* Use cmd instead of /bin/sh on Windows.
* Try to auto-detect cmd.exe's path, but default to a hard-coded path.
Note that this will require that gspawn-win[32|64]-helper.exe and
gspawn-win[32|64]-helper-console.exe are included in the Windows binary
distributions (cc: Stefan Weil).
Signed-off-by: "John Berberian, Jr" <jeb.study@gmail.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The QERR_ macros are leftovers from the days of "rich" error objects.
We've been trying to reduce their remaining use.
Get rid of a use of QERR_FEATURE_DISABLED, and improve the somewhat
imprecise error message
(qemu) x_colo_lost_heartbeat
Error: The feature 'colo' is not enabled
to
Error: VM is not in COLO mode
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230207075115.1525-12-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230207075115.1525-2-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Once that res_compatible is removed, they don't make sense anymore.
We remove the _only preffix. And to make things clearer we rename
them to must_precopy and can_postcopy.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Nothing assigns to it after previous commit.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
So remove last assignation of res_compatible.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Finish the conversion from commit fe80c0241d
("migration: using trace_ to replace DPRINTF").
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Add new function qemu_file_get_to_fd() that allows reading data from
QEMUFile and writing it straight into a given fd.
This will be used later in VFIO migration code.
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
0x80 is RAM_SAVE_FLAG_HOOK, it is in qemu-file now.
Bigger usable flag is 0x200, noticing that.
We can reuse RAM_SAVe_FLAG_FULL.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Currently running migration_incoming_state_destroy() without first running
multifd_load_cleanup() will cause a yank error:
qemu-system-x86_64: ../util/yank.c:107: yank_unregister_instance:
Assertion `QLIST_EMPTY(&entry->yankfns)' failed.
(core dumped)
The above error happens in the target host, when multifd is being used
for precopy, and then postcopy is triggered and the migration finishes.
This will crash the VM in the target host.
To avoid that, move multifd_load_cleanup() inside
migration_incoming_state_destroy(), so that the load cleanup becomes part
of the incoming state destroying process.
Running multifd_load_cleanup() twice can become an issue, though, but the
only scenario it could be ran twice is on process_incoming_migration_bh().
So removing this extra call is necessary.
On the other hand, this multifd_load_cleanup() call happens way before the
migration_incoming_state_destroy() and having this happening before
dirty_bitmap_mig_before_vm_start() and vm_start() may be a need.
So introduce a new function multifd_load_shutdown() that will mainly stop
all multifd threads and close their QIOChannels. Then use this function
instead of multifd_load_cleanup() to make sure nothing else is received
before dirty_bitmap_mig_before_vm_start().
Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Current approach will only join threads that are still running.
For the threads not joined, resources or private memory are always kept in
the process space and never reclaimed before process end, and this risks
serious memory leaks.
This should usually not represent a big problem, since multifd migration
is usually just ran at most a few times, and after it succeeds there is
not much to be done before exiting the process.
Yet still, it should not hurt performance to join all of them.
Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Before assigning "p->quit = true" for every multifd channel,
multifd_load_cleanup() will call multifd_recv_terminate_threads() which
already does the same assignment, while protected by a mutex.
So there is no point doing the same assignment again.
Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Since it's introduction in commit f986c3d256 ("migration: Create multifd
migration threads"), multifd_load_cleanup() never returned any value
different than 0, neither set up any error on errp.
Even though, on process_incoming_migration_bh() an if clause uses it's
return value to decide on setting autostart = false, which will never
happen.
In order to simplify the codebase, change multifd_load_cleanup() signature
to 'void multifd_load_cleanup(void)', and for every usage remove error
handling or decision made based on return value != 0.
Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Postcopy with preempt-mode enabled needs two channels to communicate. The
order of channel establishment is not guaranteed. It can happen that the
dest QEMU got the preempt channel connection request before the main
channel is established, then the migration may make no progress even during
precopy due to the wrong order.
To fix it, create the preempt channel only if we know the main channel is
established.
For a general postcopy migration, we delay it until postcopy_start(),
that's where we already went through some part of precopy on the main
channel. To make sure dest QEMU has already established the channel, we
wait until we got the first PONG received. That's something we do at the
start of precopy when postcopy enabled so it's guaranteed to happen sooner
or later.
