First of all, Paolo, thanks a lot for your review on this series, it really means a lot!:) > -----Original Message----- > From: linux-kernel-owner@xxxxxxxxxxxxxxx > [mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of Paolo Bonzini > Sent: Friday, September 11, 2015 7:21 PM > To: Wu, Feng; alex.williamson@xxxxxxxxxx; joro@xxxxxxxxxx; > mtosatti@xxxxxxxxxx > Cc: eric.auger@xxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v7 15/17] KVM: Update Posted-Interrupts Descriptor when > vCPU is blocked > > > > On 25/08/2015 10:50, Feng Wu wrote: > > This patch updates the Posted-Interrupts Descriptor when vCPU > > is blocked. > > > > pre-block: > > - Add the vCPU to the blocked per-CPU list > > - Set 'NV' to POSTED_INTR_WAKEUP_VECTOR > > > > post-block: > > - Remove the vCPU from the per-CPU list > > > > Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> > > --- > > arch/x86/include/asm/kvm_host.h | 5 ++ > > arch/x86/kvm/vmx.c | 151 > ++++++++++++++++++++++++++++++++++++++++ > > arch/x86/kvm/x86.c | 55 ++++++++++++--- > > include/linux/kvm_host.h | 3 + > > virt/kvm/kvm_main.c | 3 + > > 5 files changed, 207 insertions(+), 10 deletions(-) > > > > diff --git a/arch/x86/include/asm/kvm_host.h > b/arch/x86/include/asm/kvm_host.h > > index 22269b4..32af275 100644 > > --- a/arch/x86/include/asm/kvm_host.h > > +++ b/arch/x86/include/asm/kvm_host.h > > @@ -554,6 +554,8 @@ struct kvm_vcpu_arch { > > */ > > bool write_fault_to_shadow_pgtable; > > > > + bool halted; > > + > > /* set at EPT violation at this point */ > > unsigned long exit_qualification; > > > > @@ -868,6 +870,9 @@ struct kvm_x86_ops { > > > > void (*pi_clear_sn)(struct kvm_vcpu *vcpu); > > void (*pi_set_sn)(struct kvm_vcpu *vcpu); > > + > > + int (*pi_pre_block)(struct kvm_vcpu *vcpu); > > + void (*pi_post_block)(struct kvm_vcpu *vcpu); > > Just pre_block/post_block please. Also, please document the return > value of pre_block. > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index ef93fdc..fc7f222 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -5869,7 +5869,13 @@ int kvm_vcpu_halt(struct kvm_vcpu *vcpu) > > { > > ++vcpu->stat.halt_exits; > > if (irqchip_in_kernel(vcpu->kvm)) { > > - vcpu->arch.mp_state = KVM_MP_STATE_HALTED; > > + /* Handle posted-interrupt when vCPU is to be halted */ > > + if (!kvm_x86_ops->pi_pre_block || > > + (kvm_x86_ops->pi_pre_block && > > No need to test kvm_x86_ops->pi_pre_block again. > > > + kvm_x86_ops->pi_pre_block(vcpu) == 0)) { > > + vcpu->arch.halted = true; > > + vcpu->arch.mp_state = KVM_MP_STATE_HALTED; > > + } > > return 1; > > } else { > > vcpu->run->exit_reason = KVM_EXIT_HLT; > > @@ -6518,6 +6524,21 @@ static int vcpu_enter_guest(struct kvm_vcpu > *vcpu) > > kvm_vcpu_reload_apic_access_page(vcpu); > > } > > > > + /* > > + * Since posted-interrupts can be set by VT-d HW now, in this > > + * case, KVM_REQ_EVENT is not set. We move the following > > + * operations out of the if statement. > > + */ > > Just "KVM_REQ_EVENT is not set when posted interrupts are set by VT-d > hardware, so we have to update RVI unconditionally", please. > > Could we skip this (in a future patch) if PI.ON=0? Do you mean only executing the following code when PI.ON == 1? Maybe we