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2023-05-18migration: We don't need the field rate_limit_used anymoreJuan Quintela
Since previous commit, we calculate how much data we have send with migration_transferred_bytes() so no need to maintain this counter and remember to always update it. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Message-Id: <20230515195709.63843-10-quintela@redhat.com>
2023-05-18migration: Move rate_limit_max and rate_limit_used to migration_statsJuan Quintela
These way we can make them atomic and use this functions from any place. I also moved all functions that use rate_limit to migration-stats. Functions got renamed, they are not qemu_file anymore. qemu_file_rate_limit -> migration_rate_exceeded qemu_file_set_rate_limit -> migration_rate_set qemu_file_get_rate_limit -> migration_rate_get qemu_file_reset_rate_limit -> migration_rate_reset qemu_file_acct_rate_limit -> migration_rate_account. Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-Id: <20230515195709.63843-6-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-05-18qemu-file: Account for rate_limit usage on qemu_fflush()Juan Quintela
That is the moment we know we have transferred something. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Message-Id: <20230515195709.63843-5-quintela@redhat.com>
2023-05-18migration: Don't use INT64_MAX for unlimited rateJuan Quintela
Define and use RATE_LIMIT_DISABLED instead. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com> Message-Id: <20230515195709.63843-2-quintela@redhat.com>
2023-05-15qemu-file: Remove total from qemu_file_total_transferred_*()Juan Quintela
Function is already quite long. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Message-Id: <20230508130909.65420-7-quintela@redhat.com>
2023-05-15qemu-file: Make rate_limit_used an uint64_tJuan Quintela
Change all the functions that use it. It was already passed as uint64_t. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Message-Id: <20230508130909.65420-6-quintela@redhat.com>
2023-05-15qemu-file: make qemu_file_[sg]et_rate_limit() use an uint64_tJuan Quintela
It is really size_t. Everything else uses uint64_t, so move this to uint64_t as well. A size can't be negative anyways. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Message-Id: <20230508130909.65420-5-quintela@redhat.com>
2023-05-15migration: We set the rate_limit by a secondJuan Quintela
That the implementation does the check every 100 milliseconds is an implementation detail that shouldn't be seen on the interfaz. Notice that all callers of qemu_file_set_rate_limit() used the division or pass 0, so this change is a NOP. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Message-Id: <20230508130909.65420-4-quintela@redhat.com>
2023-05-08ram compress: Assert that the file buffer matches the resultLukas Straub
Before this series, "nothing to send" was handled by the file buffer being empty. Now it is tracked via param->result. Assert that the file buffer state matches the result. Signed-off-by: Lukas Straub <lukasstraub2@web.de> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-05-05qemu-file: Make ram_control_save_page() use accessors for rate_limitJuan Quintela
Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Message-Id: <20230504113841.23130-9-quintela@redhat.com>
2023-05-05qemu-file: Make total_transferred an uint64_tJuan Quintela
Change all the functions that use it. It was already passed as uint64_t. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20230504113841.23130-8-quintela@redhat.com>
2023-05-05qemu-file: remove shutdown memberJuan Quintela
The first thing that we do after setting the shutdown value is set the error as -EIO if there is not a previous error. So this value is redundant. Just remove it and use qemu_file_get_error() in the places that it was tested. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Message-Id: <20230504113841.23130-7-quintela@redhat.com>
2023-05-05qemu-file: No need to check for shutdown in qemu_file_rate_limitJuan Quintela
After calling qemu_file_shutdown() we set the error as -EIO if there is no another previous error, so no need to check it here. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20230504113841.23130-6-quintela@redhat.com>
2023-05-05migration/rdma: It makes no sense to recive that flag without RDMAJuan Quintela
This could only happen if the source sent RAM_SAVE_FLAG_HOOK (i.e. rdma) and destination don't have CONFIG_RDMA. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20230504114443.23891-5-quintela@redhat.com>
2023-05-05migration/rdma: simplify ram_control_load_hook()Juan Quintela
Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20230504114443.23891-3-quintela@redhat.com>
2023-04-20migration: mark mixed functions that can suspendPaolo Bonzini