For a postcopy recovery, we delay it to qemu_savevm_state_resume_prepare()
where we'll have round trips of data on bitmap synchronizations, which
means the main channel must have been established.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This is mostly useless, but useful for us to know whether the main channel
is correctly established without changing the migration protocol.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Since we just dropped the only case where postcopy_preempt_setup() can
return an error, it doesn't need a retval anymore because it never fails.
Move the preempt check to the caller, preparing it to be used elsewhere to
do nothing but as simple as kicking the async connection.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The whole idea of multi-channel checks was not properly done, IMHO.
Currently we check multi-channel in a lot of places, but actually that's
not needed because we only need to check it right after we get the URI and
that should be it.
If the URI check succeeded, we should never need to check it again because
we must have it. If it check fails, we should fail immediately on either
the qmp_migrate or qmp_migrate_incoming, instead of failingg it later after
the connection established.
Neither should we fail any set capabiliities like what we used to do here:
5ad15e8614 ("migration: allow enabling mutilfd for specific protocol only", 2021-10-19)
Because logically the URI will only be set later after the capability is
set, so it doesn't make a lot of sense to check the URI type when setting
the capability, because we're checking the cap with an old URI passed in,
and that may not even be the URI we're going to use later.
This patch mostly reverted all such checks for before, dropping the
variable migrate_allow_multi_channels and helpers. Instead, add a common
helper to check URI for multi-channels for either qmp_migrate and
qmp_migrate_incoming and that should do all the proper checks. The failure
will only trigger with the "migrate" or "migrate_incoming" command, or when
user specified "-incoming xxx" where "xxx" is not "defer".
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is the same with [PATCH v6 1/2], and provides avx512 support for xbzrle_encode_buffer
function to accelerate xbzrle encoding speed. Runtime check of avx512
support and benchmark for this feature are added. Compared with C
version of xbzrle_encode_buffer function, avx512 version can achieve
50%-70% performance improvement on benchmarking. In addition, if dirty
data is randomly located in 4K page, the avx512 version can achieve
almost 140% performance gain.
Signed-off-by: ling xu <ling1.xu@intel.com>
Co-authored-by: Zhou Zhao <zhou.zhao@intel.com>
Co-authored-by: Jun Jin <jun.i.jin@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
I called the helper function from the wrong top level function.
This code was introduced in:
commit c8df4a7aef
Author: Juan Quintela <quintela@redhat.com>
Date: Mon Oct 3 02:00:03 2022 +0200
migration: Split save_live_pending() into state_pending_*
We split the function into to:
- state_pending_estimate: We estimate the remaining state size without
stopping the machine.
- state pending_exact: We calculate the exact amount of remaining
state.
Thanks to Avihai Horon <avihaih@nvidia.com> for finding it.
Fixes:c8df4a7aeffcb46020f610526eea621fa5b0cd47
When we introduced that patch, we enden calling
state_pending_estimate() helper from qemu_savevm_statepending_exact()
and
state_pending_exact() helper from qemu_savevm_statepending_estimate()
This patch fixes it.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
We are going to create a new function for multifd latest in the series.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
We are recalculating ram size continously, when we know that it don't
change during migration. Create a field in RAMState to track it.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
It is just a big if in the middle of the function, and we need two
functions anways.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
Reindent to make Phillipe happy (and CODING_STYLE)
We used to return two bools, just return a single int with the
following meaning:
old return / again / new return
false false PAGE_ALL_CLEAN
false true PAGE_TRY_AGAIN
true true PAGE_DIRTY_FOUND /* We don't care about again at all */
Signed-off-by: Juan Quintela <quintela@redhat.com>
We will need later that find_dirty_block() return errors, so
simplify the loop.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Cleanup multifd_channel_connect
Signed-off-by: Li Zhang <lizhang@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
I introduced spurious files on my tree during a rebase:
commit ebfc578715
Author: Zhenzhong Duan <zhenzhong.duan@intel.com>
Date: Mon Oct 17 15:53:51 2022 +0800
multifd: Fix flush of zero copy page send request
Make IO channel flush call after the inflight request has been drained
in multifd thread, or else we may missed to flush the inflight request.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
To make things worse, it appears like Zhenzhong is the one to blame.
for(int i=0; i < 1000000; i++) {
printf("I will not do rebases when I am tired\n");
}
Sorry, Juan.
