Re: [PATCH v4 2/2] target/arm: kvm: Handle potential issue with dabt injection

[Peter Maydell]

On Fri, 3 Apr 2020 at 09:44, Andrew Jones <address@hidden> wrote:
>
> On Mon, Mar 23, 2020 at 11:32:27AM +0000, Beata Michalska wrote:
> > Injecting external data abort through KVM might trigger
> > an issue on kernels that do not get updated to include the KVM fix.
> > For those and aarch32 guests, the injected abort gets misconfigured
> > to be an implementation defined exception. This leads to the guest
> > repeatedly re-running the faulting instruction.
> >
> > Add support for handling that case.
> > [
> >   Fixed-by: 018f22f95e8a
> >       ('KVM: arm: Fix DFSR setting for non-LPAE aarch32 guests')
> >   Fixed-by: 21aecdbd7f3a
> >       ('KVM: arm: Make inject_abt32() inject an external abort instead')
> > ]
> >

> I'll leave the decision to take this KVM bug workaround patch at all to Peter,
> and I didn't actually review whether or not kvm_arm_verify_ext_dabt_pending
> is doing what it claims it's doing, so I'm reluctant to give an r-b on
> this patch. But, as far as the code goes, besides the comments above, it
> looks fine to me.

I think that having the workaround for the broken kernels is
reasonable (in fact it might have been my suggestion).

thanks
-- PMM