hw/misc/bcm2835_rng: Use qemu_guest_getrandom_nofail

The random number is intended for use by the guest.  As such, we should
honor the -seed argument for reproducibility.  Use the *_nofail routine
instead of rolling our own error handling locally.

Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

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;
 }