Merge remote-tracking branch 'remotes/rth/tags/pull-rng-20190522' into staging

Introduce qemu_guest_getrandom.
Use qemu_guest_getrandom in aspeed, nrf51, bcm2835, exynos4210 rng devices.
Use qemu_guest_getrandom in target/ppc darn instruction.
Support ARMv8.5-RNG extension.
Support x86 RDRAND extension.

Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Laurent Vivier <laurent@vivier.eu>

# gpg: Signature made Wed 22 May 2019 19:36:43 BST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-rng-20190522: (25 commits)
  target/i386: Implement CPUID_EXT_RDRAND
  target/ppc: Use qemu_guest_getrandom for DARN
  target/ppc: Use gen_io_start/end around DARN
  target/arm: Implement ARMv8.5-RNG
  target/arm: Put all PAC keys into a structure
  hw/misc/exynos4210_rng: Use qemu_guest_getrandom
  hw/misc/bcm2835_rng: Use qemu_guest_getrandom_nofail
  hw/misc/nrf51_rng: Use qemu_guest_getrandom_nofail
  aspeed/scu: Use qemu_guest_getrandom_nofail
  linux-user: Remove srand call
  linux-user/aarch64: Use qemu_guest_getrandom for PAUTH keys
  linux-user: Use qemu_guest_getrandom_nofail for AT_RANDOM
  linux-user: Call qcrypto_init if not using -seed
  linux-user: Initialize pseudo-random seeds for all guest cpus
  cpus: Initialize pseudo-random seeds for all guest cpus
  util: Add qemu_guest_getrandom and associated routines
  ui/vnc: Use gcrypto_random_bytes for start_auth_vnc
  ui/vnc: Split out authentication_failed
  crypto: Change the qcrypto_random_bytes buffer type to void*
  crypto: Use getrandom for qcrypto_random_bytes
  ...

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

36 files changed, 610 insertions, 256 deletions

diff --git a/Makefile b/Makefile
index 8598ab9..e02b88b 100644
--- a/Makefile
+++ b/Makefile
@@ -413,7 +413,7 @@ dummy := $(call unnest-vars,, \
                 block-obj-y \
                 block-obj-m \
                 crypto-obj-y \
-                crypto-aes-obj-y \
+                crypto-user-obj-y \
                 qom-obj-y \
                 io-obj-y \
                 common-obj-y \
@@ -487,7 +487,7 @@ subdir-slirp: .git-submodule-status
 	$(call quiet-command,$(MAKE) -C $(SRC_PATH)/slirp BUILD_DIR="$(BUILD_DIR)/slirp" CC="$(CC)" AR="$(AR)" LD="$(LD)" RANLIB="$(RANLIB)" CFLAGS="$(QEMU_CFLAGS) $(CFLAGS)" LDFLAGS="$(LDFLAGS)")
 
 $(SUBDIR_RULES): libqemuutil.a $(common-obj-y) \
-	$(qom-obj-y) $(crypto-aes-obj-$(CONFIG_USER_ONLY))
+	$(qom-obj-y) $(crypto-user-obj-$(CONFIG_USER_ONLY))
 
 ROMSUBDIR_RULES=$(patsubst %,romsubdir-%, $(ROMS))
 # Only keep -O and -g cflags
diff --git a/Makefile.objs b/Makefile.objs
index 485f962..d749141 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -25,7 +25,7 @@ block-obj-m = block/
 # crypto-obj-y is code used by both qemu system emulation and qemu-img
 
 crypto-obj-y = crypto/
-crypto-aes-obj-y = crypto/
+crypto-user-obj-y = crypto/
 
 #######################################################################
 # qom-obj-y is code used by both qemu system emulation and qemu-img
diff --git a/Makefile.target b/Makefile.target
index fdbe7c8..4ef4ce5 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -180,7 +180,7 @@ dummy := $(call unnest-vars,.., \
                block-obj-m \
                chardev-obj-y \
                crypto-obj-y \
-               crypto-aes-obj-y \
+               crypto-user-obj-y \
                qom-obj-y \
                io-obj-y \
                common-obj-y \
@@ -189,7 +189,7 @@ all-obj-y += $(common-obj-y)
 all-obj-y += $(qom-obj-y)
 all-obj-$(CONFIG_SOFTMMU) += $(authz-obj-y)
 all-obj-$(CONFIG_SOFTMMU) += $(block-obj-y) $(chardev-obj-y)
-all-obj-$(CONFIG_USER_ONLY) += $(crypto-aes-obj-y)
+all-obj-$(CONFIG_USER_ONLY) += $(crypto-user-obj-y)
 all-obj-$(CONFIG_SOFTMMU) += $(crypto-obj-y)
 all-obj-$(CONFIG_SOFTMMU) += $(io-obj-y)
 
diff --git a/configure b/configure
index cef51b2..528b9ff 100755
--- a/configure
+++ b/configure
@@ -2784,17 +2784,23 @@ fi
 # GNUTLS probe
 
 if test "$gnutls" != "no"; then
+    pass="no"
     if $pkg_config --exists "gnutls >= 3.1.18"; then
         gnutls_cflags=$($pkg_config --cflags gnutls)
         gnutls_libs=$($pkg_config --libs gnutls)
-        libs_softmmu="$gnutls_libs $libs_softmmu"
-        libs_tools="$gnutls_libs $libs_tools"
-	QEMU_CFLAGS="$QEMU_CFLAGS $gnutls_cflags"
-        gnutls="yes"
-    elif test "$gnutls" = "yes"; then
+        # Packaging for the static libraries is not always correct.
+        # At least ubuntu 18.04 ships only shared libraries.
+        write_c_skeleton
+        if compile_prog "" "$gnutls_libs" ; then
+            LIBS="$gnutls_libs $LIBS"
+            QEMU_CFLAGS="$QEMU_CFLAGS $gnutls_cflags"
+            pass="yes"
+        fi
+    fi
+    if test "$pass" = "no" && test "$gnutls" = "yes"; then
 	feature_not_found "gnutls" "Install gnutls devel >= 3.1.18"
     else
-        gnutls="no"
+        gnutls="$pass"
     fi
 fi
 
@@ -2849,43 +2855,52 @@ has_libgcrypt() {
 
 
 if test "$nettle" != "no"; then
+    pass="no"
     if $pkg_config --exists "nettle >= 2.7.1"; then
         nettle_cflags=$($pkg_config --cflags nettle)
         nettle_libs=$($pkg_config --libs nettle)
         nettle_version=$($pkg_config --modversion nettle)
-        libs_softmmu="$nettle_libs $libs_softmmu"
-        libs_tools="$nettle_libs $libs_tools"
-        QEMU_CFLAGS="$QEMU_CFLAGS $nettle_cflags"
-        nettle="yes"
-
-        if test -z "$gcrypt"; then
-           gcrypt="no"
+        # Link test to make sure the given libraries work (e.g for static).
+        write_c_skeleton
+        if compile_prog "" "$nettle_libs" ; then
+            LIBS="$nettle_libs $LIBS"
+            QEMU_CFLAGS="$QEMU_CFLAGS $nettle_cflags"
+            if test -z "$gcrypt"; then
+               gcrypt="no"
+            fi
+            pass="yes"
         fi
+    fi
+    if test "$pass" = "no" && test "$nettle" = "yes"; then
+        feature_not_found "nettle" "Install nettle devel >= 2.7.1"
     else
-        if test "$nettle" = "yes"; then
-            feature_not_found "nettle" "Install nettle devel >= 2.7.1"
-        else
-            nettle="no"
-        fi
+        nettle="$pass"
     fi
 fi
 
 if test "$gcrypt" != "no"; then
+    pass="no"
     if has_libgcrypt; then
         gcrypt_cflags=$(libgcrypt-config --cflags)
         gcrypt_libs=$(libgcrypt-config --libs)
-        # Debian has remove -lgpg-error from libgcrypt-config
+        # Debian has removed -lgpg-error from libgcrypt-config
         # as it "spreads unnecessary dependencies" which in
         # turn breaks static builds...
         if test "$static" = "yes"
         then
             gcrypt_libs="$gcrypt_libs -lgpg-error"
         fi
-        libs_softmmu="$gcrypt_libs $libs_softmmu"
-        libs_tools="$gcrypt_libs $libs_tools"
-        QEMU_CFLAGS="$QEMU_CFLAGS $gcrypt_cflags"
-        gcrypt="yes"
 
