From patchwork Tue Mar 3 17:43:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 229992 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 CF00CC3F2C6 for ; Tue, 3 Mar 2020 17:58:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A13C3206D5 for ; Tue, 3 Mar 2020 17:58:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583258323; bh=4fsMTC2zoau3tmshDp1FeSKoSeLg8PUslqdTX2Jfq60=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yWUHt48/r7NnejjM01AZiNQbhhlvThT1EV2CuityzBm6z5Ngd3RzzJy0HJmKJRQm/ kVYvzosGB53TcdTUMVSZVYLdl2HXwl3gykzV+tWbAsN4R0eA9rMuoHun23pfAW4pGQ KxoFRSQHDd6cOh5IYKp49Qe2mclhckBcl5oMduIs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387448AbgCCR6m (ORCPT ); Tue, 3 Mar 2020 12:58:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:41576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387427AbgCCR6l (ORCPT ); Tue, 3 Mar 2020 12:58:41 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AC75E20870; Tue, 3 Mar 2020 17:58:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583258321; bh=4fsMTC2zoau3tmshDp1FeSKoSeLg8PUslqdTX2Jfq60=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vko2aedjErbloNX1dZA4zc3gs2oZ26+uGcW1wJqF0fI48lrzF+72YzQR347kSCCOx DfAAvUnITZqyzu8lMwNIa9r+OK3yHJO35+vDbrphiNSMr6b2Qdfbj/G1p26yhAU3BY hKA613N1unEu4WeXGnST9Qq5ftX454kpa+JEQKZs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , Paolo Bonzini Subject: [PATCH 5.4 136/152] KVM: x86: Remove spurious clearing of async #PF MSR Date: Tue, 3 Mar 2020 18:43:54 +0100 Message-Id: <20200303174318.268582741@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200303174302.523080016@linuxfoundation.org> References: <20200303174302.523080016@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sean Christopherson commit 208050dac5ef4de5cb83ffcafa78499c94d0b5ad upstream. 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 Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 2 -- 1 file changed, 2 deletions(-) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9192,8 +9192,6 @@ void kvm_arch_vcpu_postcreate(struct kvm void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) { - vcpu->arch.apf.msr_val = 0; - kvm_arch_vcpu_free(vcpu); }