From: Keir Fraser <keir.fraser@eu.citrix.com>
To: Joanna Rutkowska <joanna@invisiblethingslab.com>,
"Kay, Allen M" <allen.m.kay@intel.com>
Cc: "Cihula, Joseph" <joseph.cihula@intel.com>,
"Han, Weidong" <weidong.han@intel.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: feature suggestion: DMAR table emulation for Xen
Date: Fri, 14 May 2010 10:35:59 +0100 [thread overview]
Message-ID: <C812D80F.143ED%keir.fraser@eu.citrix.com> (raw)
In-Reply-To: <4BED1672.6000903@invisiblethingslab.com>
On 14/05/2010 10:22, "Joanna Rutkowska" <joanna@invisiblethingslab.com>
wrote:
> The Intel VT-d spec says that: "USB controllers and UMA integrated
> graphics devices are the only legacy device usages identified
> that depend on DMA to reserved system memory".
>
> I think we can safely ignore the legacy integrated graphics devices,
> because I would expect any VT-d enabled platform to have a modern
> graphics device and modern OS drivers that works well with VT-d (you
> even provide a dedicated DMA Remapping Unit for your integrated graphics
> device, so I would expect it doesn't require any RMMR exceptions).
Yeah, actually the integrated graphics can implement all sorts of dirty
tricks between OS driver, video BIOS, and SMM. This can rely on fixed memory
areas for communication -- both for host accesses and DMA, the latter
requiring RMRR setup. Maybe the RMRRs are static per-chipset, but I wouldn't
be too sure of it.
-- Keir
next prev parent reply other threads:[~2010-05-14 9:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-13 14:14 feature suggestion: DMAR table emulation for Xen Joanna Rutkowska
2010-05-14 5:41 ` Kay, Allen M
2010-05-14 9:22 ` Joanna Rutkowska
2010-05-14 9:35 ` Keir Fraser [this message]
2010-05-14 10:15 ` Joanna Rutkowska
2010-05-14 10:48 ` Keir Fraser
2010-05-14 10:58 ` Joanna Rutkowska
2010-05-14 11:29 ` Keir Fraser
2010-05-14 11:47 ` philosophically about IGD pass-through (was: feature suggestion: DMAR table emulation for Xen) Joanna Rutkowska
2010-05-14 11:58 ` James Harper
2010-05-14 12:30 ` Keir Fraser
2010-05-14 15:57 ` Dan Magenheimer
2010-05-14 16:43 ` philosophically about IGD pass-through Joanna Rutkowska
2010-05-14 17:54 ` philosophically about IGD pass-through (was: feature suggestion: DMAR table emulation for Xen) Kay, Allen M
2010-05-15 16:54 ` feature suggestion: DMAR table emulation for Xen Ian Pratt
2010-05-15 17:12 ` IGD passthrough security (was Re: feature suggestion: DMAR table emulation for Xen) Joanna Rutkowska
2010-05-14 9:41 ` feature suggestion: DMAR table emulation for Xen Barde Kaushik 00901718
2010-05-14 10:16 ` Joanna Rutkowska
2010-05-14 14:25 ` Barde Kaushik 00901718
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