+        # Link test to make sure the given libraries work (e.g for static).
+        write_c_skeleton
+        if compile_prog "" "$gcrypt_libs" ; then
+            LIBS="$gcrypt_libs $LIBS"
+            QEMU_CFLAGS="$QEMU_CFLAGS $gcrypt_cflags"
+            pass="yes"
+        fi
+    fi
+    if test "$pass" = "yes"; then
+        gcrypt="yes"
         cat > $TMPC << EOF
 #include <gcrypt.h>
 int main(void) {
@@ -2898,12 +2913,10 @@ EOF
         if compile_prog "$gcrypt_cflags" "$gcrypt_libs" ; then
             gcrypt_hmac=yes
         fi
+    elif test "$gcrypt" = "yes"; then
+        feature_not_found "gcrypt" "Install gcrypt devel >= 1.5.0"
     else
-        if test "$gcrypt" = "yes"; then
-            feature_not_found "gcrypt" "Install gcrypt devel >= 1.5.0"
-        else
-            gcrypt="no"
-        fi
+        gcrypt="no"
     fi
 fi
 
@@ -5803,6 +5816,20 @@ if compile_prog "" "" ; then
 fi
 
 ##########################################
+# check for getrandom()
+
+have_getrandom=no
+cat > $TMPC << EOF
+#include <sys/random.h>
+int main(void) {
+    return getrandom(0, 0, GRND_NONBLOCK);
+}
+EOF
+if compile_prog "" "" ; then
+    have_getrandom=yes
+fi
+
+##########################################
 # checks for sanitizers
 
 have_asan=no
@@ -7191,7 +7218,9 @@ fi
 if test "$have_utmpx" = "yes" ; then
   echo "HAVE_UTMPX=y" >> $config_host_mak
 fi
-
+if test "$have_getrandom" = "yes" ; then
+  echo "CONFIG_GETRANDOM=y" >> $config_host_mak
+fi
 if test "$ivshmem" = "yes" ; then
   echo "CONFIG_IVSHMEM=y" >> $config_host_mak
 fi
diff --git a/cpus.c b/cpus.c
index e58e7ab..ffc5711 100644
--- a/cpus.c
+++ b/cpus.c
@@ -50,6 +50,7 @@
 #include "qemu/option.h"
 #include "qemu/bitmap.h"
 #include "qemu/seqlock.h"
+#include "qemu/guest-random.h"
 #include "tcg.h"
 #include "hw/nmi.h"
 #include "sysemu/replay.h"
@@ -1276,6 +1277,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg)
     /* signal CPU creation */
     cpu->created = true;
     qemu_cond_signal(&qemu_cpu_cond);
+    qemu_guest_random_seed_thread_part2(cpu->random_seed);
 
     do {
         if (cpu_can_run(cpu)) {
@@ -1319,6 +1321,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg)
     /* signal CPU creation */
     cpu->created = true;
     qemu_cond_signal(&qemu_cpu_cond);
+    qemu_guest_random_seed_thread_part2(cpu->random_seed);
 
     do {
         qemu_mutex_unlock_iothread();
@@ -1478,6 +1481,7 @@ 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_guest_random_seed_thread_part2(cpu->random_seed);
 
     /* wait for initial kick-off after machine start */
     while (first_cpu->stopped) {
@@ -1592,6 +1596,7 @@ static void *qemu_hax_cpu_thread_fn(void *arg)
 
     hax_init_vcpu(cpu);
     qemu_cond_signal(&qemu_cpu_cond);
+    qemu_guest_random_seed_thread_part2(cpu->random_seed);
 
     do {
         if (cpu_can_run(cpu)) {
@@ -1631,6 +1636,7 @@ static void *qemu_hvf_cpu_thread_fn(void *arg)
     /* signal CPU creation */
     cpu->created = true;
     qemu_cond_signal(&qemu_cpu_cond);
+    qemu_guest_random_seed_thread_part2(cpu->random_seed);
 
     do {
         if (cpu_can_run(cpu)) {
@@ -1671,6 +1677,7 @@ static void *qemu_whpx_cpu_thread_fn(void *arg)
     /* signal CPU creation */
     cpu->created = true;
     qemu_cond_signal(&qemu_cpu_cond);
+    qemu_guest_random_seed_thread_part2(cpu->random_seed);
 
     do {
         if (cpu_can_run(cpu)) {
@@ -1724,6 +1731,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
     cpu->can_do_io = 1;
     current_cpu = cpu;
     qemu_cond_signal(&qemu_cpu_cond);
+    qemu_guest_random_seed_thread_part2(cpu->random_seed);
 
     /* process any pending work */
     cpu->exit_request = 1;
@@ -2071,6 +2079,7 @@ void qemu_init_vcpu(CPUState *cpu)
     cpu->nr_cores = smp_cores;
     cpu->nr_threads = smp_threads;
     cpu->stopped = true;
+    cpu->random_seed = qemu_guest_random_seed_thread_part1();
 
     if (!cpu->as) {
         /* If the target cpu hasn't set up any address spaces itself,
diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs
index 256c9ac..7fe2fa9 100644
--- a/crypto/Makefile.objs
+++ b/crypto/Makefile.objs
@@ -19,9 +19,10 @@ crypto-obj-y += tlscredspsk.o
 crypto-obj-y += tlscredsx509.o
 crypto-obj-y += tlssession.o
 crypto-obj-y += secret.o
-crypto-obj-$(CONFIG_GCRYPT) += random-gcrypt.o
-crypto-obj-$(if $(CONFIG_GCRYPT),n,$(CONFIG_GNUTLS)) += random-gnutls.o
-crypto-obj-$(if $(CONFIG_GCRYPT),n,$(if $(CONFIG_GNUTLS),n,y)) += random-platform.o
+crypto-rng-obj-$(CONFIG_GCRYPT) += random-gcrypt.o
+crypto-rng-obj-$(if $(CONFIG_GCRYPT),n,$(CONFIG_GNUTLS)) += random-gnutls.o
+crypto-rng-obj-$(if $(CONFIG_GCRYPT),n,$(if $(CONFIG_GNUTLS),n,y)) += random-platform.o
+crypto-obj-y += $(crypto-rng-obj-y)
 crypto-obj-y += pbkdf.o
 crypto-obj-$(CONFIG_NETTLE) += pbkdf-nettle.o
 crypto-obj-$(if $(CONFIG_NETTLE),n,$(CONFIG_GCRYPT)) += pbkdf-gcrypt.o
@@ -35,7 +36,7 @@ crypto-obj-y += block.o
 crypto-obj-y += block-qcow.o
 crypto-obj-y += block-luks.o
 
-# Let the userspace emulators avoid linking gnutls/etc
-crypto-aes-obj-y = aes.o
+# Let the userspace emulators avoid linking stuff they won't use.
+crypto-user-obj-y = aes.o $(crypto-rng-obj-y) init.o
 
 stub-obj-y += pbkdf-stub.o
diff --git a/crypto/random-gcrypt.c b/crypto/random-gcrypt.c
index 9f1c9ee..7aea4ac 100644
--- a/crypto/random-gcrypt.c
+++ b/crypto/random-gcrypt.c
@@ -24,7 +24,7 @@
 
 #include <gcrypt.h>
 
-int qcrypto_random_bytes(uint8_t *buf,
+int qcrypto_random_bytes(void *buf,
                          size_t buflen,
                          Error **errp G_GNUC_UNUSED)
 {
diff --git a/crypto/random-gnutls.c b/crypto/random-gnutls.c
index 445fd6a..ed6c9ca 100644
--- a/crypto/random-gnutls.c
+++ b/crypto/random-gnutls.c
@@ -26,7 +26,7 @@
 #include <gnutls/gnutls.h>
 #include <gnutls/crypto.h>
 
