> > On Thu, Jan 12, 2017 at 03:10:25PM +0100, Christian Borntraeger wrote: > > On 01/10/2017 01:56 PM, Christian Borntraeger wrote: > > > On 01/10/2017 01:36 PM, Gonglei (Arei) wrote: > > >> Hi, > > >> > > >>> > > >>> 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? > > >>> > > >> I didn't find a documentation about how we use the priority, and I assumed > > >> people use virtio-crypto will configure hardware accelerators in the > > >> host. So I choosed the number which bigger than aesni's priority. > > > > > > Yes, but the aesni driver will only bind if there is HW support in the guest. > > > And if aesni is available in the guest (or the s390 aes function from cpacf) > > > it will always be faster than the same in the host via virtio.So your priority > > > should be smaller. > > > > > > any opinion on this? > > Going forward, we might add an emulated aesni device and that might > become slower than virtio. OTOH if or when this happens, we can solve it > by adding a priority or a feature flag to virtio to raise its priority. > > So I think I agree with Christian here, let's lower the priority. > Gonglei, could you send a patch like this? > OK, will do. Thanks, -Gonglei -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html