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

[Ian Campbell <Ian.Campbell@citrix.com>]

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@verizon.com>

For the tools side: Acked-by: Ian Campbell <ian.campbell@citrix.com>

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


> +        /*
> +         * 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. 

> +         * 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.

Ian.