Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66CDCC433EF for ; Thu, 25 Nov 2021 00:24:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344385AbhKYA2C (ORCPT ); Wed, 24 Nov 2021 19:28:02 -0500 Received: from mga14.intel.com ([192.55.52.115]:6415 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352856AbhKYAYV (ORCPT ); Wed, 24 Nov 2021 19:24:21 -0500 X-IronPort-AV: E=McAfee;i="6200,9189,10178"; a="235649693" X-IronPort-AV: E=Sophos;i="5.87,261,1631602800"; d="scan'208";a="235649693" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Nov 2021 16:21:10 -0800 X-IronPort-AV: E=Sophos;i="5.87,261,1631602800"; d="scan'208";a="675042182" Received: from ls.sc.intel.com (HELO localhost) ([143.183.96.54]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Nov 2021 16:21:10 -0800 From: isaku.yamahata@intel.com To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , erdemaktas@google.com, Connor Kuehl , Sean Christopherson , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Sean Christopherson Subject: [RFC PATCH v3 23/59] KVM: x86: Allow host-initiated WRMSR to set X2APIC regardless of CPUID Date: Wed, 24 Nov 2021 16:20:06 -0800 Message-Id: <63556f13e9608cbccf97d356be46a345772d76d3.1637799475.git.isaku.yamahata@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson Let userspace, or in the case of TDX, KVM itself, enable X2APIC even if X2APIC is not reported as supported in the guest's CPU model. KVM generally does not force specific ordering between ioctls(), e.g. this forces userspace to configure CPUID before MSRs. And for TDX, vCPUs will always run with X2APIC enabled, e.g. KVM will want/need to enable X2APIC from time zero. Signed-off-by: Sean Christopherson Signed-off-by: Isaku Yamahata --- arch/x86/kvm/x86.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f2b6a3f89e9e..0221ef691a15 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -466,8 +466,11 @@ int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { enum lapic_mode old_mode = kvm_get_apic_mode(vcpu); enum lapic_mode new_mode = kvm_apic_mode(msr_info->data); - u64 reserved_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu) | 0x2ff | - (guest_cpuid_has(vcpu, X86_FEATURE_X2APIC) ? 0 : X2APIC_ENABLE); + u64 reserved_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu) | 0x2ff; + + if (!msr_info->host_initiated && + !guest_cpuid_has(vcpu, X86_FEATURE_X2APIC)) + reserved_bits |= X2APIC_ENABLE; if ((msr_info->data & reserved_bits) != 0 || new_mode == LAPIC_MODE_INVALID) return 1; -- 2.25.1