From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 0A1F2440CD7 for ; Thu, 9 Nov 2017 10:01:50 -0500 (EST) Received: by mail-wr0-f197.google.com with SMTP id j15so3341805wre.15 for ; Thu, 09 Nov 2017 07:01:49 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id r17si416054eda.270.2017.11.09.07.01.48 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 09 Nov 2017 07:01:48 -0800 (PST) Subject: Re: [PATCH 30/30] x86, kaiser, xen: Dynamically disable KAISER when running under Xen PV References: <20171108194646.907A1942@viggo.jf.intel.com> <20171108194742.8CD79E09@viggo.jf.intel.com> From: Juergen Gross Message-ID: <7e70274c-6ad0-9f9c-0ad3-8d3306d8174a@suse.com> Date: Thu, 9 Nov 2017 16:01:42 +0100 MIME-Version: 1.0 In-Reply-To: <20171108194742.8CD79E09@viggo.jf.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, moritz.lipp@iaik.tugraz.at, daniel.gruss@iaik.tugraz.at, michael.schwarz@iaik.tugraz.at, richard.fellner@student.tugraz.at, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, x86@kernel.org On 08/11/17 20:47, Dave Hansen wrote: > From: Dave Hansen > > If you paravirtualize the MMU, you can not use KAISER. This boils down > to the fact that KAISER needs to do CR3 writes in places that it is not > feasible to do real hypercalls. > > If we detect that Xen PV is in use, do not do the KAISER CR3 switches. > > I don't think this too bug of a deal for Xen. I was under the > impression that the Xen guest kernel and Xen guest userspace didn't > share an address space *anyway* so Xen PV is not normally even exposed > to the kinds of things that KAISER protects against. > > This allows KAISER=y kernels to deployed in environments that also > require PARAVIRT=y. > > Signed-off-by: Dave Hansen Acked-by: Juergen Gross Juergen -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org