From patchwork Thu Jul 22 12:15:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 12393947 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=-17.2 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 5627DC6377D for ; Thu, 22 Jul 2021 12:17:51 +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 038F46135B for ; Thu, 22 Jul 2021 12:17:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 038F46135B 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]:37280 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m6XeA-0006QW-5u for qemu-devel@archiver.kernel.org; Thu, 22 Jul 2021 08:17:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45794) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m6XcD-0003V3-9K for qemu-devel@nongnu.org; Thu, 22 Jul 2021 08:15:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:26948) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m6XcA-0001n6-KX for qemu-devel@nongnu.org; Thu, 22 Jul 2021 08:15:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626956146; 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=YaN20WxT9swZk3ctK7m51QwSlcHWzGaIIaqOlpuC7Wg=; b=inB/DsVYZx93z5tGz5SeRHcODAldTSk4qaYiuZ5itPIi6+Aw759ZRicJveegs22vbKGJH0 mrMNeWoYiTBZly6QbzXjAHmgoGB54oT+wDNZyoL0nZvdylVufXL1Cavp55uQAnnw/C67/N 0fKvybonQ7+FdtSxfBokfVyr3d5PBi8= 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-363-YeRHXkFjOPC8aG7d_krxVQ-1; Thu, 22 Jul 2021 08:15:44 -0400 X-MC-Unique: YeRHXkFjOPC8aG7d_krxVQ-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 EB165100855D for ; Thu, 22 Jul 2021 12:15:43 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.40.195.41]) by smtp.corp.redhat.com (Postfix) with ESMTP id E25905C22B; Thu, 22 Jul 2021 12:15:33 +0000 (UTC) From: Vitaly Kuznetsov To: qemu-devel@nongnu.org, Eduardo Habkost Subject: [PATCH 2/3] i386: Support KVM_CAP_ENFORCE_PV_FEATURE_CPUID Date: Thu, 22 Jul 2021 14:15:27 +0200 Message-Id: <20210722121528.258426-3-vkuznets@redhat.com> In-Reply-To: <20210722121528.258426-1-vkuznets@redhat.com> References: <20210722121528.258426-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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=216.205.24.124; envelope-from=vkuznets@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.472, 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 , Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" By default, KVM allows the guest to use all currently supported PV features even when they were not announced in guest visible CPUIDs. Introduce a new "kvm-pv-enforce-cpuid" flag to limit the supported feature set to the exposed features. The feature is supported by Linux >= 5.10 and is not enabled by default in QEMU. Signed-off-by: Vitaly Kuznetsov --- docs/kvm-pv.txt | 13 ++++++++++++- target/i386/cpu.c | 2 ++ target/i386/cpu.h | 3 +++ target/i386/kvm/kvm.c | 10 ++++++++++ 4 files changed, 27 insertions(+), 1 deletion(-) diff --git a/docs/kvm-pv.txt b/docs/kvm-pv.txt index 84ad7fa60f8d..d1aac533feea 100644 --- a/docs/kvm-pv.txt +++ b/docs/kvm-pv.txt @@ -87,6 +87,17 @@ the number of supported vCPUs for a given configuration lower). Tells the guest that guest visible TSC value can be fully trusted for kvmclock computations and no warps are expected. -4. Useful links +4. Supplementary features +========================= + +4.1. kvm-pv-enforce-cpuid +========================= +By default, KVM allows the guest to use all currently supported PV features even +when they were not announced in guest visible CPUIDs. 'kvm-pv-enforce-cpuid' +feature alters this behavior and limits the supported feature set to the +exposed features only. + + +5. Useful links ================ Please refer to Documentation/virt/kvm in Linux for additional detail. diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 48b55ebd0a67..0a0d2cddc9d2 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -6668,6 +6668,8 @@ static Property x86_cpu_properties[] = { DEFINE_PROP_BOOL("l3-cache", X86CPU, enable_l3_cache, true), DEFINE_PROP_BOOL("kvm-no-smi-migration", X86CPU, kvm_no_smi_migration, false), + DEFINE_PROP_BOOL("kvm-pv-enforce-cpuid", X86CPU, kvm_pv_enforce_cpuid, + false), DEFINE_PROP_BOOL("vmware-cpuid-freq", X86CPU, vmware_cpuid_freq, true), DEFINE_PROP_BOOL("tcg-cpuid", X86CPU, expose_tcg, true), DEFINE_PROP_BOOL("x-migrate-smi-count", X86CPU, migrate_smi_count, diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 5d98a4e7c025..31f1f7caf116 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1768,6 +1768,9 @@ struct X86CPU { /* Stop SMI delivery for migration compatibility with old machines */ bool kvm_no_smi_migration; + /* Forcefully disable KVM PV features not exposed in guest CPUIDs */ + bool kvm_pv_enforce_cpuid; + /* Number of physical address bits supported */ uint32_t phys_bits; diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 59ed8327ac13..452b04f469b5 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -1617,6 +1617,16 @@ int kvm_arch_init_vcpu(CPUState *cs) cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused); + if (cpu->kvm_pv_enforce_cpuid) { + r = kvm_vcpu_enable_cap(cs, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, 0, 1); + if (r < 0) { + fprintf(stderr, + "failed to enable KVM_CAP_ENFORCE_PV_FEATURE_CPUID: %s", + strerror(-r)); + abort(); + } + } + for (i = 0; i <= limit; i++) { if (cpuid_i == KVM_MAX_CPUID_ENTRIES) { fprintf(stderr, "unsupported level value: 0x%x\n", limit);