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* migration: cpr-transfer modeSteve Sistare2025-01-291-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the cpr-transfer migration mode, which allows the user to transfer a guest to a new QEMU instance on the same host with minimal guest pause time, by preserving guest RAM in place, albeit with new virtual addresses in new QEMU, and by preserving device file descriptors. Pages that were locked in memory for DMA in old QEMU remain locked in new QEMU, because the descriptor of the device that locked them remains open. cpr-transfer preserves memory and devices descriptors by sending them to new QEMU over a unix domain socket using SCM_RIGHTS. Such CPR state cannot be sent over the normal migration channel, because devices and backends are created prior to reading the channel, so this mode sends CPR state over a second "cpr" migration channel. New QEMU reads the cpr channel prior to creating devices or backends. The user specifies the cpr channel in the channel arguments on the outgoing side, and in a second -incoming command-line parameter on the incoming side. The user must start old QEMU with the the '-machine aux-ram-share=on' option, which allows anonymous memory to be transferred in place to the new process by transferring a memory descriptor for each ram block. Memory-backend objects must have the share=on attribute, but memory-backend-epc is not supported. The user starts new QEMU on the same host as old QEMU, with command-line arguments to create the same machine, plus the -incoming option for the main migration channel, like normal live migration. In addition, the user adds a second -incoming option with channel type "cpr". This CPR channel must support file descriptor transfer with SCM_RIGHTS, i.e. it must be a UNIX domain socket. To initiate CPR, the user issues a migrate command to old QEMU, adding a second migration channel of type "cpr" in the channels argument. Old QEMU stops the VM, saves state to the migration channels, and enters the postmigrate state. New QEMU mmap's memory descriptors, and execution resumes. The implementation splits qmp_migrate into start and finish functions. Start sends CPR state to new QEMU, which responds by closing the CPR channel. Old QEMU detects the HUP then calls finish, which connects the main migration channel. In summary, the usage is: qemu-system-$arch -machine aux-ram-share=on ... start new QEMU with "-incoming <main-uri> -incoming <cpr-channel>" Issue commands to old QEMU: migrate_set_parameter mode cpr-transfer {"execute": "migrate", ... {"channel-type": "main"...}, {"channel-type": "cpr"...} ... } Signed-off-by: Steve Sistare <steven.sistare@oracle.com> Reviewed-by: Peter Xu <peterx@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Link: https://lore.kernel.org/r/1736967650-129648-17-git-send-email-steven.sistare@oracle.com Signed-off-by: Fabiano Rosas <farosas@suse.de>
* cpu: Move CPUClass::vmsd to SysemuCPUOpsPhilippe Mathieu-Daudé2021-05-261-2/+0
| | | | | | | | | | | | | Migration is specific to system emulation. - Move the CPUClass::vmsd field to SysemuCPUOps, - restrict VMSTATE_CPU() macro to sysemu, - vmstate_dummy is now unused, remove it. Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20210517105140.1062037-16-f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
* migration: Change SaveStateEntry.instance_id into uint32_tPeter Xu2020-01-201-1/+1
| | | | | | | | | | | | It was always used as 32bit, so define it as used to be clear. Instead of using -1 as the auto-gen magic value, we switch to UINT32_MAX. We also make sure that we don't auto-gen this value to avoid overflowed instance IDs without being noticed. Suggested-by: Juan Quintela <quintela@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>
* vmstate: replace DeviceState with VMStateIfMarc-André Lureau2020-01-061-2/+2
| | | | | | | | | Replace DeviceState dependency with VMStateIf on vmstate API. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Acked-by: Halil Pasic <pasic@linux.ibm.com>
* Include qemu-common.h exactly where neededMarkus Armbruster2019-06-121-1/+0
| | | | | | | | | | | | | | | | 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]
* migration: Move check_migratable() into qdev.cJuan Quintela2017-05-171-3/+2
| | | | | | | | | The function is only used once, and nothing else in migration knows about objects. Create the function vmstate_device_is_migratable() in savem.c that really do the bit that is related with migration. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com>
* migrate: Introduce a 'dc->vmsd' check to avoid segfault for --only-migratableAshijeet Acharya2017-02-281-0/+6
| | | | | | | | | | | | | | | | | | | | Commit a3a3d8c7 introduced a segfault bug while checking for 'dc->vmsd->unmigratable' which caused QEMU to crash when trying to add devices which do no set their 'dc->vmsd' yet while initialization. Place a 'dc->vmsd' check prior to it so that we do not segfault for such devices. NOTE: This doesn't compromise the functioning of --only-migratable option as all the unmigratable devices do set their 'dc->vmsd'. Introduce a new function check_migratable() and move the only_migratable check inside it, also use stubs to avoid user-mode qemu build failures. Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com> Message-Id: <1487009088-23891-1-git-send-email-ashijeetacharya@gmail.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
* vmstate_register_with_alias_id: Take an Error **Dr. David Alan Gilbert2017-02-061-1/+2
| | | | | | | | | I'll be adding an error to it in a subsequent patch. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20170202125956.21942-2-dgilbert@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
* tests: cleanup ptimer-testPaolo Bonzini2016-10-171-5/+0
| | | | | | | | | | | | 1) ptimer-test is not a qtest---it runs the ptimer.c code directly in the ptimer-test process 2) ptimer-test has its own stubs file, so there is no need to add more stubs to stubs/vmstate.c Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* tests: Add ptimer testsDmitry Osipenko2016-09-221-0/+5
| | | | | | | | | | Ptimer is a generic countdown timer helper that is used by many timer device models as well as by the QEMU core. Add QTests for the ptimer. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Message-id: 1de89fe6e1ccaf6c8071ee3469e1a844df948359.1473252818.git.digetx@gmail.com Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* stubs: Clean up includesPeter Maydell2016-02-041-0/+1
| | | | | | | | | | Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1454089805-5470-3-git-send-email-peter.maydell@linaro.org
* stubs: Add a vmstate_dummy struct for CONFIG_USER_ONLYAndreas Färber2013-03-121-0/+2
| | | | | | Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Andreas Färber <afaerber@suse.de>
* libqemustub: vmstate register/unregister stubsEduardo Habkost2013-01-081-0/+17
Add vmstate stub functions, so that qdev.o can be used without savevm.o when vmstate support is not necessary (i.e. by *-user). Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Andreas Färber <afaerber@suse.de>