c/s f5d947bf1b "tools/libxl: add back channel support to read stream"
made a bogus adjustment to libxl__stream_read_start(), including
removing the comment hinting at what was going on, which breaks
conversion of a legacy migration stream.
Symptoms look like:
root@anonymi:~ # xl migrate domU host
migration target: Ready to receive domain.
Saving to migration stream new xl format (info 0x1/0x0/2677)
xc: error: error polling suspend notification channel: -1: Internal error
Loading new save file <incoming migration stream> (new xl fmt info 0x1/0x0/2677)
Savefile contains xl domain config in JSON format
Parsing config from <saved>
libxl: error: libxl_stream_read.c:327:stream_header_done: Invalid ident: expected 0x4c6962786c466d74, got 0x01f00f0000000000
libxl: error: libxl_utils.c:430:libxl_read_exactly: file/stream truncated reading ipc msg header from domain 1 save/restore helper stdout pipe
The adjustment is not required for backchannel support (as there is no
interaction between back channels and legacy conversion), and caused
stream->fd to be latched in the datacopier before legacy conversion
substitutes it for the fd which is the output of the conversion script.
This causes libxl to consume data from the legacy stream rather than the
v2 stream, and for the conversion script to encounter an error as the
legacy stream appears to skip ahead.
Undo the adjustments to libxl__stream_read_start(), and introduce a
better description of what is going on. Introduce some extra assertions
to try and catch similar breakage in the future.
Reported-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: Olaf Hering <olaf@aepfle.de>
Secondary vm is running in colo mode. So we will do
the following things again and again:
1. Resume secondary vm
a. Send CHECKPOINT_SVM_READY to master.
b. If it is not the first resume, call libxl__checkpoint_devices_preresume().
c. If it is the first resume(resume right after live migration),
- call libxl__xc_domain_restore_done() to build the secondary vm.
- enable secondary vm's logdirty.
- call libxl__domain_resume() to resume secondary vm.
- call libxl__checkpoint_devices_setup() to setup checkpoint devices.
d. Send CHECKPOINT_SVM_RESUMED to master.
2. Wait a new checkpoint
a. Call libxl__checkpoint_devices_commit().
b. Read CHECKPOINT_NEW from master.
3. Suspend secondary vm
a. Suspend secondary vm.
b. Call libxl__checkpoint_devices_postsuspend().
c. Send CHECKPOINT_SVM_SUSPENDED to master.
4. Checkpoint
a. Read emulator xenstore data and emulator context
b. REC_TYPE_CHECKPOINT_END
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yang Hongyang <hongyang.yang@easystack.cn>
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
This is used by primay to read records sent by secondary.
Note: The function libxl__stream_read_checkpoint_state() will be used
in later patches called "secondary vm suspend/resume/checkpoint code" and
"primary vm suspend/resume/checkpoint code".
Signed-off-by: Yang Hongyang <hongyang.yang@easystack.cn>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Introduce enum type libxl_checkpointed_stream in IDL.
rename the last argument of migrate_receive from "remus" to
"checkpointed" since the semantics of this parameter has
changed.
NOTE:
libxl_domain_restore_params and domain_create aren't changed here,
checkpointed_stream is still an int. Because we will pass the
value from libxl to libxc.
Signed-off-by: Yang Hongyang <hongyang.yang@easystack.cn>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
stream_continue() is used for migration to read emulator
xenstore data and emulator context. For remus, if we do
failover, we have read it in the checkpoint cycle, and
we only need to complete the stream.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Read and write "toolstack" information using the new
EMULATOR_XENSTORE_DATA record, and have the conversion script take care
of the old format.
The entire libxc and libxl migration v2 streams are now bitness-neutral
in their records.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Previously, in the case of an error causing a call to
libxl__conversion_helper_abort() on a stream without legacy conversion,
libxl would fall over a NULL pointer because chs->ao was not set up.
