From patchwork Wed Jun 9 15:09:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 12310431 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 099D9C48BCD for ; Wed, 9 Jun 2021 15:09:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4303613BF for ; Wed, 9 Jun 2021 15:09:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238610AbhFIPLd (ORCPT ); Wed, 9 Jun 2021 11:11:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:21071 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235942AbhFIPL2 (ORCPT ); Wed, 9 Jun 2021 11:11:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623251369; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=124tuo5AwHCewOI3xtuEketWUcJ7rdZivpkSkrifopc=; b=fXqItI5cpz+oLvn0Z7hfY1tNBEAo7CZhNNVTNoNQKJTmvrhs8JZkGYJUx0n1RcpZrOpwOV zVyVwwKEWfdIddSTuJM6e6AJllsTPoEPjQCtOycVsDfmSTqQE5LPpQAO3mEozu5YZWAxqD cvzXxjxuJIZ1zvER6ackW/YrFJksIGY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-364-Ny_silFTNqK24--ImBdxnw-1; Wed, 09 Jun 2021 11:09:28 -0400 X-MC-Unique: Ny_silFTNqK24--ImBdxnw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3782F8030A0; Wed, 9 Jun 2021 15:09:27 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.40.194.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2E3C6620DE; Wed, 9 Jun 2021 15:09:25 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Maxim Levitsky , linux-kernel@vger.kernel.org Subject: [PATCH v3 4/4] KVM: x86: hyper-v: Deactivate APICv only when AutoEOI feature is in use Date: Wed, 9 Jun 2021 17:09:11 +0200 Message-Id: <20210609150911.1471882-5-vkuznets@redhat.com> In-Reply-To: <20210609150911.1471882-1-vkuznets@redhat.com> References: <20210609150911.1471882-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org APICV_INHIBIT_REASON_HYPERV is currently unconditionally forced upon SynIC activation as SynIC's AutoEOI is incompatible with APICv/AVIC. It is, however, possible to track whether the feature was actually used by the guest and only inhibit APICv/AVIC when needed. TLFS suggests a dedicated 'HV_DEPRECATING_AEOI_RECOMMENDED' flag to let Windows know that AutoEOI feature should be avoided. While it's up to KVM userspace to set the flag, KVM can help a bit by exposing global APICv/AVIC enablement: in case APICv/AVIC usage is impossible, AutoEOI is still preferred. Signed-off-by: Vitaly Kuznetsov --- arch/x86/include/asm/kvm_host.h | 7 +++++ arch/x86/kvm/hyperv.c | 51 +++++++++++++++++++++++++++++---- 2 files changed, 52 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index ed4e2aae13d1..01ee8f29d6e3 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -91,6 +91,8 @@ #define KVM_REQ_MSR_FILTER_CHANGED KVM_ARCH_REQ(29) #define KVM_REQ_UPDATE_CPU_DIRTY_LOGGING \ KVM_ARCH_REQ_FLAGS(30, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) +#define KVM_REQ_APICV_INPROGRESS \ + KVM_ARCH_REQ_FLAGS(31, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define CR0_RESERVED_BITS \ (~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \ @@ -936,8 +938,13 @@ struct kvm_hv { /* How many vCPUs have VP index != vCPU index */ atomic_t num_mismatched_vp_indexes; + /* How many SynICs use 'AutoEOI' feature */ + atomic_t synic_auto_eoi_used; + struct hv_partition_assist_pg *hv_pa_pg; struct kvm_hv_syndbg hv_syndbg; + + struct work_struct apic_update_work; }; struct msr_bitmap_range { diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index f00830e5202f..08cfc9ec1ef2 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -84,9 +84,32 @@ static bool synic_has_vector_auto_eoi(struct kvm_vcpu_hv_synic *synic, return false; } +static void hv_apicv_update_work(struct work_struct *work) +{ + struct kvm_hv *hv = container_of(work, struct kvm_hv, + apic_update_work); + struct kvm_arch *ka = container_of(hv, struct kvm_arch, + hyperv); + struct kvm *kvm = container_of(ka, struct kvm, arch); + struct kvm_vcpu *vcpu; + int i; + + mutex_lock(&kvm->lock); + kvm_request_apicv_update(kvm, atomic_read(&hv->synic_auto_eoi_used) == 0, + APICV_INHIBIT_REASON_HYPERV); + kvm_for_each_vcpu(i, vcpu, kvm) + kvm_clear_request(KVM_REQ_APICV_INPROGRESS, vcpu); + mutex_unlock(&kvm->lock); +} + static void synic_update_vector(struct kvm_vcpu_hv_synic *synic, int vector) { + struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic); + struct kvm_hv *hv = to_kvm_hv(vcpu->kvm); + int auto_eoi_old, auto_eoi_new; + bool apicv_update_needed = false; + if (vector < HV_SYNIC_FIRST_VALID_VECTOR) return; @@ -95,10 +118,28 @@ static void synic_update_vector(struct kvm_vcpu_hv_synic *synic, else __clear_bit(vector, synic->vec_bitmap); + auto_eoi_old = bitmap_weight(synic->auto_eoi_bitmap, 256); + if (synic_has_vector_auto_eoi(synic, vector)) __set_bit(vector, synic->auto_eoi_bitmap); else __clear_bit(vector, synic->auto_eoi_bitmap); + + auto_eoi_new = bitmap_weight(synic->auto_eoi_bitmap, 256); + + /* Hyper-V SynIC auto EOI SINTs are not compatible with APICv */ + if (!auto_eoi_old && auto_eoi_new) { + if (atomic_inc_return(&hv->synic_auto_eoi_used) == 1) + apicv_update_needed = true; + } else if (!auto_eoi_new && auto_eoi_old) { + if (atomic_dec_return(&hv->synic_auto_eoi_used) == 0) + apicv_update_needed = true; + } + + if (apicv_update_needed) { + kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_APICV_INPROGRESS); + schedule_work(&hv->apic_update_work); + } } static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint, @@ -931,12 +972,6 @@ int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages) synic = to_hv_synic(vcpu); - /* - * Hyper-V SynIC auto EOI SINT's are - * not compatible with APICV, so request - * to deactivate APICV permanently. - */ - kvm_request_apicv_update(vcpu->kvm, false, APICV_INHIBIT_REASON_HYPERV); synic->active = true; synic->dont_zero_synic_pages = dont_zero_synic_pages; synic->control = HV_SYNIC_CONTROL_ENABLE; @@ -2041,6 +2076,7 @@ void kvm_hv_init_vm(struct kvm *kvm) mutex_init(&hv->hv_lock); idr_init(&hv->conn_to_evt); + INIT_WORK(&hv->apic_update_work, hv_apicv_update_work); } void kvm_hv_destroy_vm(struct kvm *kvm) @@ -2052,6 +2088,7 @@ void kvm_hv_destroy_vm(struct kvm *kvm) idr_for_each_entry(&hv->conn_to_evt, eventfd, i) eventfd_ctx_put(eventfd); idr_destroy(&hv->conn_to_evt); + cancel_work_sync(&hv->apic_update_work); } static int kvm_hv_eventfd_assign(struct kvm *kvm, u32 conn_id, int fd) @@ -2206,6 +2243,8 @@ int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, ent->eax |= HV_X64_ENLIGHTENED_VMCS_RECOMMENDED; if (!cpu_smt_possible()) ent->eax |= HV_X64_NO_NONARCH_CORESHARING; + if (enable_apicv) + ent->eax |= HV_DEPRECATING_AEOI_RECOMMENDED; /* * Default number of spinlock retry attempts, matches * HyperV 2016.