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Thu, 23 Apr 2020 02:39:11 -0700 (PDT) Received: from [192.168.10.150] ([93.56.170.5]) by smtp.gmail.com with ESMTPSA id j13sm3015373wrq.24.2020.04.23.02.39.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Apr 2020 02:39:10 -0700 (PDT) Subject: Re: [PATCH v2 4/5] KVM: X86: TSCDEADLINE MSR emulation fastpath To: Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Haiwei Li References: <1587632507-18997-1-git-send-email-wanpengli@tencent.com> <1587632507-18997-5-git-send-email-wanpengli@tencent.com> From: Paolo Bonzini Message-ID: <1309372a-0dcf-cba6-9d65-e50139bbe46b@redhat.com> Date: Thu, 23 Apr 2020 11:37:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <1587632507-18997-5-git-send-email-wanpengli@tencent.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 23/04/20 11:01, Wanpeng Li wrote: > + > +void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data) > +{ > + if (__kvm_set_lapic_tscdeadline_msr(vcpu, data)) > + start_apic_timer(vcpu->arch.apic); > +} > + > +int kvm_set_lapic_tscdeadline_msr_fast(struct kvm_vcpu *vcpu, u64 data) > +{ > + struct kvm_lapic *apic = vcpu->arch.apic; > + > + if (__kvm_set_lapic_tscdeadline_msr(vcpu, data)) { > + atomic_set(&apic->lapic_timer.pending, 0); > + if (start_hv_timer(apic)) > + return tscdeadline_expired_timer_fast(vcpu); > + } > + > + return 1; > } > > +static int tscdeadline_expired_timer_fast(struct kvm_vcpu *vcpu) > +{ > + if (kvm_check_request(KVM_REQ_PENDING_TIMER, vcpu)) { > + kvm_clear_request(KVM_REQ_PENDING_TIMER, vcpu); > + kvm_inject_apic_timer_irqs_fast(vcpu); > + atomic_set(&vcpu->arch.apic->lapic_timer.pending, 0); > + } > + > + return 0; > +} This could also be handled in apic_timer_expired. For example you can add an argument from_timer_fn and do if (!from_timer_fn) { WARN_ON(kvm_get_running_vcpu() != vcpu); kvm_inject_apic_timer_irqs_fast(vcpu); return; } if (kvm_use_posted_timer_interrupt(apic->vcpu)) { ... } atomic_inc(&apic->lapic_timer.pending); kvm_set_pending_timer(vcpu); and then you don't need kvm_set_lapic_tscdeadline_msr_fast and everything else. Anyway thanks, this is already much better. Paoo