From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joanna Rutkowska Subject: Re: Does xc_map_foreign_pages() update IOMMU tables? Date: Thu, 13 May 2010 14:39:53 +0200 Message-ID: <4BEBF319.3020202@invisiblethingslab.com> References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0022325519==" Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: "xen-devel@lists.xensource.com" , Rafal Wojtczuk List-Id: xen-devel@lists.xenproject.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --===============0022325519== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig68242CF80D383CFB406C5A48" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig68242CF80D383CFB406C5A48 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 05/13/2010 02:27 PM, Keir Fraser wrote: > On 13/05/2010 13:09, "Joanna Rutkowska" = > wrote: >=20 >>> Seeing as how xc_map_foreign_pages() maps pages into a particular >>> guest-process virtual address space, whereas IOMMU tables are a mappi= ng from >>> guest-physical address space, it's clear that x_m_f_p() cannot sensib= ly be >>> having any effect on the IOMMU. >>> >> Interesting. That suggests the graphics drivers we tested do not use D= MA >> for XShmPutImage()... >=20 > Ah, actually dom0 is special in that it gets a 1:1 mapping of all of RA= M > (except for some private Xen areas). See > drivers/passthrough/vtd/x86/vtd.c:iommu_set_dom0_mapping(). I forgot ab= out > that when I wrote my previous reply! >=20 Ah, indeed! In fact Rafal and I even had this very fragment of code in our slides 2 years ago and we both forgot about it :) [Back then it was in drivers/passthrough/vtd/iommu.c:intel_iommu_domain_init(). Thanks for clarifying! joanna. --------------enig68242CF80D383CFB406C5A48 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/ iEYEARECAAYFAkvr8xkACgkQORdkotfEW85DIACguGRHZScuhQDkWAEQb9/GTG3+ WkYAoNpuA1t3MJyIN9pIHzw+iVvqnKUZ =IjJ+ -----END PGP SIGNATURE----- --------------enig68242CF80D383CFB406C5A48-- --===============0022325519== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel --===============0022325519==--