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path: root/hw/vfio/migration.c
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2020-11-23vfio: Make migration support experimentalAlex Williamson
Support for migration of vfio devices is still in flux. Developers are attempting to add support for new devices and new architectures, but none are yet readily available for validation. We have concerns whether we're transferring device resources at the right point in the migration, whether we're guaranteeing that updates during pre-copy are migrated, and whether we can provide bit-stream compatibility should any of this change. Even the question of whether devices should participate in dirty page tracking during pre-copy seems contentious. In short, migration support has not had enough soak time and it feels premature to mark it as supported. Create an experimental option such that we can continue to develop. [Retaining previous acks/reviews for a previously identical code change with different specifics in the commit log.] Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Acked-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-12Fix use after free in vfio_migration_probeKirti Wankhede
Fixes Coverity issue: CID 1436126: Memory - illegal accesses (USE_AFTER_FREE) Fixes: a9e271ec9b36 ("vfio: Add migration region initialization and finalize function") Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: David Edmondson <dme@dme.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01qapi: Add VFIO devices migration stats in Migration statsKirti Wankhede
Added amount of bytes transferred to the VM at destination by all VFIO devices Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01vfio: Add function to start and stop dirty pages trackingKirti Wankhede
Call VFIO_IOMMU_DIRTY_PAGES ioctl to start and stop dirty pages tracking for VFIO devices. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01vfio: Get migration capability flags for containerKirti Wankhede
Added helper functions to get IOMMU info capability chain. Added function to get migration capability information from that capability chain for IOMMU container. Similar change was proposed earlier: https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg03759.html Disable migration for devices if IOMMU module doesn't support migration capability. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Cc: Eric Auger <eric.auger@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01vfio: Add load state functions to SaveVMHandlersKirti Wankhede
Sequence during _RESUMING device state: While data for this device is available, repeat below steps: a. read data_offset from where user application should write data. b. write data of data_size to migration region from data_offset. c. write data_size which indicates vendor driver that data is written in staging buffer. For user, data is opaque. User should write data in the same order as received. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Yan Zhao <yan.y.zhao@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01vfio: Add save state functions to SaveVMHandlersKirti Wankhede
Added .save_live_pending, .save_live_iterate and .save_live_complete_precopy functions. These functions handles pre-copy and stop-and-copy phase. In _SAVING|_RUNNING device state or pre-copy phase: - read pending_bytes. If pending_bytes > 0, go through below steps. - read data_offset - indicates kernel driver to write data to staging buffer. - read data_size - amount of data in bytes written by vendor driver in migration region. - read data_size bytes of data from data_offset in the migration region. - Write data packet to file stream as below: {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data, VFIO_MIG_FLAG_END_OF_STATE } In _SAVING device state or stop-and-copy phase a. read config space of device and save to migration file stream. This doesn't need to be from vendor driver. Any other special config state from driver can be saved as data in following iteration. b. read pending_bytes. If pending_bytes > 0, go through below steps. c. read data_offset - indicates kernel driver to write data to staging buffer. d. read data_size - amount of data in bytes written by vendor driver in migration region. e. read data_size bytes of data from data_offset in the migration region. f. Write data packet as below: {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data} g. iterate through steps b to f while (pending_bytes > 0) h. Write {VFIO_MIG_FLAG_END_OF_STATE} When data region is mapped, its user's responsibility to read data from data_offset of data_size before moving to next steps. Added fix suggested by Artem Polyakov to reset pending_bytes in vfio_save_iterate(). Added fix suggested by Zhi Wang to add 0 as data size in migration stream and add END_OF_STATE delimiter to indicate phase complete. Suggested-by: Artem Polyakov <artemp@nvidia.com> Suggested-by: Zhi Wang <zhi.wang.linux@gmail.com> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Yan Zhao <yan.y.zhao@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01vfio: Register SaveVMHandlers for VFIO deviceKirti Wankhede
Define flags to be used as delimiter in migration stream for VFIO devices. Added .save_setup and .save_cleanup functions. Map & unmap migration region from these functions at source during saving or pre-copy phase. Set VFIO device state depending on VM's state. During live migration, VM is running when .save_setup is called, _SAVING | _RUNNING state is set for VFIO device. During save-restore, VM is paused, _SAVING state is set for VFIO device. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Yan Zhao <yan.y.zhao@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01vfio: Add migration state change notifierKirti Wankhede
Added migration state change notifier to get notification on migration state change. These states are translated to VFIO device state and conveyed to vendor driver. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01vfio: Add VM state change handler to know state of VMKirti Wankhede
VM state change handler is called on change in VM's state. Based on VM state, VFIO device state should be changed. Added read/write helper functions for migration region. Added function to set device_state. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> [aw: lx -> HWADDR_PRIx, remove redundant parens] Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-11-01vfio: Add migration region initialization and finalize functionKirti Wankhede
Whether the VFIO device supports migration or not is decided based of migration region query. If migration region query is successful and migration region initialization is successful then migration is supported else migration is blocked. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Neo Jia <cjia@nvidia.com> Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>