void qemu_seedrandom_main(const char *optarg, Error **errp);
+
+/**
+ * qemu_seedrandom_thread_part1(void)
+ *
+ * If qemu_getrandom is in deterministic mode, returns an
+ * independant seed for the new thread. Otherwise returns 0.
+ */
+uint64_t qemu_seedrandom_thread_part1(void);
+
+/**
+ * qemu_seedrandom_thread_part2(uint64_t seed)
+ * @seed: a value for the new thread.
+ *
+ * If qemu_getrandom is in deterministic mode, this stores an
+ * independant seed for the new thread. Otherwise a no-op.
+ */
+void qemu_seedrandom_thread_part2(uint64_t seed);
+
+/**
+ * qemu_getrandom(void *buf, size_t len, bool nonblock)
+ * @buf: a buffer of bytes to be written
+ * @len: the number of bytes in @buf
+ * @nonblock: do not delay if the entropy pool is low
+ *
+ * Fills len bytes in buf with random data. If nonblock is false,
+ * this may require a delay while the entropy pool fills. Returns
+ * true if the call is successful, but the only non-successful case
+ * is when nonblock is true.
+ *
+ * The value of len must be <= 256, so that the BSD getentropy(3)
+ * function can be used to implement this.
+ */
+bool qemu_getrandom(void *buf, size_t len, bool nonblock);
+
+#endif /* QEMU_RANDOM_H */
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 1d6099e5d4..343cc6d51e 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -372,6 +372,7 @@ struct CPUState {
int singlestep_enabled;
int64_t icount_budget;
int64_t icount_extra;
+ uint64_t random_seed;
sigjmp_buf jmp_env;
QemuMutex work_mutex;
diff --git a/cpus.c b/cpus.c
index e83f72b48b..b5d3f46220 100644
--- a/cpus.c
+++ b/cpus.c
@@ -49,6 +49,7 @@
#include "qemu/option.h"
#include "qemu/bitmap.h"
#include "qemu/seqlock.h"
+#include "qemu/random.h"
#include "tcg.h"
#include "hw/nmi.h"
#include "sysemu/replay.h"
@@ -1275,6 +1276,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg)
/* signal CPU creation */
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
+ qemu_seedrandom_thread_part2(cpu->random_seed);
do {
if (cpu_can_run(cpu)) {
@@ -1318,6 +1320,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg)
/* signal CPU creation */
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
+ qemu_seedrandom_thread_part2(cpu->random_seed);
do {
qemu_mutex_unlock_iothread();
@@ -1477,6 +1480,7 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
cpu->created = true;
cpu->can_do_io = 1;
qemu_cond_signal(&qemu_cpu_cond);
+ qemu_seedrandom_thread_part2(cpu->random_seed);
/* wait for initial kick-off after machine start */
while (first_cpu->stopped) {
@@ -1591,6 +1595,7 @@ static void *qemu_hax_cpu_thread_fn(void *arg)
hax_init_vcpu(cpu);
qemu_cond_signal(&qemu_cpu_cond);
+ qemu_seedrandom_thread_part2(cpu->random_seed);
do {
if (cpu_can_run(cpu)) {
@@ -1630,6 +1635,7 @@ static void *qemu_hvf_cpu_thread_fn(void *arg)
/* signal CPU creation */
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
+ qemu_seedrandom_thread_part2(cpu->random_seed);
do {
if (cpu_can_run(cpu)) {
@@ -1670,6 +1676,7 @@ static void *qemu_whpx_cpu_thread_fn(void *arg)
/* signal CPU creation */
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
+ qemu_seedrandom_thread_part2(cpu->random_seed);
do {
if (cpu_can_run(cpu)) {
@@ -1723,6 +1730,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
cpu->can_do_io = 1;
current_cpu = cpu;
qemu_cond_signal(&qemu_cpu_cond);
+ qemu_seedrandom_thread_part2(cpu->random_seed);
/* process any pending work */
cpu->exit_request = 1;
@@ -2070,6 +2078,7 @@ void qemu_init_vcpu(CPUState *cpu)
cpu->nr_cores = smp_cores;
cpu->nr_threads = smp_threads;
cpu->stopped = true;
+ cpu->random_seed = qemu_seedrandom_thread_part1();
if (!cpu->as) {
/* If the target cpu hasn't set up any address spaces itself,
diff --git a/linux-user/main.c b/linux-user/main.c
index a0aba9cb1e..37300230f5 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -33,6 +33,7 @@
#include "tcg.h"
#include "qemu/timer.h"
#include "qemu/envlist.h"
+#include "qemu/random.h"
#include "elf.h"
#include "trace/control.h"
#include "target_elf.h"
@@ -291,13 +292,7 @@ static void handle_arg_pagesize(const char *arg)
static void handle_arg_randseed(const char *arg)
{
- unsigned long long seed;
-
- if (parse_uint_full(arg, &seed, 0) != 0 || seed > UINT_MAX) {
- fprintf(stderr, "Invalid seed number: %s\n", arg);
- exit(EXIT_FAILURE);
- }
- srand(seed);
+ qemu_seedrandom_main(arg, &error_fatal);
}
static void handle_arg_gdb(const char *arg)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 208fd1813d..18d98f5a08 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -110,6 +110,7 @@
#include "uname.h"
#include "qemu.h"
+#include "qemu/random.h"
#include "fd-trans.h"
#ifndef CLONE_IO
@@ -5448,6 +5449,7 @@ static void *clone_func(void *arg)
put_user_u32(info->tid, info->child_tidptr);
if (info->parent_tidptr)
put_user_u32(info->tid, info->parent_tidptr);
+ qemu_seedrandom_thread_part2(cpu->random_seed);
/* Enable signals. */
sigprocmask(SIG_SETMASK, &info->sigmask, NULL);
/* Signal to the parent that we're ready. */
@@ -5534,6 +5536,7 @@ static int do_fork(CPUArchState *env, unsigned int flags,
abi_ulong newsp,
initializing, so temporarily block all signals. */
sigfillset(&sigmask);
sigprocmask(SIG_BLOCK, &sigmask, &info.sigmask);
+ cpu->random_seed = qemu_seedrandom_thread_part1();
/* If this is our first additional thread, we need to ensure we
* generate code for parallel execution and flush old translations.
