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Re: [Qemu-devel] [PATCH 0/7] IGNORE, SORRY (was: Improve PCI IO window o


From: David Gibson
Subject: Re: [Qemu-devel] [PATCH 0/7] IGNORE, SORRY (was: Improve PCI IO window orgnaization for pseries)
Date: Wed, 12 Oct 2016 15:43:20 +1100
User-agent: Mutt/1.7.0 (2016-08-17)

On Wed, Oct 12, 2016 at 03:29:45PM +1100, David Gibson wrote:
> The current way we organize the IO windows into PCI space for the
> pseries machine type has several problems.
> 
>   - It makes it difficult to create very large MMIO spaces which is
>     necessary for certain PCI devices with very large BARs.  This
>     problem has been known for a while.
> 
>   - More recently we discovered a more serious problem: it prevents
>     more than 1TiB of RAM being added to a pseries guest.
> 
>   - It doesn't make very efficient use of address space.
> 
> Fixing this is complicated by keeping migration from old versionss
> working and working out what things belong on which side of the
> abstraction barrier between the machine type and the host bridge
> device.
> 
> This series addresses all these problems.  Patches 1-3/7 perform
> preliminary cleanups to the spapr specific PCI test code, which we'll
> need to get the tests working with the changed implementation.  4-5/7
> represent a minimal fix for the most serious problem (the 1 TiB limit)
> - once polished, I'll consider submiting these for the stable branch.
> 6-7/7 complete a more comprehensive fix.

Sorry, realised I stupidly left a debug fprintf in there, and also got
one of the recipient emails wrong.  New spin coming momentarily.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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