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From: Chris Wright <chrisw-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: chrisw-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	suresh.b.siddha-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	mingo-X9Un+BFzKDI@public.gmane.org,
	Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH 2/2] iommu: dmar -- reserve mmio space used by IOMMU
Date: Wed, 6 Jun 2012 16:56:22 -0700	[thread overview]
Message-ID: <20120606235622.GJ12686@x200.localdomain> (raw)
In-Reply-To: <1338972329.26785.34.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>

* David Woodhouse (dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org) wrote:
> On Wed, 2012-06-06 at 10:29 +0200, Ingo Molnar wrote:
> > So for all practical purposes we get 99% of the warning power 
> > without going into chicken-and-egg problems like how do we 
> > determine that there's an IOMMU area there if there's no IOMMU 
> > aware code in the kernel, right? 
> 
> That's not a chicken-and-egg problem. It's hardly difficult to see the
> DMAR ACPI table and take a *basic* look at the DRHD entries. You don't
> even need to fully parse it.

I had the same impression as Ingo.  Patch is basically good as is (fixing
most of the problem), and could be augmented later to close the final gap
(when no IOMMU code).  While parsing the DMAR table is trivial, what are
you recommending to use to inform if the region is not properly reserved?

thanks,
-chris

  parent reply	other threads:[~2012-06-06 23:56 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-04 21:29 [PATCH 0/2]intel-iommu: reserve IOMMU register space Donald Dutile
     [not found] ` <1338845342-12464-1-git-send-email-ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-06-04 21:29   ` [PATCH 1/2] iommu: dmar: replace printks with appropriate pr_*() Donald Dutile
     [not found]     ` <1338845342-12464-2-git-send-email-ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-06-04 22:15       ` Joe Perches
2012-06-04 22:28         ` Don Dutile
2012-06-04 21:29   ` [PATCH 2/2] iommu: dmar -- reserve mmio space used by IOMMU Donald Dutile
     [not found]     ` <1338845342-12464-3-git-send-email-ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-06-04 22:37       ` David Woodhouse
     [not found]         ` <1338849430.10884.288.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-06-04 23:09           ` Don Dutile
     [not found]             ` <4FCD401D.9000304-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-06-04 23:23               ` David Woodhouse
     [not found]                 ` <1338852196.26785.10.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-06-04 23:52                   ` Don Dutile
2012-06-06  8:16                   ` Ingo Molnar
     [not found]                     ` <20120606081600.GB5991-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-06-06  8:26                       ` David Woodhouse
     [not found]                         ` <1338971183.26785.33.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-06-06  8:29                           ` Ingo Molnar
     [not found]                             ` <20120606082900.GF5991-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-06-06  8:45                               ` David Woodhouse
     [not found]                                 ` <1338972329.26785.34.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-06-06 23:56                                   ` Chris Wright [this message]
2012-06-06 23:58                   ` Chris Wright

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