diff --git a/util/random.c b/util/random.c
new file mode 100644
index 0000000000..ded8725a3b
--- /dev/null
+++ b/util/random.c
@@ -0,0 +1,76 @@
+/*
+ * QEMU random functions
+ *
+ * Copyright 2019 Linaro, Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/cutils.h"
+#include "qapi/error.h"
+#include "qemu/random.h"
+
+
+/*
+ * While jrand48 is not technically thread safe, jrand48_r is glibc specific.
+ * However, the only other global state are the A and C values, which are
+ * otherwise constant. The only way to muck with those is with lcong48(3).
+ * So if we don't do that, jrand48 *is* thread-safe.
+ */
+static __thread uint16_t xsubi[3];
+
+/* Deterministic implementation using libc functions. */
+bool qemu_getrandom(void *buf, size_t len, bool nonblock)
+{
+ size_t i;
+ uint32_t val;
+
+ g_assert_cmpuint(len, <=, 256);
+
+ for (i = 0; i + 4 <= len; i += 4) {
+ val = jrand48(xsubi);
+ __builtin_memcpy(buf + i, &val, 4);
+ }
+ if (i < len) {
+ val = jrand48(xsubi);
+ __builtin_memcpy(buf + i, &val, len - i);
+ }
+
+ return true;
+}
+
+uint64_t qemu_seedrandom_thread_part1(void)
+{
+ uint64_t ret;
+ qemu_getrandom(&ret, sizeof(ret), false);
+ return ret;
+}
+
+void qemu_seedrandom_thread_part2(uint64_t seed)
+{
+ xsubi[0] = seed;
+ xsubi[1] = seed >> 16;
+ xsubi[2] = seed >> 32;
+}
+
+void qemu_seedrandom_main(const char *optarg, Error **errp)
+{
+ unsigned long long seed;
+ if (parse_uint_full(optarg, &seed, 0)) {
+ error_setg(errp, "Invalid seed number: %s", optarg);
+ } else {
+ qemu_seedrandom_thread_part2(seed);
+ }
+}
+
+static void __attribute__((constructor)) initialize(void)
+{
+ /* Make sure A and C parameters are initialized. */
+ srand48(0);
+ qemu_seedrandom_thread_part2(time(NULL) + getpid() * 1500450271ull);
+}
diff --git a/vl.c b/vl.c
index 027b853d92..5daf12f74a 100644
--- a/vl.c
+++ b/vl.c
@@ -128,6 +128,7 @@ int main(int argc, char **argv)
#include "qapi/qapi-commands-ui.h"
#include "qapi/qmp/qerror.h"
#include "sysemu/iothread.h"
+#include "qemu/random.h"
#define MAX_VIRTIO_CONSOLES 1
@@ -3330,6 +3331,9 @@ int main(int argc, char **argv, char **envp)
case QEMU_OPTION_DFILTER:
qemu_set_dfilter_ranges(optarg, &error_fatal);
break;
+ case QEMU_OPTION_seed:
+ qemu_seedrandom_main(optarg, &error_fatal);
+ break;
case QEMU_OPTION_s:
add_device_config(DEV_GDB, "tcp::" DEFAULT_GDBSTUB_PORT);
break;
diff --git a/qemu-options.hx b/qemu-options.hx
index 8693f5fa3c..a45ae70d33 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3598,6 +3598,16 @@ the 0x200 sized block starting at 0xffffffc000080000 and
another 0x1000 sized
block starting at 0xffffffc00005f000.
ETEXI
+DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
+ "-seed number seed the psudorandom number generator\n",
+ QEMU_ARCH_ALL)
+STEXI
+@item -seed @var{number}
+@findex -seed
+Force qemu to use a deterministic pseudo random number generator,
+seeded with @var{number}.
+ETEXI
+
DEF("L", HAS_ARG, QEMU_OPTION_L, \
"-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
QEMU_ARCH_ALL)
diff --git a/util/Makefile.objs b/util/Makefile.objs
index 835fcd69e2..bc7405c535 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -53,5 +53,6 @@ util-obj-y += iova-tree.o
util-obj-$(CONFIG_INOTIFY1) += filemonitor-inotify.o
util-obj-$(CONFIG_LINUX) += vfio-helpers.o
util-obj-$(CONFIG_OPENGL) += drm.o
+util-obj-y += random.o
stub-obj-y += filemonitor-stub.o
--
2.17.1