There should be no paths from a coroutine_fn to aio_poll, however in practice coroutine_mixed_fn will call aio_poll in the !qemu_in_coroutine() path. By marking mixed functions, we can track accurately the call paths that execute entirely in coroutine context, and find more missing coroutine_fn markers. This results in more accurate checks that coroutine code does not end up blocking. If the marking were extended transitively to all functions that call these ones, static analysis could be done much more efficiently. However, this is a start and makes it possible to use vrc's path-based searches to find potential bugs where coroutine_fns call blocking functions. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-02-15migration/qemu-file: Add qemu_file_get_to_fd()Avihai Horon
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>
2022-11-21migration: Fix race on qemu_file_shutdown()Peter Xu
In qemu_file_shutdown(), there's a possible race if with current order of operation. There're two major things to do: (1) Do real shutdown() (e.g. shutdown() syscall on socket) (2) Update qemufile's last_error We must do (2) before (1) otherwise there can be a race condition like: page receiver other thread ------------- ------------ qemu_get_buffer() do shutdown() returns 0 (buffer all zero) (meanwhile we didn't check this retcode) try to detect IO error last_error==NULL, IO okay install ALL-ZERO page set last_error --> guest crash! To fix this, we can also check retval of qemu_get_buffer(), but not all APIs can be properly checked and ultimately we still need to go back to qemu_file_get_error(). E.g. qemu_get_byte() doesn't return error. Maybe some day a rework of qemufile API is really needed, but for now keep using qemu_file_get_error() and fix it by not allowing that race condition to happen. Here shutdown() is indeed special because the last_error was emulated. For real -EIO errors it'll always be set when e.g. sendmsg() error triggers so we won't miss those ones, only shutdown() is a bit tricky here. Cc: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2022-07-20migration: remove unreachable code after reading dataDaniel P. Berrangé
The code calls qio_channel_read() in a loop when it reports QIO_CHANNEL_ERR_BLOCK. This code is reported when errno==EAGAIN. As such the later block of code will always hit the 'errno != EAGAIN' condition, making the final 'else' unreachable. Fixes: Coverity CID 1490203 Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20220627135318.156121-1-berrange@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-07-20migration: Postcopy recover with preempt enabledPeter Xu
To allow postcopy recovery, the ram fast load (preempt-only) dest QEMU thread needs similar handling on fault tolerance. When ram_load_postcopy() fails, instead of stopping the thread it halts with a semaphore, preparing to be kicked again when recovery is detected. A mutex is introduced to make sure there's no concurrent operation upon the socket. To make it simple, the fast ram load thread will take the mutex during its whole procedure, and only release it if it's paused. The fast-path socket will be properly released by the main loading thread safely when there's network failures during postcopy with that mutex held. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20220707185506.27257-1-peterx@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-23migration: remove the QEMUFileOps abstractionDaniel P. Berrangé
Now that all QEMUFile callbacks are removed, the entire concept can be deleted. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-23migration: remove the QEMUFileOps 'get_return_path' callbackDaniel P. Berrangé
This directly implements the get_return_path logic using QIOChannel APIs. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-23migration: remove the QEMUFileOps 'writev_buffer' callbackDaniel P. Berrangé
This directly implements the writev_buffer logic using QIOChannel APIs. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-23migration: remove the QEMUFileOps 'get_buffer' callbackDaniel P. Berrangé
This directly implements the get_buffer logic using QIOChannel APIs. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: Fixup len = *-*EIO as spotted by Peter Xu
2022-06-22migration: remove the QEMUFileOps 'close' callbackDaniel P. Berrangé
This directly implements the close logic using QIOChannel APIs. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-22migration: remove the QEMUFileOps 'set_blocking' callbackDaniel P. Berrangé
This directly implements the set_blocking logic using QIOChannel APIs. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-22migration: remove the QEMUFileOps 'shut_down' callbackDaniel P. Berrangé
This directly implements the shutdown logic using QIOChannel APIs. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-22migration: introduce new constructors for QEMUFileDaniel P. Berrangé
Prepare for the elimination of QEMUFileOps by introducing a pair of new constructors. This lets us distinguish between an input and output file object explicitly rather than via the existance of specific callbacks. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-22migration: hardcode assumption that QEMUFile is backed with QIOChannelDaniel P. Berrangé
