Re: [Qemu-devel] [PATCH v8 1/1] crypto: add virtio-crypto driver

[Christian Borntraeger]

On 12/15/2016 03:03 AM, Gonglei wrote:
[...]
> +
> +static struct crypto_alg virtio_crypto_algs[] = { {
> +     .cra_name = "cbc(aes)",
> +     .cra_driver_name = "virtio_crypto_aes_cbc",
> +     .cra_priority = 501,


This is still higher than the hardware-accelerators (like intel aesni or the
s390 cpacf functions or the arm hw). aesni and s390/cpacf are supported by the
hardware virtualization and available to the guests. I do not see a way how 
virtio
crypto can be faster than that (in the end it might be cpacf/aesni + overhead)
instead it will very likely be slower.
So we should use a number that is higher than software implementations but
lower than the hw ones.

Just grepping around, the software ones seem be be around 100 and the hardware 
ones around 200-400. So why was 150 not enough?

Christian