[libvirt] [PATCH v3 0/5] libxl: PVHv2 support

[Jim Fehlig]

On 9/30/18 8:15 PM, Marek Marczykowski-Górecki wrote:
> This is a respin of my old PVHv1 patch[1], converted to PVHv2.
> Should the code use "PVH" name (as libxl does internally), or "PVHv2" as in
> many places in Xen documentation? I've chosen the former, but want to confirm
> it.

"PVH".

> 
> Also, not sure about VIR_DOMAIN_OSTYPE_XENPVH (as discussed on PVHv1 patch) -
> while it will be messy in many cases, there is
> libxl_domain_build_info.u.{hvm,pv,pvh} which would be good to not mess up.
> Also, PVHv2 needs different kernel features than PV (CONFIG_XEN_PVH vs
> CONFIG_XEN_PV), so keeping the same VIR_DOMAIN_OSTYPE_XEN could be
> confusing.

These are good reasons for going with VIR_DOMAIN_OSTYPE_XENPVH. Another is it 
avoids the STREQ(def->os.machine, "xenpvh"), which I think others will find 
appealing.

> On the other hand, libxl_domain_build_info.u.pv is used in very few places (one
> section of libxlMakeDomBuildInfo), so guarding u.hvm access with
> VIR_DOMAIN_OSTYPE_HVM may be enough.
> For now I've reused VIR_DOMAIN_OSTYPE_XEN - in the driver itself, most of
> the code is the same as for PV.

I'll reiterate my rationalization for using VIR_DOMAIN_OSTYPE_XEN for both and 
differentiating them with os.machine: both PV and PVH are OS types that have 
been modified to run on Xen.

I'd still like to get some opinions from other maintainers on this. Anyone care 
to share their thoughts on which approach best models PVH?

(Perhaps trying to add PVH support in virt-manager on top of this series will 
help flesh out the better approach. I'll give it a try...)

Regards,
Jim

> Since PVHv2 relies on features in newer Xen versions, I needed to convert also
> some older code. For example b_info->u.hvm.nested_hvm was deprecated in favor
> of b_info->nested_hvm. While the code do handle both old and new versions
> (obviously refusing PVHv2 if Xen is too old), this isn't the case for tests.
> How it should be handled, if at all?
> 
> First few preparatory patches can be applied independently.
> 
> [1] https://www.redhat.com/archives/libvir-list/2016-August/msg00376.html
> 
> Changes in v2:
>   - drop "docs: don't refer to deprecated 'linux' ostype in example" patch -
>     migrating further away from "linux" os type is offtopic to this series and
>     apparently is a controversial thing
>   - drop "docs: update domain schema for machine attribute" patch -
>     already applied
>   - apply review comments from Jim
>   - rebase on master
> 
> Changes in v3:
>   - rebase on master, drop already applied patches
>   - use #ifdef LIBXL_DOMAIN_TYPE_PVH to detect PVH support, fix compilation
>     failure on older Xen
>   - exclude PVH from VIR_DOMAIN_OSTYPE_XEN <-> VIR_DOMAIN_OSTYPE_LINUX conversion
>   - fix reported capabilities for PVH
> 
> Marek Marczykowski-Górecki (5):
>    libxl: reorder libxlMakeDomBuildInfo for upcoming PVH support
>    libxl: add support for PVH
>    tests: add basic Xen PVH test
>    xenconfig: add support for parsing type= xl config entry
>    xenconfig: add support for type="pvh"
> 
>   docs/formatcaps.html.in                     |  4 +-
>   docs/schemas/domaincommon.rng               |  1 +-
>   src/conf/domain_conf.c                      |  6 +-
>   src/libxl/libxl_capabilities.c              | 47 +++++++++++---
>   src/libxl/libxl_conf.c                      | 76 ++++++++++++++++------
>   src/libxl/libxl_driver.c                    |  6 +-
>   src/xenconfig/xen_common.c                  | 27 ++++++--
>   src/xenconfig/xen_xl.c                      |  5 +-
>   tests/libxlxml2domconfigdata/basic-pvh.json | 49 ++++++++++++++-
>   tests/libxlxml2domconfigdata/basic-pvh.xml  | 28 ++++++++-
>   tests/libxlxml2domconfigtest.c              |  3 +-
>   tests/testutilsxen.c                        |  3 +-
>   tests/xlconfigdata/test-fullvirt-type.cfg   | 21 ++++++-
>   tests/xlconfigdata/test-fullvirt-type.xml   | 27 ++++++++-
>   tests/xlconfigdata/test-paravirt-type.cfg   | 13 ++++-
>   tests/xlconfigdata/test-paravirt-type.xml   | 25 +++++++-
>   tests/xlconfigdata/test-pvh-type.cfg        | 13 ++++-
>   tests/xlconfigdata/test-pvh-type.xml        | 25 +++++++-
>   tests/xlconfigtest.c                        |  3 +-
>   19 files changed, 346 insertions(+), 36 deletions(-)
>   create mode 100644 tests/libxlxml2domconfigdata/basic-pvh.json
>   create mode 100644 tests/libxlxml2domconfigdata/basic-pvh.xml
>   create mode 100644 tests/xlconfigdata/test-fullvirt-type.cfg
>   create mode 100644 tests/xlconfigdata/test-fullvirt-type.xml
>   create mode 100644 tests/xlconfigdata/test-paravirt-type.cfg
>   create mode 100644 tests/xlconfigdata/test-paravirt-type.xml
>   create mode 100644 tests/xlconfigdata/test-pvh-type.cfg
>   create mode 100644 tests/xlconfigdata/test-pvh-type.xml
> 
> base-commit: 199eee6aae7af3d813fbe98660c7e0fa1a8ae7b7
>