On Wed, Feb 17, 2021, Paolo Bonzini wrote: > On 17/02/21 18:29, Sean Christopherson wrote: > > All that being said, I'm pretty we can eliminate setting > > inject_page_fault dynamically. I think that would yield more > > maintainable code. Following these flows is a nightmare. The change > > itself will be scarier, but I'm pretty sure the end result will be a lot > > cleaner. > > I had a similar reaction, though my proposal was different. > > The only thing we're changing in complete_mmu_init is the page fault > callback for init_kvm_softmmu, so couldn't that be the callback directly > (i.e. something like context->inject_page_fault = > kvm_x86_ops.inject_softmmu_page_fault)? And then adding is_guest_mode to > the conditional that is already in vmx_inject_page_fault_nested and > svm_inject_page_fault_nested. Heh, that exact code crossed my mind as well. > That said, I'm also rusty on _why_ this code is needed. Why isn't it enough > to inject the exception normally, and let nested_vmx_check_exception decide > whether to inject a vmexit to L1 or an exception into L2? Hmm, I suspect it was required at one point due to deficiencies elsewhere. Handling this in the common fault handler logic does seem like the right approach. > Also, bonus question which should have been in the 5/7 changelog: are there > kvm-unit-tests testcases that fail with npt=0, and if not could we write > one? [Answer: the mode_switch testcase fails, but I haven't checked why]. > > > Paolo >
