From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753942AbbKYN1q (ORCPT ); Wed, 25 Nov 2015 08:27:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56352 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751832AbbKYN1o (ORCPT ); Wed, 25 Nov 2015 08:27:44 -0500 Subject: Re: [PATCH] KVM: x86: don't expose syscall/sysret to intel 32-bit guest To: Wanpeng Li References: <564DACF5.9090908@redhat.com> Cc: Wanpeng li , kvm , "linux-kernel@vger.kernel.org" From: Paolo Bonzini Message-ID: <5655B74C.6070305@redhat.com> Date: Wed, 25 Nov 2015 14:27:40 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/11/2015 13:45, Wanpeng Li wrote: > 2015-11-19 19:05 GMT+08:00 Paolo Bonzini : >> >> 1) Clear F(SYSCALL) in kvm_update_cpuid, like you are doing here but >> only if F(LM) is already clear (in addition to the vendor being Intel). > > It seems that F(LM) is always set in the case of qemu-system-x86_64 w/ > 32-bit guest, vmware also exposes LM bit to 32 bit guest(however it > doesn't expose syscall/sysret) Does it expose the SYSCALL bit? Paolo