Re: [PATCH] book3s_hv_rmhandlers:Pass the correct trap argument to kvmhv_commence_exit

From: Gautham R Shenoy
Date: Mon Aug 17 2015 - 01:54:04 EST


Hi Sam,

On Fri, Aug 14, 2015 at 03:07:28PM +1000, Sam Bobroff wrote:
> On Thu, May 21, 2015 at 01:57:04PM +0530, Gautham R. Shenoy wrote:
> > In guest_exit_cont we call kvmhv_commence_exit which expects the trap
> > number as the argument. However r3 doesn't contain the trap number at
> > this point and as a result we would be calling the function with a
> > spurious trap number.
> >
> > Fix this by copying r12 into r3 before calling kvmhv_commence_exit as
> > r12 contains the trap number
> >
> > Signed-off-by: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>
>
> Hi Gautham,
>
> I agree with your logic: r3 is quite clearly corrupted in that path. So:
>
> Reviewed-by: Sam Bobroff <sam.bobroff@xxxxxxxxxxx>
>
> Just one comment: Do you have a case of this causing some visible problem due
> to the corrupted trap number? (I'll test the patch if you do.)
>

Actually no! I found this bug while reviewing the code for some other issue.

> Cheers,
> Sam.

--
Thanks and Regards
gautham.

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