Re: [PATCH] target/riscv: Use existing lookup tables for AES MixColumns

[Richard Henderson]

On 7/27/23 00:03, Ard Biesheuvel wrote:
> @@ -606,8 +606,7 @@ static const uint32_t AES_Te4[256] = {
>       0x41414141U, 0x99999999U, 0x2d2d2d2dU, 0x0f0f0f0fU,
>       0xb0b0b0b0U, 0x54545454U, 0xbbbbbbbbU, 0x16161616U,
>   };
> -
> -static const uint32_t AES_Td0[256] = {
> +const uint32_t AES_Td0[256] = {

Don't drop the blank line.

> @@ -62,18 +39,21 @@ static inline target_ulong aes32_operation(target_ulong 
> shamt,
>       if (enc) {
>           so = AES_sbox[si];
>           if (mix) {
> -            mixed = aes_mixcolumn_byte(so, true);
> +            mixed = AES_Te0[si];
>           } else {
>               mixed = so;
>           }
>       } else {
>           so = AES_isbox[si];
>           if (mix) {
> -            mixed = aes_mixcolumn_byte(so, false);
> +            mixed = AES_Td0[si];
>           } else {
>               mixed = so;
>           }
>       }
> +    if (!HOST_BIG_ENDIAN && mix) {
> +        mixed = bswap32(mixed);
> +    }
>       mixed = rol32(mixed, shamt);

Better as

    if (enc) {
        if (mix) {
            mixed = be32_to_cpu(AES_Te0[si]);
        } else {
            mixed = AES_sbox[si];
        }
    } else {
        ...
    }
    mixed = rol32(mixed, shamt);

But thanks for the update -- I had ignored rv32 when doing the other AES bits.

r~