Re: [PATCH v5 0/4] Xen ABI feature control

[Jürgen Groß <jgross@xxxxxxxx>]

On 03.12.20 13:41, Paul Durrant wrote:
> From: Paul Durrant <pdurrant@xxxxxxxxxx>
>
> This series was previously called "evtchn: Introduce a per-guest knob to
> control FIFO ABI". It is been extensively re-worked and extended to cover
> another ABI feature.
>
> Paul Durrant (4):
>    domctl: introduce a new domain create flag,
>      XEN_DOMCTL_CDF_evtchn_fifo, ...
>    domctl: introduce a new domain create flag,
>      XEN_DOMCTL_CDF_evtchn_upcall, ...
>    libxl: introduce a 'libxl_xen_abi_features' enumeration...
>    xl: introduce a 'xen-abi-features' option...
>
>   docs/man/xl.cfg.5.pod.in         | 50 ++++++++++++++++++++++++++++++++
>   tools/include/libxl.h            | 10 +++++++
>   tools/libs/light/libxl_arm.c     | 22 +++++++++-----
>   tools/libs/light/libxl_create.c  | 31 ++++++++++++++++++++
>   tools/libs/light/libxl_types.idl |  7 +++++
>   tools/libs/light/libxl_x86.c     | 17 ++++++++++-
>   tools/ocaml/libs/xc/xenctrl.ml   |  2 ++
>   tools/ocaml/libs/xc/xenctrl.mli  |  2 ++
>   tools/xl/xl_parse.c              | 50 ++++++++++++++++++++++++++++++--
>   xen/arch/arm/domain.c            |  3 +-
>   xen/arch/arm/domain_build.c      |  3 +-
>   xen/arch/arm/setup.c             |  3 +-
>   xen/arch/x86/domain.c            |  8 +++++
>   xen/arch/x86/hvm/hvm.c           |  3 ++
>   xen/arch/x86/setup.c             |  4 ++-
>   xen/common/domain.c              |  3 +-
>   xen/common/event_channel.c       | 24 +++++++++++++--
>   xen/include/public/domctl.h      |  6 +++-
>   18 files changed, 229 insertions(+), 19 deletions(-)
> ---
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> Cc: Christian Lindig <christian.lindig@xxxxxxxxxx>
> Cc: David Scott <dave@xxxxxxxxxx>
> Cc: George Dunlap <george.dunlap@xxxxxxxxxx>
> Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Julien Grall <julien@xxxxxxx>
> Cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
> Cc: Wei Liu <wl@xxxxxxx>
Do we want to add a create flag for each such feature, or would it be
better to set options like those via hypfs?

It would be fairly easy to ad dynamic hypfs paths, e.g.:

/domain/<domid>/abi-features/evtchn-fifo
/domain/<domid>/abi-features/evtchn-upcall

which would have boolean type and could be set as long as the domain
hasn't been started.

xl support could even be rather generic, without the need to add coding
to xl for each new feature.

This is no objection to this series, but just an idea how to avoid
extending the use of unstable interfaces.

Thoughts?


Juergen

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