From patchwork Mon Mar 15 14:37:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 12139671 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 ABFC4C2BA1A for ; Mon, 15 Mar 2021 14:39:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84BC764E74 for ; Mon, 15 Mar 2021 14:39:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233374AbhCOOij (ORCPT ); Mon, 15 Mar 2021 10:38:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:39527 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239821AbhCOOhU (ORCPT ); Mon, 15 Mar 2021 10:37:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615819040; 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=twIrqfzsNtHvqJ7vSwQnUKzlQW5N7NMT68476wDhutM=; b=c1IvyNWorNEUEQhFDYjChroHv63Ekrd31vDJiP6/IaNATGPS0ttq8h42Nk/0DNg7qyjHZr 7qoLf1PcPviF0m5zdNJkGjwn9gKLSdg2Nk4pHIm1EnafEJLINAG4/1zqPEFD7tDUSvuoHl YbMnfV95nGor/UQ0WRXTTT6TeYeicpM= 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-427-n5mCGrdjOb-lBdbH3LQt-w-1; Mon, 15 Mar 2021 10:37:18 -0400 X-MC-Unique: n5mCGrdjOb-lBdbH3LQt-w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E6E21108BD08; Mon, 15 Mar 2021 14:37:16 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.40.195.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0D3E15C3E6; Mon, 15 Mar 2021 14:37:14 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Marcelo Tosatti Subject: [PATCH 3/4] KVM: x86: hyper-v: Track Hyper-V TSC page status Date: Mon, 15 Mar 2021 15:37:05 +0100 Message-Id: <20210315143706.859293-4-vkuznets@redhat.com> In-Reply-To: <20210315143706.859293-1-vkuznets@redhat.com> References: <20210315143706.859293-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Create an infrastructure for tracking Hyper-V TSC page status, i.e. if it was updated from guest/host side or if we've failed to set it up (because e.g. guest wrote some garbage to HV_X64_MSR_REFERENCE_TSC) and there's no need to retry. Also, in a hypothetical situation when we are in 'always catchup' mode for TSC we can now avoid contending 'hv->hv_lock' on every guest enter by setting the state to HV_TSC_PAGE_BROKEN after compute_tsc_page_parameters() returns false. Signed-off-by: Vitaly Kuznetsov --- arch/x86/include/asm/kvm_host.h | 9 +++++++++ arch/x86/kvm/hyperv.c | 23 +++++++++++++++++------ 2 files changed, 26 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 9bc091ecaaeb..87448e9e6b28 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -884,12 +884,21 @@ struct kvm_hv_syndbg { u64 options; }; +enum hv_tsc_page_status { + HV_TSC_PAGE_UNSET = 0, + HV_TSC_PAGE_GUEST_CHANGED, + HV_TSC_PAGE_HOST_CHANGED, + HV_TSC_PAGE_SET, + HV_TSC_PAGE_BROKEN, +}; + /* Hyper-V emulation context */ struct kvm_hv { struct mutex hv_lock; u64 hv_guest_os_id; u64 hv_hypercall; u64 hv_tsc_page; + enum hv_tsc_page_status hv_tsc_page_status; /* Hyper-v based guest crash (NT kernel bugcheck) parameters */ u64 hv_crash_param[HV_X64_MSR_CRASH_PARAMS]; diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index eefb85b86fe8..2a8d078b16cb 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1087,7 +1087,7 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, BUILD_BUG_ON(sizeof(tsc_seq) != sizeof(hv->tsc_ref.tsc_sequence)); BUILD_BUG_ON(offsetof(struct ms_hyperv_tsc_page, tsc_sequence) != 0); - if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE)) + if (hv->hv_tsc_page_status == HV_TSC_PAGE_BROKEN) return; mutex_lock(&hv->hv_lock); @@ -1101,7 +1101,7 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, */ if (unlikely(kvm_read_guest(kvm, gfn_to_gpa(gfn), &tsc_seq, sizeof(tsc_seq)))) - goto out_unlock; + goto out_err; /* * While we're computing and writing the parameters, force the @@ -1110,15 +1110,15 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, hv->tsc_ref.tsc_sequence = 0; if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence))) - goto out_unlock; + goto out_err; if (!compute_tsc_page_parameters(hv_clock, &hv->tsc_ref)) - goto out_unlock; + goto out_err; /* Ensure sequence is zero before writing the rest of the struct. */ smp_wmb(); if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref))) - goto out_unlock; + goto out_err; /* * Now switch to the TSC page mechanism by writing the sequence. @@ -1133,6 +1133,12 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm, hv->tsc_ref.tsc_sequence = tsc_seq; kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence)); + + hv->hv_tsc_page_status = HV_TSC_PAGE_SET; + goto out_unlock; + +out_err: + hv->hv_tsc_page_status = HV_TSC_PAGE_BROKEN; out_unlock: mutex_unlock(&hv->hv_lock); } @@ -1193,8 +1199,13 @@ static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data, } case HV_X64_MSR_REFERENCE_TSC: hv->hv_tsc_page = data; - if (hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) + if (hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) { + if (!host) + hv->hv_tsc_page_status = HV_TSC_PAGE_GUEST_CHANGED; + else + hv->hv_tsc_page_status = HV_TSC_PAGE_HOST_CHANGED; kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu); + } break; case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4: return kvm_hv_msr_set_crash_data(kvm,