Re: [PATCH v8 01/12] Documentation/x86: Document Key Locker

From: Chang S. Bae
Date: Tue Jun 06 2023 - 00:18:21 EST


On 6/5/2023 7:17 PM, Randy Dunlap wrote:
On 6/3/23 08:22, Chang S. Bae wrote:
+
+* AES-KL implements support for 128-bit and 256-bit keys, but there is no
+ AES-KL instruction to process an 192-bit key. The AES-KL cipher
+ implementation logs a warning message with a 192-bit key and then falls
+ back to AES-NI. So, this 192-bit key-size limitation is only documented,

Is it logged anywhere? i.e., a kernel log message?

Yes, this is the relevant change in the last patch:

> +static int aeskl_setkey(struct crypto_tfm *tfm, void *raw_ctx, const u8 *in_key,
> + unsigned int keylen)
> +{
...
> + if (unlikely(keylen == AES_KEYSIZE_192)) {
> + pr_warn_once("AES-KL does not support 192-bit key. Use AES-NI.\n");
...
> +}

Thanks,
Chang