From patchwork Mon Jul 12 06:09:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 476311 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=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 AF11DC11F66 for ; Mon, 12 Jul 2021 06:23:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F12E610E5 for ; Mon, 12 Jul 2021 06:23:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235169AbhGLG0Q (ORCPT ); Mon, 12 Jul 2021 02:26:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:46660 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234647AbhGLGZS (ORCPT ); Mon, 12 Jul 2021 02:25:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C82FA610E5; Mon, 12 Jul 2021 06:22:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626070950; bh=id9z8FpgwbAPyQ6YvL4U2wN00hzcj0Zs81YLXgiL3rA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RjkuSnLY4kUrtaYulRfU/1pGhphWVGgjmANuHHQJ2giIwe46rIC+Gjt4VoREJJTRD RkzqquC1IxKPyIbLirBSMAJFLt/RlP6a29FPq1G0xuSNjPK2shTKMguEhFKmgXhk8H lBhHv7LbVWk0oPsQaTXNJFgNhT0uN0Jxow5uK8Hc= 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 5.4 167/348] KVM: nVMX: Ensure 64-bit shift when checking VMFUNC bitmap Date: Mon, 12 Jul 2021 08:09:11 +0200 Message-Id: <20210712060723.055400739@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060659.886176320@linuxfoundation.org> References: <20210712060659.886176320@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 3f63bd7421ac..023bd3e1aa0d 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5099,7 +5099,7 @@ 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) {