On Tue, 2008-06-10 at 10:33 -0500, Jerone Young wrote: > On Tue, 2008-06-10 at 10:12 -0500, Hollis Blanchard wrote: > > On Mon, 2008-06-09 at 18:56 -0500, Jerone Young wrote: > > > > > If an IAC is matched before we enter the guest it will be caught host > > > > > that catches it. > > > > > > > > But that won't happen because you've disabled MSR[DE]. > > > > > > Ah... you don't rember the whole imprecise interrupts ;-) . When MSR[DE] > > > =0 and an IAC will go off but not at the exact address. This was fun > > > figuring out. > > > > Right. Now, when will the deferred debug event fire, and who will handle > > it? What can we do about that? > > If the debug registers are turned off before we disable MSR[DE], there > will be no debug events at all. > > This is what I was talking about in my first couple of emails. If a > debug event does go off and the host does not handle it, the only way to > know is the dbsr register (and there is no way to save that off). So in > the end it could end up going off in the guest. > > This is why I said you should not do host debugging if you want to do > guest debugging at the sametime, as a work around for now. As I said before, forget host debugging! In fact, here is the exact text I sent to you on Friday, which you don't appear to have read, in which I said exactly the same thing: On Fri, 2008-06-06 at 14:27 -0500, Hollis Blanchard wrote: > On Fri, 2008-06-06 at 14:11 -0500, Jerone Young wrote: > > That is an issue if you are using the IAC registers in the host > also > at the same time. > > That is a totally separate issue. Imagine this in the host: > > 0xc0001000 load_guest_debug_registers: > MSR[DE] = 0 > IAC[0] = 0xc0001080 > ... > 0xc0001080 > ... > enter guest > > IAC1 matched. Now what happens? Please think about this scenario. > I can clear the dbsr registers also when disabling the debug interrupts > as a solution? I think you're on the right track, but what you propose here simply won't affect the above scenario. -- Hollis Blanchard IBM Linux Technology Center -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
