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Re: [Xen-devel] [PATCH for 4.5 v8 1/1] Add mmio_hole

On 10/22/14 07:21, Ian Campbell wrote:
On Tue, 2014-10-21 at 08:42 -0400, Don Slutz wrote:
If you add enough PCI devices then all mmio may not fit below 4G
which may not be the layout the user wanted. This allows you to
increase the below 4G address space that PCI devices can use and
therefore in more cases not have any mmio that is above 4G.

There are real PCI cards that do not support mmio over 4G, so if you
want to emulate them precisely, you may also need to increase the
space below 4G for them. There are drivers for these cards that also
do not work if they have their mmio space mapped above 4G.

This allows growing the MMIO hole to the size needed.

This may help with using pci passthru and HVM.

In the tools this is named mmio_hole_memkb.

Signed-off-by: Don Slutz <dslutz@xxxxxxxxxxx>
For the tools side: Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

Has this had a release exception? Or acks for the hvmloader side of

On Tue, 14 Oct 2014 11:56:22 -0400, Konrad Rzeszutek Wilk said:

I am OK with this patch going in Xen 4.5 (as a release-manager)
but it can't go anywhere unless there is an Ack/Review.

On Mon, 20 Oct 2014 15:10:25 +0100, George Dunlap said:

I haven't done a full review, but all of my previous concerns have
been addressed:

Acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

This was on v7. There is no change to tools/firmware/* from v7 to v8. So as I said:

Changes from v7 to v8:

  George Dunlap
    Acked-by: George Dunlap<george.dunlap@xxxxxxxxxxxxx>
      Did not add do changes to many parts.
      No change to tools/firmware/* so I think it still
        applies there.

Hope this is enough for you.

+        /*
+         * At the moment qemu-xen can't deal with relocated memory regions.
+         * It's too close to the release to make a proper fix; for now,
This isn't really accurate any more.


No need for a v9 for this, and it would be inappropriate to change it in
what is otherwise a code motion part of the patch.


   -Don Slutz

+         * only allow the MMIO hole to grow large enough to move guest memory
+         * if we're running qemu-traditional.  Items that don't fit will be
+         * relocated into the 64-bit address space.

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