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Tracked down with the help of scripts/clean-includes.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230202133830.2152150-21-armbru@redhat.com>
To support query migration thread infomation, save and delete
thread(live_migration and multifdsend) information at thread
creation and finish.
Signed-off-by: Jiang Jiacheng <jiangjiacheng@huawei.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Introduce interface query-migrationthreads. The interface is used
to query information about migration threads and returns with
migration thread's name and its id.
Introduce threadinfo.c to manage threads with migration.
Signed-off-by: Jiang Jiacheng <jiangjiacheng@huawei.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Make IO channel flush call after the inflight request has been drained
in multifd thread, or else we may missed to flush the inflight request.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
In multifd_queue_page() MultiFDPages_t.block is checked twice.
Between the two checks, MultiFDPages_t.block may be reset to NULL
by multifd thread. This lead to the 2nd check always true then a
redundant page submitted to multifd thread again.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Current logic assumes that channel connections on the destination side are
always established in the same order as the source and the first one will
always be the main channel followed by the multifid or post-copy
preemption channel. This may not be always true, as even if a channel has a
connection established on the source side it can be in the pending state on
the destination side and a newer connection can be established first.
Basically causing out of order mapping of channels on the destination side.
Currently, all channels except post-copy preempt send a magic number, this
patch uses that magic number to decide the type of channel. This logic is
applicable only for precopy(multifd) live migration, as mentioned, the
post-copy preempt channel does not send any magic number. Also, tls live
migrations already does tls handshake before creating other channels, so
this issue is not possible with tls, hence this logic is avoided for tls
live migrations. This patch uses read peek to check the magic number of
channels so that current data/control stream management remains
un-effected.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Suggested-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: manish.mishra <manish.mishra@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
MSG_PEEK peeks at the channel, The data is treated as unread and
the next read shall still return this data. This support is
currently added only for socket class. Extra parameter 'flags'
is added to io_readv calls to pass extra read flags like MSG_PEEK.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Suggested-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: manish.mishra <manish.mishra@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The value of "Sample Pages" is confusing in mode other than page-sampling.
See below:
(qemu) calc_dirty_rate -b 10 520
(qemu) info dirty_rate
Status: measuring
Start Time: 11646834 (ms)
Sample Pages: 520 (per GB)
Period: 10 (sec)
Mode: dirty-bitmap
Dirty rate: (not ready)
(qemu) info dirty_rate
Status: measured
Start Time: 11646834 (ms)
Sample Pages: 0 (per GB)
Period: 10 (sec)
Mode: dirty-bitmap
Dirty rate: 2 (MB/s)
While it's totally useless in dirty-ring and dirty-bitmap mode, fix to
show it only in page-sampling mode.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Perform a check on vmsd structures during test runs in the hope
of catching any missing terminators and other simple screwups.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
We fairly regularly forget VMSTATE_END_OF_LIST markers off descriptions;
given that the current check is only for ->name being NULL, sometimes
we get unlucky and the code apparently works and no one spots the error.
Explicitly add a flag, VMS_END that should be set, and assert it is
set during the traversal.
Note: This can't go in until we update the copy of vmstate.h in slirp.
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
upon errors. As the documentation in include/io/channel.h states, only
-1 and QIO_CHANNEL_ERR_BLOCK should be returned upon error. Other
values have the potential to confuse the call sites.
error_setg is used rather than error_setg_errno, because there are
certain code paths where -1 (as a non-errno) is propagated up (e.g.
starting from qemu_rdma_block_for_wrid or qemu_rdma_post_recv_control)
all the way to qio_channel_rdma_{readv,writev}.
Similar to a216ec85b7 ("migration/channel-block: fix return value for
qio_channel_block_{readv,writev}").
Suggested-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The downtime should be displayed during postcopy phase because the
switchover phase is done. OTOH it's weird to show "expected downtime"
which can confuse what does that mean if the switchover has already
happened anyway.
This is a slight ABI change on QMP, but I assume it shouldn't affect
anyone.
