From mboxrd@z Thu Jan 1 00:00:00 1970 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=-16.1 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 05DC2C433ED for ; Tue, 18 May 2021 14:44:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D6A4660FF2 for ; Tue, 18 May 2021 14:44:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237943AbhEROpW (ORCPT ); Tue, 18 May 2021 10:45:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:38460 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237718AbhEROpU (ORCPT ); Tue, 18 May 2021 10:45:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621349041; 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=PK9785qy152K2v/cWuZE7z93ZB9DyVJp3ViNZm41hmE=; b=SJuJHx43vGIKyvHPruJy2hk8CPrUonCa+N4sZCw4hKwg/F/tCz8Nto2sQutzx3pnRunCM/ 8Pq/ESWtGeFK1GLW+s3tA655+SMMnqb5NoUXNgHX1+05fVUt3yl5Mz7mXjyNceTlxZY1he /UhkkUfV6Yi/BikU58uUj0pdFzxdZfo= 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-136-maPbbbHOMU2t64xYeg-I1A-1; Tue, 18 May 2021 10:44:00 -0400 X-MC-Unique: maPbbbHOMU2t64xYeg-I1A-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 D580B107ACF2; Tue, 18 May 2021 14:43:58 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.40.193.194]) by smtp.corp.redhat.com (Postfix) with ESMTP id DD9525B4B3; Tue, 18 May 2021 14:43:56 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Maxim Levitsky , Kechen Lu , linux-kernel@vger.kernel.org Subject: [PATCH v2 5/5] KVM: x86: hyper-v: Deactivate APICv only when AutoEOI feature is in use Date: Tue, 18 May 2021 16:43:39 +0200 Message-Id: <20210518144339.1987982-6-vkuznets@redhat.com> In-Reply-To: <20210518144339.1987982-1-vkuznets@redhat.com> References: <20210518144339.1987982-1-vkuznets@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 | 3 +++ arch/x86/kvm/hyperv.c | 27 +++++++++++++++++++++------ 2 files changed, 24 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index bf5807d35339..5e03ab4c0e4f 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -936,6 +936,9 @@ 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; }; diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index f98370a39936..89e7d5b99279 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -87,6 +87,10 @@ static bool synic_has_vector_auto_eoi(struct kvm_vcpu_hv_synic *synic, 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; + if (vector < HV_SYNIC_FIRST_VALID_VECTOR) return; @@ -95,10 +99,25 @@ 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) + kvm_request_apicv_update(vcpu->kvm, false, + APICV_INHIBIT_REASON_HYPERV); + } else if (!auto_eoi_new && auto_eoi_old) { + if (atomic_dec_return(&hv->synic_auto_eoi_used) == 0) + kvm_request_apicv_update(vcpu->kvm, true, + APICV_INHIBIT_REASON_HYPERV); + } } static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint, @@ -931,12 +950,6 @@ 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; @@ -2198,6 +2211,8 @@ 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. -- 2.31.1