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[91.219.240.2]) by smtp.gmail.com with ESMTPSA id e5sm23214697wru.92.2020.04.15.02.07.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2020 02:07:55 -0700 (PDT) From: Vitaly Kuznetsov To: Tianjia Zhang Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, pbonzini@redhat.com, sean.j.christopherson@intel.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, maz@kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com Subject: Re: [PATCH] KVM: Optimize kvm_arch_vcpu_ioctl_run function In-Reply-To: References: <20200413034523.110548-1-tianjia.zhang@linux.alibaba.com> <875ze2ywhy.fsf@vitty.brq.redhat.com> Date: Wed, 15 Apr 2020 11:07:53 +0200 Message-ID: <87a73dxgk6.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Tianjia Zhang writes: > On 2020/4/14 22:26, Vitaly Kuznetsov wrote: >> Tianjia Zhang writes: >> >>> kvm_arch_vcpu_ioctl_run() is only called in the file kvm_main.c, >>> where vcpu->run is the kvm_run parameter, so it has been replaced. >>> >>> Signed-off-by: Tianjia Zhang >>> --- >>> arch/x86/kvm/x86.c | 8 ++++---- >>> virt/kvm/arm/arm.c | 2 +- >>> 2 files changed, 5 insertions(+), 5 deletions(-) >>> >>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>> index 3bf2ecafd027..70e3f4abbd4d 100644 >>> --- a/arch/x86/kvm/x86.c >>> +++ b/arch/x86/kvm/x86.c >>> @@ -8726,18 +8726,18 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) >>> r = -EAGAIN; >>> if (signal_pending(current)) { >>> r = -EINTR; >>> - vcpu->run->exit_reason = KVM_EXIT_INTR; >>> + kvm_run->exit_reason = KVM_EXIT_INTR; >> >> I have a more generic question: why do we need to pass 'kvm_run' to >> kvm_arch_vcpu_ioctl_run() if it can be extracted from 'struct kvm_vcpu'? >> The only call site looks like >> >> virt/kvm/kvm_main.c: r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run); >> > > In the earlier version, kvm_run is used to pass parameters with user > mode and is not included in the vcpu structure, so it has been retained > until now. > In case this is no longer needed I'd suggest we drop 'kvm_run' parameter and extract it from 'struct kvm_vcpu' when needed. This looks like a natural add-on to your cleanup patch. -- Vitaly