The only callers of qemu_fopen_ops pass 'true' for the 'has_ioc' parameter, so hardcode this assumption in QEMUFile, by passing in the QIOChannel object as a non-opaque parameter. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: Fixed long line
2022-06-22migration: stop passing 'opaque' parameter to QEMUFile hooksDaniel P. Berrangé
The only user of the hooks is RDMA which provides a QIOChannel backed impl of QEMUFile. It can thus use the qemu_file_get_ioc() method. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-22migration: rename qemu_file_update_transfer to qemu_file_acct_rate_limitDaniel P. Berrangé
The qemu_file_update_transfer name doesn't give a clear guide on what its purpose is, and how it differs from the qemu_file_credit_transfer method. The latter is specifically for accumulating for total migration traffic, while the former is specifically for accounting in thue rate limit calculations. The new name give better guidance on its usage. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-22migration: rename qemu_update_position to qemu_file_credit_transferDaniel P. Berrangé
The qemu_update_position method name gives the misleading impression that it is changing the current file offset. Most of the files are just streams, however, so there's no concept of a file offset in the general case. What this method is actually used for is to report on the number of bytes that have been transferred out of band from the main I/O methods. This new name better reflects this purpose. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-06-22migration: rename qemu_ftell to qemu_file_total_transferredDaniel P. Berrangé
The name 'ftell' gives the misleading impression that the QEMUFile objects are seekable. This is not the case, as in general we just have an opaque stream. The users of this method are only interested in the total bytes processed. This switches to a new name that reflects the intended usage. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: Wrapped long line
2022-06-22migration: rename 'pos' field in QEMUFile to 'bytes_processed'Daniel P. Berrangé
The field name 'pos' gives the misleading impression that the QEMUFile objects are seekable. This is not the case, as in general we just have an opaque stream. The users of this method are only interested in the total bytes processed. This switches to a new name that reflects the intended usage. Every QIOChannel backed impl of QEMUFile is currently ignoring the 'pos' field. The only QEMUFile impl using 'pos' as an offset for I/O is the block device vmstate. A later patch is introducing a QIOChannel impl for the vmstate, and to handle this it is tracking a file offset itself internally to the QIOChannel impl. So when we later eliminate the QEMUFileOps callbacks later, the 'pos' field will no longer be used from any I/O read/write methods. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: Fixed long line
2022-06-22migration: rename rate limiting fields in QEMUFileDaniel P. Berrangé
This renames the following QEMUFile fields * bytes_xfer -> rate_limit_used * xfer_limit -> rate_limit_max The intent is to make it clear that 'bytes_xfer' is specifically related to rate limiting of data and applies to data queued, which need not have been transferred on the wire yet if a flush hasn't taken place. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2022-02-21include: Move qemu_madvise() and related #defines to new qemu/madvise.hPeter Maydell
The function qemu_madvise() and the QEMU_MADV_* constants associated with it are used in only 10 files. Move them out of osdep.h to a new qemu/madvise.h header that is included where it is needed. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20220208200856.3558249-2-peter.maydell@linaro.org
2021-07-26migration: Teach QEMUFile to be QIOChannel-awarePeter Xu
migration uses QIOChannel typed qemufiles. In follow up patches, we'll need the capability to identify this fact, so that we can get the backing QIOChannel from a QEMUFile. We can also define types for QEMUFile but so far since we only need to be able to identify QIOChannel, introduce a boolean which is simpler. Introduce another helper qemu_file_get_ioc() to return the ioc backend of a qemufile if has_ioc is set. No functional change. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20210722175841.938739-5-peterx@redhat.com> Reviewed-by: Lukas Straub <lukasstraub2@web.de> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-07-05migration: fix the memory overwriting risk in add_to_iovecFeng Lin
