Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754821AbbKRWFp (ORCPT ); Wed, 18 Nov 2015 17:05:45 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:47717 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750735AbbKRWFo (ORCPT ); Wed, 18 Nov 2015 17:05:44 -0500 Subject: Re: [PATCH 1/3] x86/xen: Avoid fast syscall path for Xen PV guests To: Andy Lutomirski , Brian Gerst References: <1447877179-2775-1-git-send-email-boris.ostrovsky@oracle.com> <1447877179-2775-2-git-send-email-boris.ostrovsky@oracle.com> Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , David Vrabel , Konrad Rzeszutek Wilk , Andrew Lutomirski , Borislav Petkov , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xenproject.org" , Linux Virtualization From: Boris Ostrovsky Message-ID: <564CF623.40502@oracle.com> Date: Wed, 18 Nov 2015 17:05:23 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 753 Lines: 20 On 11/18/2015 03:58 PM, Andy Lutomirski wrote: > On Wed, Nov 18, 2015 at 12:50 PM, Brian Gerst wrote: >> >> Can you just add !xen_pv_domain() to the opportunistic SYSRET check >> instead? Bury the alternatives in that macro, ie. >> static_cpu_has(X86_FEATURE_XENPV). That would likely benefit other >> code as well. > We could, but that won't help the 64-bit case where we want to keep > the full asm path. I don't think I understand what you mean here. Which full asm path? -boris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/