hw/mips: boston: 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 FDT node is part of the DT specification.

I'd do the same for other MIPS platforms but boston is the only one that
seems to use FDT.

Cc: Paul Burton <paulburton@kernel.org>
Cc: Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>
Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Message-Id: <20220719120843.134392-1-Jason@zx2c4.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/hw/mips/boston.c b/hw/mips/boston.c
index 1debca18ecf2dcf2958535f55ae180db064d23ba..d2ab9da1a01f028c0ecf8dded9c081764ad55097 100644 (file)
--- a/hw/mips/boston.c
+++ b/hw/mips/boston.c
@@ -34,6 +34,7 @@
 #include "hw/qdev-properties.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
+#include "qemu/guest-random.h"
 #include "qemu/log.h"
 #include "chardev/char.h"
 #include "sysemu/device_tree.h"
@@ -363,6 +364,7 @@ static const void *boston_fdt_filter(void *opaque, const void *fdt_orig,
     size_t ram_low_sz, ram_high_sz;
     size_t fdt_sz = fdt_totalsize(fdt_orig) * 2;
     g_autofree void *fdt = g_malloc0(fdt_sz);
+    uint8_t rng_seed[32];
 
     err = fdt_open_into(fdt_orig, fdt, fdt_sz);
     if (err) {
@@ -370,6 +372,9 @@ static const void *boston_fdt_filter(void *opaque, const void *fdt_orig,
         return NULL;
     }
 
+    qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
+    qemu_fdt_setprop(fdt, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed));
+
     cmdline = (machine->kernel_cmdline && machine->kernel_cmdline[0])
             ? machine->kernel_cmdline : " ";
     err = qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);