From patchwork Wed Sep 26 17:02:56 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 10616369 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9D5FF15A6 for ; Wed, 26 Sep 2018 17:03:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 868B620499 for ; Wed, 26 Sep 2018 17:03:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 79E1428537; Wed, 26 Sep 2018 17:03:24 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2014D284B9 for ; Wed, 26 Sep 2018 17:03:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728818AbeIZXRL (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?b?UmFkaW0gS3LEjW3DocWZ?= , 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: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 Reviewed-by: Roman Kagan --- 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;