Now multifd's logic is designed to have no spurious wakeup. I still
remember a talk to Juan and he seems to agree we should drop it now, and if
my memory was right it was there because multifd used to hit that when
still debugging.
Let's drop it and see what can explode; as long as it's not reaching
soft-freeze.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-15-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
This patch redefines the interfacing of ->send_prepare(). It further
simplifies multifd_send_thread() especially on zero copy.
Now with the new interface, we require the hook to do all the work for
preparing the IOVs to send. After it's completed, the IOVs should be ready
to be dumped into the specific multifd QIOChannel later.
So now the API looks like:
p->pages -----------> send_prepare() -------------> IOVs
This also prepares for the case where the input can be extended to even not
any p->pages. But that's for later.
This patch will achieve similar goal of what Fabiano used to propose here:
https://lore.kernel.org/r/20240126221943.26628-1-farosas@suse.de
However the send() interface may not be necessary. I'm boldly attaching a
"Co-developed-by" for Fabiano.
Co-developed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-14-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Introduce a helper multifd_send_prepare_header() to setup the header packet
for multifd sender.
It's fine to setup the IOV[0] _before_ send_prepare() because the packet
buffer is already ready, even if the content is to be filled in.
With this helper, we can already slightly clean up the zero copy path.
Note that I explicitly put it into multifd.h, because I want it inlined
directly into multifd*.c where necessary later.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-13-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Move them into fill/unfill of packets. With that, we can further cleanup
the send/recv thread procedure, and remove one more temp var.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-12-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Just like the previous patch, move the accounting for total_normal_pages on
both src/dst sides into the packet fill/unfill procedures.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-11-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
This field, no matter whether on src or dest, is only used for debugging
purpose.
They can even be removed already, unless it still more or less provide some
accounting on "how many packets are sent/recved for this thread". The
other more important one is called packet_num, which is embeded in the
multifd packet headers (MultiFDPacket_t).
So let's keep them for now, but make them much easier to understand, by
doing below:
- Rename both of them to packets_sent / packets_recved, the old
name (num_packets) are waaay too confusing when we already have
MultiFDPacket_t.packets_num.
- Avoid worrying on the "initial packet": we know we will send it, that's
good enough. The accounting won't matter a great deal to start with 0 or
with 1.
- Move them to where we send/recv the packets. They're:
- multifd_send_fill_packet() for senders.
- multifd_recv_unfill_packet() for receivers.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-10-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
The sender thread will yield the p->mutex before IO starts, trying to not
block the requester thread. This may be unnecessary lock optimizations,
because the requester can already read pending_job safely even without the
lock, because the requester is currently the only one who can assign a
task.
Drop that lock complication on both sides:
(1) in the sender thread, always take the mutex until job done
(2) in the requester thread, check pending_job clear lockless
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-8-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Multifd provide a threaded model for processing jobs. On sender side,
there can be two kinds of job: (1) a list of pages to send, or (2) a sync
request.
The sync request is a very special kind of job. It never contains a page
array, but only a multifd packet telling the dest side to synchronize with
sent pages.
Before this patch, both requests use the pending_job field, no matter what
the request is, it will boost pending_job, while multifd sender thread will
decrement it after it finishes one job.
However this should be racy, because SYNC is special in that it needs to
set p->flags with MULTIFD_FLAG_SYNC, showing that this is a sync request.
Consider a sequence of operations where:
- migration thread enqueue a job to send some pages, pending_job++ (0->1)
- [...before the selected multifd sender thread wakes up...]
- migration thread enqueue another job to sync, pending_job++ (1->2),
setup p->flags=MULTIFD_FLAG_SYNC
- multifd sender thread wakes up, found pending_job==2
- send the 1st packet with MULTIFD_FLAG_SYNC and list of pages
- send the 2nd packet with flags==0 and no pages
This is not expected, because MULTIFD_FLAG_SYNC should hopefully be done
after all the pages are received. Meanwhile, the 2nd packet will be
completely useless, which contains zero information.
I didn't verify above, but I think this issue is still benign in that at
least on the recv side we always receive pages before handling
MULTIFD_FLAG_SYNC. However that's not always guaranteed and just tricky.
One other reason I want to separate it is using p->flags to communicate
between the two threads is also not clearly defined, it's very hard to read
and understand why accessing p->flags is always safe; see the current impl
of multifd_send_thread() where we tried to cache only p->flags. It doesn't
need to be that complicated.
