From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joanna Rutkowska Subject: Re: The mfn of the frame, that holds a mlock-ed PV domU usermode page, can change Date: Mon, 12 Apr 2010 23:36:39 +0200 Message-ID: <4BC39267.3010807@invisiblethingslab.com> References: <20100412185454.GC3671@emperor2.itldev.org> <4BC37C32.1060805@goop.org> <4BC380E2.8060605@invisiblethingslab.com> <4BC3850F.7070108@goop.org> <4BC38E62.2080703@invisiblethingslab.com> <4BC39003.9090301@goop.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0502083415==" Return-path: In-Reply-To: <4BC39003.9090301@goop.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jeremy Fitzhardinge Cc: xen-devel@lists.xensource.com, Rafal Wojtczuk , qubes-devel@googlegroups.com List-Id: xen-devel@lists.xenproject.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --===============0502083415== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig5FB29D011F2D7C7EA5E3428F" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig5FB29D011F2D7C7EA5E3428F Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 04/12/2010 11:26 PM, Jeremy Fitzhardinge wrote: > On 04/12/2010 02:19 PM, Joanna Rutkowska wrote: >> Right, that's for the "ring" page, which we use to implement a ring >> buffer, and we then pass mfns of the actual Xorg's composition buffers= >> over this ring buffer to Dom0. >> >> Interestingly, I have never seen a garbage in any of the composition >> buffers (which are directly displayed by our appviewers, so it would b= e >> immediately visible), just like if only the mfn for the "ring" page >> could be modified, but the composition buffer's mfn were somehow pinne= d... >> >> This might suggest that the memory used by the composition buffers >> (which are in usermode) is somehow locked? >> =20 >=20 > Worth looking into. >=20 > I'm not at all familiar with how X manages composition buffers, but it > seems to me that in normal use, one would want to be able to either > allocate that buffer in texture memory (so it can be used as a texture > source), or at least copy updates into texture memory. Couldn't you > hook into that transfer to the composition hardware (ie, dom0)? >=20 We will definitely look into this. Thanks a lot for your help, Jeremy! joanna. --------------enig5FB29D011F2D7C7EA5E3428F 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/ iEYEARECAAYFAkvDkmcACgkQORdkotfEW85RTQCeLFCo0cpJHwtF5Anz+Aj+EeMq xTUAoNUAL92KwaW5Lf2RsD+QxVwNOUrR =0RxF -----END PGP SIGNATURE----- --------------enig5FB29D011F2D7C7EA5E3428F-- --===============0502083415== 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 --===============0502083415==--