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

From: linmiaohe
Date: Thu Feb 06 2020 - 21:48:29 EST


Hi:
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? Thanks for your review anyway. :)