[PATCH v4 09/46] powerpc/64s: remove KVM SKIP test from instruction breakpoint handler

[Nicholas Piggin]

Excerpts from Paul Mackerras's message of March 31, 2021 2:54 pm:
> On Tue, Mar 23, 2021 at 11:02:28AM +1000, Nicholas Piggin wrote:
>> The code being executed in KVM_GUEST_MODE_SKIP is hypervisor code with
>> MSR[IR]=0, so the faults of concern are the d-side ones caused by access
>> to guest context by the hypervisor.
>> 
>> Instruction breakpoint interrupts are not a concern here. It's unlikely
>> any good would come of causing breaks in this code, but skipping the
>> instruction that caused it won't help matters (e.g., skip the mtmsr that
>> sets MSR[DR]=0 or clears KVM_GUEST_MODE_SKIP).
>> 
>> Reviewed-by: Daniel Axtens <dja at axtens.net>
>> Reviewed-by: Fabiano Rosas <farosas at linux.ibm.com>
>> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> 
> It might be worth noting in the commit message that the 0x1300
> interrupt was dropped from the architecture a long time ago and is not
> generated by P7, P8, P9 or P10.

Good background, I'll add that.

Thanks,
Nick

> 
> Acked-by: Paul Mackerras <paulus at ozlabs.org>
>