diff mbox series

hw/openrisc: pass random seed to fdt

Message ID 20220612215949.134807-1-Jason@zx2c4.com (mailing list archive)
State New, archived
Headers show
Series hw/openrisc: pass random seed to fdt | expand

Commit Message

Jason A. Donenfeld June 12, 2022, 9:59 p.m. UTC
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.

Cc: Stafford Horne <shorne@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 hw/openrisc/openrisc_sim.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Stafford Horne June 13, 2022, 1:23 a.m. UTC | #1
On Sun, Jun 12, 2022 at 11:59:49PM +0200, Jason A. Donenfeld 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 is confirmed to successfully initialize the
> RNG on Linux 5.19-rc2.
>
> Cc: Stafford Horne <shorne@gmail.com>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
>  hw/openrisc/openrisc_sim.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
> index 35adce17ac..41821b5f30 100644
> --- a/hw/openrisc/openrisc_sim.c
> +++ b/hw/openrisc/openrisc_sim.c
> @@ -20,6 +20,7 @@
>  
>  #include "qemu/osdep.h"
>  #include "qemu/error-report.h"
> +#include "qemu/guest-random.h"
>  #include "qapi/error.h"
>  #include "cpu.h"
>  #include "hw/irq.h"
> @@ -115,6 +116,7 @@ static void openrisc_create_fdt(Or1ksimState *state,
>      int cpu;
>      char *nodename;
>      int pic_ph;
> +    uint8_t rng_seed[32];
>  
>      fdt = state->fdt = create_device_tree(&state->fdt_size);
>      if (!fdt) {
> @@ -165,6 +167,10 @@ static void openrisc_create_fdt(Or1ksimState *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");
>  }

This all looks fine to me.  I will queue it with my current changes.  Since this
is only applying to openrisc_sim I would like to also apply it to virt.  To do
that I need to have a common core openrisc system creation api.  That way I
don't end up copying and pasting this to every platform.

-Stafford
Jason A. Donenfeld June 13, 2022, 10:58 a.m. UTC | #2
On 6/13/22, Stafford Horne <shorne@gmail.com> wrote:
> On Sun, Jun 12, 2022 at 11:59:49PM +0200, Jason A. Donenfeld 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 is confirmed to successfully initialize the
>> RNG on Linux 5.19-rc2.
>>
>> Cc: Stafford Horne <shorne@gmail.com>
>> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
>> ---
>>  hw/openrisc/openrisc_sim.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
>> index 35adce17ac..41821b5f30 100644
>> --- a/hw/openrisc/openrisc_sim.c
>> +++ b/hw/openrisc/openrisc_sim.c
>> @@ -20,6 +20,7 @@
>>
>>  #include "qemu/osdep.h"
>>  #include "qemu/error-report.h"
>> +#include "qemu/guest-random.h"
>>  #include "qapi/error.h"
>>  #include "cpu.h"
>>  #include "hw/irq.h"
>> @@ -115,6 +116,7 @@ static void openrisc_create_fdt(Or1ksimState *state,
>>      int cpu;
>>      char *nodename;
>>      int pic_ph;
>> +    uint8_t rng_seed[32];
>>
>>      fdt = state->fdt = create_device_tree(&state->fdt_size);
>>      if (!fdt) {
>> @@ -165,6 +167,10 @@ static void openrisc_create_fdt(Or1ksimState *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");
>>  }
>
> This all looks fine to me.  I will queue it with my current changes.  Since
> this
> is only applying to openrisc_sim I would like to also apply it to virt.  To
> do
> that I need to have a common core openrisc system creation api.  That way I
> don't end up copying and pasting this to every platform.

Sure. Or just do it on the virt board only if that's easier.

Jason
Philippe Mathieu-Daudé June 13, 2022, 1:52 p.m. UTC | #3
On 13/6/22 12:58, Jason A. Donenfeld wrote:
> On 6/13/22, Stafford Horne <shorne@gmail.com> wrote:
>> On Sun, Jun 12, 2022 at 11:59:49PM +0200, Jason A. Donenfeld 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 is confirmed to successfully initialize the
>>> RNG on Linux 5.19-rc2.
>>>
>>> Cc: Stafford Horne <shorne@gmail.com>
>>> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
>>> ---
>>>   hw/openrisc/openrisc_sim.c | 6 ++++++
>>>   1 file changed, 6 insertions(+)

>> This all looks fine to me.  I will queue it with my current changes.  Since
>> this
>> is only applying to openrisc_sim I would like to also apply it to virt.  To
>> do
>> that I need to have a common core openrisc system creation api.  That way I
>> don't end up copying and pasting this to every platform.

Looking at commit cb57df6f7f ("hw/arm/raspi: Make machines children of
abstract RaspiMachineClass") and around could help.

> 
> Sure. Or just do it on the virt board only if that's easier.
> 
> Jason
>
diff mbox series

Patch

diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
index 35adce17ac..41821b5f30 100644
--- a/hw/openrisc/openrisc_sim.c
+++ b/hw/openrisc/openrisc_sim.c
@@ -20,6 +20,7 @@ 
 
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
+#include "qemu/guest-random.h"
 #include "qapi/error.h"
 #include "cpu.h"
 #include "hw/irq.h"
@@ -115,6 +116,7 @@  static void openrisc_create_fdt(Or1ksimState *state,
     int cpu;
     char *nodename;
     int pic_ph;
+    uint8_t rng_seed[32];
 
     fdt = state->fdt = create_device_tree(&state->fdt_size);
     if (!fdt) {
@@ -165,6 +167,10 @@  static void openrisc_create_fdt(Or1ksimState *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");
 }