This patch introduces pending_sync, a separate flag just to show that the
requester needs a sync. Alongside, we remove the tricky caching of
p->flags now because after this patch p->flags should only be used by
multifd sender thread now, which will be crystal clear. So it is always
thread safe to access p->flags.
With that, we can also safely convert the pending_job into a boolean,
because we don't support >1 pending jobs anyway.
Always use atomic ops to access both flags to make sure no cache effect.
When at it, drop the initial setting of "pending_job = 0" because it's
always allocated using g_new0().
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-7-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
This array is redundant when p->pages exists. Now we extended the life of
p->pages to the whole period where pending_job is set, it should be safe to
always use p->pages->offset[] rather than p->normal[]. Drop the array.
Alongside, the normal_num is also redundant, which is the same to
p->pages->num.
This doesn't apply to recv side, because there's no extra buffering on recv
side, so p->normal[] array is still needed.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Now we reset MultiFDPages_t object in the multifd sender thread in the
middle of the sending job. That's not necessary, because the "*pages"
struct will not be reused anyway until pending_job is cleared.
Move that to the end after the job is completed, provide a helper to reset
a "*pages" object. Use that same helper when free the object too.
This prepares us to keep using p->pages in the follow up patches, where we
may drop p->normal[].
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-5-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Multifd send side has two fields to indicate error quits:
- MultiFDSendParams.quit
- &multifd_send_state->exiting
Merge them into the global one. The replacement is done by changing all
p->quit checks into the global var check. The global check doesn't need
any lock.
A few more things done on top of this altogether:
- multifd_send_terminate_threads()
Moving the xchg() of &multifd_send_state->exiting upper, so as to cover
the tracepoint, migrate_set_error() and migrate_set_state().
- multifd_send_sync_main()
In the 2nd loop, add one more check over the global var to make sure we
don't keep the looping if QEMU already decided to quit.
- multifd_tls_outgoing_handshake()
Use multifd_send_terminate_threads() to set the error state. That has
a benefit of updating MigrationState.error to that error too, so we can
persist that 1st error we hit in that specific channel.
- multifd_new_send_channel_async()
Take similar approach like above, drop the migrate_set_error() because
multifd_send_terminate_threads() already covers that. Unwrap the helper
multifd_new_send_channel_cleanup() along the way; not really needed.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
When a multifd sender thread hit errors, it always needs to kick the main
thread by kicking all the semaphores that it can be waiting upon.
Provide a helper for it and deduplicate the code.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
We've already done that with multifd_flush_after_each_section, for multifd
in general. Drop the stale "TODO-like" comment.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
A memory page poisoned from the hypervisor level is no longer readable.
The migration of a VM will crash Qemu when it tries to read the
memory address space and stumbles on the poisoned page with a similar
stack trace:
Program terminated with signal SIGBUS, Bus error.
#0 _mm256_loadu_si256
#1 buffer_zero_avx2
#2 select_accel_fn
#3 buffer_is_zero
#4 save_zero_page
#5 ram_save_target_page_legacy
#6 ram_save_host_page
#7 ram_find_and_save_block
#8 ram_save_iterate
#9 qemu_savevm_state_iterate
#10 migration_iteration_run
#11 migration_thread
#12 qemu_thread_start
To avoid this VM crash during the migration, prevent the migration
when a known hardware poison exists on the VM.
Signed-off-by: William Roche <william.roche@oracle.com>
Link: https://lore.kernel.org/r/20240130190640.139364-2-william.roche@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Documentation of commands guest-ssh-get-authorized-keys,
guest-ssh-add-authorized-keys, and guest-ssh-remove-authorized-keys
describes the command's purpose after its arguments. Everywhere else,
we do it the other way round. Move it for consistency.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240129115008.674248-6-armbru@redhat.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Documentation of type BlockdevOptionsIscsi describes the type's
purpose after its members. Everywhere else, we do it the other way
round. Move it for consistency.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240129115008.674248-5-armbru@redhat.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Documentation of BlockExportRemoveMode has
Potential additional modes to be added in the future:
hide: Just hide export from new clients, leave existing connections
as is. Remove export after all clients are disconnected.
soft: Hide export from new clients, answer with ESHUTDOWN for all
further requests from existing clients.
I think this is useful only for developers. Elide it from generated
documentation by turning it into a TODO section.
