From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= Subject: Re: pre Sandy bridge IOMMU support (gm45) Date: Mon, 1 Feb 2016 13:28:56 +0100 Message-ID: <20160201122856.GU1702@mail-itl> References: <56A63F9502000078000CAAD1@prv-mh.provo.novell.com> <56A75DF402000078000CAFAF@prv-mh.provo.novell.com> <56A7687102000078000CB035@prv-mh.provo.novell.com> <20160130014758.GA24446@mail-itl> <56AF1E5402000078000CCBDF@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============7512545835921766878==" Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aQDbL-00068A-K8 for xen-devel@lists.xenproject.org; Mon, 01 Feb 2016 12:29:03 +0000 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id 0E7B32FE08 for ; Mon, 1 Feb 2016 07:29:01 -0500 (EST) In-Reply-To: <56AF1E5402000078000CCBDF@prv-mh.provo.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: xen-devel , Thierry Laurion List-Id: xen-devel@lists.xenproject.org --===============7512545835921766878== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="FLPM4o+7JoHGki3m" Content-Disposition: inline --FLPM4o+7JoHGki3m Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 01, 2016 at 12:59:00AM -0700, Jan Beulich wrote: > >>> On 30.01.16 at 02:47, wrote: > > On Tue, Jan 26, 2016 at 04:37:05AM -0700, Jan Beulich wrote: > >> (re-adding xen-devel) > >>=20 > >> >>> On 26.01.16 at 12:28, wrote: > >> > Iommu=3D0 let the whole Qubes system work, without enforcing hardware > >> > compartimentalisation (iommu is enforced in software mode) > >> >=20 > >> > When iommu=3Dno-igfx is enforced, shell console boot up works flawle= ssly. All > >> > domu machines get booted up. A system hang will happen at the moment= a domu > >> > machine does graphic rendering, > >>=20 > >> And this is (other than I originally implied) without passing through > >> the IGD to the DomU? If so, I can't see the difference between a > >> guest rendering to its display (and vncviewer or whatever frontend > >> you use converting this to rendering on the host) and rendering > >> which originates in the host. > >=20 > > Not sure if relevant, but window content is mapped from PV domU directly > > into X server (in dom0) address space, using xc_map_foreign_pages. It is > > done by hacking XShmAttach function. Not sure what graphics driver do > > with it next. Theoretically it could be possible that driver will direc= t IGD > > to do DMA directly from that place, but I guess it does not. >=20 > Interesting. This then really needs to be investigated from the > Qubes end rather than here. Possible resulting patches, if > relevant outside of that unusual setup, would then of course be > appreciated to be sent here. Note that Thierry said "The point is the iommu=3Dno-igfx doesn't fix the issue", so either it is totally unrelated issue, or iommu=3Dno-igfx is broken. Does iommu=3Dno-igfx have any meaning when IDG is _not_ passed through to some domU? And generally - is IOMMU used in any way for dom0 devices? Is Linux kernel able to utilize it for its own purposes (my guess: no)? Somehow unrelated: I've tried to get p2m iommu mapping using `xl debug-key o`, but it's too long (and xenconsoled isn't fast enough to catch it into hypervisor.log). Is is possible to enlarge console ring buffer at runtime? If not, is `conring_size` the right option? How large it should be (aprox) for `xl debug-key o` output?=20 --=20 Best Regards, Marek Marczykowski-G=C3=B3recki 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? --FLPM4o+7JoHGki3m Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJWr0+JAAoJENuP0xzK19cs464H/Rl1msS/PJkLthxHr68XGatT M08b8iu0FtpSk0z17W7m+T9LXRyRKO48JzkWYr6yW6nJU9lhEjtXiKq9zKs7rMml V4g19jt9oBPNKda7ebczANACUQocUakbGQpV0EXF1MEGwbKc7B/CeAeGR3CmbJ6T dBvqsjlTQypUoZgu1rIgiIYhv9t85RaXHUyC+ut4LlBsjs+LQ9N+1GkK4jpygaTx 8glPX1yoA+NScl2+/JUhMoSLiET18r6xiKpSYwTrjAEomQE3hh4L/jO57Wwaz5Y+ 18i6uL4P+xElWfJ6a5f58MGfj7//3W7sKwVNSidx/dG2A79SyufAO8HIRglQv34= =M0b4 -----END PGP SIGNATURE----- --FLPM4o+7JoHGki3m-- --===============7512545835921766878== 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.xen.org http://lists.xen.org/xen-devel --===============7512545835921766878==--