Re: [Xen-devel] [PATCH 0/3] xen/arm: Inject an exception to the guest rather than crashing it

[Julien Grall <julien.grall@xxxxxxx>]

On 30/01/18 16:38, Andrew Cooper wrote:
> On 30/01/18 16:14, Julien Grall wrote:
> > Hi all,
> >
> > This small series replaces all call to domain_crash_synchronous by injecting
> > an exception to the guest.
> >
> > This will result to a nicer trace from the guest (no need to manually walk
> > the stack) and give a chance to the guest to give a bit more information on
> > what it was doing.
> >
> > Cheers,
> >
> > Julien Grall (3):
> >    xen/arm: io: Distinguish unhandled IO from aborted one
> >    xen/arm: Don't crash domain on bad MMIO emulation
> >    xen/arm: Don't crash the domain on invalid HVC immediate
> Thanks.
>
> I don't feel qualified to review these, but some notes.
>
> Patch 1.  s/avodi/avoid/ in the commit message
>
> Patches 2 and 3.  You probably want to convert the printks to
> gdprintk()s, otherwise guests can choke up the ratelimited log.  Doing
> so will also mean that the vcpu will be identified consistently, which
> it isn't currently.
We didn't use g*printk because it would be more confusing to print the 
current vCPU in some cases (e.g when accessing the re-distributor of 
another vCPU) or does not matter (e.g for ITS).
The problem with the debug version is those information are actually 
quite useful in non-debug build. We found quite a few issues thanks to them.
I think it would make more sense for Xen to provide per-guest 
ratelimited than hiding those messages in non-debug build.
> ~Andrew
--
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel