Re: [Xen-devel] [PATCH v2] Livepatch for ARM 64 and 32.

[Julien Grall <julien.grall@xxxxxxx>]

On 25/08/16 14:37, Konrad Rzeszutek Wilk wrote:
> Hey!
Hi Konrad,

> Since v1 (and RFC): 
> [https://lists.xen.org/archives/html/xen-devel/2016-08/msg01835.html]
>  - Acted on most all comments.
>  - Added ARM32 support.
>
> The patches are based on: [PATCH v4] Livepatch fixes and features for v4.8.
> (https://lists.xen.org/archives/html/xen-devel/2016-08/msg02705.html)
>
> And the git tree is:
>  git://xenbits.xen.org/people/konradwilk/xen.git livepatch.v4.8.v4
>
> There are two outstanding questions that should be addressed at some point:
>  -  #16 "livepatch: tests: Make them compile under ARM64"
>     We chatted about adding a specific CPU bit (LIVEPATCH) so that alternative
>     code always gets exercised. This being for both x86 and ARM. But this has
>     a side effect that it gets exposed to the toolstack and can also be
>     exposed to the guests. I think it is better if we do not do that
>     so left it to be enabled based on the most common errata (or feature
>     on x86).
There is no common errata on ARM. I spoke with Andrew which mentioned 
that on x86 they have architectural xen feature bits which are not 
exposed to the toolstack/guest.
Furthermore, I think it would be unwise to let the toolstack aware of 
some errata and possibly setting/clearing them. So adding a specific 
feature bit is fine by me.
>  -  #13 "livepatch: Initial ARM64 support."
>     Need to look in erratum #843419 on some Cortex-A53 and figuring
>     out how to avoid payloads having R_AARCH64_ADR_PREL_PG_HI21 relocations.
I will not considered this has a blocker for this series. Having 
livepatching on all the other boards for Xen 4.8 would still be awesome :).
Regards,

--
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel