Re: [PATCH 5/8] KVM: SVM: Re-inject INT3/INTO instead of retrying the instruction

[Maciej S. Szmigiero]

> > > index 47e7427d0395..a770a1c7ddd2 100644
> > > --- a/arch/x86/kvm/svm/svm.h
> > > +++ b/arch/x86/kvm/svm/svm.h
> > > @@ -230,8 +230,8 @@ struct vcpu_svm {
> > >   	bool nmi_singlestep;
> > >   	u64 nmi_singlestep_guest_rflags;
> > >   
> > > -	unsigned int3_injected;
> > > -	unsigned long int3_rip;
> > > +	unsigned soft_int_injected;
> > > +	unsigned long soft_int_linear_rip;
> > >   
> > >   	/* optional nested SVM features that are enabled for this guest  */
> > >   	bool nrips_enabled                : 1;
> >
> >
> > I mostly agree with this patch, but think that it doesn't address the
> > original issue that Maciej wanted to address:
> >
> > Suppose that there is *no* instruction in L2 code which caused the software
> > exception, but rather L1 set arbitrary next_rip, and set EVENTINJ to software
> > exception with some vector, and that injection got interrupted.
> >
> > I don't think that this code will support this.
>
> Argh, you're right.  Maciej's selftest injects without an instruction, but it doesn't
> configure the scenario where that injection fails due to an exception+VM-Exit that
> isn't intercepted by L1 and is handled by L0.  The event_inj test gets the coverage
> for the latter, but always has a backing instruction.

Still reviewing the whole patch set, but want to clear this point quickly:
The selftest does have an implicit intervening NPF (handled by L0) while
injecting the first L1 -> L2 event.

Thanks,
Maciej