Commit graph

1986 commits

Author SHA1 Message Date
Kevin Wolf 2b3912f135 block: Mark bdrv_first_blk() and bdrv_is_root_node() GRAPH_RDLOCK
This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_first_blk() and bdrv_is_root_node() need to hold a reader lock
for the graph. These functions are the only functions in block-backend.c
that access the parent list of a node.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230929145157.45443-5-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12 16:31:33 +02:00
Peter Xu 5e79a4bf03 migration: Add migration_rp_wait|kick()
It's just a simple wrapper for rp_sem on either wait() or kick(), make it
even clearer on how it is used.  Prepared to be used even for other things.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-ID: <20231004220240.167175-8-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-10-11 11:17:05 +02:00
Peter Xu 1015ff5476 migration: Remember num of ramblocks to sync during recovery
Instead of only relying on the count of rp_sem, make the counter be part of
RAMState so it can be used in both threads to synchronize on the process.

rp_sem will be further reused in follow up patches, as a way to kick the
main thread, e.g., on recovery failures.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-7-peterx@redhat.com>
2023-10-11 11:17:05 +02:00
Peter Xu f4b897f485 qemufile: Always return a verbose error
There're a lot of cases where we only have an errno set in last_error but
without a detailed error description.  When this happens, try to generate
an error contains the errno as a descriptive error.

This will be helpful in cases where one relies on the Error*.  E.g.,
migration state only caches Error* in MigrationState.error.  With this,
we'll display correct error messages in e.g. query-migrate when the error
was only set by qemu_file_set_error().

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-6-peterx@redhat.com>
2023-10-11 11:17:05 +02:00
Peter Xu 2b2f6f411e migration: Introduce migrate_has_error()
Introduce a helper to detect whether MigrationState.error is set for
whatever reason.

This is preparation work for any thread (e.g. source return path thread) to
setup errors in an unified way to MigrationState, rather than relying on
its own way to set errors (mark_source_rp_bad()).

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-3-peterx@redhat.com>
2023-10-11 11:17:05 +02:00
Peter Xu c94143e587 migration: Display error in query-migrate irrelevant of status
Display it as long as being set, irrelevant of FAILED status.  E.g., it may
also be applicable to PAUSED stage of postcopy, to provide hint on what has
gone wrong.

The error_mutex seems to be overlooked when referencing the error, add it
to be very safe.

This will change QAPI behavior by showing up error message outside !FAILED
status, but it's intended and doesn't expect to break anyone.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-2-peterx@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 2c88739cfd migration/rdma: Replace flawed device detail dump by tracing
qemu_rdma_dump_id() dumps RDMA device details to stdout.

rdma_start_outgoing_migration() calls it via qemu_rdma_source_init()
and qemu_rdma_resolve_host() to show source device details.
rdma_start_incoming_migration() arranges its call via
rdma_accept_incoming_migration() and qemu_rdma_accept() to show
destination device details.

Two issues:

1. rdma_start_outgoing_migration() can run in HMP context.  The
   information should arguably go the monitor, not stdout.

2. ibv_query_port() failure is reported as error.  Its callers remain
   unaware of this failure (qemu_rdma_dump_id() can't fail), so
   reporting this to the user as an error is problematic.

Fixable, but the device detail dump is noise, except when
troubleshooting.  Tracing is a better fit.  Similar function
qemu_rdma_dump_id() was converted to tracing in commit
733252deb8 (Tracify migration/rdma.c).

Convert qemu_rdma_dump_id(), too.

While there, touch up qemu_rdma_dump_gid()'s outdated comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-54-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster ff4c919459 migration/rdma: Use error_report() & friends instead of stderr
error_report() obeys -msg, reports the current error location if any,
and reports to the current monitor if any.  Reporting to stderr
directly with fprintf() or perror() is wrong, because it loses all
this.

Fix the offenders.  Bonus: resolves a FIXME about problematic use of
errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-53-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 5cec563d0c migration/rdma: Downgrade qemu_rdma_cleanup() errors to warnings
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_source_init(), qemu_rdma_connect(),
rdma_start_incoming_migration(), and rdma_start_outgoing_migration()
violate this principle: they call error_report() via
qemu_rdma_cleanup().

Moreover, qemu_rdma_cleanup() can't fail.  It is called on error
paths, and QIOChannel close and finalization.  Are the conditions it
reports really errors?  I doubt it.

