Re: [RFC PATCH 1/1] xen: Use a global mapping for runstate

[Julien Grall <julien@xxxxxxx>]

Hi,

On 29/05/2020 14:26, Roger Pau Monné wrote:
> TBH I would just remove the error message on Arm from the current
> hypercall, I don't think it's useful.
The message is part of the helpers get_page_from_gva() which is also 
used by copy_{to, from}_guest. While it may not be useful in the context 
of the runstate, it was introduced because there was some other weird 
bug happening before KPTI even existed (see [1]). I haven't yet managed 
to find the bottom line of the issue.
So I would still very much like to keep the message in place. Although 
we could reduce the number of cases where this is hapenning based on the 
fault.
Note this is a dprintk(XENLOG_G_DEBUG,...) so the verbosity of the 
logging is only for debug build.
Cheers,

[1] https://lists.xen.org/archives/html/xen-devel/2017-11/msg00942.html

--
Julien Grall