From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

QEMU currently asserts if you try and create a PCI device
on the end of a very long chain, because the ID string
exceeds the maximum length, and ends up aliasing.

Fail with a clean error in this common case;  there's
lots of other places that call the various registration
functions that now check for this error; I've only made
sure the common qdev path fails cleanly.

With these patches it fails with the slightly cleaner:

qemu-system-x86_64: -device x3130-upstream,id=pci.52,bus=pci.51,addr=0x0: Path too long for VMState (0000:00:0f.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0:00.0)

I don't think in real uses we'll end up with paths this long,
so I'm not intending to fix the paths to be dynamic lengths
unless we find a really good case where it happens.

This corresponds to:
  https://bugzilla.redhat.com/show_bug.cgi?id=1342434

Dave

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

v2
  Fix some indents on the last patch

Dr. David Alan Gilbert (3):
  vmstate_register_with_alias_id: Take an Error **
  migration: Check for ID length
  vmstate registration: check return values

 hw/core/qdev.c              |  9 ++++++---
 hw/intc/apic_common.c       |  2 +-
 include/migration/vmstate.h |  7 +++++--
 migration/savevm.c          | 24 ++++++++++++++++++------
 stubs/vmstate.c             |  3 ++-
 5 files changed, 32 insertions(+), 13 deletions(-)

-- 
2.9.3