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From: "Jan Beulich" <JBeulich@suse.com>
To: Donald D Dugger <donald.d.dugger@intel.com>,
	Kevin Tian <kevin.tian@intel.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: dom0 / hypervisor hang  on dom0 boot
Date: Tue, 21 May 2013 09:03:59 +0100	[thread overview]
Message-ID: <519B468F02000078000D7810@nat28.tlf.novell.com> (raw)
In-Reply-To: <6AF484C0160C61439DE06F17668F3BCB526C1380@ORSMSX102.amr.corp.intel.com>

>>> On 20.05.13 at 16:30, "Dugger, Donald D" <donald.d.dugger@intel.com> wrote:
> The only trick for i915 in dom0, in my mind, is to have CONFIG_DMAR enabled in
> dom0 although dom0 is not actually exposed with a VT-d engine. This sets need_dmar
> flag in i915, ensures i915 to use Xen DMA interface instead of virt_to_phys, so that
> MFN is written to GTT entries. Otherwise, having GPFN in GTT entries is bogus, since
> GPU will DMA to wrong locations then, and thus cause random issues.

Enabling CONFIG_DMAR (or really CONFIG_INTEL_IOMMU in recent
kernels) is not an option. However, we patch all respective sites to
also take effect on Xen (of course that doesn't help pv-ops, but here
we're talking about a forward ported kernel anyway).

> Once we also identified a regression in 3.8, where need_dmar is not honored in
> i915 driver:

Dietmar had already tested with 3.9, so this ought to not affect
him.

Jan

  reply	other threads:[~2013-05-21  8:03 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-14 12:35 dom0 / hypervisor hang on dom0 boot Dietmar Hahn
2013-05-14 12:42 ` Andrew Cooper
2013-05-14 12:50   ` Dietmar Hahn
2013-05-14 12:51     ` Andrew Cooper
2013-05-14 13:25       ` Dietmar Hahn
2013-05-14 13:27 ` Jan Beulich
2013-05-15  6:53   ` Dietmar Hahn
2013-05-15  8:35     ` Jan Beulich
2013-05-15  9:12       ` Dietmar Hahn
2013-05-15  9:42         ` Jan Beulich
2013-05-16 11:07           ` Dietmar Hahn
2013-05-16 12:10             ` Jan Beulich
2013-05-16 13:16               ` Dietmar Hahn
2013-05-16 13:45                 ` Jan Beulich
2013-05-17  7:10                   ` Dietmar Hahn
2013-05-16 14:50               ` Dugger, Donald D
2013-05-20 14:30               ` Dugger, Donald D
2013-05-21  8:03                 ` Jan Beulich [this message]
2013-05-21  8:28                   ` Tian, Kevin
2013-05-21  8:47                     ` Jan Beulich
2013-05-17 22:28             ` Konrad Rzeszutek Wilk
2013-05-21  7:39               ` Dietmar Hahn
2013-05-21 14:10                 ` Konrad Rzeszutek Wilk

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