cannot do that, since 'ON' can be cleared by hypervisor in lots of places. > > > + if (kvm_lapic_enabled(vcpu)) { > > + /* > > + * Update architecture specific hints for APIC > > + * virtual interrupt delivery. > > + */ > > + if (kvm_x86_ops->hwapic_irr_update) > > + kvm_x86_ops->hwapic_irr_update(vcpu, > > + kvm_lapic_find_highest_irr(vcpu)); > > + } > > + > > if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) { > > kvm_apic_accept_events(vcpu); > > if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) { > > @@ -6534,13 +6555,6 @@ static int vcpu_enter_guest(struct kvm_vcpu > *vcpu) > > kvm_x86_ops->enable_irq_window(vcpu); > > > > if (kvm_lapic_enabled(vcpu)) { > > - /* > > - * Update architecture specific hints for APIC > > - * virtual interrupt delivery. > > - */ > > - if (kvm_x86_ops->hwapic_irr_update) > > - kvm_x86_ops->hwapic_irr_update(vcpu, > > - kvm_lapic_find_highest_irr(vcpu)); > > update_cr8_intercept(vcpu); > > kvm_lapic_sync_to_vapic(vcpu); > > } > > @@ -6711,10 +6725,31 @@ static int vcpu_run(struct kvm_vcpu *vcpu) > > > > for (;;) { > > if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE && > > - !vcpu->arch.apf.halted) > > + !vcpu->arch.apf.halted) { > > + /* > > + * For some cases, we can get here with > > + * vcpu->arch.halted being true. > > + */ > > Which cases? See the following scenario: vcpu_run() { ...... vcpu_enter_guest() --> VM_EXIT -> kvm_vcpu_halt() --> vcpu->arch.halted = true; ........ kvm_check_async_pf_completion() --> ...... --> kvm_arch_async_page_present(), in which it set vcpu->arch.apf.halted to false and vcpu->arch.mp_state to KVM_MP_STATE_RUNNABLE, then next time we re-enter the for (;;) loop, it will end up vcpu->arch.halted being true } Thanks, Feng > > Paolo > > > + if (kvm_x86_ops->pi_post_block && vcpu->arch.halted) { > > + kvm_x86_ops->pi_post_block(vcpu); > > + vcpu->arch.halted = false; > > + } > > + > > r = vcpu_enter_guest(vcpu); > > - else > > + } else { > > r = vcpu_block(kvm, vcpu); > > + > > + /* > > + * pi_post_block() must be called after > > + * pi_pre_block() which is called in > > + * kvm_vcpu_halt(). > > + */ > > + if (kvm_x86_ops->pi_post_block && vcpu->arch.halted) { > > + kvm_x86_ops->pi_post_block(vcpu); > > + vcpu->arch.halted = false; > > + } > > + } > > + > > if (r <= 0) > > break; > > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > index f4005dc..6aa69f4 100644 > > --- a/include/linux/kvm_host.h > > +++ b/include/linux/kvm_host.h > > @@ -233,6 +233,9 @@ struct kvm_vcpu { > > unsigned long requests; > > unsigned long guest_debug; > > > > + int pre_pcpu; > > + struct list_head blocked_vcpu_list; > > + > > struct mutex mutex; > > struct kvm_run *run; > > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > index 8b8a444..191c7eb 100644 > > --- a/virt/kvm/kvm_main.c > > +++ b/virt/kvm/kvm_main.c > > @@ -220,6 +220,9 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm > *kvm, unsigned id) > > init_waitqueue_head(&vcpu->wq); > > kvm_async_pf_vcpu_init(vcpu); > > > > + vcpu->pre_pcpu = -1; > > + INIT_LIST_HEAD(&vcpu->blocked_vcpu_list); > > + > > page = alloc_page(GFP_KERNEL | __GFP_ZERO); > > if (!page) { > > r = -ENOMEM; > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
