[Xen-devel] [PATCH v12 0/1] toolstack-assisted approach to PVHVM guest kexec

[Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>]

This is the only not merged patch from the original 'toolstack-assisted
approach to PVHVM guest kexec' series.

Changes since v11:
- Minor description change in xl.cfg.pod.5 [Wei Liu]
- Goto-style error handling in do_domain_soft_reset() [Wei Liu]

Original description of the series:

The list of currently known issues blocking kexec (and why the series is
required) is:
- Bound event channels.
- Registered vcpu_info.
- PIRQ/emuirq mappings.
- shared_info frame after XENMAPSPACE_shared_info operation.
- Active grant mappings.

Previously there were several attempts to solve these issues in different ways:
- Individual 'shutdown' hypercalls (e.g. VCPUOP_reset_vcpu_info) (we agreed
  that one 'reset everything' hypercall is better).
- Try building new domain reassigning old domain's memory (memory reassignment
  turned out being too cumbersome).
- Toolstack-less 'reset everything' (turned out being impossible because there
  is not enough knowledge in the hypervisor, e.g. interdomain channels are
  being set up by the toolstack).

This series is a mix of the previously sent 'toolstack-based' and
'reset everything' series. Here are some key points:
- No new domain is created.
- Domain is asking for soft reset with SCHEDOP_shutdown with
  SHUTDOWN_soft_reset shutdown reason.
- XEN_DOMCTL_soft_reset is being called by the toolstack.
- Device model is being restarted.

With regards to active grants. In this series we restart domain's device model,
remove it from xenstore and introduce it back. The only 'misbehaving' backend
keeping active mapping I currently observe is xenconsoled: currently it has no
interface to disconnect from a domain (it just periodically scans all domains
to determine if any of them are dead). This is not an issue for us because:
- This matches standard domain startup as this grant mapping is being set up by
  the toolstack.
- Guest domain is aware of this special page.
grant_table_warn_active_grants() is required to find possible misbehaving
backends in future.

v11 of the 'toolstack-assisted approach to pvhvm guest kexec' is available here:
http://lists.xenproject.org/archives/html/xen-devel/2015-09/msg00547.html

Vitaly Kuznetsov (1):
  (lib)xl: soft reset support

 docs/man/xl.cfg.pod.5        |   8 +-
 tools/libxl/libxl.c          |  22 ++++-
 tools/libxl/libxl.h          |  15 ++++
 tools/libxl/libxl_create.c   | 196 ++++++++++++++++++++++++++++++++++++++-----
 tools/libxl/libxl_internal.h |   4 +
 tools/libxl/libxl_types.idl  |   2 +
 tools/libxl/xl.h             |   1 +
 tools/libxl/xl_cmdimpl.c     |  25 +++++-
 8 files changed, 246 insertions(+), 27 deletions(-)

-- 
2.4.3


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