Re: [PATCH RFC] xen/libxl/libxl: RIP PV superpage.

[Wei Liu <wei.liu2@citrix.com>]

You have two "libxl" in subject line.

On Fri, Jan 29, 2016 at 10:30:46AM -0500, Konrad Rzeszutek Wilk wrote:
> The last bastion of users is moving away from needing
> this.
> 
> Please note that there was an partial removal by
> c/s 9b3c6b13e0c085ceb53210f8e682a073096b94fa
> "libxc: remove superpages option for pv domains" so an user
> could not even run PV guests with superpage.
> 
> HVM guests are not affected - they have been able to use
> superpages (called hugepages) if the CPU supports 2MB or 1GB
> since Xen 3.3.
> 
> This is reported in the ring buffer:
> (XEN) HVM: HAP page sizes: 4kB, 2MB, 1GB
> 
> AMD CPUs that support 2MB require NPT aka Rapid Virtualization
> Indexing. This was introduced in third generation Opteron -
> Barcelona.
> 
> Intel CPUs that support 2MB require EPT aka Extended Page Tables.
> This was introduced in Westmere microarchitecture.
> 
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  docs/misc/xen-command-line.markdown |   7 --
>  tools/libxc/include/xenguest.h      |   3 +-
>  tools/libxc/xc_nomigrate.c          |   2 +-
>  tools/libxc/xc_sr_restore.c         |   6 +-
>  tools/libxl/libxl_internal.h        |   2 +-
>  tools/libxl/libxl_save_callout.c    |   4 +-
>  tools/libxl/libxl_save_helper.c     |   3 +-
>  tools/libxl/libxl_stream_read.c     |   2 +-

Changes to toolstack code are done only to internal functions and only
delete the extra argument for superpage flag. They look sensible.

Wei.