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.

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 hw/microblaze/boot.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/microblaze/boot.c b/hw/microblaze/boot.c
index 8b92a9801a..25ad54754e 100644
--- a/hw/microblaze/boot.c
+++ b/hw/microblaze/boot.c
@@ -30,6 +30,7 @@
 #include "qemu/option.h"
 #include "qemu/config-file.h"
 #include "qemu/error-report.h"
+#include "qemu/guest-random.h"
 #include "sysemu/device_tree.h"
 #include "sysemu/reset.h"
 #include "hw/boards.h"
@@ -75,6 +76,7 @@ static int microblaze_load_dtb(hwaddr addr,
     int fdt_size;
     void *fdt = NULL;
     int r;
+    uint8_t rng_seed[32];
 
     if (dtb_filename) {
         fdt = load_device_tree(dtb_filename, &fdt_size);
@@ -83,6 +85,9 @@ static int microblaze_load_dtb(hwaddr addr,
         return 0;
     }
 
+    qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
+    qemu_fdt_setprop(fdt, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed));
+
     if (kernel_cmdline) {
         r = qemu_fdt_setprop_string(fdt, "/chosen", "bootargs",
                                     kernel_cmdline);
-- 
2.37.3

On Thu, Sep 8, 2022 at 11:40 AM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
> 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.
>
> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
>  hw/microblaze/boot.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/hw/microblaze/boot.c b/hw/microblaze/boot.c
> index 8b92a9801a..25ad54754e 100644
> --- a/hw/microblaze/boot.c
> +++ b/hw/microblaze/boot.c
> @@ -30,6 +30,7 @@
>  #include "qemu/option.h"
>  #include "qemu/config-file.h"
>  #include "qemu/error-report.h"
> +#include "qemu/guest-random.h"
>  #include "sysemu/device_tree.h"
>  #include "sysemu/reset.h"
>  #include "hw/boards.h"
> @@ -75,6 +76,7 @@ static int microblaze_load_dtb(hwaddr addr,
>      int fdt_size;
>      void *fdt = NULL;
>      int r;
> +    uint8_t rng_seed[32];
>
>      if (dtb_filename) {
>          fdt = load_device_tree(dtb_filename, &fdt_size);
> @@ -83,6 +85,9 @@ static int microblaze_load_dtb(hwaddr addr,
>          return 0;
>      }
>
> +    qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
> +    qemu_fdt_setprop(fdt, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed));
> +
>      if (kernel_cmdline) {
>          r = qemu_fdt_setprop_string(fdt, "/chosen", "bootargs",
>                                      kernel_cmdline);
> --
> 2.37.3
>

Bumping this patch. Could somebody queue this up?

On Wed, Sep 21, 2022 at 12:32:37PM +0200, Jason A. Donenfeld wrote:
> On Thu, Sep 8, 2022 at 11:40 AM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> >
> > 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.
> >
> > Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
> > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> > ---
> >  hw/microblaze/boot.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/hw/microblaze/boot.c b/hw/microblaze/boot.c
> > index 8b92a9801a..25ad54754e 100644
> > --- a/hw/microblaze/boot.c
> > +++ b/hw/microblaze/boot.c
> > @@ -30,6 +30,7 @@
> >  #include "qemu/option.h"
> >  #include "qemu/config-file.h"
> >  #include "qemu/error-report.h"
> > +#include "qemu/guest-random.h"
> >  #include "sysemu/device_tree.h"
> >  #include "sysemu/reset.h"
> >  #include "hw/boards.h"
> > @@ -75,6 +76,7 @@ static int microblaze_load_dtb(hwaddr addr,
> >      int fdt_size;
> >      void *fdt = NULL;
> >      int r;
> > +    uint8_t rng_seed[32];
> >
> >      if (dtb_filename) {
> >          fdt = load_device_tree(dtb_filename, &fdt_size);
> > @@ -83,6 +85,9 @@ static int microblaze_load_dtb(hwaddr addr,
> >          return 0;
> >      }
> >
> > +    qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
> > +    qemu_fdt_setprop(fdt, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed));
> > +
> >      if (kernel_cmdline) {
> >          r = qemu_fdt_setprop_string(fdt, "/chosen", "bootargs",
> >                                      kernel_cmdline);
> > --
> > 2.37.3
> >
> 
> Bumping this patch. Could somebody queue this up?

Hi Jason,

I've just sent a pull-request with this patch.

Thanks,
Edgar