This effectively reverts my own commit b71fd73cc4 (Revert "qapi:
BlockExportRemoveMode: move comments to TODO"). At the time, I was
about to elide TODO sections from the generated manual, I wasn't sure
about this one, and decided to avoid change. And now I've made up my
mind.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240129115008.674248-4-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Documentation generated for dump-skeys contains
This command is only supported on s390 architecture.
and
If
~~
"TARGET_S390X"
The former became redundant in commit 901a34a400 (qapi: add 'If:'
section to generated documentation) added the latter. Drop the
former.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240129115008.674248-3-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Documentation generated for SchemaInfo looks like
The members of "SchemaInfoBuiltin" when "meta-type" is ""builtin""
The members of "SchemaInfoEnum" when "meta-type" is ""enum""
The members of "SchemaInfoArray" when "meta-type" is ""array""
The members of "SchemaInfoObject" when "meta-type" is ""object""
The members of "SchemaInfoAlternate" when "meta-type" is ""alternate""
The members of "SchemaInfoCommand" when "meta-type" is ""command""
The members of "SchemaInfoEvent" when "meta-type" is ""event""
Additional members depend on the value of "meta-type".
The last line became redundant when commit 88f63467c5 (qapi2texi:
Generate reference to base type members) added the lines preceding it.
Drop it.
BlockdevOptions has the same issue. Drop
Remaining options are determined by the block driver.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240129115008.674248-2-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Without this padding, an unwind through the signal handler
will pick up the unwind info for the preceding syscall.
This fixes gcc's 30_threads/thread/native_handle/cancel.cc.
Cc: qemu-stable@nongnu.org
Fixes: ee95fae075 ("linux-user/aarch64: Add vdso")
Resolves: https://linaro.atlassian.net/browse/GNU-974
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240202034427.504686-1-richard.henderson@linaro.org>
These macros are no longer used.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-23-richard.henderson@linaro.org>
Represent each fcc field separately from the rest of fsr.
This vastly simplifies floating-point comparisons.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-22-richard.henderson@linaro.org>
Drop this field as a tcg global, loading it explicitly in the
few places required. This means that all FPop helpers may
once again be TCG_CALL_NO_WG.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-21-richard.henderson@linaro.org>
These two fields are adjusted by all FPop insns.
Having them separate makes it easier to set without masking.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-20-richard.henderson@linaro.org>
If an exception is to be raised, the destination fp register
should be unmodified. The current implementation is incorrect,
in that double results will be written back before calling
gen_helper_check_ieee_exceptions, despite the placement of
gen_store_fpr_D, since gen_dest_fpr_D returns cpu_fpr[].
We can simplify the entire implementation by having each
FPOp helper call check_ieee_exceptions. For the moment this
requires that all FPop helpers write to the TCG global cpu_fsr,
so remove TCG_CALL_NO_WG from the DEF_HELPER_FLAGS_*.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-19-richard.henderson@linaro.org>
Don't do the clearing explicitly before each FPop,
rather do it as part of the rest of exception handling.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-18-richard.henderson@linaro.org>
This field is read-only. It is easier to store it separately
and merge it only upon read.
While we're at it, use FSR_VER_SHIFT to initialize fpu_version.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-17-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-16-richard.henderson@linaro.org>
These are no longer used for passing data to/from helpers.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-15-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-14-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-13-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-12-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-11-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-10-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-9-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-8-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-7-richard.henderson@linaro.org>
These are simple bit manipulation insns.
Begin using i128 for float128.
Implement FMOVq with do_qq.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-6-richard.henderson@linaro.org>
Use them for trans_FMOVq.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-5-richard.henderson@linaro.org>
Replace with tcg_temp_new_i32.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-4-richard.henderson@linaro.org>
Align the operation to the 32-byte cacheline.
Use 2 i128 instead of 4 i64.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-3-richard.henderson@linaro.org>
Align the operation to the 32-byte cacheline.
Use 2 pair of i128 instead of 8 pair of i32.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20231103173841.33651-2-richard.henderson@linaro.org>
Because there are more call clobbered registers than
call saved registers, we begin with all registers as
call clobbered and then reset those that are saved.
This was missed when we introduced the LSX support.
Cc: qemu-stable@nongnu.org
Fixes: 16288ded94 ("tcg/loongarch64: Lower basic tcg vec ops to LSX")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2136
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20240201233414.500588-1-richard.henderson@linaro.org>
The `if not probe_proc_self_mem` check never passes, because
probe_proc_self_mem is a function object, which is a truthy value.
Add parentheses in order to perform a function call.
Fixes: dc84d50a7f9b ("tests/tcg: Add the PROT_NONE gdbstub test")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20240131220245.235993-1-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
For user-only mode, use MMU_USER_IDX.
For system mode, use CPUClass.mmu_index.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
