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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 DC670C43382 for ; Wed, 26 Sep 2018 17:03:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A014521533 for ; Wed, 26 Sep 2018 17:03:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A014521533 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728841AbeIZXRL (ORCPT ); Wed, 26 Sep 2018 19:17:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34948 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728645AbeIZXRK (ORCPT ); Wed, 26 Sep 2018 19:17:10 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6FF3130001E2; Wed, 26 Sep 2018 17:03:17 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.43.2.217]) by smtp.corp.redhat.com (Postfix) with ESMTP id DB0A660BE7; Wed, 26 Sep 2018 17:03:14 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Roman Kagan , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , "Michael Kelley (EOSG)" , Mohammed Gamal , Cathy Avery , Wanpeng Li , linux-kernel@vger.kernel.org Subject: [PATCH v6 4/7] KVM: x86: hyperv: keep track of mismatched VP indexes Date: Wed, 26 Sep 2018 19:02:56 +0200 Message-Id: <20180926170259.29796-5-vkuznets@redhat.com> In-Reply-To: <20180926170259.29796-1-vkuznets@redhat.com> References: <20180926170259.29796-1-vkuznets@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Wed, 26 Sep 2018 17:03:17 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In most common cases VP index of a vcpu matches its vcpu index. Userspace is, however, free to set any mapping it wishes and we need to account for that when we need to find a vCPU with a particular VP index. To keep search algorithms optimal in both cases introduce 'num_mismatched_vp_indexes' counter showing how many vCPUs with mismatching VP index we have. In case the counter is zero we can assume vp_index == vcpu_idx. Signed-off-by: Vitaly Kuznetsov --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/hyperv.c | 26 +++++++++++++++++++++++--- 2 files changed, 26 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 09b2e3e2cf1b..711f79f1b5e6 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -781,6 +781,9 @@ struct kvm_hv { u64 hv_reenlightenment_control; u64 hv_tsc_emulation_control; u64 hv_tsc_emulation_status; + + /* How many vCPUs have VP index != vCPU index */ + atomic_t num_mismatched_vp_indexes; }; enum kvm_irqchip_mode { diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index c8764faf783b..6a19c8e3c432 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1045,11 +1045,31 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host) struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv; switch (msr) { - case HV_X64_MSR_VP_INDEX: - if (!host || (u32)data >= KVM_MAX_VCPUS) + case HV_X64_MSR_VP_INDEX: { + struct kvm_hv *hv = &vcpu->kvm->arch.hyperv; + int vcpu_idx = kvm_vcpu_get_idx(vcpu); + u32 new_vp_index = (u32)data; + + if (!host || new_vp_index >= KVM_MAX_VCPUS) return 1; - hv_vcpu->vp_index = (u32)data; + + if (new_vp_index == hv_vcpu->vp_index) + return 0; + + /* + * VP index is changing, increment num_mismatched_vp_indexes in + * case it was equal to vcpu_idx before; on the other hand, if + * the new VP index matches vcpu_idx num_mismatched_vp_indexes + * needs to be decremented. + */ + if (hv_vcpu->vp_index == vcpu_idx) + atomic_inc(&hv->num_mismatched_vp_indexes); + else if (new_vp_index == vcpu_idx) + atomic_dec(&hv->num_mismatched_vp_indexes); + + hv_vcpu->vp_index = new_vp_index; break; + } case HV_X64_MSR_VP_ASSIST_PAGE: { u64 gfn; unsigned long addr; -- 2.17.1