From c6fe3e6b4cd8d7b98ea37bf37fb3686ecd1304fe Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Wed, 22 Jun 2022 13:45:13 +0200
Subject: [PATCH] hw/openrisc: virt: pass random seed to fdt

If the FDT contains /chosen/rng-seed, then the Linux RNG will use it to
initialize early. Set this using the usual guest random number
generation function. This is confirmed to successfully initialize the
RNG on Linux 5.19-rc2.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>
---
 hw/openrisc/virt.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/openrisc/virt.c b/hw/openrisc/virt.c
index 9a78234a28..f8a68a6a6b 100644
--- a/hw/openrisc/virt.c
+++ b/hw/openrisc/virt.c
@@ -8,6 +8,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
+#include "qemu/guest-random.h"
 #include "qapi/error.h"
 #include "cpu.h"
 #include "exec/address-spaces.h"
@@ -130,6 +131,7 @@ static void openrisc_create_fdt(OR1KVirtState *state,
     void *fdt;
     int cpu;
     char *nodename;
+    uint8_t rng_seed[32];
 
     fdt = state->fdt = create_device_tree(&state->fdt_size);
     if (!fdt) {
@@ -186,6 +188,10 @@ static void openrisc_create_fdt(OR1KVirtState *state,
         qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);
     }
 
+    /* Pass seed to RNG. */
+    qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
+    qemu_fdt_setprop(fdt, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed));
+
     /* Create aliases node for use by devices. */
     qemu_fdt_add_subnode(fdt, "/aliases");
 }
-- 
2.30.2