Reviewed-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Let's factor out this check, to be used in virtio-mem context next.
While at it, fix a spelling error in a related comment.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>S
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
For virtio-mem, we want to have the plugged/unplugged state of memory
blocks available before migrating any actual RAM content, and perform
sanity checks before touching anything on the destination. This
information is immutable on the migration source while migration is active,
We want to use this information for proper preallocation support with
migration: currently, we don't preallocate memory on the migration target,
and especially with hugetlb, we can easily run out of hugetlb pages during
RAM migration and will crash (SIGBUS) instead of catching this gracefully
via preallocation.
Migrating device state via a VMSD before we start iterating is currently
impossible: the only approach that would be possible is avoiding a VMSD
and migrating state manually during save_setup(), to be restored during
load_state().
Let's allow for migrating device state via a VMSD early, during the
setup phase in qemu_savevm_state_setup(). To keep it simple, we
indicate applicable VMSD's using an "early_setup" flag.
Note that only very selected devices (i.e., ones seriously messing with
RAM setup) are supposed to make use of such early state migration.
While at it, also use a bool for the "unmigratable" member.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>S
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
... and store it in the migration state. This is a preparation for
storing selected vmds's already in qemu_savevm_state_setup().
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Let's move more code into vmstate_save(), reducing code duplication and
preparing for reuse of vmstate_save() in qemu_savevm_state_setup(). We
have to move vmstate_save() to make the compiler happy.
We'll now also trace from qemu_save_device_state(), triggering the same
tracepoints as previously called from
qemu_savevm_state_complete_precopy_non_iterable() only. Note that
qemu_save_device_state() ignores iterable device state, such as RAM,
and consequently doesn't trigger some other trace points (e.g.,
trace_savevm_state_setup()).
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
ram_block_populate_read() already optimizes for RamDiscardManager.
However, ram_write_tracking_start() will still try protecting discarded
memory ranges.
Let's optimize, because discarded ranges don't map any pages and
(1) For anonymous memory, trying to protect using uffd-wp without a mapped
page is ignored by the kernel and consequently a NOP.
(2) For shared/file-backed memory, we will fill present page tables in the
range with PTE markers. However, we will even allocate page tables
just to fill them with unnecessary PTE markers and effectively
waste memory.
So let's exclude these ranges, just like ram_block_populate_read()
already does.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
ram_mig_ram_block_resized() will abort migration (including background
snapshots) when resizing a RAMBlock. ram_block_populate_read() will only
populate RAM up to used_length, so at least for anonymous memory
protecting everything between used_length and max_length won't
actually be protected and is just a NOP.
So let's only protect everything up to used_length.
Note: it still makes sense to register uffd-wp for max_length, such
that RAM_UF_WRITEPROTECT is independent of a changing used_length.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
When unregistering uffd-wp, older kernels before commit f369b07c86143
("mm/uffd:reset write protection when unregister with wp-mode") won't
clear the uffd-wp PTE bit. When re-registering uffd-wp, the previous
uffd-wp PTE bits would trigger again. With above commit, the kernel will
clear the uffd-wp PTE bits when unregistering itself.
Consequently, we'll clear the uffd-wp PTE bits now twice -- whereby we
don't care about clearing them at all: a new background snapshot will
re-register uffd-wp and re-protect all memory either way.
So let's skip the manual clearing of uffd-wp. If ever relevant, we
could clear conditionally in uffd_unregister_memory() -- we just need a
way to figure out more recent kernels.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
If something goes wrong during uffd_change_protection(), we would miss
to unregister uffd-wp and not release our reference. Fix it by
performing the uffd_change_protection(true) last.
Note that a uffd_change_protection(false) on the recovery path without a
prior uffd_change_protection(false) is fine.
Fixes: 278e2f551a ("migration: support UFFD write fault processing in ram_save_iterate()")
Cc: qemu-stable@nongnu.org
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Unfortunately, commit f7b9dcfbcf broke populate_read_range(): the loop
end condition is very wrong, resulting in that function not populating the
full range. Lets' fix that.
Fixes: f7b9dcfbcf ("migration/ram: Factor out populating pages readable in ram_block_populate_pages()")
Cc: qemu-stable@nongnu.org
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Add a helper to create the uffd handle.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
