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>

diff --git a/hw/openrisc/virt.c b/hw/openrisc/virt.c
index 9a78234a287110f339306cf24890ff455ce1b2a4..f8a68a6a6b1f46db6d2fc1b2f559f7229d0f5743 100644 (file)
--- 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");
 }