On Mon, 2025-05-19 at 12:01 +0800, Yan Zhao wrote: > On Sat, May 17, 2025 at 06:11:59AM +0800, Edgecombe, Rick P wrote: > > On Fri, 2025-05-16 at 17:17 +0800, Yan Zhao wrote: > > > > Shouldn't this BUG_ON be handled in the split_external_spt implementation? I > > > > don't think we need another one. > > > Ok. But kvm_x86_split_external_spt() is not for TDX only. > > > Is it good for KVM MMU core to rely on each implementation to trigger BUG_ON? > > > > It effectively is for TDX only. At least for the foreseeable future. The naming > > basically means that people don't have to see "TDX" everywhere when they look in > > the MMU code. > Hmm, another reason to add the BUG_ON is to align it with remove_external_spte(). > There's also a KVM_BUG_ON() following the remove_external_spte hook. > > I interpret this as error handling in the KVM MMU core, which returns "void", > so issuing BUG_ON if ret != 0. This is related to the other thread about how to handle demote failure. Let's continue there. But in general, the amount of KVM_BUG_ON()s we have for mirror EPT is a bit of a code smell. It's not exclusive to this series. But I'd love if we could keep it from getting worse.
