Liran Alon <liran.alon@xxxxxxxxxx> writes: >> On 24 Jun 2019, at 16:30, Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> wrote: >> >> >> +bool nested_enlightened_vmentry(struct kvm_vcpu *vcpu, u64 *evmptr) > > I prefer to rename evmptr to evmcs_ptr. I think it’s more readable and sufficiently short. > In addition, I think you should return either -1ull or assist_page.current_nested_vmcs. > i.e. Don’t return evmcs_ptr by pointer but instead as a return-value > and get rid of the bool. Actually no, sorry, I'm having second thoughts here: in handle_vmclear() we don't care about the value of evmcs_ptr, we only want to check that enlightened vmentry bit is enabled in assist page. If we switch to checking evmcs_ptr against '-1', for example, we will make '-1' a magic value which is not in the TLFS. Windows may decide to use it for something else - and we will get a hard-to-debug bug again. If you still dislike nested_enlightened_vmentry() having the side effect of fetching evmcs_ptr I can get rid of it by splitting the function into two, however, it will be less efficient for nested_vmx_handle_enlightened_vmptrld(). Or we can just leave things as they are there and use the newly introduced function in handle_vmclear() only. -- Vitaly
