Re: [PATCH] KVM: x86: remove duplicated KVM_REQ_EVENT request

From: Vitaly Kuznetsov
Date: Fri Feb 07 2020 - 04:05:40 EST


linmiaohe <linmiaohe@xxxxxxxxxx> writes:

> Hiï
> Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> writes:
>> linmiaohe <linmiaohe@xxxxxxxxxx> writes:
>>> From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>>>
>>> The KVM_REQ_EVENT request is already made in kvm_set_rflags(). We
>>> should not make it again.
>>> kvm_rip_write(vcpu, ctxt->eip);
>>> kvm_set_rflags(vcpu, ctxt->eflags);
>>> - kvm_make_request(KVM_REQ_EVENT, vcpu);
>>
>> I would've actually done it the other way around and removed
>> kvm_make_request() from kvm_set_rflags() as it is not an obvious behavior (e.g. why kvm_rip_write() doens't do that and kvm_set_rflags() does ?) adding kvm_make_request() to all call sites.
>>
>>In case this looks like too big of a change with no particular gain I'd suggest you at least leave a comment above kvm_set_rflags(), something like
>>
>>"kvm_make_request() also requests KVM_REQ_EVENT"
>
> I think adding kvm_make_request() to all call sites is too big without particular gain. And also leave a comment above
> kvm_set_rflags() maybe isn't needed as rflags updates is an site that can trigger event injection. Please see commit
> (3842d135ff24 KVM: Check for pending events before attempting injection) for detail.
>
> What do you think?

I don't have a strong opinion on this and your change is correct so feel
free to throw my

Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>


--
Vitaly