Re: stable request

Thomas Backlund
2021-03-16T12:29:07Z

Den 16.3.2021 kl. 14:15, skrev Thomas Backlund:
>
> Den 16.3.2021 kl. 12:17, skrev Ard Biesheuvel:
>> On Tue, 16 Mar 2021 at 10:21, Thomas Backlund <tmb@tmb.nu> wrote:
>>> Den 16.3.2021 kl. 08:37, skrev Ard Biesheuvel:
>>>> Please consider backporting commit
>>>>
>>>> 86ad60a65f29dd862a11c22bb4b5be28d6c5cef1
>>>> crypto: x86/aes-ni-xts - use direct calls to and 4-way stride
>>>>
>>>> to stable. It addresses a rather substantial retpoline-related
>>>> performance regression in the AES-NI XTS code, which is a widely used
>>>> disk encryption algorithm on x86.
>>>>
>>> To get all the nice bits, we added the following in Mageia 5.10 / 5.11
>>> series kerenels (the 2 first is needed to get the third to apply/build
>>> nicely):
>>>
>> I will leave it up to the -stable maintainers to decide, but I will
>> point out that none of the additional patches fix any bugs, so this
>> may violate the stable kernel rules. In fact, I deliberately split the
>> XTS changes into two patches so that the first one could be
>> backported individually.
>
> Yes, I understand that.
>
> but commit
>
> 86ad60a65f29dd862a11c22bb4b5be28d6c5cef1
> crypto: x86/aes-ni-xts - use direct calls to and 4-way stride
>
> only applies cleanly on 5.11.
>
>
> So if it's wanted in 5.10 you need the 2 others too... unless you intend to provide a tested backport...
> and IIRC GregKH prefers 1:1 matching of patches between -stable and linus tree unless they are too intrusive.
>
>
> As for the last one I seem to remember comments that it too was part of the "affects performance", but I might be remembering wrong... and since you are Author of them I assume you know better about the facts :)
>
>
> That's why I listed them as an extra "hopefully helfpful" info and datapoint that they work...
> We have been carrying them in 5.10 series since we rebased to 5.10.8 on January 17th, 2021
>
>
> but in the end it's up to the -stable maintainers as you point out...

and now  I re-checked...

Only the first is needed to get your fix to apply cleanly on 5.10

the second came in as a pre-req for the fourth patch...

--

Thomas

> --
> Thomas
>
>> --
>> Ard.
>>
>>
>>> applied in this order:
>>>
>>> From 032d049ea0f45b45c21f3f02b542aa18bc6b6428 Mon Sep 17 00:00:00 2001
>>> From: Uros Bizjak <ubizjak@gmail.com>
>>> Date: Fri, 27 Nov 2020 10:44:52 +0100
>>> Subject: [PATCH] crypto: aesni - Use TEST %reg,%reg instead of CMP $0,%reg
>>>
>>> From ddf169a98f01d6fd46295ec0dd4c1d6385be65d4 Mon Sep 17 00:00:00 2001
>>> From: Ard Biesheuvel <ardb@kernel.org>
>>> Date: Tue, 8 Dec 2020 00:34:02 +0100
>>> Subject: [PATCH] crypto: aesni - implement support for cts(cbc(aes))
>>>
>>> From 86ad60a65f29dd862a11c22bb4b5be28d6c5cef1 Mon Sep 17 00:00:00 2001
>>> From: Ard Biesheuvel <ardb@kernel.org>
>>> Date: Thu, 31 Dec 2020 17:41:54 +0100
>>> Subject: [PATCH] crypto: x86/aes-ni-xts - use direct calls to and 4-way
>>> stride
>>>
>>> From 2481104fe98d5b016fdd95d649b1235f21e491ba Mon Sep 17 00:00:00 2001
>>> From: Ard Biesheuvel <ardb@kernel.org>
>>> Date: Thu, 31 Dec 2020 17:41:55 +0100
>>> Subject: [PATCH] crypto: x86/aes-ni-xts - rewrite and drop indirections
>>> via glue helper
>>>
>>> --
>>> Thomas
>>>