Downgrade qemu_rdma_cleanup()'s errors to warnings.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-52-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster b765d21e4a migration/rdma: Silence qemu_rdma_register_and_get_keys()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_write_one() violates this principle: it reports errors to
stderr via qemu_rdma_register_and_get_keys().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up: silence qemu_rdma_register_and_get_keys().  I believe
the caller's error reports suffice.  If they don't, we need to convert
to Error instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-51-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 7555c7713d migration/rdma: Silence qemu_rdma_block_for_wrid()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_post_send_control(), qemu_rdma_exchange_get_response(), and
qemu_rdma_write_one() violate this principle: they call
error_report(), fprintf(stderr, ...), and perror() via
qemu_rdma_block_for_wrid(), qemu_rdma_poll(), and
qemu_rdma_wait_comp_channel().  I elected not to investigate how
callers handle the error, i.e. precise impact is not known.

Clean this up by dropping the error reporting from qemu_rdma_poll(),
qemu_rdma_wait_comp_channel(), and qemu_rdma_block_for_wrid().  I
believe the callers' error reports suffice.  If they don't, we need to
convert to Error instead.

Bonus: resolves a FIXME about problematic use of errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-50-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 8dee156c1d migration/rdma: Don't report received completion events as error
When qemu_rdma_wait_comp_channel() receives an event from the
completion channel, it reports an error "receive cm event while wait
comp channel,cm event is T", where T is the numeric event type.
However, the function fails only when T is a disconnect or device
removal.  Events other than these two are not actually an error, and
reporting them as an error is wrong.  If we need to report them to the
user, we should use something else, and what to use depends on why we
need to report them to the user.

For now, report this error only when the function actually fails.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-49-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 01efb10637 migration/rdma: Silence qemu_rdma_reg_control()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_source_init() and qemu_rdma_accept() violate this principle:
they call error_report() via qemu_rdma_reg_control().  I elected not
to investigate how callers handle the error, i.e. precise impact is
not known.

Clean this up by dropping the error reporting from
qemu_rdma_reg_control().  I believe the callers' error reports
suffice.  If they don't, we need to convert to Error instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-48-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 35b1561e3e migration/rdma: Silence qemu_rdma_connect()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_connect() violates this principle: it calls error_report()
and perror().  I elected not to investigate how callers handle the
error, i.e. precise impact is not known.

Clean this up: replace perror() by changing error_setg() to
error_setg_errno(), and drop error_report().  I believe the callers'
error reports suffice then.  If they don't, we need to convert to
Error instead.

Bonus: resolves a FIXME about problematic use of errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-47-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster e6696d3ee9 migration/rdma: Silence qemu_rdma_resolve_host()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_resolve_host() violates this principle: it calls
error_report().

Clean this up: drop error_report().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-46-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 07d5b94653 migration/rdma: Convert qemu_rdma_alloc_pd_cq() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_source_init() violates this principle: it calls
error_report() via qemu_rdma_alloc_pd_cq().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_alloc_pd_cq() to Error.

The conversion loses a piece of advice on one of two failure paths:

    Your mlock() limits may be too low. Please check $ ulimit -a # and search for 'ulimit -l' in the output

Not worth retaining.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-45-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 3c0c3eba8d migration/rdma: Convert qemu_rdma_post_recv_control() to Error
Just for symmetry with qemu_rdma_post_send_control().  Error messages
lose detail I consider of no use to users.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-44-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster f3805964f8 migration/rdma: Convert qemu_rdma_post_send_control() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_exchange_send() violates this principle: it calls
error_report() via qemu_rdma_post_send_control().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_post_send_control() to Error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-43-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 446e559c43 migration/rdma: Convert qemu_rdma_write() to Error
Just for consistency with qemu_rdma_write_one() and
qemu_rdma_write_flush(), and for slightly simpler code.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-42-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 557c34ca60 migration/rdma: Convert qemu_rdma_write_one() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_write_flush() violates this principle: it calls
error_report() via qemu_rdma_write_one().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_write_one() to Error.  Bonus:
resolves a FIXME about problematic use of errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-41-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 5609547781 migration/rdma: Convert qemu_rdma_write_flush() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qio_channel_rdma_writev() violates this principle: it calls
error_report() via qemu_rdma_write_flush().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_write_flush() to Error.

