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* migration: simplify error reporting after channel readDaniel P. Berrangé2025-10-031-5/+1
| | | | | | | | | | | | | The code handling the return value of qio_channel_read proceses len == 0 (EOF) separately from len < 1 (error), but in both cases ends up calling qemu_file_set_error_obj() with -EIO as the errno. This logic can be merged into one codepath to simplify it. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Prasad Pandit <pjp@fedoraproject.org> Link: https://lore.kernel.org/r/20250801170212.54409-2-berrange@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
* migration: Update qemu_file_get_return_path() docs and remove dead checksArun Menon2025-10-031-1/+0
| | | | | | | | | | | | | | | | | | | | The documentation of qemu_file_get_return_path() states that it can return NULL on failure. However, a review of the current implementation reveals that it is guaranteed that it will always succeed and will never return NULL. As a result, the NULL checks post calling the function become redundant. This commit updates the documentation for the function and removes all NULL checks throughout the migration code. Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Arun Menon <armenon@redhat.com> Tested-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp> Link: https://lore.kernel.org/r/20250918-propagate_tpm_error-v14-12-36f11a6fb9d3@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
* migration: qemu_file_set_blocking(): add errp parameterVladimir Sementsov-Ogievskiy2025-09-191-2/+2
| | | | | | | | | | | | | | | | | | | | qemu_file_set_blocking() is a wrapper on qio_channel_set_blocking(), so let's passthrough the errp. Note the migration should not be using &error_abort in these calls, however, this is done to expedite the API conversion. The original code would have eventually ended up calling either qemu_socket_set_nonblock which would asset on Linux, or g_unix_set_fd_nonblocking which would propagate errors. We never saw asserts in practice, and conceptually they should not happen, but ideally this code will be later adapted to remove use of &error_abort. Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
* migration/qemu-file: don't make incoming fds blocking againVladimir Sementsov-Ogievskiy2025-09-191-1/+2
| | | | | | | | | | | | | | | In migration we want to pass fd "as is", not changing its blocking status. The only current user of these fds is CPR state (through VMSTATE_FD), which of-course doesn't want to modify fds on target when source is still running and use these fds. Suggested-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
* cleanup: Drop pointless return at end of functionMarkus Armbruster2025-04-241-2/+0
| | | | | | | | | | | A few functions now end with a label. The next commit will clean them up. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-ID: <20250407082643.2310002-3-armbru@redhat.com> [Straightforward conflict with commit 988ad4ccebb6 (hw/loongarch/virt: Fix cpuslot::cpu set at last in virt_cpu_plug()) resolved]
* migration: SCM_RIGHTS for QEMUFileSteve Sistare2025-01-291-4/+80
| | | | | | | | | | | | | | Define functions to put/get file descriptors to/from a QEMUFile, for qio channels that support SCM_RIGHTS. Maintain ordering such that put(A), put(fd), put(B) followed by get(A), get(fd), get(B) always succeeds. Other get orderings may succeed but are not guaranteed. Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/1736967650-129648-14-git-send-email-steven.sistare@oracle.com Signed-off-by: Fabiano Rosas <farosas@suse.de>
* migration: remove unnecessary zlib dependencyPaolo Bonzini2024-05-251-1/+0
| | | | | | zlib code is only used by the emulators, not by the tests. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* migration: Remove non-multifd compressionFabiano Rosas2024-05-081-78/+0
| | | | | | | | | | | | | | | The 'compress' migration capability enables the old compression code which has shown issues over the years and is thought to be less stable and tested than the more recent multifd-based compression. The old compression code has been deprecated in 8.2 and now is time to remove it. Deprecation commit 864128df46 ("migration: Deprecate old compression method"). Acked-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Fabiano Rosas <farosas@suse.de>
* migration: Report error when shutdown failsCédric Le Goater2024-03-111-1/+4
| | | | | | | | | | This will help detect issues regarding I/O channels usage. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com> Link: https://lore.kernel.org/r/20240304122844.1888308-7-clg@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com>
* migration/qemu-file: add utility methods for working with seekable channelsFabiano Rosas2024-03-011-0/+106
| | | | | | | | | | Add utility methods that will be needed when implementing 'mapped-ram' migration capability. Signed-off-by: Fabiano Rosas <farosas@suse.de> Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com> Link: https://lore.kernel.org/r/20240229153017.2221-7-farosas@suse.de Signed-off-by: Peter Xu <peterx@redhat.com>
