[Xen-devel] [PATCH RFC 0/4] Allow qemu to provide emulated disks for devices with hotplug scripts

[George Dunlap <george.dunlap@xxxxxxxxxx>]

Qemu in dom0 can only provide emulated disks when the qemu process has
access to an image of the file.  At the moment, this only includes
plain files or physical devices in dom0; it does not include anything
to do with a hotplug script.

However, hotplug scripts run from dom0 generally do, as a necessary
side effect of their activity, create a block device which could be
passed to domain 0; this block device can be passed to a qemu device
running in dom0 to provide emulated disk support.

This series allows qemu to gain access to that block device, giving it
full parity with PV guests for all disks whose backend is in domain 0.

It also takes steps towards generalizing the "local attach"
funcitonality which is used by pygrub to access non-local disks, so
that in the future qemu can access emulated disks by attaching them to
dom0.

RFC because I haven't tested it since forward-porting it.


George Dunlap (4):
  libxl: Move check for local access to a funciton
  libxl: Share logic for finding path between qemuu and pygrub
  tools/hotplug: Add a "dummy" hotplug script for testing
  libxl: Allow local access for block devices with hotplug scripts

 tools/hotplug/Linux/Makefile        |   1 +
 tools/hotplug/Linux/block-common.sh |   5 +-
 tools/hotplug/Linux/block-dummy     | 107 +++++++++++++++++++++++++++++++++
 tools/libxl/libxl.c                 | 115 +++++++++++++++++++++++++++++-------
 tools/libxl/libxl_bootloader.c      |   1 +
 tools/libxl/libxl_dm.c              |  66 ++++++++++++++-------
 tools/libxl/libxl_internal.h        |  12 +++-
 7 files changed, 262 insertions(+), 45 deletions(-)
 create mode 100644 tools/hotplug/Linux/block-dummy

-- 
2.1.4


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