Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758269AbcJRGEg (ORCPT ); Tue, 18 Oct 2016 02:04:36 -0400 Received: from mail-lf0-f67.google.com ([209.85.215.67]:33566 "EHLO mail-lf0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753805AbcJRGEb (ORCPT ); Tue, 18 Oct 2016 02:04:31 -0400 MIME-Version: 1.0 In-Reply-To: <1476469291-5039-3-git-send-email-pbonzini@redhat.com> References: <1476469291-5039-1-git-send-email-pbonzini@redhat.com> <1476469291-5039-3-git-send-email-pbonzini@redhat.com> From: Wanpeng Li Date: Tue, 18 Oct 2016 14:04:28 +0800 Message-ID: Subject: Re: [PATCH 2/5] KVM: x86: do not scan IRR twice on APICv vmentry To: Paolo Bonzini Cc: "linux-kernel@vger.kernel.org" , kvm , Radim Krcmar , Yang Zhang , feng.wu@intel.com, "Michael S. Tsirkin" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5562 Lines: 153 2016-10-15 2:21 GMT+08:00 Paolo Bonzini : > Calling apic_find_highest_irr results in IRR being scanned twice, > once in vmx_sync_pir_from_irr and once in apic_search_irr. Change s/from/to > sync_pir_from_irr to do the RVI write and kvm_apic_update_irr to > compute the new RVI on the fly. > > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/lapic.c | 25 +++++++++++++++++-------- > arch/x86/kvm/lapic.h | 4 ++-- > arch/x86/kvm/vmx.c | 24 +++++++++++++----------- > arch/x86/kvm/x86.c | 3 +-- > 4 files changed, 33 insertions(+), 23 deletions(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 63a442aefc12..a24492a88643 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -317,7 +317,7 @@ static int find_highest_vector(void *bitmap) > vec >= 0; vec -= APIC_VECTORS_PER_REG) { > reg = bitmap + REG_POS(vec); > if (*reg) > - return fls(*reg) - 1 + vec; > + return __fls(*reg) + vec; > } > > return -1; > @@ -337,27 +337,36 @@ static u8 count_vectors(void *bitmap) > return count; > } > > -void __kvm_apic_update_irr(u32 *pir, void *regs) > +int __kvm_apic_update_irr(u32 *pir, void *regs) > { > - u32 i, pir_val; > + u32 i, vec; > + u32 pir_val, irr_val; > + int max_irr = -1; > > - for (i = 0; i <= 7; i++) { > + for (i = vec = 0; i <= 7; i++, vec += 32) { > pir_val = READ_ONCE(pir[i]); > + irr_val = *((u32 *)(regs + APIC_IRR + i * 0x10)); > if (pir_val) { > - pir_val = xchg(&pir[i], 0); > - *((u32 *)(regs + APIC_IRR + i * 0x10)) |= pir_val; > + irr_val |= xchg(&pir[i], 0); > + *((u32 *)(regs + APIC_IRR + i * 0x10)) = irr_val; > } > + if (irr_val) > + max_irr = __fls(irr_val) + vec; > } > + > + return max_irr; > } > EXPORT_SYMBOL_GPL(__kvm_apic_update_irr); > > -void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir) > +int kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir) > { > struct kvm_lapic *apic = vcpu->arch.apic; > + int max_irr; > > - __kvm_apic_update_irr(pir, apic->regs); > + max_irr = __kvm_apic_update_irr(pir, apic->regs); > > kvm_make_request(KVM_REQ_EVENT, vcpu); > + return max_irr; > } > EXPORT_SYMBOL_GPL(kvm_apic_update_irr); > > diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h > index f60d01c29d51..fc72828c3782 100644 > --- a/arch/x86/kvm/lapic.h > +++ b/arch/x86/kvm/lapic.h > @@ -70,8 +70,8 @@ int kvm_lapic_reg_read(struct kvm_lapic *apic, u32 offset, int len, > bool kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source, > int short_hand, unsigned int dest, int dest_mode); > > -void __kvm_apic_update_irr(u32 *pir, void *regs); > -void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir); > +int __kvm_apic_update_irr(u32 *pir, void *regs); > +int kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir); > int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq, > struct dest_map *dest_map); > int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type); > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 7c79d6c6b6ed..c985ec8736d3 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -4856,17 +4856,6 @@ static void vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector) > kvm_vcpu_kick(vcpu); > } > > -static void vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu) > -{ > - struct vcpu_vmx *vmx = to_vmx(vcpu); > - > - if (!pi_test_on(&vmx->pi_desc)) > - return; > - > - pi_clear_on(&vmx->pi_desc); > - kvm_apic_update_irr(vcpu, vmx->pi_desc.pir); > -} > - > /* > * Set up the vmcs's constant host-state fields, i.e., host-state fields that > * will not change in the lifetime of the guest. > @@ -8613,6 +8602,19 @@ static void vmx_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr) > } > } > > +static void vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu) > +{ > + struct vcpu_vmx *vmx = to_vmx(vcpu); > + int max_irr; > + > + if (!pi_test_on(&vmx->pi_desc)) > + return; > + > + pi_clear_on(&vmx->pi_desc); > + max_irr = kvm_apic_update_irr(vcpu, vmx->pi_desc.pir); > + vmx_hwapic_irr_update(vcpu, max_irr); > +} > + > static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap) > { > if (!kvm_vcpu_apicv_active(vcpu)) > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 3ee8a91a78c3..3d29be9d9db4 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -6611,8 +6611,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) > * virtual interrupt delivery. > */ > if (vcpu->arch.apicv_active) > - kvm_x86_ops->hwapic_irr_update(vcpu, > - kvm_lapic_find_highest_irr(vcpu)); > + kvm_x86_ops->sync_pir_to_irr(vcpu); > } > > if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) { > -- > 1.8.3.1 > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html