On 28 May 2018 at 23:17, Cédric Le Goater <c...@kaod.org> wrote:
> Hello Joel,
>
> On 05/28/2018 02:46 PM, Joel Stanley wrote:
>> The ASPEED SoCs contain a single register that returns random data when
>> read. This models that register so that guests can use it.
>>
>> Signed-off-by: Joel Stanley <j...@jms.id.au>
>> ---
>> hw/misc/aspeed_scu.c | 19 +++++++++++++++++++
>> 1 file changed, 19 insertions(+)
>>
>> diff --git a/hw/misc/aspeed_scu.c b/hw/misc/aspeed_scu.c
>> index 5e6d5744eeca..8fa0cecf0fa1 100644
>> --- a/hw/misc/aspeed_scu.c
>> +++ b/hw/misc/aspeed_scu.c
>> @@ -16,6 +16,7 @@
>> #include "qapi/visitor.h"
>> #include "qemu/bitops.h"
>> #include "qemu/log.h"
>> +#include "crypto/random.h"
>> #include "trace.h"
>>
>> #define TO_REG(offset) ((offset) >> 2)
>> @@ -154,6 +155,18 @@ static const uint32_t
>> ast2500_a1_resets[ASPEED_SCU_NR_REGS] = {
>> [BMC_DEV_ID] = 0x00002402U
>> };
>>
>> +static uint32_t aspeed_scu_get_random(void)
>> +{
>> + Error *err = NULL;
>> + uint32_t num;
>> +
>> + if (qcrypto_random_bytes((uint8_t *)&num, sizeof(num), &err)) {
>> + error_report_err(err);
>> + }
>> +
>> + return num;
>> +}
>> +
>> static uint64_t aspeed_scu_read(void *opaque, hwaddr offset, unsigned size)
>> {
>> AspeedSCUState *s = ASPEED_SCU(opaque);
>> @@ -167,6 +180,9 @@ static uint64_t aspeed_scu_read(void *opaque, hwaddr
>> offset, unsigned size)
>> }
>>
>> switch (reg) {
>> + case RNG_DATA:
>> + return aspeed_scu_get_random();
>
> may be we could test bit 1 of RNG_CTRL to check if it is enabled or not.
The RNG is enabled by default, and I didn't find any software that
disables it, but it can't hurt to have that check.
I'll send a v2 with that check.
>
>> + break;
>> case WAKEUP_EN:
>> qemu_log_mask(LOG_GUEST_ERROR,
>> "%s: Read of write-only offset 0x%" HWADDR_PRIx "\n",
>> @@ -287,6 +303,9 @@ static void aspeed_scu_realize(DeviceState *dev, Error
>> **errp)
>> TYPE_ASPEED_SCU, SCU_IO_REGION_SIZE);
>>
>> sysbus_init_mmio(sbd, &s->iomem);
>> +
>> + if (qcrypto_random_init(errp))
>> + return;
>> }
>
> Isn't this routine called from main() already ?
It is indirectly called, yes. I'll remove this.
Cheers,
Joel
