From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 87259CA9EAF for ; Tue, 22 Oct 2019 02:02:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CA7A207FC for ; Tue, 22 Oct 2019 02:02:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387637AbfJVCC0 (ORCPT ); Mon, 21 Oct 2019 22:02:26 -0400 Received: from mga14.intel.com ([192.55.52.115]:61595 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387532AbfJVB7s (ORCPT ); Mon, 21 Oct 2019 21:59:48 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Oct 2019 18:59:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,325,1566889200"; d="scan'208";a="196293834" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.41]) by fmsmga008.fm.intel.com with ESMTP; 21 Oct 2019 18:59:46 -0700 From: Sean Christopherson To: Marc Zyngier , James Hogan , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Cc: James Morse , Julien Thierry , Suzuki K Poulose , David Hildenbrand , Cornelia Huck , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 21/45] KVM: x86: Remove spurious clearing of async #PF MSR Date: Mon, 21 Oct 2019 18:59:01 -0700 Message-Id: <20191022015925.31916-22-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20191022015925.31916-1-sean.j.christopherson@intel.com> References: <20191022015925.31916-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Remove a bogus clearing of apf.msr_val from kvm_arch_vcpu_destroy(). apf.msr_val is only set to a non-zero value by kvm_pv_enable_async_pf(), which is only reachable by kvm_set_msr_common(), i.e. by writing MSR_KVM_ASYNC_PF_EN. KVM does not autonomously write said MSR, i.e. can only be written via KVM_SET_MSRS or KVM_RUN. Since KVM_SET_MSRS and KVM_RUN are vcpu ioctls, they require a valid vcpu file descriptor. kvm_arch_vcpu_destroy() is only called if KVM_CREATE_VCPU fails, and KVM declares KVM_CREATE_VCPU successful once the vcpu fd is installed and thus visible to userspace. Ergo, apf.msr_val cannot be non-zero when kvm_arch_vcpu_destroy() is called. Fixes: 344d9588a9df0 ("KVM: Add PV MSR to enable asynchronous page faults delivery.") Signed-off-by: Sean Christopherson --- arch/x86/kvm/x86.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index dd667df37d63..dfd5c5244a6b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9097,8 +9097,6 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) { - vcpu->arch.apf.msr_val = 0; - kvm_arch_vcpu_free(vcpu); } -- 2.22.0