Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751963AbdFZNZG (ORCPT ); Mon, 26 Jun 2017 09:25:06 -0400 Received: from smtp.eu.citrix.com ([185.25.65.24]:12720 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751427AbdFZNY6 (ORCPT ); Mon, 26 Jun 2017 09:24:58 -0400 X-IronPort-AV: E=Sophos;i="5.39,395,1493683200"; d="scan'208";a="48392847" From: Paul Durrant To: =?utf-8?B?J01hcmVrIE1hcmN6eWtvd3NraS1Hw7NyZWNraSc=?= CC: =?utf-8?B?SnVlcmdlbiBHcm/Dnw==?= , Andrew Cooper , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , "xen-devel@lists.xenproject.org" , "Boris Ostrovsky" Subject: RE: [Xen-devel] [PATCH] x86/xen: allow userspace access during hypercalls Thread-Topic: [Xen-devel] [PATCH] x86/xen: allow userspace access during hypercalls Thread-Index: AQHS7n82HjVhrDYfTUyj9rC/4aNSWKI3IZSA Date: Mon, 26 Jun 2017 13:24:55 +0000 Message-ID: <6a2c9fea81ef4e4ba7d533dba604223b@AMSPEX02CL03.citrite.net> References: <1498222072-18217-1-git-send-email-marmarek@invisiblethingslab.com> <6f8113d8-10a2-b23f-16c1-8b97b2fba0bb@suse.com> <20170626124505.GV1268@mail-itl> <2a846dd6006c46819c563113b6255d85@AMSPEX02CL03.citrite.net> <20170626132157.GW1268@mail-itl> In-Reply-To: <20170626132157.GW1268@mail-itl> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id v5QDP8TJ018955 Content-Length: 2395 Lines: 60 > -----Original Message----- > From: 'Marek Marczykowski-Górecki' > [mailto:marmarek@invisiblethingslab.com] > Sent: 26 June 2017 14:22 > To: Paul Durrant > Cc: Juergen Groß ; Andrew Cooper > ; x86@kernel.org; linux- > kernel@vger.kernel.org; stable@vger.kernel.org; xen- > devel@lists.xenproject.org; Boris Ostrovsky > Subject: Re: [Xen-devel] [PATCH] x86/xen: allow userspace access during > hypercalls > > On Mon, Jun 26, 2017 at 01:09:58PM +0000, Paul Durrant wrote: > > > -----Original Message----- > > > From: Xen-devel [mailto:xen-devel-bounces@lists.xen.org] On Behalf Of > > > Marek Marczykowski-Górecki > > > Sent: 26 June 2017 13:45 > > > To: Juergen Groß > > > Cc: Andrew Cooper ; x86@kernel.org; > linux- > > > kernel@vger.kernel.org; stable@vger.kernel.org; xen- > > > devel@lists.xenproject.org; Boris Ostrovsky > > > > Subject: Re: [Xen-devel] [PATCH] x86/xen: allow userspace access during > > > hypercalls > > > > > > On Mon, Jun 26, 2017 at 02:05:48PM +0200, Juergen Groß wrote: > > > > On 06/23/2017 02:47 PM, Marek Marczykowski-Górecki wrote: > > > > > Userspace application can do a hypercall through /dev/xen/privcmd, > and > > > > > some for some hypercalls argument is a pointers to user-provided > > > > > structure. When SMAP is supported and enabled, hypervisor can't > access. > > > > > So, lets allow it. > > > > > > > > What about HYPERVISOR_dm_op? > > > > > > Indeed, arguments copied to kernel space there are only addresses of > > > buffers. Will send v2 in a moment. > > > But I can't test it right now, as for my understanding this require > > > HVM/PVHv2 dom0 or stubdomain... > > > > > > > No, you don't need anything particularly special to use dm_op. Just up-to- > date xen, privcmd, and QEMU. QEMU should end up using dm_op by default > if all three are in place. > > But the issue this patch fixes applies only to hypercalls issued from HVM. Oh, I see what you mean. Well I guess you could manually run QEMU from an HVM domain, but it would be a bit of a faff to set up. Paul > > -- > Best Regards, > Marek Marczykowski-Górecki > Invisible Things Lab > A: Because it messes up the order in which people normally read text. > Q: Why is top-posting such a bad thing?