When testing migration, a Segmentation fault qemu core is generated. 0 error_free (err=0x1) 1 0x00007f8b862df647 in qemu_fclose (f=f@entry=0x55e06c247640) 2 0x00007f8b8516d59a in migrate_fd_cleanup (s=s@entry=0x55e06c0e1ef0) 3 0x00007f8b8516d66c in migrate_fd_cleanup_bh (opaque=0x55e06c0e1ef0) 4 0x00007f8b8626a47f in aio_bh_poll (ctx=ctx@entry=0x55e06b5a16d0) 5 0x00007f8b8626e71f in aio_dispatch (ctx=0x55e06b5a16d0) 6 0x00007f8b8626a33d in aio_ctx_dispatch (source=<optimized out>, callback=<optimized out>, user_data=<optimized out>) 7 0x00007f8b866bdba4 in g_main_context_dispatch () 8 0x00007f8b8626cde9 in glib_pollfds_poll () 9 0x00007f8b8626ce62 in os_host_main_loop_wait (timeout=<optimized out>) 10 0x00007f8b8626cffd in main_loop_wait (nonblocking=nonblocking@entry=0) 11 0x00007f8b862ef01f in main_loop () Using gdb print the struct QEMUFile f = { ..., iovcnt = 65, last_error = 21984, last_error_obj = 0x1, shutdown = true } Well iovcnt is overflow, because the max size of MAX_IOV_SIZE is 64. struct QEMUFile { ...; struct iovec iov[MAX_IOV_SIZE]; unsigned int iovcnt; int last_error; Error *last_error_obj; bool shutdown; }; iovcnt and last_error is overwrited by add_to_iovec(). Right now, add_to_iovec() increase iovcnt before check the limit. And it seems that add_to_iovec() assumes that iovcnt will set to zero in qemu_fflush(). But qemu_fflush() will directly return when f->shutdown is true. The situation may occur when libvirtd restart during migration, after f->shutdown is set, before calling qemu_file_set_error() in qemu_file_shutdown(). So the safiest way is checking the iovcnt before increasing it. Signed-off-by: Feng Lin <linfeng23@huawei.com> Message-Id: <20210625062138.1899-1-linfeng23@huawei.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Fix typo in 'writeable' which is actually misnamed 'writable'
2021-02-08migration/qemu-file: Fix maybe uninitialized on qemu_get_buffer_in_place()Wainer dos Santos Moschetta
Fixed error when compiling migration/qemu-file.c with -Werror=maybe-uninitialized as shown here: ../migration/qemu-file.c: In function 'qemu_get_buffer_in_place': ../migration/qemu-file.c:604:18: error: 'src' may be used uninitialized in this function [-Werror=maybe-uninitialized] 604 | *buf = src; | ~~~~~^~~~~ cc1: all warnings being treated as errors Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com> Message-Id: <20210128130625.569900-1-wainersm@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-06-26osdep: Make MIN/MAX evaluate arguments only onceEric Blake
I'm not aware of any immediate bugs in qemu where a second runtime evaluation of the arguments to MIN() or MAX() causes a problem, but proactively preventing such abuse is easier than falling prey to an unintended case down the road. At any rate, here's the conversation that sparked the current patch: https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg05718.html Update the MIN/MAX macros to only evaluate their argument once at runtime; this uses typeof(1 ? (a) : (b)) to ensure that we are promoting the temporaries to the same type as the final comparison (we have to trigger type promotion, as typeof(bitfield) won't compile; and we can't use typeof((a) + (b)) or even typeof((a) + 0), as some of our uses of MAX are on void* pointers where such addition is undefined). However, we are unable to work around gcc refusing to compile ({}) in a constant context (such as the array length of a static variable), even when only used in the dead branch of a __builtin_choose_expr(), so we have to provide a second macro pair MIN_CONST and MAX_CONST for use when both arguments are known to be compile-time constants and where the result must also be usable as a constant; this second form evaluates arguments multiple times but that doesn't matter for constants. By using a void expression as the expansion if a non-constant is presented to this second form, we can enlist the compiler to ensure the double evaluation is not attempted on non-constants. Alas, as both macros now rely on compiler intrinsics, they are no longer usable in preprocessor #if conditions; those will just have to be open-coded or the logic rewritten into #define or runtime 'if' conditions (but where the compiler dead-code-elimination will probably still apply). I tested that both gcc 10.1.1 and clang 10.0.0 produce errors for all forms of macro mis-use. As the errors can sometimes be cryptic, I'm demonstrating the gcc output: Use of MIN when MIN_CONST is needed: In file included from /home/eblake/qemu/qemu-img.c:25: /home/eblake/qemu/include/qemu/osdep.h:249:5: error: braced-group within expression allowed only inside a function 249 | ({ \ | ^ /home/eblake/qemu/qemu-img.c:92:12: note: in expansion of macro ‘MIN’ 92 | char array[MIN(1, 2)] = ""; | ^~~ Use of MIN_CONST when MIN is needed: /home/eblake/qemu/qemu-img.c: In function ‘is_allocated_sectors’: /home/eblake/qemu/qemu-img.c:1225:15: error: void value not ignored as it ought to be 1225 | i = MIN_CONST(i, n); | ^ Use of MIN in the preprocessor: In file included from /home/eblake/qemu/accel/tcg/translate-all.c:20: /home/eblake/qemu/accel/tcg/translate-all.c: In function ‘page_check_range’: /home/eblake/qemu/include/qemu/osdep.h:249:6: error: token "{" is not valid in preprocessor expressions 249 | ({ \ | ^ Fix the resulting callsites that used #if or computed a compile-time constant min or max to use the new macros. cpu-defs.h is interesting, as CPU_TLB_DYN_MAX_BITS is sometimes used as a constant and sometimes dynamic. It may be worth improving glib's MIN/MAX definitions to be saner, but that is a task for another day. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20200625162602.700741-1-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-29migration/compress: compress QEMUFile is not writableWei Yang