* migration: Refactor error handling in source return pathPeter Xu2023-11-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | rp_state.error was a boolean used to show error happened in return path thread. That's not only duplicating error reporting (migrate_set_error), but also not good enough in that we only do error_report() and set it to true, we never can keep a history of the exact error and show it in query-migrate. To make this better, a few things done: - Use error_setg() rather than error_report() across the whole lifecycle of return path thread, keeping the error in an Error*. - With above, no need to have mark_source_rp_bad(), remove it, alongside with rp_state.error itself. - Use migrate_set_error() to apply that captured error to the global migration object when error occured in this thread. - Do the same when detected qemufile error in source return path We need to re-export qemu_file_get_error_obj() to do the last one. Signed-off-by: Peter Xu <peterx@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: <20231017202633.296756-2-peterx@redhat.com>
* qemu-file: Make qemu_fflush() return errorsJuan Quintela2023-10-311-16/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This let us simplify code of this shape. qemu_fflush(f); int ret = qemu_file_get_error(f); if (ret) { return ret; } into: int ret = qemu_fflush(f); if (ret) { return ret; } I updated all callers where there is any error check. qemu_fclose() don't need to check for f->last_error because qemu_fflush() returns it at the beggining of the function. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231025091117.6342-13-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
* qemu-file: Simplify qemu_file_get_error()Juan Quintela2023-10-311-1/+1
| | | | | | | | If we pass a NULL error is the same that returning directly the value. Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231025091117.6342-10-quintela@redhat.com>
* qemu-file: Remove _noflush from qemu_file_transferred_noflush()Juan Quintela2023-10-311-1/+1
| | | | | | | | | | qemu_file_transferred() don't exist anymore, so we can reuse the name. Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231025091117.6342-7-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
* qemu_file: Remove unused qemu_file_transferred()Juan Quintela2023-10-311-7/+0
| | | | | | Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231025091117.6342-6-quintela@redhat.com>
* qemu_file: total_transferred is not used anymoreJuan Quintela2023-10-311-4/+0
| | | | | | Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231025091117.6342-4-quintela@redhat.com>
* qemu_file: Use a stat64 for qemu_file_transferredJuan Quintela2023-10-311-2/+3
| | | | | | | | | | This way we can read it from any thread. I checked that it gives the same value as the current one. We never use two qemu_files at the same time. Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231025091117.6342-3-quintela@redhat.com>
* qemu-file: Don't increment qemu_file_transferred at qemu_file_fill_bufferJuan Quintela2023-10-311-1/+3
| | | | | | | | | | We only call qemu_file_transferred_* on the sending side. Remove the increment at qemu_file_fill_buffer() and add asserts to qemu_file_transferred* functions. Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231025091117.6342-2-quintela@redhat.com>
* qemu-file: Remove QEMUFileHooksJuan Quintela2023-10-171-6/+0
| | | | | | | | | The only user was rdma, and its use is gone. Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Li Zhijian <lizhijian@fujitsu.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231011203527.9061-8-quintela@redhat.com>
* migration/rdma: Create rdma_control_save_page()Juan Quintela2023-10-171-20/+0
| | | | | | | | | | | The only user of ram_control_save_page() and save_page() hook was rdma. Just move the function to rdma.c, rename it to rdma_control_save_page(). Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Li Zhijian <lizhijian@fujitsu.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231011203527.9061-7-quintela@redhat.com>
* migration/rdma: Unfold hook_ram_load()Juan Quintela2023-10-171-10/+0
| | | | | | | | There is only one flag called with: RAM_CONTROL_BLOCK_REG. Reviewed-by: Li Zhijian <lizhijian@fujitsu.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231011203527.9061-6-quintela@redhat.com>
* migration/rdma: Unfold ram_control_after_iterate()Juan Quintela2023-10-171-12/+0
| | | | | | | | | | | | Once there: - Remove unused data parameter - unfold it in its callers - change all callers to call qemu_rdma_registration_stop() - We need to call QIO_CHANNEL_RDMA() after we check for migrate_rdma() Reviewed-by: Li Zhijian <lizhijian@fujitsu.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231011203527.9061-4-quintela@redhat.com>
* migration/rdma: Unfold ram_control_before_iterate()Juan Quintela2023-10-171-12/+1
| | | | | | | | | | | | | Once there: - Remove unused data parameter - unfold it in its callers. - change all callers to call qemu_rdma_registration_start() - We need to call QIO_CHANNEL_RDMA() after we check for migrate_rdma() Reviewed-by: Li Zhijian <lizhijian@fujitsu.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20231011203527.9061-3-quintela@redhat.com>
* qemufile: Always return a verbose errorPeter Xu2023-10-111-3/+12
| | | | | | | | | | | | | | | | | 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>
* migration/rdma: Simplify the function that saves a pageJuan Quintela2023-09-291-6/+6
| | | | | | | | | | | | | | | | | | | | | When we sent a page through QEMUFile hooks (RDMA) there are three posiblities: - We are not using RDMA. return RAM_SAVE_CONTROL_DELAYED and control_save_page() returns false to let anything else to proceed. - There is one error but we are using RDMA. Then we return a negative value, control_save_page() needs to return true. - Everything goes well and RDMA start the sent of the page asynchronously. It returns RAM_SAVE_CONTROL_DELAYED and we need to return 1 for ram_save_page_legacy. Clear? I know, I know, the interface is as bad as it gets. I think that now it is a bit clearer, but this needs to be done some other way. Reviewed-by: Leonardo Bras <leobras@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-Id: <20230515195709.63843-16-quintela@redhat.com>
