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=-19.5 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, 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 A5C56C47E51 for ; Mon, 12 Jul 2021 07:40:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 629366124C for ; Mon, 12 Jul 2021 07:40:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348389AbhGLHk5 (ORCPT ); Mon, 12 Jul 2021 03:40:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:42268 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244180AbhGLHK3 (ORCPT ); Mon, 12 Jul 2021 03:10:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2F6CA613B9; Mon, 12 Jul 2021 07:06:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626073612; bh=YCb/SEytGyNVfPLdMRL6NO9tGa6sjoFDQBhuC4TjDkM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WV1hDLrHm0OuA5bxtLNssBc9FzHvy3S4N1ZNBKB6DT3PRNOB5YriTpjn96YmQu9Ee zBtavcXcQtszVXcQBX0KmbPM5Y7aOoAYb2Pu/dC9ROHOOJI1F4uq+k4+qGIR5+R99S Rj4J+Qu0Njp5vXm7W+dZmH5iMkz/PKHyG715CmZs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , Paolo Bonzini , Sasha Levin Subject: [PATCH 5.12 298/700] KVM: nVMX: Ensure 64-bit shift when checking VMFUNC bitmap Date: Mon, 12 Jul 2021 08:06:21 +0200 Message-Id: <20210712061008.056432309@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060924.797321836@linuxfoundation.org> References: <20210712060924.797321836@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson [ Upstream commit 0e75225dfa4c5d5d51291f54a3d2d5895bad38da ] Use BIT_ULL() instead of an open-coded shift to check whether or not a function is enabled in L1's VMFUNC bitmap. This is a benign bug as KVM supports only bit 0, and will fail VM-Enter if any other bits are set, i.e. bits 63:32 are guaranteed to be zero. Note, "function" is bounded by hardware as VMFUNC will #UD before taking a VM-Exit if the function is greater than 63. Before: if ((vmcs12->vm_function_control & (1 << function)) == 0) 0x000000000001a916 <+118>: mov $0x1,%eax 0x000000000001a91b <+123>: shl %cl,%eax 0x000000000001a91d <+125>: cltq 0x000000000001a91f <+127>: and 0x128(%rbx),%rax After: if (!(vmcs12->vm_function_control & BIT_ULL(function & 63))) 0x000000000001a955 <+117>: mov 0x128(%rbx),%rdx 0x000000000001a95c <+124>: bt %rax,%rdx Fixes: 27c42a1bb867 ("KVM: nVMX: Enable VMFUNC for the L1 hypervisor") Signed-off-by: Sean Christopherson Message-Id: <20210609234235.1244004-3-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/vmx/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index eca3db08d183..d3774d79916d 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5524,7 +5524,7 @@ static int handle_vmfunc(struct kvm_vcpu *vcpu) } vmcs12 = get_vmcs12(vcpu); - if ((vmcs12->vm_function_control & (1 << function)) == 0) + if (!(vmcs12->vm_function_control & BIT_ULL(function))) goto fail; switch (function) { -- 2.30.2