-int qcrypto_random_bytes(uint8_t *buf,
+int qcrypto_random_bytes(void *buf,
                          size_t buflen,
                          Error **errp)
 {
diff --git a/crypto/random-platform.c b/crypto/random-platform.c
index 7541b4c..6662410 100644
--- a/crypto/random-platform.c
+++ b/crypto/random-platform.c
@@ -27,68 +27,88 @@
 #include <wincrypt.h>
 static HCRYPTPROV hCryptProv;
 #else
-static int fd; /* a file handle to either /dev/urandom or /dev/random */
+# ifdef CONFIG_GETRANDOM
+#  include <sys/random.h>
+# endif
+/* This is -1 for getrandom(), or a file handle for /dev/{u,}random.  */
+static int fd;
 #endif
 
 int qcrypto_random_init(Error **errp)
 {
-#ifndef _WIN32
-    /* TBD perhaps also add support for BSD getentropy / Linux
-     * getrandom syscalls directly */
-    fd = open("/dev/urandom", O_RDONLY);
-    if (fd == -1 && errno == ENOENT) {
-        fd = open("/dev/random", O_RDONLY);
-    }
-
-    if (fd < 0) {
-        error_setg(errp, "No /dev/urandom or /dev/random found");
-        return -1;
-    }
-#else
+#ifdef _WIN32
     if (!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL,
                              CRYPT_SILENT | CRYPT_VERIFYCONTEXT)) {
         error_setg_win32(errp, GetLastError(),
                          "Unable to create cryptographic provider");
         return -1;
     }
+#else
+# ifdef CONFIG_GETRANDOM
+    if (getrandom(NULL, 0, 0) == 0) {
+        /* Use getrandom() */
+        fd = -1;
+        return 0;
+    }
+    /* Fall through to /dev/urandom case.  */
+# endif
+    fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
+    if (fd == -1 && errno == ENOENT) {
+        fd = open("/dev/random", O_RDONLY | O_CLOEXEC);
+    }
+    if (fd < 0) {
+        error_setg_errno(errp, errno, "No /dev/urandom or /dev/random");
+        return -1;
+    }
 #endif
-
     return 0;
 }
 
-int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
-                         size_t buflen G_GNUC_UNUSED,
+int qcrypto_random_bytes(void *buf,
+                         size_t buflen,
                          Error **errp)
 {
-#ifndef _WIN32
-    int ret = -1;
-    int got;
-
-    while (buflen > 0) {
-        got = read(fd, buf, buflen);
-        if (got < 0) {
-            error_setg_errno(errp, errno,
-                             "Unable to read random bytes");
-            goto cleanup;
-        } else if (!got) {
-            error_setg(errp,
-                       "Unexpected EOF reading random bytes");
-            goto cleanup;
-        }
-        buflen -= got;
-        buf += got;
-    }
-
-    ret = 0;
- cleanup:
-    return ret;
-#else
+#ifdef _WIN32
     if (!CryptGenRandom(hCryptProv, buflen, buf)) {
         error_setg_win32(errp, GetLastError(),
                          "Unable to read random bytes");
         return -1;
     }
-
-    return 0;
+#else
+# ifdef CONFIG_GETRANDOM
+    if (likely(fd < 0)) {
+        while (1) {
+            ssize_t got = getrandom(buf, buflen, 0);
+            if (likely(got == buflen)) {
+                return 0;
+            }
+            if (got >= 0) {
+                buflen -= got;
+                buf += got;
+            } else if (errno != EINTR) {
+                error_setg_errno(errp, errno, "getrandom");
+                return -1;
+            }
+        }
+    }
+    /* Fall through to /dev/urandom case.  */
+# endif
+    while (1) {
+        ssize_t got = read(fd, buf, buflen);
+        if (likely(got == buflen)) {
+            return 0;
+        }
+        if (got > 0) {
+            buflen -= got;
+            buf += got;
+        } else if (got == 0) {
+            error_setg(errp, "Unexpected EOF reading random bytes");
+            return -1;
+        } else if (errno != EINTR) {
+            error_setg_errno(errp, errno, "Unable to read random bytes");
+            return -1;
+        }
+    }
 #endif
+    return 0;
 }
diff --git a/hw/misc/aspeed_scu.c b/hw/misc/aspeed_scu.c
index c8217740..ab1e18e 100644
--- a/hw/misc/aspeed_scu.c
+++ b/hw/misc/aspeed_scu.c
@@ -16,7 +16,7 @@
 #include "qapi/visitor.h"
 #include "qemu/bitops.h"
 #include "qemu/log.h"
-#include "crypto/random.h"
+#include "qemu/guest-random.h"
 #include "trace.h"
 
 #define TO_REG(offset) ((offset) >> 2)
@@ -157,14 +157,8 @@ static const uint32_t ast2500_a1_resets[ASPEED_SCU_NR_REGS] = {
 
 static uint32_t aspeed_scu_get_random(void)
 {
-    Error *err = NULL;
     uint32_t num;
-
-    if (qcrypto_random_bytes((uint8_t *)&num, sizeof(num), &err)) {
-        error_report_err(err);
-        exit(1);
-    }
-
+    qemu_guest_getrandom_nofail(&num, sizeof(num));
     return num;
 }
 
diff --git a/hw/misc/bcm2835_rng.c b/hw/misc/bcm2835_rng.c
index 4d62143..fe59c86 100644
--- a/hw/misc/bcm2835_rng.c
+++ b/hw/misc/bcm2835_rng.c
@@ -9,30 +9,26 @@
 
 #include "qemu/osdep.h"
 #include "qemu/log.h"
-#include "qapi/error.h"
-#include "crypto/random.h"
+#include "qemu/guest-random.h"
 #include "hw/misc/bcm2835_rng.h"
 
 static uint32_t get_random_bytes(void)
 {
     uint32_t res;
-    Error *err = NULL;
-
-    if (qcrypto_random_bytes((uint8_t *)&res, sizeof(res), &err) < 0) {
-        /* On failure we don't want to return the guest a non-random
-         * value in case they're really using it for cryptographic
-         * purposes, so the best we can do is die here.
-         * This shouldn't happen unless something's broken.
-         * In theory we could implement this device's full FIFO
-         * and interrupt semantics and then just stop filling the
-         * FIFO. That's a lot of work, though, so we assume any
-         * errors are systematic problems and trust that if we didn't
-         * fail as the guest inited then we won't fail later on
-         * mid-run.
-         */
-        error_report_err(err);
-        exit(1);
-    }
+
+    /*
+     * On failure we don't want to return the guest a non-random
+     * value in case they're really using it for cryptographic
+     * purposes, so the best we can do is die here.
+     * This shouldn't happen unless something's broken.
+     * In theory we could implement this device's full FIFO
+     * and interrupt semantics and then just stop filling the
+     * FIFO. That's a lot of work, though, so we assume any
+     * errors are systematic problems and trust that if we didn't
+     * fail as the guest inited then we won't fail later on
+     * mid-run.
+     */
+    qemu_guest_getrandom_nofail(&res, sizeof(res));
     return res;
 }
 
diff --git a/hw/misc/exynos4210_rng.c b/hw/misc/exynos4210_rng.c
index 4ecbebd..0e70ffb 100644
--- a/hw/misc/exynos4210_rng.c
+++ b/hw/misc/exynos4210_rng.c
@@ -18,10 +18,10 @@
  */
 
 #include "qemu/osdep.h"
-#include "crypto/random.h"
 #include "hw/sysbus.h"
 #include "qapi/error.h"
 #include "qemu/log.h"
+#include "qemu/guest-random.h"
 
 #define DEBUG_EXYNOS_RNG 0
 
@@ -109,7 +109,6 @@ static void exynos4210_rng_set_seed(Exynos4210RngState *s, unsigned int i,
 static void exynos4210_rng_run_engine(Exynos4210RngState *s)
 {
     Error *err = NULL;
-    int ret;
 
     /* Seed set? */
     if ((s->reg_status & EXYNOS4210_RNG_STATUS_SEED_SETTING_DONE) == 0) {
@@ -127,13 +126,11 @@ static void exynos4210_rng_run_engine(Exynos4210RngState *s)
     }
 