* migration: Remove unused qemu_file_credit_transfer()Juan Quintela2023-09-291-5/+0
| | | | | | | | | After this change, nothing abuses QEMUFile to account for data transferrefd during migration. Reviewed-by: Leonardo Bras <leobras@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-Id: <20230515195709.63843-15-quintela@redhat.com>
* migration/rdma: Don't use imaginary transfersJuan Quintela2023-09-291-4/+1
| | | | | | | | | | | RDMA protocol is completely asynchronous, so in qemu_rdma_save_page() they "invent" that a byte has been transferred. And then they call qemu_file_credit_transfer() and ram_transferred_add() with that byte. Just remove that calls as nothing has been sent. Reviewed-by: Leonardo Bras <leobras@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Message-Id: <20230515195709.63843-14-quintela@redhat.com>
* migration/rdma: Split qemu_fopen_rdma() into input/output functionsJuan Quintela2023-07-261-12/+0
| | | | | | | | | This is how everything else in QEMUFile is structured. As a bonus they are three less lines of code. Reviewed-by: Peter Xu <peterx@redhat.com> Message-ID: <20230530183941.7223-17-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
* qemu-file: Make qemu_file_get_error_obj() staticJuan Quintela2023-07-261-1/+1
| | | | | | | | It was not used outside of qemu_file.c anyways. Reviewed-by: Peter Xu <peterx@redhat.com> Message-ID: <20230530183941.7223-21-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
* qemu-file: Simplify qemu_file_shutdown()Juan Quintela2023-07-261-4/+2
| | | | | | Reviewed-by: Peter Xu <peterx@redhat.com> Message-ID: <20230530183941.7223-20-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
* qemu_file: Make qemu_file_is_writable() staticJuan Quintela2023-07-261-1/+1
| | | | | | | | It is not used outside of qemu_file, and it shouldn't. Signed-off-by: Juan Quintela <quintela@redhat.com> Message-ID: <20230530183941.7223-19-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
* qemu-file: Rename qemu_file_transferred_ fast -> noflushJuan Quintela2023-07-261-1/+1
| | | | | | | | | Fast don't say much. Noflush indicates more clearly that it is like qemu_file_transferred but without the flush. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-ID: <20230530183941.7223-2-quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
* migration: We don't need the field rate_limit_used anymoreJuan Quintela2023-05-181-4/+0
| | | | | | | | | | 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>
* migration: Move rate_limit_max and rate_limit_used to migration_statsJuan Quintela2023-05-181-50/+2
| | | | | | | | | | | | | | | | | | | 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>
* qemu-file: Account for rate_limit usage on qemu_fflush()Juan Quintela2023-05-181-4/+3
| | | | | | | | 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>
* migration: Don't use INT64_MAX for unlimited rateJuan Quintela2023-05-181-1/+5
| | | | | | | | 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>
* qemu-file: Remove total from qemu_file_total_transferred_*()Juan Quintela2023-05-151-2/+2
| | | | | | | | 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>
* qemu-file: Make rate_limit_used an uint64_tJuan Quintela2023-05-151-2/+2
| | | | | | | | | | 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>
* qemu-file: make qemu_file_[sg]et_rate_limit() use an uint64_tJuan Quintela2023-05-151-3/+3
| | | | | | | | | 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>
* migration: We set the rate_limit by a secondJuan Quintela2023-05-151-1/+5
| | | | | | | | | | | 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>
* ram compress: Assert that the file buffer matches the resultLukas Straub2023-05-081-0/+11
| | | | | | | | | | | 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>
* qemu-file: Make ram_control_save_page() use accessors for rate_limitJuan Quintela2023-05-051-1/+1
| | | | | | | 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>
* qemu-file: Make total_transferred an uint64_tJuan Quintela2023-05-051-4/+4
| | | | | | | | | 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>
* qemu-file: remove shutdown memberJuan Quintela2023-05-051-7/+3
| | | | | | | | | | | | | 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>
* qemu-file: No need to check for shutdown in qemu_file_rate_limitJuan Quintela2023-05-051-3/+0
| | | | | | | | | | 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>
* migration/rdma: It makes no sense to recive that flag without RDMAJuan Quintela2023-05-051-8/+0
| | | | | | | | | 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>
* migration/rdma: simplify ram_control_load_hook()Juan Quintela2023-05-051-4/+2
| | | | | | Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20230504114443.23891-3-quintela@redhat.com>
* migration: mark mixed functions that can suspendPaolo Bonzini2023-04-201-7/+7
| | | | | | | | | | | | | | | | 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>
* migration/qemu-file: Add qemu_file_get_to_fd()Avihai Horon2023-02-151-0/+34
| | | | | | | | | | | | | 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>
* migration: Fix race on qemu_file_shutdown()Peter Xu2022-11-211-3/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>