From patchwork Tue Jun 8 12:08:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 12306649 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 D04D7C4743E for ; Tue, 8 Jun 2021 12:15:34 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8411161246 for ; Tue, 8 Jun 2021 12:15:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8411161246 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47386 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lqadp-00013g-O4 for qemu-devel@archiver.kernel.org; Tue, 08 Jun 2021 08:15:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55294) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lqaXH-0000bn-5O for qemu-devel@nongnu.org; Tue, 08 Jun 2021 08:08:47 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:23460) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lqaXF-0001r9-FH for qemu-devel@nongnu.org; Tue, 08 Jun 2021 08:08:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623154124; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=51CXz5zudz8r6+Ysqa9Ng1IA4d6iN7C68KcoxRlBQyg=; b=Jy4MpThRNtFaQiBNlfnJaiH1r8Vt7BE5fuGWlpY/f+DWU70s6Oa9dx1IfWyzvbNqF4YBzf DhyQb8Hatl4Tm40Uux1udQ/Ue/gy/FiUgle8lE4HiriAXPxQFPODoh9uiIQR4ZMfnZT506 aewsHncDxhy18rMnzVUZrThBxaUH5AM= 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-192-UOz97iokM-ap819Q1Fjd2Q-1; Tue, 08 Jun 2021 08:08:43 -0400 X-MC-Unique: UOz97iokM-ap819Q1Fjd2Q-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 ED4C7BBEE1; Tue, 8 Jun 2021 12:08:42 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.40.194.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id B23465B826; Tue, 8 Jun 2021 12:08:37 +0000 (UTC) From: Vitaly Kuznetsov To: qemu-devel@nongnu.org, Eduardo Habkost Subject: [PATCH v8 7/9] i386: HV_HYPERCALL_AVAILABLE privilege bit is always needed Date: Tue, 8 Jun 2021 14:08:15 +0200 Message-Id: <20210608120817.1325125-8-vkuznets@redhat.com> In-Reply-To: <20210608120817.1325125-1-vkuznets@redhat.com> References: <20210608120817.1325125-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=vkuznets@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=vkuznets@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.197, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Marcelo Tosatti , "Michael S. Tsirkin" , Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" According to TLFS, Hyper-V guest is supposed to check HV_HYPERCALL_AVAILABLE privilege bit before accessing HV_X64_MSR_GUEST_OS_ID/HV_X64_MSR_HYPERCALL MSRs but at least some Windows versions ignore that. As KVM is very permissive and allows accessing these MSRs unconditionally, no issue is observed. We may, however, want to tighten the checks eventually. Conforming to the spec is probably also a good idea. Enable HV_HYPERCALL_AVAILABLE bit unconditionally. Reviewed-by: Eduardo Habkost Signed-off-by: Vitaly Kuznetsov --- target/i386/kvm/kvm.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 1cce0969067e..33830117fa31 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -810,8 +810,6 @@ static struct { [HYPERV_FEAT_RELAXED] = { .desc = "relaxed timing (hv-relaxed)", .flags = { - {.func = HV_CPUID_FEATURES, .reg = R_EAX, - .bits = HV_HYPERCALL_AVAILABLE}, {.func = HV_CPUID_ENLIGHTMENT_INFO, .reg = R_EAX, .bits = HV_RELAXED_TIMING_RECOMMENDED} } @@ -820,7 +818,7 @@ static struct { .desc = "virtual APIC (hv-vapic)", .flags = { {.func = HV_CPUID_FEATURES, .reg = R_EAX, - .bits = HV_HYPERCALL_AVAILABLE | HV_APIC_ACCESS_AVAILABLE}, + .bits = HV_APIC_ACCESS_AVAILABLE}, {.func = HV_CPUID_ENLIGHTMENT_INFO, .reg = R_EAX, .bits = HV_APIC_ACCESS_RECOMMENDED} } @@ -829,8 +827,7 @@ static struct { .desc = "clocksources (hv-time)", .flags = { {.func = HV_CPUID_FEATURES, .reg = R_EAX, - .bits = HV_HYPERCALL_AVAILABLE | HV_TIME_REF_COUNT_AVAILABLE | - HV_REFERENCE_TSC_AVAILABLE} + .bits = HV_TIME_REF_COUNT_AVAILABLE | HV_REFERENCE_TSC_AVAILABLE} } }, [HYPERV_FEAT_CRASH] = { @@ -1343,6 +1340,9 @@ static int hyperv_fill_cpuids(CPUState *cs, c->ebx = hv_build_cpuid_leaf(cs, HV_CPUID_FEATURES, R_EBX); c->edx = hv_build_cpuid_leaf(cs, HV_CPUID_FEATURES, R_EDX); + /* Unconditionally required with any Hyper-V enlightenment */ + c->eax |= HV_HYPERCALL_AVAILABLE; + /* Not exposed by KVM but needed to make CPU hotplug in Windows work */ c->edx |= HV_CPU_DYNAMIC_PARTITIONING_AVAILABLE;