Necessitates setting an error when qemu_rdma_write_one() failed.
Since this error will go away later in this series, simply use "FIXME
temporary error message" there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-40-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster de1aa35f8d migration/rdma: Convert qemu_rdma_reg_whole_ram_blocks() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_exchange_send() violates this principle: it calls
error_report() via callback qemu_rdma_reg_whole_ram_blocks().  I
elected not to investigate how callers handle the error, i.e. precise
impact is not known.

Clean this up by converting the callback to Error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-39-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 3765ec1f43 migration/rdma: Convert qemu_rdma_exchange_get_response() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_exchange_send() and qemu_rdma_exchange_recv() violate this
principle: they call error_report() via
qemu_rdma_exchange_get_response().  I elected not to investigate how
callers handle the error, i.e. precise impact is not known.

Clean this up by converting qemu_rdma_exchange_get_response() to
Error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-38-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster c4c78dce0b migration/rdma: Convert qemu_rdma_exchange_send() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qio_channel_rdma_writev() violates this principle: it calls
error_report() via qemu_rdma_exchange_send().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_exchange_send() to Error.

Necessitates setting an error when qemu_rdma_post_recv_control(),
callback(), or qemu_rdma_exchange_get_response() failed.  Since these
errors will go away later in this series, simply use "FIXME temporary
error message" there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-37-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 96f363d839 migration/rdma: Convert qemu_rdma_exchange_recv() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qio_channel_rdma_readv() violates this principle: it calls
error_report() via qemu_rdma_exchange_recv().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_exchange_recv() to Error.

Necessitates setting an error when qemu_rdma_exchange_get_response()
failed.  Since this error will go away later in this series, simply
use "FIXME temporary error message" there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-36-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster dcf07e72a4 migration/rdma: Drop "@errp is clear" guards around error_setg()
These guards are all redundant now.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-35-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 071d5ae4f3 migration/rdma: Fix error handling around rdma_getaddrinfo()
qemu_rdma_resolve_host() and qemu_rdma_dest_init() iterate over
addresses to find one that works, holding onto the first Error from
qemu_rdma_broken_ipv6_kernel() for use when no address works.  Issues:

1. If @errp was &error_abort or &error_fatal, we'd terminate instead
   of trying the next address.  Can't actually happen, since no caller
   passes these arguments.

2. When @errp is a pointer to a variable containing NULL, and
   qemu_rdma_broken_ipv6_kernel() fails, the variable no longer
   contains NULL.  Subsequent iterations pass it again, violating
   Error usage rules.  Dangerous, as setting an error would then trip
   error_setv()'s assertion.  Works only because
   qemu_rdma_broken_ipv6_kernel() and the code following the loops
   carefully avoids setting a second error.

3. If qemu_rdma_broken_ipv6_kernel() fails, and then a later iteration
   finds a working address, @errp still holds the first error from
   qemu_rdma_broken_ipv6_kernel().  If we then run into another error,
   we report the qemu_rdma_broken_ipv6_kernel() failure instead.

4. If we don't run into another error, we leak the Error object.

Use a local error variable, and propagate to @errp.  This fixes 3. and
also cleans up 1 and partly 2.

Free this error when we have a working address.  This fixes 4.

Pass the local error variable to qemu_rdma_broken_ipv6_kernel() only
until it fails.  Pass null on any later iterations.  This cleans up
the remainder of 2.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-34-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 8fd471bd77 migration/rdma: Retire macro ERROR()
ERROR() has become "error_setg() unless an error has been set
already".  Hiding the conditional in the macro is in the way of
further work.  Replace the macro uses by their expansion, and delete
the macro.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-33-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster 1718f238d1 migration/rdma: Delete inappropriate error_report() in macro ERROR()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

Macro ERROR() violates this principle.  Delete the error_report()
there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-32-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster e518b0050d migration/rdma: Plug a memory leak and improve a message
When migration capability @rdma-pin-all is true, but the server cannot
honor it, qemu_rdma_connect() calls macro ERROR(), then returns
success.

ERROR() sets an error.  Since qemu_rdma_connect() returns success, its
caller rdma_start_outgoing_migration() duly assumes @errp is still
clear.  The Error object leaks.

ERROR() additionally reports the situation to the user as an error:

    RDMA ERROR: Server cannot support pinning all memory. Will register memory dynamically.