     /* Get randoms */
-    ret = qcrypto_random_bytes((uint8_t *)s->randr_value,
-                               sizeof(s->randr_value), &err);
-    if (!ret) {
+    if (qemu_guest_getrandom(s->randr_value, sizeof(s->randr_value), &err)) {
+        error_report_err(err);
+    } else {
         /* Notify that PRNG is ready */
         s->reg_status |= EXYNOS4210_RNG_STATUS_PRNG_DONE;
-    } else {
-        error_report_err(err);
     }
 
 out:
diff --git a/hw/misc/nrf51_rng.c b/hw/misc/nrf51_rng.c
index d188f04..3400e90 100644
--- a/hw/misc/nrf51_rng.c
+++ b/hw/misc/nrf51_rng.c
@@ -14,7 +14,7 @@
 #include "qapi/error.h"
 #include "hw/arm/nrf51.h"
 #include "hw/misc/nrf51_rng.h"
-#include "crypto/random.h"
+#include "qemu/guest-random.h"
 
 static void update_irq(NRF51RNGState *s)
 {
@@ -145,7 +145,7 @@ static void nrf51_rng_timer_expire(void *opaque)
 {
     NRF51RNGState *s = NRF51_RNG(opaque);
 
-    qcrypto_random_bytes(&s->value, 1, &error_abort);
+    qemu_guest_getrandom_nofail(&s->value, 1);
 
     s->event_valrdy = 1;
     qemu_set_irq(s->eep_valrdy, 1);
diff --git a/include/crypto/random.h b/include/crypto/random.h
index 8764ca0..fde5929 100644
--- a/include/crypto/random.h
+++ b/include/crypto/random.h
@@ -34,7 +34,7 @@
  *
  * Returns 0 on success, -1 on error
  */
-int qcrypto_random_bytes(uint8_t *buf,
+int qcrypto_random_bytes(void *buf,
                          size_t buflen,
                          Error **errp);
 
diff --git a/include/qemu/guest-random.h b/include/qemu/guest-random.h
new file mode 100644
index 0000000..09ff9c2
--- /dev/null
+++ b/include/qemu/guest-random.h
@@ -0,0 +1,68 @@
+/*
+ * QEMU guest-visible 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_GUEST_RANDOM_H
+#define QEMU_GUEST_RANDOM_H
+
+/**
+ * qemu_guest_random_seed_main(const char *optarg, Error **errp)
+ * @optarg: a non-NULL pointer to a C string
+ * @errp: an error indicator
+ *
+ * The @optarg value is that which accompanies the -seed argument.
+ * This forces qemu_guest_getrandom into deterministic mode.
+ *
+ * Returns 0 on success, < 0 on failure while setting *errp.
+ */
+int qemu_guest_random_seed_main(const char *optarg, Error **errp);
+
+/**
+ * qemu_guest_random_seed_thread_part1(void)
+ *
+ * If qemu_getrandom is in deterministic mode, returns an
+ * independent seed for the new thread.  Otherwise returns 0.
+ */
+uint64_t qemu_guest_random_seed_thread_part1(void);
+
+/**
+ * qemu_guest_random_seed_thread_part2(uint64_t seed)
+ * @seed: a value for the new thread.
+ *
+ * If qemu_guest_getrandom is in deterministic mode, this stores an
+ * independent seed for the new thread.  Otherwise a no-op.
+ */
+void qemu_guest_random_seed_thread_part2(uint64_t seed);
+
+/**
+ * qemu_guest_getrandom(void *buf, size_t len, Error **errp)
+ * @buf: a buffer of bytes to be written
+ * @len: the number of bytes in @buf
+ * @errp: an error indicator
+ *
+ * Fills len bytes in buf with random data.  This should only be used
+ * for data presented to the guest.  Host-side crypto services should
+ * use qcrypto_random_bytes.
+ *
+ * Returns 0 on success, < 0 on failure while setting *errp.
+ */
+int qemu_guest_getrandom(void *buf, size_t len, Error **errp);
+
+/**
+ * qemu_guest_getrandom_nofail(void *buf, size_t len)
+ * @buf: a buffer of bytes to be written
+ * @len: the number of bytes in @buf
+ *
+ * Like qemu_guest_getrandom, but will assert for failure.
+ * Use this when there is no reasonable recovery.
+ */
+void qemu_guest_getrandom_nofail(void *buf, size_t len);
+
+#endif /* QEMU_GUEST_RANDOM_H */
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 32983f2..98e12d9 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -375,6 +375,7 @@ 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/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
index d75fd9d..2f2f63e 100644
--- a/linux-user/aarch64/cpu_loop.c
+++ b/linux-user/aarch64/cpu_loop.c
@@ -20,6 +20,7 @@
 #include "qemu/osdep.h"
 #include "qemu.h"
 #include "cpu_loop-common.h"
+#include "qemu/guest-random.h"
 
 #define get_user_code_u32(x, gaddr, env)                \
     ({ abi_long __r = get_user_u32((x), (gaddr));       \
@@ -147,24 +148,6 @@ void cpu_loop(CPUARMState *env)
     }
 }
 
-static uint64_t arm_rand64(void)
-{
-    int shift = 64 - clz64(RAND_MAX);
-    int i, n = 64 / shift + (64 % shift != 0);
-    uint64_t ret = 0;
-
-    for (i = 0; i < n; i++) {
-        ret = (ret << shift) | rand();
-    }
-    return ret;
-}
-
-void arm_init_pauth_key(ARMPACKey *key)
-{
-    key->lo = arm_rand64();
-    key->hi = arm_rand64();
-}
-
 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
 {
     ARMCPU *cpu = arm_env_get_cpu(env);
@@ -192,11 +175,7 @@ void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
 #endif
 
     if (cpu_isar_feature(aa64_pauth, cpu)) {
-        arm_init_pauth_key(&env->apia_key);
-        arm_init_pauth_key(&env->apib_key);
-        arm_init_pauth_key(&env->apda_key);
-        arm_init_pauth_key(&env->apdb_key);
-        arm_init_pauth_key(&env->apga_key);
+        qemu_guest_getrandom_nofail(&env->keys, sizeof(env->keys));
     }
 
     ts->stack_base = info->start_stack;
diff --git a/linux-user/aarch64/target_syscall.h b/linux-user/aarch64/target_syscall.h
index b595e5d..995e475 100644
--- a/linux-user/aarch64/target_syscall.h
+++ b/linux-user/aarch64/target_syscall.h
@@ -29,6 +29,4 @@ struct target_pt_regs {
 # define TARGET_PR_PAC_APDBKEY   (1 << 3)
 # define TARGET_PR_PAC_APGAKEY   (1 << 4)
 
-void arm_init_pauth_key(ARMPACKey *key);
-
 #endif /* AARCH64_TARGET_SYSCALL_H */
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index ef42e02..1e06b90 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -7,6 +7,7 @@
 #include "qemu.h"
 #include "disas/disas.h"
 #include "qemu/path.h"
+#include "qemu/guest-random.h"
 
 #ifdef _ARCH_PPC64
 #undef ARCH_DLINFO
@@ -1883,12 +1884,9 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
     }
 
     /*
-     * Generate 16 random bytes for userspace PRNG seeding (not
-     * cryptically secure but it's not the aim of QEMU).
+     * Generate 16 random bytes for userspace PRNG seeding.
      */
-    for (i = 0; i < 16; i++) {
-        k_rand_bytes[i] = rand();
-    }
+    qemu_guest_getrandom_nofail(k_rand_bytes, sizeof(k_rand_bytes));
     if (STACK_GROWS_DOWN) {
         sp -= 16;
         u_rand_bytes = sp;
diff --git a/linux-user/main.c b/linux-user/main.c
index 3d22303..689bcf4 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -34,10 +34,12 @@
 #include "tcg.h"
 #include "qemu/timer.h"
 #include "qemu/envlist.h"
+#include "qemu/guest-random.h"
 #include "elf.h"
 #include "trace/control.h"
 #include "target_elf.h"
 #include "cpu_loop-common.h"
+#include "crypto/init.h"
 
 char *exec_path;
 
@@ -48,6 +50,7 @@ static int gdbstub_port;
 static envlist_t *envlist;
 static const char *cpu_model;
 static const char *cpu_type;
+static const char *seed_optarg;
 unsigned long mmap_min_addr;
 unsigned long guest_base;
 int have_guest_base;
@@ -290,15 +293,9 @@ static void handle_arg_pagesize(const char *arg)
     }
 }
 
