Re: [PATCH v2 2/3] KVM: TDX: Fix the exit reason handling

[Xiaoyao Li]

On 8/11/2026 11:20 PM, Edgecombe, Rick P wrote:
> On Tue, 2026-08-11 at 09:32 +0800, Xiaoyao Li wrote:
> > > We could make this return instead be a goto err; that returns this. Bonus is
> > > the
> > > comment on the other one can cover them both. What do you think?
> >
> > Given 1) this patch is here mainly to avoid the false-positive on
> > bus_lock_detected after the next patch,
>
> Hmm. Before this patch these are just one line returns. So a "goto err" would be
> unneeded. After this single line is expanded to be something more elaborate, and
> a comment is added around one of these more elaborate returns, but not the
> other. So I consider it a bit of a style regression. Which makes it appropriate
> to adjust it in the patch IMO.

Well, actually the added comment cannot be shared. For the 
EXIT_REASON_EPT_MISCONFIG case, the reason to return a synthesized 
invalid Exit Reason is to differentiate with the case of 
TDVMCALL(ept_violation), where the exit reason is updated to EPT_MISCONFIG.

In fact, we don't need such trick for real EPT_MISCONFIG, because there 
is handling for real EPT_MISCONFIG in tdx_handle_exit()

	if (unlikely(vp_enter_ret == EXIT_REASON_EPT_MISCONFIG)) {
		KVM_BUG_ON(1, vcpu->kvm);
		return -EIO;
	}

before the handling of transformed EPT_MISCONFIG from 
TDVMCALL(ept_violation)

	switch (exit_reason.basic) {
	...
	case EXIT_REASON_EPT_MISCONFIG:
		return tdx_emulate_mmio(vcpu);

But it's not urgent to fix it and it's not mandatory to enable Bus Lock 
VM exit on TDX. Let's leave it to the follow-up series.