We open a file with empty_ops for compress QEMUFile, which means this is not writable. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2020-01-29qemu-file: Don't do IO after shutdownJuan Quintela
Be sure that we are not doing neither read/write after shutdown of the QEMUFile. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-09-12migration/qemu-file: fix potential buf waste for extra buf_index adjustmentWei Yang
In add_to_iovec(), qemu_fflush() will be called if iovec is full. If this happens, buf_index is reset. Currently, this is not checked and buf_index would always been adjust with buf size. This is not harmful, but will waste some space in file buffer. This patch make add_to_iovec() return 1 when it has flushed the file. Then the caller could check the return value to see whether it is necessary to adjust the buf_index any more. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20190911132839.23336-3-richard.weiyang@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-09-12migration/qemu-file: remove check on writev_buffer in qemu_put_compression_dataWei Yang
The check of writev_buffer is in qemu_fflush, which means it is not harmful if it is NULL. And removing it will make the code consistent since all other add_to_iovec() is called without the check. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20190911132839.23336-2-richard.weiyang@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-09-12qemu-file: Rework old qemu_fflush commentDr. David Alan Gilbert
Commit 11808bb removed the non-iovec based write support, the comment hung on. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20190823103946.7388-1-dgilbert@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-08-14migration: add qemu_file_update_transfer interfaceIvan Ren
Add qemu_file_update_transfer for just update bytes_xfer for speed limitation. This will be used for further migration feature such as multifd migration. Signed-off-by: Ivan Ren <ivanren@tencent.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <1564464816-21804-2-git-send-email-ivanren@tencent.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-08-14migration: Add error_desc for file channel errorsYury Kotov
Currently, there is no information about error if outgoing migration was failed because of file channel errors. Example (QMP session): -> { "execute": "migrate", "arguments": { "uri": "exec:head -c 1" }} <- { "return": {} } ... -> { "execute": "query-migrate" } <- { "return": { "status": "failed" }} // There is not error's description And even in the QEMU's output there is nothing. This patch 1) Adds errp for the most of QEMUFileOps 2) Adds qemu_file_get_error_obj/qemu_file_set_error_obj 3) And finally using of qemu_file_get_error_obj in migration.c And now, the status for the mentioned fail will be: -> { "execute": "query-migrate" } <- { "return": { "status": "failed", "error-desc": "Unable to write to command: Broken pipe" }} Signed-off-by: Yury Kotov <yury-kotov@yandex-team.ru> Message-Id: <20190422103420.15686-1-yury-kotov@yandex-team.ru> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-06-12Include qemu-common.h exactly where neededMarkus Armbruster
No header includes qemu-common.h after this commit, as prescribed by qemu-common.h's file comment. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190523143508.25387-5-armbru@redhat.com> [Rebased with conflicts resolved automatically, except for include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and net/tap-bsd.c fixed up]
2018-08-22migration: disable RDMA WRITE after postcopy startedLidong Chen
RDMA WRITE operations are performed with no notification to the destination qemu, then the destination qemu can not wakeup. This patch disable RDMA WRITE after postcopy started. Signed-off-by: Lidong Chen <lidongchen@tencent.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-04-25migration: detect compression and decompression errorsXiao Guangrong
Currently the page being compressed is allowed to be updated by the VM on the source QEMU, correspondingly the destination QEMU just ignores the decompression error. However, we completely miss the chance to catch real errors, then the VM is corrupted silently To make the migration more robuster, we copy the page to a buffer first to avoid it being written by VM, then detect and handle the errors of both compression and decompression errors properly Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com> Message-Id: <20180330075128.26919-5-xiaoguangrong@tencent.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>