From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH] KVM: Optimize kvm_arch_vcpu_ioctl_run function References: <20200413034523.110548-1-tianjia.zhang@linux.alibaba.com> <17097df45c7fe76ee3c09ac180b844d2@kernel.org> From: Tianjia Zhang Message-ID: Date: Mon, 13 Apr 2020 17:07:28 +0800 MIME-Version: 1.0 In-Reply-To: <17097df45c7fe76ee3c09ac180b844d2@kernel.org> Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: To: Marc Zyngier Cc: pbonzini@redhat.com, sean.j.christopherson@intel.com, vkuznets@redhat.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, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org On 2020/4/13 16:56, Marc Zyngier wrote: > Tianjia, > > On 2020-04-13 04:45, Tianjia Zhang wrote: >> 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; >>              ++vcpu->stat.signal_exits; >>          } >>          goto out; >>      } >> >> -    if (vcpu->run->kvm_valid_regs & ~KVM_SYNC_X86_VALID_FIELDS) { >> +    if (kvm_run->kvm_valid_regs & ~KVM_SYNC_X86_VALID_FIELDS) { >>          r = -EINVAL; >>          goto out; >>      } >> >> -    if (vcpu->run->kvm_dirty_regs) { >> +    if (kvm_run->kvm_dirty_regs) { >>          r = sync_regs(vcpu); >>          if (r != 0) >>              goto out; >> @@ -8767,7 +8767,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu >> *vcpu, struct kvm_run *kvm_run) >> >>  out: >>      kvm_put_guest_fpu(vcpu); >> -    if (vcpu->run->kvm_valid_regs) >> +    if (kvm_run->kvm_valid_regs) >>          store_regs(vcpu); >>      post_kvm_run_save(vcpu); >>      kvm_sigset_deactivate(vcpu); >> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c >> index 48d0ec44ad77..ab9d7966a4c8 100644 >> --- a/virt/kvm/arm/arm.c >> +++ b/virt/kvm/arm/arm.c >> @@ -659,7 +659,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, >> struct kvm_run *run) >>          return ret; >> >>      if (run->exit_reason == KVM_EXIT_MMIO) { >> -        ret = kvm_handle_mmio_return(vcpu, vcpu->run); >> +        ret = kvm_handle_mmio_return(vcpu, run); >>          if (ret) >>              return ret; >>      } > > Do you have any number supporting the idea that you are optimizing anything > here? Performance, code size, register pressure or any other relevant > metric? > > Thanks, > >         M. This is only a simplified implementation of the function, the impact on performance and register pressure can be ignored. Thanks, Tianjia