Re: [PATCH 0/5] libxc: support building large pv-domains

[Juergen Gross <jgross@suse.com>]

On 09/11/2015 03:28 PM, Ian Campbell wrote:
> On Fri, 2015-09-11 at 14:32 +0200, Juergen Gross wrote:
>> The Xen hypervisor supports starting a dom0 with large memory (up to
>> the TB range) by not including the initrd and p2m list in the initial
>> kernel mapping. Especially the p2m list can grow larger than the
>> available virtual space in the initial mapping.
>>
>> The started kernel is indicating the support of each feature via
>> elf notes.
>>
>> This series enables the domain builder in libxc to do the same as the
>> hypervisor. This enables starting of huge pv-domUs via xl.
>>
>> Unmapped initrd is supported for 64 and 32 bit domains, omitting the
>> p2m from initial kernel mapping is possible for 64 bit domains only.
>>
>> Tested with:
>> - 32 bit domU (kernel not supporting unmapped initrd)
>> - 32 bit domU (kernel supporting unmapped initrd)
>> - 1 GB 64 bit domU (kernel supporting unmapped initrd, not p2m)
>> - 1 GB 64 bit domU (kernel supporting unmapped initrd and p2m)
>> - 900GB 64 bit domU (kernel supporting unmapped initrd and p2m)
>>
>> Juergen Gross (5):
>>    libxc: remove allocate member from struct xc_dom_image
>>    libxc: do initrd processing of domain builder in own function
>>    libxc: create unmapped initrd in domain builder if supported
>>    libxc: split p2m allocation in domain builder from other magic pages
>>    libxc: create p2m list outside of kernel mapping if supported
>>
>>   tools/libxc/include/xc_dom.h |   4 +-
>>   tools/libxc/xc_dom_core.c    | 123 +++++++++++++++++++++++++++++--------------
>>   tools/libxc/xc_dom_x86.c     | 120 ++++++++++++++++++++++++++++++++++++++++-
>
> How much is this going to conflict with Roger's "Introduce HVM without dm
> and new boot ABI" changes to HVM building?

As it is touching the pv domain builder only, I don't think there will
be a conflict. All rights of being wrong reserved. :-)

Juergen