Re: [PATCH v4 3/6] KVM: selftests: Introduce UCALL_UNHANDLED for unhandled vector reporting

[Ricardo Koller <ricarkol@google.com>]

On Thu, Jul 29, 2021 at 06:15:27PM +0000, Sean Christopherson wrote:
> On Thu, Jun 10, 2021, Ricardo Koller wrote:
> > diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> > index fcd8e3855111..beb76d6deaa9 100644
> > --- a/tools/testing/selftests/kvm/include/kvm_util.h
> > +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> > @@ -349,6 +349,7 @@ enum {
> >  	UCALL_SYNC,
> >  	UCALL_ABORT,
> >  	UCALL_DONE,
> > +	UCALL_UNHANDLED,
> >  };
> 
> ...
> 
> > @@ -1254,16 +1254,13 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
> >  
> >  void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid)
> >  {
> > -	if (vcpu_state(vm, vcpuid)->exit_reason == KVM_EXIT_IO
> > -		&& vcpu_state(vm, vcpuid)->io.port == UNEXPECTED_VECTOR_PORT
> > -		&& vcpu_state(vm, vcpuid)->io.size == 4) {
> > -		/* Grab pointer to io data */
> > -		uint32_t *data = (void *)vcpu_state(vm, vcpuid)
> > -			+ vcpu_state(vm, vcpuid)->io.data_offset;
> > -
> > -		TEST_ASSERT(false,
> > -			    "Unexpected vectored event in guest (vector:0x%x)",
> > -			    *data);
> > +	struct ucall uc;
> > +
> > +	if (get_ucall(vm, vcpuid, &uc) == UCALL_UNHANDLED) {
> 
> UCALL_UNHANDLED is a bit of an odd name.  Without the surrounding context, I would
> have no idea that it's referring to an unhandled event, e.g. my gut reaction would
> be that it means the ucall itself was unhandled. Maybe UCALL_UNHANDLED_EVENT?

I see. I can send a new patch (this was commited as 75275d7fbe) with a
new name. The only name I can think of that's more descriptive would be
UCALL_UNHANDLED_EXCEPTION, but that's even longer.

> It's rather long, but I don't think that will be problematic for any of the code.
> 
> 
> > +		uint64_t vector = uc.args[0];
> > +
> > +		TEST_FAIL("Unexpected vectored event in guest (vector:0x%lx)",
> > +			  vector);
> >  	}
> >  }
> >  
> > -- 
> > 2.32.0.272.g935e593368-goog
> >