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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 C9536C43381 for ; Fri, 22 Mar 2019 12:59:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 993AB213F2 for ; Fri, 22 Mar 2019 12:59:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553259565; bh=14K6QcrZIMwy1VNyACkwitEs+UFcU47o/OnCKsgMkmU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=G3QIUhrLckE72WBJ2t/h8IBB8OIORSjvLHwjqYJ4xRRHaKweoCnmBjgSdjAzpspTm ykY09FR4ov5uRoxMf2cy+FR+VBf9lZ+z5S1Iy55hXYmfG3Akc7TmWrsJuvd3cZgR/5 ieG84r/1FZEwYmyOxzXtBpLO/4lNqYJ53jKHUvsA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730976AbfCVLpi (ORCPT ); Fri, 22 Mar 2019 07:45:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:48722 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728239AbfCVLph (ORCPT ); Fri, 22 Mar 2019 07:45:37 -0400 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 0C192218B0; Fri, 22 Mar 2019 11:45:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553255136; bh=14K6QcrZIMwy1VNyACkwitEs+UFcU47o/OnCKsgMkmU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tUW7XeGpi5qS3Haq7ypwzWtdcw6g4YNkJZIqSysudbYrjXz8Rwsnl+HgxFgZypRBj UAUq/NcVvFwcyJ+RGvbhNG2rtLWOrAM42prBp/ZNf4FWm0ATBPqUI0O/8Tc7tMKzkb jdpN7cJCkY8wGox3feX8iIA29Z7ZIAFn5qzef2Ig= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , Paolo Bonzini Subject: [PATCH 4.9 117/118] KVM: nVMX: Ignore limit checks on VMX instructions using flat segments Date: Fri, 22 Mar 2019 12:16:29 +0100 Message-Id: <20190322111224.541514316@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190322111215.873964544@linuxfoundation.org> References: <20190322111215.873964544@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson commit 34333cc6c2cb021662fd32e24e618d1b86de95bf upstream. Regarding segments with a limit==0xffffffff, the SDM officially states: When the effective limit is FFFFFFFFH (4 GBytes), these accesses may or may not cause the indicated exceptions. Behavior is implementation-specific and may vary from one execution to another. In practice, all CPUs that support VMX ignore limit checks for "flat segments", i.e. an expand-up data or code segment with base=0 and limit=0xffffffff. This is subtly different than wrapping the effective address calculation based on the address size, as the flat segment behavior also applies to accesses that would wrap the 4g boundary, e.g. a 4-byte access starting at 0xffffffff will access linear addresses 0xffffffff, 0x0, 0x1 and 0x2. Fixes: f9eb4af67c9d ("KVM: nVMX: VMX instructions: add checks for #GP/#SS exceptions") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -7092,10 +7092,16 @@ static int get_vmx_mem_address(struct kv /* Protected mode: #GP(0)/#SS(0) if the segment is unusable. */ exn = (s.unusable != 0); - /* Protected mode: #GP(0)/#SS(0) if the memory - * operand is outside the segment limit. + + /* + * Protected mode: #GP(0)/#SS(0) if the memory operand is + * outside the segment limit. All CPUs that support VMX ignore + * limit checks for flat segments, i.e. segments with base==0, + * limit==0xffffffff and of type expand-up data or code. */ - exn = exn || (off + sizeof(u64) > s.limit); + if (!(s.base == 0 && s.limit == 0xffffffff && + ((s.type & 8) || !(s.type & 4)))) + exn = exn || (off + sizeof(u64) > s.limit); } if (exn) { kvm_queue_exception_e(vcpu,