Is this an error or not?  It actually isn't; we disable @rdma-pin-all
and carry on.  "Correcting" the user's configuration decisions that
way feels problematic, but that's a topic for another day.

Replace ERROR() by warn_report().  This plugs the memory leak, and
emits a clearer message to the user.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-31-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 4a10217962 migration/rdma: Check negative error values the same way everywhere
When a function returns 0 on success, negative value on error,
checking for non-zero suffices, but checking for negative is clearer.
So do that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-30-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster c0d77702d2 migration/rdma: Drop superfluous assignments to @ret
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-29-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster b86c94a49e migration/rdma: Replace int error_state by bool errored
All we do with the value of RDMAContext member @error_state is test
whether it's zero.  Change to bool and rename to @errored.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-28-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster ec48697453 migration/rdma: Dumb down remaining int error values to -1
This is just to make the error value more obvious.  Callers don't
mind.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-27-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 8c6513f750 migration/rdma: Return -1 instead of negative errno code
Several functions return negative errno codes on failure.  Callers
check for specific codes exactly never.  For some of the functions,
callers couldn't check even if they wanted to, because the functions
also return negative values that aren't errno codes, leaving readers
confused on what the function actually returns.

Clean up and simplify: return -1 instead of negative errno code.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-26-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 0724982221 migration/rdma: Fix rdma_getaddrinfo() error checking
rdma_getaddrinfo() returns 0 on success.  On error, it returns one of
the EAI_ error codes like getaddrinfo() does, or -1 with errno set.
This is broken by design: POSIX implicitly specifies the EAI_ error
codes to be non-zero, no more.  They could clash with -1.  Nothing we
can do about this design flaw.

Both callers of rdma_getaddrinfo() only recognize negative values as
error.  Works only because systems elect to make the EAI_ error codes
negative.

Best not to rely on that: change the callers to treat any non-zero
value as failure.  Also change them to return -1 instead of the value
received from getaddrinfo() on failure, to avoid positive error
values.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-25-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 0110c6b86a migration/rdma: Fix QEMUFileHooks method return values
The QEMUFileHooks methods don't come with a written contract.  Digging
through the code calling them, we find:

* save_page():

  Negative values RAM_SAVE_CONTROL_DELAYED and
  RAM_SAVE_CONTROL_NOT_SUPP are special.  Any other negative value is
  an unspecified error.

  qemu_rdma_save_page() returns -EIO or rdma->error_state on error.  I
  believe the latter is always negative.  Nothing stops either of them
  to clash with the special values, though.  Feels unlikely, but fix
  it anyway to return only the special values and -1.

* before_ram_iterate(), after_ram_iterate():

  Negative value means error.  qemu_rdma_registration_start() and
  qemu_rdma_registration_stop() comply as far as I can tell.  Make
  them comply *obviously*, by returning -1 on error.

* hook_ram_load:

  Negative value means error.  rdma_load_hook() already returns -1 on
  error.  Leave it alone.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-24-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster d63f4016b1 migration/rdma: Drop dead qemu_rdma_data_init() code for !@host_port
qemu_rdma_data_init() neglects to set an Error when it fails because
@host_port is null.  Fortunately, no caller passes null, so this is
merely a latent bug.  Drop the flawed code handling null argument.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-23-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster f35c0d9b07 migration/rdma: Fix qemu_get_cm_event_timeout() to always set error
qemu_get_cm_event_timeout() neglects to set an error when it fails
because rdma_get_cm_event() fails.  Harmless, as its caller
qemu_rdma_connect() substitutes a generic error then.  Fix it anyway.

qemu_rdma_connect() also sets the generic error when its own call of
rdma_get_cm_event() fails.  Make the error handling more obvious: set
a specific error right after rdma_get_cm_event() fails.  Delete the
generic error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-22-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 142bd685ae migration/rdma: Fix qemu_rdma_broken_ipv6_kernel() to set error
qemu_rdma_resolve_host() and qemu_rdma_dest_init() try addresses until
they find on that works.  If none works, they return the first Error
set by qemu_rdma_broken_ipv6_kernel(), or else return a generic one.

qemu_rdma_broken_ipv6_kernel() neglects to set an Error when
ibv_open_device() fails.  If a later address fails differently, we use
that Error instead, or else the generic one.  Harmless enough, but
needs fixing all the same.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-21-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster de3e05e8b9 migration/rdma: Replace dangerous macro CHECK_ERROR_STATE()
Hiding return statements in macros is a bad idea.  Use a function
instead, and open code the return part.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-20-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 8e262e0b3d migration/rdma: Fix io_writev(), io_readv() methods to obey contract
QIOChannelClass methods qio_channel_rdma_readv() and
qio_channel_rdma_writev() violate their method contract when
rdma->error_state is non-zero:

1. They return whatever is in rdma->error_state then.  Only -1 will be
   fine.  -2 will be misinterpreted as "would block".  Anything less
   than -2 isn't defined in the contract.  A positive value would be
   misinterpreted as success, but I believe that's not actually
   possible.

