Re: [PATCH 06/24] hw: Model ASPEED's Hash and Crypto Engine

[Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>]

On 4/7/2021 2:16 PM, Cédric Le Goater wrote:
> From: Joel Stanley <joel@jms.id.au>
> 
> The HACE (Hash and Crypto Engine) is a device that offloads MD5, SHA1,
> SHA2, RSA and other cryptographic algorithms.
> 
> This initial model implements a subset of the device's functionality;
> currently only direct access (non-scatter gather) hashing.

> +
> +static void aspeed_hace_write(void *opaque, hwaddr addr, uint64_t data,
> +                              unsigned int size)
> +{
> +    AspeedHACEState *s = ASPEED_HACE(opaque);
> +    AspeedHACEClass *ahc = ASPEED_HACE_GET_CLASS(s);
> +
> +    addr >>= 2;
> +
> +    if (addr >= ASPEED_HACE_NR_REGS) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: Out-of-bounds write at offset 0x%" HWADDR_PRIx "\n",
> +                      __func__, addr << 2);
> +        return;
> +    }
> +
> +    switch (addr) {
> +    case R_STATUS:
> +        if (data & HASH_IRQ) {
> +            data &= ~HASH_IRQ;
> +
> +            if (s->regs[addr] & HASH_IRQ) {
> +                qemu_irq_lower(s->irq);
> +            }
> +        }
> +        break;
> +    case R_HASH_SRC:
> +        data &= ahc->src_mask;
> +        break;
> +    case R_HASH_DEST:
> +        data &= ahc->dest_mask;
> +        break;
> +    case R_HASH_SRC_LEN:
> +        data &= 0x0FFFFFFF;
> +        break;
> +    case R_HASH_CMD: {
> +        int algo = -1;
> +        if ((data & HASH_HMAC_MASK)) {
> +            qemu_log_mask(LOG_UNIMP,
> +                          "%s: HMAC engine command mode %"PRIx64" not implemented",
> +                          __func__, (data & HASH_HMAC_MASK) >> 8);
> +        }
> +        if (data & HASH_SG_EN) {
> +            qemu_log_mask(LOG_UNIMP,
> +                          "%s: Hash scatter gather mode not implemented",
> +                          __func__);
> +        }
> +        if (data & BIT(1)) {
> +            qemu_log_mask(LOG_UNIMP,
> +                          "%s: Cascaded mode not implemented",
> +                          __func__);
> +       if the guest is requesting a command that is not implemented, wouldn't it be safer to bail out
and return instead of just logging and continue?


  -Klaus

-- 
Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>