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

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

On Fri, 2015-09-11 at 15:42 +0200, Juergen Gross wrote:
> 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.

The reason I asked is that the first thing Roger's series does is cause HVM
domains to be built using the PV domain builder...

>  All rights of being wrong reserved. :-)

Warranty void to the limit of your statutory rights ;-)

Ian.