Re: [PATCH] libxl, hvmloader: Don't relocate memory for MMIO hole

[George Dunlap <george.dunlap@eu.citrix.com>]

On 17/06/13 17:43, George Dunlap wrote:
> At the moment, qemu-xen can't handle memory being relocated by
> hvmloader.  This may happen if a device with a large enough memory
> region is passed through to the guest.  At the moment, if this
> happens, then at some point in the future qemu will crash and the
> domain will hang.  (qemu-traditional is fine.)
>
> It's too late in the release to do a proper fix, so we try to do
> damage control.
>
> hvmloader already has mechanisms to relocate memory to 64-bit space
> if it can't make a big enough MMIO hole.  By default this is 2GiB; if
> we just refuse to make the hole bigger if it will overlap with guest
> memory, then this codepath will be taken by default.
>
> Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
> CC: Ian Campbell <ian.campbell@citrix.com>
> CC: Ian Jackson <ian.jackson@citrix.com>
> CC: Stefano Stabellini <stefano.stabellini@citrix.com>
> CC: Hanweidong <hanweidong@huawei.com>

Unfortunatley, I don't have an easy way to test this, as all of the 
devices on my system are far smaller than 256MiB.

Weidong, could you give this patch a try and see if it works for you?

  -George