-static void handle_arg_randseed(const char *arg)
+static void handle_arg_seed(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);
+    seed_optarg = arg;
 }
 
 static void handle_arg_gdb(const char *arg)
@@ -433,7 +430,7 @@ static const struct qemu_argument arg_table[] = {
      "",           "run in singlestep mode"},
     {"strace",     "QEMU_STRACE",      false, handle_arg_strace,
      "",           "log system calls"},
-    {"seed",       "QEMU_RAND_SEED",   true,  handle_arg_randseed,
+    {"seed",       "QEMU_RAND_SEED",   true,  handle_arg_seed,
      "",           "Seed for pseudo-random number generator"},
     {"trace",      "QEMU_TRACE",       true,  handle_arg_trace,
      "",           "[[enable=]<pattern>][,events=<file>][,file=<file>]"},
@@ -626,8 +623,6 @@ int main(int argc, char **argv, char **envp)
 
     cpu_model = NULL;
 
-    srand(time(NULL));
-
     qemu_add_opts(&qemu_trace_opts);
 
     optind = parse_args(argc, argv);
@@ -689,8 +684,20 @@ int main(int argc, char **argv, char **envp)
         do_strace = 1;
     }
 
-    if (getenv("QEMU_RAND_SEED")) {
-        handle_arg_randseed(getenv("QEMU_RAND_SEED"));
+    if (seed_optarg == NULL) {
+        seed_optarg = getenv("QEMU_RAND_SEED");
+    }
+    {
+        Error *err = NULL;
+        if (seed_optarg != NULL) {
+            qemu_guest_random_seed_main(seed_optarg, &err);
+        } else {
+            qcrypto_init(&err);
+        }
+        if (err) {
+            error_reportf_err(err, "cannot initialize crypto: ");
+            exit(1);
+        }
     }
 
     target_environ = envlist_to_environ(envlist, NULL);
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index efa3ec2..3de792a 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -107,6 +107,8 @@
 #include "uname.h"
 
 #include "qemu.h"
+#include "qemu/guest-random.h"
+#include "qapi/error.h"
 #include "fd-trans.h"
 
 #ifndef CLONE_IO
@@ -5482,6 +5484,7 @@ 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_guest_random_seed_thread_part2(cpu->random_seed);
     /* Enable signals.  */
     sigprocmask(SIG_SETMASK, &info->sigmask, NULL);
     /* Signal to the parent that we're ready.  */
@@ -5568,6 +5571,7 @@ 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_guest_random_seed_thread_part1();
 
         /* If this is our first additional thread, we need to ensure we
          * generate code for parallel execution and flush old translations.
@@ -9762,25 +9766,45 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                     int all = (TARGET_PR_PAC_APIAKEY | TARGET_PR_PAC_APIBKEY |
                                TARGET_PR_PAC_APDAKEY | TARGET_PR_PAC_APDBKEY |
                                TARGET_PR_PAC_APGAKEY);
+                    int ret = 0;
+                    Error *err = NULL;
+
                     if (arg2 == 0) {
                         arg2 = all;
                     } else if (arg2 & ~all) {
                         return -TARGET_EINVAL;
                     }
                     if (arg2 & TARGET_PR_PAC_APIAKEY) {
-                        arm_init_pauth_key(&env->apia_key);
+                        ret |= qemu_guest_getrandom(&env->keys.apia,
+                                                    sizeof(ARMPACKey), &err);
                     }
                     if (arg2 & TARGET_PR_PAC_APIBKEY) {
-                        arm_init_pauth_key(&env->apib_key);
+                        ret |= qemu_guest_getrandom(&env->keys.apib,
+                                                    sizeof(ARMPACKey), &err);
                     }
                     if (arg2 & TARGET_PR_PAC_APDAKEY) {
-                        arm_init_pauth_key(&env->apda_key);
+                        ret |= qemu_guest_getrandom(&env->keys.apda,
+                                                    sizeof(ARMPACKey), &err);
                     }
                     if (arg2 & TARGET_PR_PAC_APDBKEY) {
-                        arm_init_pauth_key(&env->apdb_key);
+                        ret |= qemu_guest_getrandom(&env->keys.apdb,
+                                                    sizeof(ARMPACKey), &err);
                     }
                     if (arg2 & TARGET_PR_PAC_APGAKEY) {
-                        arm_init_pauth_key(&env->apga_key);
+                        ret |= qemu_guest_getrandom(&env->keys.apga,
+                                                    sizeof(ARMPACKey), &err);
+                    }
+                    if (ret != 0) {
+                        /*
+                         * Some unknown failure in the crypto.  The best
+                         * we can do is log it and fail the syscall.
+                         * The real syscall cannot fail this way.
+                         */
+                        qemu_log_mask(LOG_UNIMP,
+                                      "PR_PAC_RESET_KEYS: Crypto failure: %s",
+                                      error_get_pretty(err));
+                        error_free(err);
+                        return -TARGET_EIO;
                     }
                     return 0;
                 }
diff --git a/qemu-options.hx b/qemu-options.hx
index 5daa5a8..7ae3373 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3641,6 +3641,16 @@ 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 pseudo-random number generator\n",
+    QEMU_ARCH_ALL)
+STEXI
+@item -seed @var{number}
+@findex -seed
+Force the guest to use a deterministic pseudo-random number generator, seeded
+with @var{number}.  This does not affect crypto routines within the host.
+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/target/arm/cpu.h b/target/arm/cpu.h
index 733b840..c342076 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -636,11 +636,13 @@ typedef struct CPUARMState {
     } iwmmxt;
 
 #ifdef TARGET_AARCH64
-    ARMPACKey apia_key;
-    ARMPACKey apib_key;
-    ARMPACKey apda_key;
-    ARMPACKey apdb_key;
-    ARMPACKey apga_key;
+    struct {
+        ARMPACKey apia;
+        ARMPACKey apib;
+        ARMPACKey apda;
+        ARMPACKey apdb;
+        ARMPACKey apga;
+    } keys;
 #endif
 
 #if defined(CONFIG_USER_ONLY)
@@ -3519,6 +3521,11 @@ static inline bool isar_feature_aa64_condm_5(const ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64isar0, ID_AA64ISAR0, TS) >= 2;
 }
 
+static inline bool isar_feature_aa64_rndr(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64isar0, ID_AA64ISAR0, RNDR) != 0;
+}
+
 static inline bool isar_feature_aa64_jscvt(const ARMISARegisters *id)
 {
     return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, JSCVT) != 0;
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 228906f..835f73c 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -310,6 +310,7 @@ static void aarch64_max_initfn(Object *obj)
         t = FIELD_DP64(t, ID_AA64ISAR0, DP, 1);
         t = FIELD_DP64(t, ID_AA64ISAR0, FHM, 1);
         t = FIELD_DP64(t, ID_AA64ISAR0, TS, 2); /* v8.5-CondM */
+        t = FIELD_DP64(t, ID_AA64ISAR0, RNDR, 1);
         cpu->isar.id_aa64isar0 = t;
 
         t = cpu->isar.id_aa64isar1;
diff --git a/target/arm/helper.c b/target/arm/helper.c
index e2d5c8e..acd23c5 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -22,6 +22,8 @@
 #include "fpu/softfloat.h"
 #include "qemu/range.h"
 #include "qapi/qapi-commands-target.h"
+#include "qapi/error.h"
+#include "qemu/guest-random.h"
 
