Re: [RFC PATCH v2 10/19] RISC-V: KVM: Handle WFI exits for VCPU

[Paolo Bonzini]

On 05/08/19 09:12, Anup Patel wrote:
> On Fri, Aug 2, 2019 at 2:33 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>>
>> On 02/08/19 09:47, Anup Patel wrote:
>>> +             if (!kvm_riscv_vcpu_has_interrupt(vcpu)) {
>>
>> This can be kvm_arch_vcpu_runnable instead, since kvm_vcpu_block will
>> check it anyway before sleeping.
> 
> I think we can skip this check here because kvm_vcpu_block() is
> checking it anyway. Agree ??

Yes, but it's quite a bit faster to do this outside the call.  There's a
bunch of setup before kvm_vcpu_block reaches that point, and it includes
mfences too once you add srcu_read_unlock/lock here.

Paolo