[PATCH] hw/openrisc: pass random seed to fdt

[PATCH] hw/openrisc: pass random seed to fdt

[Jason A. Donenfeld]

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");
 }
-- 
2.35.1

Re: [PATCH] hw/openrisc: pass random seed to fdt

[Stafford Horne]

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

Re: [PATCH] hw/openrisc: pass random seed to fdt

[Jason A. Donenfeld]

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

Re: [PATCH] hw/openrisc: pass random seed to fdt

[Philippe Mathieu-Daudé via]

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
> 

[PATCH v2] hw/openrisc: virt: pass random seed to fdt

[Jason A. Donenfeld]

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>
---
Changes v1->v2:
- This is rebased on top of your "or1k-virt-2" branch.
- It makes the change to the new "virt" platform, since that's where it
  makes most sense to have.

 hw/openrisc/virt.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/openrisc/virt.c b/hw/openrisc/virt.c
index 13b0a1d7dc..f1d62fcb7d 100644
--- a/hw/openrisc/virt.c
+++ b/hw/openrisc/virt.c
@@ -19,6 +19,7 @@
 
 #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"
@@ -141,6 +142,7 @@ 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) {
@@ -197,6 +199,10 @@ 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");
 }
-- 
2.35.1

Re: [PATCH v2] hw/openrisc: virt: pass random seed to fdt

[Stafford Horne]

On Wed, Jun 22, 2022 at 01:45:13PM +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>
> ---
> Changes v1->v2:
> - This is rebased on top of your "or1k-virt-2" branch.
> - It makes the change to the new "virt" platform, since that's where it
>   makes most sense to have.

Thanks I have placed this on my or1k-virt-2 branch.

-Stafford