> -----邮件原件----- > 发件人: Paolo Bonzini <pbonzini@xxxxxxxxxx> > 发送时间: 2021年10月19日 15:29 > 收件人: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>; Li,Rongqing > <lirongqing@xxxxxxxxx> > 抄送: seanjc@xxxxxxxxxx; wanpengli@xxxxxxxxxxx; jmattson@xxxxxxxxxx; > joro@xxxxxxxxxx; tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; bp@xxxxxxxxx; > x86@xxxxxxxxxx; hpa@xxxxxxxxx; kvm@xxxxxxxxxxxxxxx > 主题: Re: [PATCH] KVM: Clear pv eoi pending bit only when it is set > > On 19/10/21 09:23, Vitaly Kuznetsov wrote: > >> > >> -static void pv_eoi_clr_pending(struct kvm_vcpu *vcpu) > >> +static void pv_eoi_clr_pending(struct kvm_vcpu *vcpu, bool pending) > > Nitpick (and probably a matter of personal taste): > > pv_eoi_clr_pending() has only one user and the change doesn't make its > > interface much nicer, I'd suggest we just inline in instead. (we can > > probably do the same to > > pv_eoi_get_pending()/pv_eoi_set_pending() too). > > Alternatively, merge pv_eoi_get_pending and pv_eoi_clr_pending into a single > function pv_eoi_test_and_clear_pending, which returns the value of the > pending bit. > > So the caller can do essentially: > > - pending = pv_eoi_get_pending(vcpu); > - pv_eoi_clr_pending(vcpu); > - if (pending) > + if (pv_eoi_test_and_clear_pending(vcpu)) > return; > > It is better to implement pv_eoi_test_and_clear_pending(), and it can fix the race that Vitaly suggested And I will write a new function kvm_test_and_clear_bit_guest_cached, to be called in pv_eoi_test_and_clear_pending Bool kvm_test_and_clear_bit_guest_cached（struct kvm_vcpu *vcpu， struct gfn_to_hva_cache * ghc， long nr） -Li > Paolo
