Aurelien Jarno wrote: > Jun Koi a écrit : >> On Wed, Apr 14, 2010 at 12:28 AM, Jan Kiszka <jan.kis...@siemens.com> wrote: >>> Alexander Graf wrote: >>>> On 13.04.2010, at 15:36, Jan Kiszka wrote: >>>> >>>>> Jun Koi wrote: >>>>>> Hi, >>>>>> >>>>>> I am looking into the singlestep command in monitor interface, and it >>>>>> seems that we only take into account the singlestep flag when we are >>>>>> translating code. >>>>>> So for the already-translated code, we will miss singlestep? >>>>> This feature is broken. For TCG, it should at least flush the >>>>> translation buffer, and for KVM it has to enable single-stepping in the >>>>> kernel. That's what happens automatically when you call cpu_single_step. >>>>> I guess 'singlestep' wants to be somehow orthogonal to this. But this is >>>>> the wrong approach. >>>>> >>>>> Does anyone actually used this feature or still does so? It looks fairly >>>>> redundant to me, kind of a poor-man's gdb front-end as part of the >>>>> monitor console. >>>> Not sure what it does, but I use -singlestep quite a lot to get register >>>> dumps for instructions when using -d cpu. >>> Ah, "singlestep" is not about stopping the VM after each instruction but >>> about limiting the TB length to a single instruction. Badly named and >>> poorly documented. >>> >>> In that case, the dynamic switch should already be fine by adding a >>> tb_flush() on enable. Still, someone should also patch at least the docs. >>> > > What's the real point of flushing the tb to get it retranslated again? > It will be retranslated in the exact same way.
Nope. AFAIU, 'singlestep' will enforce single-instruction TBs. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