 #define ARM_CPU_FREQ 1000000000 /* FIXME: 1 GHz, should be configurable */
 
@@ -5707,43 +5709,82 @@ static const ARMCPRegInfo pauth_reginfo[] = {
     { .name = "APDAKEYLO_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 2, .opc2 = 0,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apda_key.lo) },
+      .fieldoffset = offsetof(CPUARMState, keys.apda.lo) },
     { .name = "APDAKEYHI_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 2, .opc2 = 1,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apda_key.hi) },
+      .fieldoffset = offsetof(CPUARMState, keys.apda.hi) },
     { .name = "APDBKEYLO_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 2, .opc2 = 2,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apdb_key.lo) },
+      .fieldoffset = offsetof(CPUARMState, keys.apdb.lo) },
     { .name = "APDBKEYHI_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 2, .opc2 = 3,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apdb_key.hi) },
+      .fieldoffset = offsetof(CPUARMState, keys.apdb.hi) },
     { .name = "APGAKEYLO_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 3, .opc2 = 0,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apga_key.lo) },
+      .fieldoffset = offsetof(CPUARMState, keys.apga.lo) },
     { .name = "APGAKEYHI_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 3, .opc2 = 1,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apga_key.hi) },
+      .fieldoffset = offsetof(CPUARMState, keys.apga.hi) },
     { .name = "APIAKEYLO_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 1, .opc2 = 0,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apia_key.lo) },
+      .fieldoffset = offsetof(CPUARMState, keys.apia.lo) },
     { .name = "APIAKEYHI_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 1, .opc2 = 1,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apia_key.hi) },
+      .fieldoffset = offsetof(CPUARMState, keys.apia.hi) },
     { .name = "APIBKEYLO_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 1, .opc2 = 2,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apib_key.lo) },
+      .fieldoffset = offsetof(CPUARMState, keys.apib.lo) },
     { .name = "APIBKEYHI_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 2, .crm = 1, .opc2 = 3,
       .access = PL1_RW, .accessfn = access_pauth,
-      .fieldoffset = offsetof(CPUARMState, apib_key.hi) },
+      .fieldoffset = offsetof(CPUARMState, keys.apib.hi) },
+    REGINFO_SENTINEL
+};
+
+static uint64_t rndr_readfn(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    Error *err = NULL;
+    uint64_t ret;
+
+    /* Success sets NZCV = 0000.  */
+    env->NF = env->CF = env->VF = 0, env->ZF = 1;
+
+    if (qemu_guest_getrandom(&ret, sizeof(ret), &err) < 0) {
+        /*
+         * ??? Failed, for unknown reasons in the crypto subsystem.
+         * The best we can do is log the reason and return the
+         * timed-out indication to the guest.  There is no reason
+         * we know to expect this failure to be transitory, so the
+         * guest may well hang retrying the operation.
+         */
+        qemu_log_mask(LOG_UNIMP, "%s: Crypto failure: %s",
+                      ri->name, error_get_pretty(err));
+        error_free(err);
+
+        env->ZF = 0; /* NZCF = 0100 */
+        return 0;
+    }
+    return ret;
+}
+
+/* We do not support re-seeding, so the two registers operate the same.  */
+static const ARMCPRegInfo rndr_reginfo[] = {
+    { .name = "RNDR", .state = ARM_CP_STATE_AA64,
+      .type = ARM_CP_NO_RAW | ARM_CP_SUPPRESS_TB_END | ARM_CP_IO,
+      .opc0 = 3, .opc1 = 3, .crn = 2, .crm = 4, .opc2 = 0,
+      .access = PL0_R, .readfn = rndr_readfn },
+    { .name = "RNDRRS", .state = ARM_CP_STATE_AA64,
+      .type = ARM_CP_NO_RAW | ARM_CP_SUPPRESS_TB_END | ARM_CP_IO,
+      .opc0 = 3, .opc1 = 3, .crn = 2, .crm = 4, .opc2 = 1,
+      .access = PL0_R, .readfn = rndr_readfn },
     REGINFO_SENTINEL
 };
 #endif
@@ -6690,6 +6731,9 @@ void register_cp_regs_for_features(ARMCPU *cpu)
     if (cpu_isar_feature(aa64_pauth, cpu)) {
         define_arm_cp_regs(cpu, pauth_reginfo);
     }
+    if (cpu_isar_feature(aa64_rndr, cpu)) {
+        define_arm_cp_regs(cpu, rndr_reginfo);
+    }
 #endif
 
     /*
diff --git a/target/arm/pauth_helper.c b/target/arm/pauth_helper.c
index d750f96..7f30ae7 100644
--- a/target/arm/pauth_helper.c
+++ b/target/arm/pauth_helper.c
@@ -403,7 +403,7 @@ uint64_t HELPER(pacia)(CPUARMState *env, uint64_t x, uint64_t y)
         return x;
     }
     pauth_check_trap(env, el, GETPC());
-    return pauth_addpac(env, x, y, &env->apia_key, false);
+    return pauth_addpac(env, x, y, &env->keys.apia, false);
 }
 
 uint64_t HELPER(pacib)(CPUARMState *env, uint64_t x, uint64_t y)
@@ -413,7 +413,7 @@ uint64_t HELPER(pacib)(CPUARMState *env, uint64_t x, uint64_t y)
         return x;
     }
     pauth_check_trap(env, el, GETPC());
-    return pauth_addpac(env, x, y, &env->apib_key, false);
+    return pauth_addpac(env, x, y, &env->keys.apib, false);
 }
 
 uint64_t HELPER(pacda)(CPUARMState *env, uint64_t x, uint64_t y)
@@ -423,7 +423,7 @@ uint64_t HELPER(pacda)(CPUARMState *env, uint64_t x, uint64_t y)
         return x;
     }
     pauth_check_trap(env, el, GETPC());
-    return pauth_addpac(env, x, y, &env->apda_key, true);
+    return pauth_addpac(env, x, y, &env->keys.apda, true);
 }
 
 uint64_t HELPER(pacdb)(CPUARMState *env, uint64_t x, uint64_t y)
@@ -433,7 +433,7 @@ uint64_t HELPER(pacdb)(CPUARMState *env, uint64_t x, uint64_t y)
         return x;
     }
     pauth_check_trap(env, el, GETPC());
-    return pauth_addpac(env, x, y, &env->apdb_key, true);
+    return pauth_addpac(env, x, y, &env->keys.apdb, true);
 }
 
 uint64_t HELPER(pacga)(CPUARMState *env, uint64_t x, uint64_t y)
@@ -441,7 +441,7 @@ uint64_t HELPER(pacga)(CPUARMState *env, uint64_t x, uint64_t y)
     uint64_t pac;
 
     pauth_check_trap(env, arm_current_el(env), GETPC());
-    pac = pauth_computepac(x, y, env->apga_key);
+    pac = pauth_computepac(x, y, env->keys.apga);
 
     return pac & 0xffffffff00000000ull;
 }
@@ -453,7 +453,7 @@ uint64_t HELPER(autia)(CPUARMState *env, uint64_t x, uint64_t y)
         return x;
     }
     pauth_check_trap(env, el, GETPC());
-    return pauth_auth(env, x, y, &env->apia_key, false, 0);
+    return pauth_auth(env, x, y, &env->keys.apia, false, 0);
 }
 
 uint64_t HELPER(autib)(CPUARMState *env, uint64_t x, uint64_t y)
@@ -463,7 +463,7 @@ uint64_t HELPER(autib)(CPUARMState *env, uint64_t x, uint64_t y)
         return x;
     }
     pauth_check_trap(env, el, GETPC());
-    return pauth_auth(env, x, y, &env->apib_key, false, 1);
+    return pauth_auth(env, x, y, &env->keys.apib, false, 1);
 }
 
 uint64_t HELPER(autda)(CPUARMState *env, uint64_t x, uint64_t y)
@@ -473,7 +473,7 @@ uint64_t HELPER(autda)(CPUARMState *env, uint64_t x, uint64_t y)
         return x;
     }
     pauth_check_trap(env, el, GETPC());
-    return pauth_auth(env, x, y, &env->apda_key, true, 0);
+    return pauth_auth(env, x, y, &env->keys.apda, true, 0);
 }
 
 uint64_t HELPER(autdb)(CPUARMState *env, uint64_t x, uint64_t y)
@@ -483,7 +483,7 @@ uint64_t HELPER(autdb)(CPUARMState *env, uint64_t x, uint64_t y)
         return x;
     }
     pauth_check_trap(env, el, GETPC());
-    return pauth_auth(env, x, y, &env->apdb_key, true, 1);
+    return pauth_auth(env, x, y, &env->keys.apdb, true, 1);
 }
 
 uint64_t HELPER(xpaci)(CPUARMState *env, uint64_t a)
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 2f151da..536d7d1 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -730,13 +730,14 @@ static void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
           CPUID_EXT_MONITOR | CPUID_EXT_SSSE3 | CPUID_EXT_CX16 | \
           CPUID_EXT_SSE41 | CPUID_EXT_SSE42 | CPUID_EXT_POPCNT | \
           CPUID_EXT_XSAVE | /* CPUID_EXT_OSXSAVE is dynamic */   \
-          CPUID_EXT_MOVBE | CPUID_EXT_AES | CPUID_EXT_HYPERVISOR)
+          CPUID_EXT_MOVBE | CPUID_EXT_AES | CPUID_EXT_HYPERVISOR | \
+          CPUID_EXT_RDRAND)
           /* missing:
           CPUID_EXT_DTES64, CPUID_EXT_DSCPL, CPUID_EXT_VMX, CPUID_EXT_SMX,
           CPUID_EXT_EST, CPUID_EXT_TM2, CPUID_EXT_CID, CPUID_EXT_FMA,
           CPUID_EXT_XTPR, CPUID_EXT_PDCM, CPUID_EXT_PCID, CPUID_EXT_DCA,
           CPUID_EXT_X2APIC, CPUID_EXT_TSC_DEADLINE_TIMER, CPUID_EXT_AVX,
-          CPUID_EXT_F16C, CPUID_EXT_RDRAND */
+          CPUID_EXT_F16C */
 
