Paolo Bonzini <pbonzini@xxxxxxxxxx> writes: > On 25/07/2018 14:50, Vitaly Kuznetsov wrote: >>> >>> But is L0 allowed to write to hv_clean_fields? >> It is kinda expected to: currently I reset it in vmx_vcpu_run() and (if >> I remember correctly) L1 Hyper-V only clears bits in this mask when it >> touches certain fields so if we don't set it to 'all clean' it stays >> zeroed forever. > > Oh, good. I didn't understand it was bidirectional. > > So nothing stops us from doing >> >> if (hv_evmcs && vmx->nested.dirty_vmcs12) >> hv_evmcs->hv_clean_fields &= >> ~HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL; >> >> in prepare_vmcs02() I guess. > > In prepare_vmcs02, or rather in the enlightened VMPTRLD? > Doing it in nested_vmx_handle_enlightened_vmptrld() is even better: we can simplify copy_enlightened_to_vmcs12() too! The other place where we set dirty_vmcs12 is the newly introduced vmx_set_nested_state() but I think I'm going to add support for eVMCS there later and just return something like -ENOTSUPP for now. Too many people work on nested simultaneously :-) -- Vitaly
