On 02/10/2016 07:04 PM, Corneliu ZUZU wrote: >>> @@ -27,9 +33,8 @@ bool_t hvm_event_cr(unsigned int index, unsigned >>> long value, >>> #define hvm_event_crX(what, new, old) \ >>> hvm_event_cr(VM_EVENT_X86_##what, new, old) >>> void hvm_event_msr(unsigned int msr, uint64_t value); >>> -/* Called for current VCPU: returns -1 if no listener */ >>> -int hvm_event_int3(unsigned long rip); >>> -int hvm_event_single_step(unsigned long rip); >>> +int hvm_event_breakpoint(unsigned long rip, >>> + enum hvm_event_breakpoint_type type); >> I guess the comment was here for a reason, and this reason doesn't >> go away with this code folding. But I'll leave it to the VM event code >> maintainers to judge. >> >> Jan > > That comment seemed & still seems wrong to me, I don't see any code > paths out of which that function would return -1.
That seems to be true. Those functions return whatever hvm_event_traps() returns, which is 0 on success, 1 (maybe the minus is a typo?) if there's no ring, or whatever value vm_event_claim_slot() returns. Vm_event_claim_slot()'s documentation says that it can only return 0 (on success), -ENOSYS or -EBUSY, none of which translate to -1 (and the code seems to agree with that claim). Maybe I'm missing some macro wizardry here, but I don't think so - it looks like the comment is stale. Tamas, maybe you remember more, should those functions return -1 if no listener is present? Thanks, Razvan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