 #ifdef TARGET_X86_64
 #define TCG_EXT2_X86_64_FEATURES (CPUID_EXT2_SYSCALL | CPUID_EXT2_LM)
diff --git a/target/i386/helper.h b/target/i386/helper.h
index 6fb8fb9..8f9e190 100644
--- a/target/i386/helper.h
+++ b/target/i386/helper.h
@@ -226,3 +226,5 @@ DEF_HELPER_3(rcrl, tl, env, tl, tl)
 DEF_HELPER_3(rclq, tl, env, tl, tl)
 DEF_HELPER_3(rcrq, tl, env, tl, tl)
 #endif
+
+DEF_HELPER_1(rdrand, tl, env)
diff --git a/target/i386/int_helper.c b/target/i386/int_helper.c
index 4dc5c65..334469c 100644
--- a/target/i386/int_helper.c
+++ b/target/i386/int_helper.c
@@ -22,6 +22,8 @@
 #include "exec/exec-all.h"
 #include "qemu/host-utils.h"
 #include "exec/helper-proto.h"
+#include "qapi/error.h"
+#include "qemu/guest-random.h"
 
 //#define DEBUG_MULDIV
 
@@ -470,3 +472,22 @@ void helper_cr4_testbit(CPUX86State *env, uint32_t bit)
         raise_exception_ra(env, EXCP06_ILLOP, GETPC());
     }
 }
+
+target_ulong HELPER(rdrand)(CPUX86State *env)
+{
+    Error *err = NULL;
+    target_ulong ret;
+
+    if (qemu_guest_getrandom(&ret, sizeof(ret), &err) < 0) {
+        qemu_log_mask(LOG_UNIMP, "rdrand: Crypto failure: %s",
+                      error_get_pretty(err));
+        error_free(err);
+        /* Failure clears CF and all other flags, and returns 0.  */
+        env->cc_src = 0;
+        return 0;
+    }
+
+    /* Success sets CF and clears all others.  */
+    env->cc_src = CC_C;
+    return ret;
+}
diff --git a/target/i386/translate.c b/target/i386/translate.c
index 77d6b73..03150a8 100644
--- a/target/i386/translate.c
+++ b/target/i386/translate.c
@@ -5332,31 +5332,63 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
     case 0x1c7: /* cmpxchg8b */
         modrm = x86_ldub_code(env, s);
         mod = (modrm >> 6) & 3;
-        if ((mod == 3) || ((modrm & 0x38) != 0x8))
-            goto illegal_op;
-#ifdef TARGET_X86_64
-        if (dflag == MO_64) {
-            if (!(s->cpuid_ext_features & CPUID_EXT_CX16))
+        switch ((modrm >> 3) & 7) {
+        case 1: /* CMPXCHG8, CMPXCHG16 */
+            if (mod == 3) {
                 goto illegal_op;
-            gen_lea_modrm(env, s, modrm);
-            if ((s->prefix & PREFIX_LOCK) && (tb_cflags(s->base.tb) & CF_PARALLEL)) {
-                gen_helper_cmpxchg16b(cpu_env, s->A0);
-            } else {
-                gen_helper_cmpxchg16b_unlocked(cpu_env, s->A0);
             }
-        } else
+#ifdef TARGET_X86_64
+            if (dflag == MO_64) {
+                if (!(s->cpuid_ext_features & CPUID_EXT_CX16)) {
+                    goto illegal_op;
+                }
+                gen_lea_modrm(env, s, modrm);
+                if ((s->prefix & PREFIX_LOCK) &&
+                    (tb_cflags(s->base.tb) & CF_PARALLEL)) {
+                    gen_helper_cmpxchg16b(cpu_env, s->A0);
+                } else {
+                    gen_helper_cmpxchg16b_unlocked(cpu_env, s->A0);
+                }
+                set_cc_op(s, CC_OP_EFLAGS);
+                break;
+            }
 #endif        
-        {
-            if (!(s->cpuid_features & CPUID_CX8))
+            if (!(s->cpuid_features & CPUID_CX8)) {
                 goto illegal_op;
+            }
             gen_lea_modrm(env, s, modrm);
-            if ((s->prefix & PREFIX_LOCK) && (tb_cflags(s->base.tb) & CF_PARALLEL)) {
+            if ((s->prefix & PREFIX_LOCK) &&
+                (tb_cflags(s->base.tb) & CF_PARALLEL)) {
                 gen_helper_cmpxchg8b(cpu_env, s->A0);
             } else {
                 gen_helper_cmpxchg8b_unlocked(cpu_env, s->A0);
             }
+            set_cc_op(s, CC_OP_EFLAGS);
+            break;
+
+        case 7: /* RDSEED */
+        case 6: /* RDRAND */
+            if (mod != 3 ||
+                (s->prefix & (PREFIX_LOCK | PREFIX_REPZ | PREFIX_REPNZ)) ||
+                !(s->cpuid_ext_features & CPUID_EXT_RDRAND)) {
+                goto illegal_op;
+            }
+            if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
+                gen_io_start();
+            }
+            gen_helper_rdrand(s->T0, cpu_env);
+            rm = (modrm & 7) | REX_B(s);
+            gen_op_mov_reg_v(s, dflag, rm, s->T0);
+            set_cc_op(s, CC_OP_EFLAGS);
+            if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
+                gen_io_end();
+                gen_jmp(s, s->pc - s->cs_base);
+            }
+            break;
+
+        default:
+            goto illegal_op;
         }
-        set_cc_op(s, CC_OP_EFLAGS);
         break;
 
         /**************************/
diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c
index f6a088a..9af779a 100644
--- a/target/ppc/int_helper.c
+++ b/target/ppc/int_helper.c
@@ -23,6 +23,8 @@
 #include "exec/helper-proto.h"
 #include "crypto/aes.h"
 #include "fpu/softfloat.h"
+#include "qapi/error.h"
+#include "qemu/guest-random.h"
 
 #include "helper_regs.h"
 /*****************************************************************************/
@@ -158,24 +160,37 @@ uint32_t helper_cmpeqb(target_ulong ra, target_ulong rb)
 #undef hasvalue
 
 /*
- * Return invalid random number.
- *
- * FIXME: Add rng backend or other mechanism to get cryptographically suitable
- * random number
+ * Return a random number.
  */
-target_ulong helper_darn32(void)
+uint64_t helper_darn32(void)
 {
-    return -1;
+    Error *err = NULL;
+    uint32_t ret;
+
+    if (qemu_guest_getrandom(&ret, sizeof(ret), &err) < 0) {
+        qemu_log_mask(LOG_UNIMP, "darn: Crypto failure: %s",
+                      error_get_pretty(err));
+        error_free(err);
+        return -1;
+    }
+
+    return ret;
 }
 
-target_ulong helper_darn64(void)
+uint64_t helper_darn64(void)
 {
-    return -1;
-}
+    Error *err = NULL;
+    uint64_t ret;
 
-#endif
+    if (qemu_guest_getrandom(&ret, sizeof(ret), &err) < 0) {
+        qemu_log_mask(LOG_UNIMP, "darn: Crypto failure: %s",
+                      error_get_pretty(err));
+        error_free(err);
+        return -1;
+    }
 
