Messages in this thread | | | Subject | Re: [PATCH 4/7] KVM: nVMX: move inject_page_fault tweak to .complete_mmu_init | From | Paolo Bonzini <> | Date | Wed, 17 Feb 2021 18:37:25 +0100 |
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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.
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?
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
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