From: Alex Williamson <alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Joerg Roedel <joerg.roedel-5C7GfCeVMHo@public.gmane.org>
Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org"
<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
"Khan, Shuah" <shuah.khan-VXdhtT5mjnY@public.gmane.org>,
David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
"Mingarelli,
Thomas" <Thomas.Mingarelli-VXdhtT5mjnY@public.gmane.org>
Subject: Re: [PATCH v2] Intel IOMMU patch to reprocess RMRR info
Date: Fri, 28 Sep 2012 06:40:08 -0600 [thread overview]
Message-ID: <1348836008.2320.284.camel@ul30vt.home> (raw)
In-Reply-To: <20120928094301.GH10549-5C7GfCeVMHo@public.gmane.org>
On Fri, 2012-09-28 at 11:43 +0200, Joerg Roedel wrote:
> On Thu, Sep 27, 2012 at 03:34:07PM -0600, Alex Williamson wrote:
>
> > It really seems like RMRRs are incompatible with IOMMU API use
> > though.
>
> I don't think so. The concept of RMRR is just not defined well enough
> (like the concept of unity mappings on the AMD side which is similar to
> RMRR). The definition says, that any memory region must be mapped at
> any time for the device. But that is not true (at least I have no
> counter-example yet). The right definition would be, that the RMRR
> regions are only necessary as long as the operating system does not
> control the particular device. And assigning a device to a guest also
> counts a 'taking control over the device'.
I think HP folks would be very unhappy with that definition. As David
indicates, that's how things like USB use RMRR, but the actual
definition in the spec leaves much more room for abuse. Thanks,
Alex
next prev parent reply other threads:[~2012-09-28 12:40 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-18 16:49 [PATCH v2] Intel IOMMU patch to reprocess RMRR info Tom Mingarelli
[not found] ` <20120918164955.12296.28799.sendpatchset-jP8EmR9A9vELnkn81s9yt/egYHeGw8Jk@public.gmane.org>
2012-09-18 17:46 ` Don Dutile
2012-09-27 20:36 ` Alex Williamson
[not found] ` <1348778200.2320.241.camel-85EaTFmN5p//9pzu0YdTqQ@public.gmane.org>
2012-09-27 21:10 ` Mingarelli, Thomas
[not found] ` <9774516974AF5F4C8A2C3C69CD3412332338F452-KNyhpuZufFMSZAcGdq5asR6epYMZPwEe5NbjCUgZEJk@public.gmane.org>
2012-09-27 21:34 ` Alex Williamson
[not found] ` <1348781647.2320.264.camel-85EaTFmN5p//9pzu0YdTqQ@public.gmane.org>
2012-09-27 21:50 ` David Woodhouse
[not found] ` <1348782605.2036.117.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-09-28 9:46 ` Joerg Roedel
[not found] ` <20120928094625.GI10549-5C7GfCeVMHo@public.gmane.org>
2012-09-28 10:23 ` David Woodhouse
[not found] ` <1348827803.2036.121.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-09-28 12:03 ` Joerg Roedel
2012-09-27 21:50 ` Linda Knippers
[not found] ` <5064CA2D.3030206-VXdhtT5mjnY@public.gmane.org>
2012-09-27 21:48 ` Mingarelli, Thomas
2012-09-27 21:52 ` Alex Williamson
2012-09-28 9:43 ` Joerg Roedel
[not found] ` <20120928094301.GH10549-5C7GfCeVMHo@public.gmane.org>
2012-09-28 12:40 ` Alex Williamson [this message]
[not found] ` <1348836008.2320.284.camel-85EaTFmN5p//9pzu0YdTqQ@public.gmane.org>
2012-09-28 12:52 ` Joerg Roedel
[not found] ` <20120928125246.GK10549-5C7GfCeVMHo@public.gmane.org>
2012-09-28 13:21 ` Alex Williamson
-- strict thread matches above, loose matches on Subject: below --
2012-09-18 17:27 Tom Mingarelli
2012-09-28 15:52 David Woodhouse
[not found] ` <uh6q9m8bwu6c2jov69m2aivu.1348847561292-2ueSQiBKiTY7tOexoI0I+QC/G2K4zDHf@public.gmane.org>
2012-09-28 16:30 ` Alex Williamson
2012-09-28 16:36 ` Linda Knippers
[not found] ` <5065D1F5.1090003-VXdhtT5mjnY@public.gmane.org>
2012-09-28 17:01 ` Joerg Roedel
[not found] ` <20120928170106.GE18962-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2012-09-28 17:06 ` Joerg Roedel
2012-09-28 17:28 ` Alex Williamson
2012-09-28 19:15 ` David Woodhouse
[not found] ` <1348859719.2036.128.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-09-28 19:21 ` Mingarelli, Thomas
2012-09-28 19:35 ` Shuah Khan
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