-#if defined(TARGET_PPC64)
+    return ret;
+}
 
 uint64_t helper_bpermd(uint64_t rs, uint64_t rb)
 {
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index b5217f6..4a5de28 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -1847,13 +1847,22 @@ static void gen_darn(DisasContext *ctx)
 {
     int l = L(ctx->opcode);
 
-    if (l == 0) {
-        gen_helper_darn32(cpu_gpr[rD(ctx->opcode)]);
-    } else if (l <= 2) {
-        /* Return 64-bit random for both CRN and RRN */
-        gen_helper_darn64(cpu_gpr[rD(ctx->opcode)]);
-    } else {
+    if (l > 2) {
         tcg_gen_movi_i64(cpu_gpr[rD(ctx->opcode)], -1);
+    } else {
+        if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
+            gen_io_start();
+        }
+        if (l == 0) {
+            gen_helper_darn32(cpu_gpr[rD(ctx->opcode)]);
+        } else {
+            /* Return 64-bit random for both CRN and RRN */
+            gen_helper_darn64(cpu_gpr[rD(ctx->opcode)]);
+        }
+        if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
+            gen_io_end();
+            gen_stop_exception(ctx);
+        }
     }
 }
 #endif
diff --git a/ui/vnc.c b/ui/vnc.c
index 1871422..d83f4a6 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -43,6 +43,7 @@
 #include "crypto/hash.h"
 #include "crypto/tlscredsanon.h"
 #include "crypto/tlscredsx509.h"
+#include "crypto/random.h"
 #include "qom/object_interfaces.h"
 #include "qemu/cutils.h"
 #include "io/dns-resolver.h"
@@ -2535,14 +2536,16 @@ void start_client_init(VncState *vs)
     vnc_read_when(vs, protocol_client_init, 1);
 }
 
-static void make_challenge(VncState *vs)
+static void authentication_failed(VncState *vs)
 {
-    int i;
-
-    srand(time(NULL)+getpid()+getpid()*987654+rand());
-
-    for (i = 0 ; i < sizeof(vs->challenge) ; i++)
-        vs->challenge[i] = (int) (256.0*rand()/(RAND_MAX+1.0));
+    vnc_write_u32(vs, 1); /* Reject auth */
+    if (vs->minor >= 8) {
+        static const char err[] = "Authentication failed";
+        vnc_write_u32(vs, sizeof(err));
+        vnc_write(vs, err, sizeof(err));
+    }
+    vnc_flush(vs);
+    vnc_client_error(vs);
 }
 
 static int protocol_client_auth_vnc(VncState *vs, uint8_t *data, size_t len)
@@ -2609,21 +2612,23 @@ static int protocol_client_auth_vnc(VncState *vs, uint8_t *data, size_t len)
     return 0;
 
 reject:
-    vnc_write_u32(vs, 1); /* Reject auth */
-    if (vs->minor >= 8) {
-        static const char err[] = "Authentication failed";
-        vnc_write_u32(vs, sizeof(err));
-        vnc_write(vs, err, sizeof(err));
-    }
-    vnc_flush(vs);
-    vnc_client_error(vs);
+    authentication_failed(vs);
     qcrypto_cipher_free(cipher);
     return 0;
 }
 
 void start_auth_vnc(VncState *vs)
 {
-    make_challenge(vs);
+    Error *err = NULL;
+
+    if (qcrypto_random_bytes(vs->challenge, sizeof(vs->challenge), &err)) {
+        trace_vnc_auth_fail(vs, vs->auth, "cannot get random bytes",
+                            error_get_pretty(err));
+        error_free(err);
+        authentication_failed(vs);
+        return;
+    }
+
     /* Send client a 'random' challenge */
     vnc_write(vs, vs->challenge, sizeof(vs->challenge));
     vnc_flush(vs);
@@ -2638,13 +2643,7 @@ static int protocol_client_auth(VncState *vs, uint8_t *data, size_t len)
      * must pick the one we sent. Verify this */
     if (data[0] != vs->auth) { /* Reject auth */
        trace_vnc_auth_reject(vs, vs->auth, (int)data[0]);
-       vnc_write_u32(vs, 1);
-       if (vs->minor >= 8) {
-           static const char err[] = "Authentication failed";
-           vnc_write_u32(vs, sizeof(err));
-           vnc_write(vs, err, sizeof(err));
-       }
-       vnc_client_error(vs);
+       authentication_failed(vs);
     } else { /* Accept requested auth */
        trace_vnc_auth_start(vs, vs->auth);
        switch (vs->auth) {
@@ -2673,13 +2672,7 @@ static int protocol_client_auth(VncState *vs, uint8_t *data, size_t len)
 
        default: /* Should not be possible, but just in case */
            trace_vnc_auth_fail(vs, vs->auth, "Unhandled auth method", "");
-           vnc_write_u8(vs, 1);
-           if (vs->minor >= 8) {
-               static const char err[] = "Authentication failed";
-               vnc_write_u32(vs, sizeof(err));
-               vnc_write(vs, err, sizeof(err));
-           }
-           vnc_client_error(vs);
+           authentication_failed(vs);
        }
     }
     return 0;
diff --git a/util/Makefile.objs b/util/Makefile.objs
index 9206878..c27a923 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -54,5 +54,6 @@ 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 += guest-random.o
 
 stub-obj-y += filemonitor-stub.o
diff --git a/util/guest-random.c b/util/guest-random.c
new file mode 100644
index 0000000..e8124a3
--- /dev/null
+++ b/util/guest-random.c
@@ -0,0 +1,93 @@
+/*
+ * QEMU guest-visible 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/guest-random.h"
+#include "crypto/random.h"
+
+
+static __thread GRand *thread_rand;
+static bool deterministic;
+
+
+static int glib_random_bytes(void *buf, size_t len)
+{
+    GRand *rand = thread_rand;
+    size_t i;
+    uint32_t x;
+
+    if (unlikely(rand == NULL)) {
+        /* Thread not initialized for a cpu, or main w/o -seed.  */
+        thread_rand = rand = g_rand_new();
+    }
+
+    for (i = 0; i + 4 <= len; i += 4) {
+        x = g_rand_int(rand);
+        __builtin_memcpy(buf + i, &x, 4);
+    }
+    if (i < len) {
+        x = g_rand_int(rand);
+        __builtin_memcpy(buf + i, &x, i - len);
+    }
+    return 0;
+}
+
+int qemu_guest_getrandom(void *buf, size_t len, Error **errp)
+{
+    if (unlikely(deterministic)) {
+        /* Deterministic implementation using Glib's Mersenne Twister.  */
+        return glib_random_bytes(buf, len);
+    } else {
+        /* Non-deterministic implementation using crypto routines.  */
+        return qcrypto_random_bytes(buf, len, errp);
+    }
+}
+
+void qemu_guest_getrandom_nofail(void *buf, size_t len)
+{
+    qemu_guest_getrandom(buf, len, &error_fatal);
+}
+
+uint64_t qemu_guest_random_seed_thread_part1(void)
+{
+    if (deterministic) {
+        uint64_t ret;
+        glib_random_bytes(&ret, sizeof(ret));
+        return ret;
+    }
+    return 0;
+}
+
+void qemu_guest_random_seed_thread_part2(uint64_t seed)
+{
+    g_assert(thread_rand == NULL);
+    if (deterministic) {
+        thread_rand =
+            g_rand_new_with_seed_array((const guint32 *)&seed,
+                                       sizeof(seed) / sizeof(guint32));
+    }
+}
+
+int qemu_guest_random_seed_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);
+        return -1;
+    } else {
+        deterministic = true;
+        qemu_guest_random_seed_thread_part2(seed);
+        return 0;
+    }
+}
diff --git a/vl.c b/vl.c
index 201144b..5550bd7 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/guest-random.h"
 
 #define MAX_VIRTIO_CONSOLES 1
 
@@ -3349,6 +3350,9 @@ 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_guest_random_seed_main(optarg, &error_fatal);
+                break;
             case QEMU_OPTION_s:
                 add_device_config(DEV_GDB, "tcp::" DEFAULT_GDBSTUB_PORT);
                 break;