| Message ID | 1432196824-21791-1-git-send-email-ego@linux.vnet.ibm.com |
|---|---|
| State | New, archived |
| Headers | show |
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@linux.vnet.ibm.com> Hi Gautham, I agree with your logic: r3 is quite clearly corrupted in that path. So: Reviewed-by: Sam Bobroff <sam.bobroff@au1.ibm.com> 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.) Cheers, Sam. -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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@linux.vnet.ibm.com> > > Hi Gautham, > > I agree with your logic: r3 is quite clearly corrupted in that path. So: > > Reviewed-by: Sam Bobroff <sam.bobroff@au1.ibm.com> > > 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. -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 4d70df2..f0d7c54 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1170,6 +1170,7 @@ mc_cont: bl kvmhv_accumulate_time #endif + mr r3, r12 /* Increment exit count, poke other threads to exit */ bl kvmhv_commence_exit nop
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@linux.vnet.ibm.com> --- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 1 + 1 file changed, 1 insertion(+)