Excerpts from Daniel Axtens's message of February 19, 2021 4:03 pm: > Hi Nick, > >> +maybe_skip: >> + cmpwi r12,0x200 >> + beq 1f >> + cmpwi r12,0x300 >> + beq 1f >> + cmpwi r12,0x380 >> + beq 1f >> +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE >> + /* XXX: cbe stuff? instruction breakpoint? */ >> + cmpwi r12,0xe02 >> + beq 2f >> +#endif >> + b no_skip >> +1: mfspr r9,SPRN_SRR0 >> + addi r9,r9,4 >> + mtspr SPRN_SRR0,r9 >> + ld r12,HSTATE_SCRATCH0(r13) >> + ld r9,HSTATE_SCRATCH2(r13) >> + GET_SCRATCH0(r13) >> + RFI_TO_KERNEL >> +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE >> +2: mfspr r9,SPRN_HSRR0 >> + addi r9,r9,4 >> + mtspr SPRN_HSRR0,r9 >> + ld r12,HSTATE_SCRATCH0(r13) >> + ld r9,HSTATE_SCRATCH2(r13) >> + GET_SCRATCH0(r13) >> + HRFI_TO_KERNEL >> +#endif > > If I understand correctly, label 1 is the kvmppc_skip_interrupt and > label 2 is the kvmppc_skip_Hinterrupt. Would it be easier to understand > if we used symbolic labels, or do you think the RFI_TO_KERNEL vs > HRFI_TO_KERNEL and other changes are sufficient? Yeah my thinking was it's okay this way because we've got all the context there, whereas prior to this patch those were branched to from far away places so the names helped more. If the discontiguity or nesting was any larger then yes I would say naming the labels is probably a good idea (e.g., maybe_skip / no_skip). > Apart from that, I haven't checked the precise copy-paste to make sure > nothing has changed by accident, but I am able to follow the general > idea of the patch and am vigorously in favour of anything that > simplifies our exception/interrupt paths! Thanks, Nick