2. They neglect to set an error then.  If something up the call stack
   dereferences the error when failure is returned, it will crash.  If
   it ignores the return value and checks the error instead, it will
   miss the error.

Crap like this happens when return statements hide in macros,
especially when their uses are far away from the definition.

I elected not to investigate how callers are impacted.

Expand the two bad macro uses, so we can set an error and return -1.
The next commit will then get rid of the macro altogether.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-19-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 1b6e1da6e7 migration/rdma: Ditch useless numeric error codes in error messages
Several error messages include numeric error codes returned by failed
functions:

* ibv_poll_cq() returns an unspecified negative value.  Useless.

* rdma_accept and rdma_get_cm_event() return -1.  Useless.

* qemu_rdma_poll() returns either -1 or an unspecified negative
  value.  Useless.

* qemu_rdma_block_for_wrid(), qemu_rdma_write_flush(),
  qemu_rdma_exchange_send(), qemu_rdma_exchange_recv(),
  qemu_rdma_write() return a negative value that may or may not be an
  errno value.  While reporting human-readable errno
  information (which a number is not) can be useful, reporting an
  error code that may or may not be an errno value is useless.

Drop these error codes from the error messages.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-18-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 0bc2604508 migration/rdma: Fix or document problematic uses of errno
We use errno after calling Libibverbs functions that are not
documented to set errno (manual page does not mention errno), or where
the documentation is unclear ("returns [...] the value of errno on
failure").  While this could be read as "sets errno and returns it",
a glance at the source code[*] kills that hope:

    static inline int ibv_post_send(struct ibv_qp *qp, struct ibv_send_wr *wr,
                                    struct ibv_send_wr **bad_wr)
    {
            return qp->context->ops.post_send(qp, wr, bad_wr);
    }

The callback can be

    static int mana_post_send(struct ibv_qp *ibqp, struct ibv_send_wr *wr,
                              struct ibv_send_wr **bad)
    {
            /* This version of driver supports RAW QP only.
             * Posting WR is done directly in the application.
             */
            return EOPNOTSUPP;
    }

Neither of them touches errno.

One of these errno uses is easy to fix, so do that now.  Several more
will go away later in the series; add temporary FIXME commments.
Three will remain; add TODO comments.  TODO, not FIXME, because the
bug might be in Libibverbs documentation.

[*] https://github.com/linux-rdma/rdma-core.git
    commit 55fa316b4b18f258d8ac1ceb4aa5a7a35b094dcf

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-17-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 89997ac318 migration/rdma: Use bool for two RDMAContext flags
@error_reported and @received_error are flags.  The latter is even
assigned bool true.  Change them from int to bool.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-16-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 6a3792d78d migration/rdma: Make qemu_rdma_buffer_mergeable() return bool
qemu_rdma_buffer_mergeable() is semantically a predicate.  It returns
int 0 or 1.  Return bool instead, and fix the function name's
spelling.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-15-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 87e6bdabf0 migration/rdma: Drop qemu_rdma_search_ram_block() error handling
qemu_rdma_search_ram_block() can't fail.  Return void, and drop the
unreachable error handling.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-14-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 0610d7a1d8 migration/rdma: Drop rdma_add_block() error handling
rdma_add_block() can't fail.  Return void, and drop the unreachable
error handling.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-13-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster b16defbbfe migration/rdma: Eliminate error_propagate()
When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-12-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster 3c03f21cb5 migration/rdma: Put @errp parameter last
include/qapi/error.h demands:

 * - Functions that use Error to report errors have an Error **errp
 *   parameter.  It should be the last parameter, except for functions
 *   taking variable arguments.

qemu_rdma_connect() does not conform.  Clean it up.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-11-armbru@redhat.com>
2023-10-11 11:17:03 +02:00