Arrange for all ->ao's to be set up at _init() time, by having each
_init() function assert that their caller has done the right thing.
While doing so, introduce a previously-missing save_helper_init() in
stream_read_init().
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Part of the callback contract with check_all_finished() is that each
running parallel task shall call it exactly once.
Previously, it was possible for stream_continue() or
write_toolstack_record() to fail and call into check_all_finished(). As
the save helpers callback has fired, it no longer counts as in use,
which causes check_all_finished() to fire the stream callback. Then,
unwinding the stack back and calling check_all_finished() a second time
results in the same conditions being observed, and the stream callback
being fired a second time.
To avoid this, check_all_finished() is called before any other actions
which continue the stream functionality, and the stream is only
continued if it has not been torn down. This guarantees not to continue
stream operations if the stream does not owe a callback to
check_all_finished().
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Avoid stacking of check_all_finished() via synchronous teardown of
tasks. If the _abort() functions call back synchronously,
stream->completion_callback() ends up getting called twice, as first
and last check_all_finished() frames observe each task being finished.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Only ever set stream->rc in check_all_finished(). The first version of
the migration v2 series had separate rc and joined_rc parameters, where
this logic worked. However when combining the two, the teardown path
fails to trigger if stream_complete() records stream->rc itself. A side
effect of this is that stream_done() needs to take an rc parameter.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
All of these are UNUSED_VALUE defects where a default value is
unconditionally overwritten. They are not particularly interesting,
bug wise, but keeping these defects at bay helps prevent real bugs
going unnoticed in the volume.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Applying the series out of order led to d72befc35f "tools/libxl:
Identify copywhat in stream v2 datacopiers" unintentionally reverting
part of 21d9b079e5 "tools/libxl: Initialise the fd of the unused
half of a datacopier".
Put this back.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
This is the final bit of untangling for Remus.
When libxc issues a checkpoint callback, start reading and buffering
all libxl records from the stream. Once a CHECKPOINT_END record is
encountered, start processing all records.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
---
v4: Adjustments in line with review for earlier patches in the series
v3: Simplify, use named constants for API
This is a complicated set of changes which must be done together for
bisectability.
* libxl-save-helper is updated to unconditionally use libxc migration
v2.
* libxl compatibility workarounds in libxc are disabled for restore
operations.
* libxl__stream_read_start() is logically spliced into the event
location where libxl__xc_domain_restore() used to reside.
* Ownership of the save_helper_state moves to stream_read_state.
The parameters 'hvm', 'pae', and 'superpages' were previously
superfluous, and are completely unused in migration
v2. callbacks->toolstack_restore is handled via a migration v2 record
now, rather than via a callback from libxc.
NB: this change breaks Remus. Further untangling needs to happen
before Remus will function.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
---
v4:
* Don't use _init() needlessly
v3:
* Simplify from v2.
* Alter the ownership of save_helper_state
v2:
* Drop "legacy_width" from the IDL
* Gain a LIBXL_HAVE_ to signify support of migration v2 streams
For backwards compatibility, a legacy stream needs converting before
it can be read by the v2 stream logic.
This causes the v2 stream logic to need to juggle two parallel tasks.
check_all_finished() is introduced for the purpose of joining the
tasks in both success and error cases.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
---
v4: Alter logic layout in check_all_finished()
v3: Simplified greatly from v2. No practical change.
This contains the event machinery and state machines to read an act on
a non-checkpointed migration v2 stream (with the exception of the
xc_domain_restore() handling which is spliced later in a bisectable
way).
It also contains some boilerplate to help support checkpointed
streams, which shall be introduced in a later patch.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
---
v4:
* Don't make _init() mandatory
* Don't unilaterally clobber rc from datacopier callback
* Comment adjustments
* More assertions
v3: More descriptions of the internal state, shuffle function order, add
an _init() call, condense error handling
Andrew Cooper
Wen Congyang
Roger Pau Monne
Ian Campbell
Ross Lagerwall