On Tue, 2014-06-17 at 11:25 +0200, Alexander Graf wrote: > On 17.06.14 11:22, Benjamin Herrenschmidt wrote: > > On Tue, 2014-06-17 at 10:54 +0200, Alexander Graf wrote: > >> Also, why don't we use twi always or something else that actually is > >> defined as illegal instruction? I would like to see this shared with > >> book3s_32 PR. > > twi will be directed to the guest on HV no ? We want a real illegal > > because those go to the host (for potential emulation by the HV). > > Ah, good point. I guess we need different one for PR and HV then to > ensure compatibility with older ISAs on PR. Well, we also need to be careful with what happens if a PR guest puts that instruction in, do that stop its HV guest/host ? What if it's done in userspace ? Do that stop the kernel ? :-) Maddy, I haven't checked, does your patch ensure that we only ever stop if the instruction is at a recorded bkpt address ? It still means that a userspace process can practically DOS its kernel by issuing a lot of these causing a crapload of exits. Cheers, Ben. > Alex > > > I'm > > trying to see if I can get the architect to set one in stone in a future > > proof way. > > > > Cheers, > > Ben. > > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
