From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754706AbeCVMiO (ORCPT ); Thu, 22 Mar 2018 08:38:14 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:59642 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753076AbeCVMiL (ORCPT ); Thu, 22 Mar 2018 08:38:11 -0400 Subject: Re: [PATCH] KVM: X86: Fix the decoding of segment overrides in 64bit mode To: Andrew Cooper , Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= References: <1521707651-9375-1-git-send-email-wanpengli@tencent.com> <49454fe4-16e2-4d8b-7ad5-9e488afc786e@citrix.com> From: Paolo Bonzini Message-ID: <9bd82cb0-d88f-4891-a111-3704802e1d4e@redhat.com> Date: Thu, 22 Mar 2018 13:38:05 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22/03/2018 12:04, Andrew Cooper wrote: > We've got a Force Emulation Prefix (ud2a; .ascii "xen") for doing > magic.  Originally, this was used for PV guests to explicitly request an > emulated CPUID, but I extended it to HVM guests for "emulate the next > instruction", after we had some guest user => guest kernel privilege > escalations because of incorrect emulation. Wanpeng, why don't you add it behind a new kvm module parameter? :) Paolo