From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754714AbaIQL0H (ORCPT ); Wed, 17 Sep 2014 07:26:07 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:48221 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753107AbaIQL0E (ORCPT ); Wed, 17 Sep 2014 07:26:04 -0400 Message-ID: <1410953151.3040.101.camel@decadent.org.uk> Subject: Re: [PATCH 3.13 044/187] x86_64/entry/xen: Do not invoke espfix64 on Xen From: Ben Hutchings To: Kamal Mostafa Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com, Andy Lutomirski , "H. Peter Anvin" Date: Wed, 17 Sep 2014 12:25:51 +0100 In-Reply-To: <1410818997-9432-45-git-send-email-kamal@canonical.com> References: <1410818997-9432-1-git-send-email-kamal@canonical.com> <1410818997-9432-45-git-send-email-kamal@canonical.com> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-Ehnw/tIPYlBKT9aXGGHj" X-Mailer: Evolution 3.12.5-1+b1 Mime-Version: 1.0 X-SA-Exim-Connect-IP: 2001:470:1f08:1539:cde6:1b3a:bf85:5ca0 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-Ehnw/tIPYlBKT9aXGGHj Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2014-09-15 at 15:07 -0700, Kamal Mostafa wrote: > 3.13.11.7 -stable review patch. If anyone has any objections, please let= me know. >=20 > ------------------ >=20 > From: Andy Lutomirski >=20 > commit 7209a75d2009dbf7745e2fd354abf25c3deb3ca3 upstream. >=20 > This moves the espfix64 logic into native_iret. To make this work, > it gets rid of the native patch for INTERRUPT_RETURN: > INTERRUPT_RETURN on native kernels is now 'jmp native_iret'. >=20 > This changes the 16-bit SS behavior on Xen from OOPSing to leaking > some bits of the Xen hypervisor's RSP (I think). >=20 > [ hpa: this is a nonzero cost on native, but probably not enough to > measure. Xen needs to fix this in their own code, probably doing > something equivalent to espfix64. ] >=20 > Signed-off-by: Andy Lutomirski > Link: http://lkml.kernel.org/r/7b8f1d8ef6597cb16ae004a43c56980a7de3cf94.1= 406129132.git.luto@amacapital.net > Signed-off-by: H. Peter Anvin > Signed-off-by: Kamal Mostafa [...] There's another fix related to espfix on Xen, commit 8762e5092828 ("x86/espfix/xen: Fix allocation of pages for paravirt page tables"). But I'm not sure whether it's actually needed after this. Ben. --=20 Ben Hutchings Beware of programmers who carry screwdrivers. - Leonard Brandwein --=-Ehnw/tIPYlBKT9aXGGHj Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIVAwUAVBlvxOe/yOyVhhEJAQoMpQ//a5rwP0sy6W4fib+y0LV1U0yJd1zRumlw 7PuMAQiB/T5ana7yUVu+hhp6QlgqE0p24ZfHUX6e7lbvSwOgYpDEPzLjSLt6me9a wTdYIubzk6BFjJqa1Vf0OXT/JBS3ThuGFL+a3aXFbJNqiwhT44Sz3a69YPUcRTyv znaqHA8oNkeuJ91VvQ7GIx7DjKUjQBxWiDge2uP4U5Veq8u59TB8Wp4uYOU0VW+w L3CgptDSwwAZJJlNKMrmJvyUSc7bRwSyNHvgQtzPyHKAYy9jI8q+s4KlKRFRPTGz vtZncQQ2fmP6pVvQK+Virqfw8hhpU5pHqzLh5ekW/aSN3QFXpKkrHyfvAjplgaan Rr0qk89sUgZvwlV8aJ35uhS/QYv7xDWcLRVadSPuso+1ZZdiBDXommdUsoxmpki0 Ezb0ZkUQGsffMGH/rkv1UYZkUpLAt6uInm0JVcHFlMq2iauy6Baco9fbAFtrRRmf KFtbWpWPt4AspHS7DkiEG4bzwO/sW66db29XAMywJN79mUogOc/Q1Xaoebhtg3EA pNoRtPNvLjJ3NhRL0yGiGpHMib6h9iy8AK+RP6MfbX77U3Yftp3+FilF28SuJieT zV2KoiPJ3SeV0rlteXwMSs4cAVitUYPipWTX4Pzy1WA/OaEqoaz/esoA3z/UxCCa t08o+CNlPMY= =HU/x -----END PGP SIGNATURE----- --=-Ehnw/tIPYlBKT9aXGGHj--