-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
vfio/virtio: Add support for the basic live migration functionality
Add support for basic live migration functionality in VFIO over virtio-net devices, aligned with the virtio device specification 1.4. This includes the following VFIO features: VFIO_MIGRATION_STOP_COPY, VFIO_MIGRATION_P2P. The implementation registers with the VFIO subsystem using vfio_pci_core and then incorporates the virtio-specific logic for the migration process. The migration follows the definitions in uapi/vfio.h and leverages the virtio VF-to-PF admin queue command channel for execution device parts related commands. Additional Notes: ----------------- The kernel protocol between the source and target devices contains a header with metadata, including record size, tag, and flags. The record size allows the target to recognize and read a complete image from the source before passing the device part data. This adheres to the virtio device specification, which mandates that partial device parts cannot be supplied. The tag and flags serve as placeholders for future extensions of the kernel protocol between the source and target, ensuring backward and forward compatibility. Both the source and target comply with the virtio device specification by using a device part object with a unique ID as part of the migration process. Since this resource is limited to a maximum of 255, its lifecycle is confined to periods with an active live migration flow. According to the virtio specification, a device has only two modes: RUNNING and STOPPED. As a result, certain VFIO transitions (i.e., RUNNING_P2P->STOP, STOP->RUNNING_P2P) are treated as no-ops. When transitioning to RUNNING_P2P, the device state is set to STOP, and it will remain STOPPED until the transition out of RUNNING_P2P->RUNNING, at which point it returns to RUNNING. During transition to STOP, the virtio device only stops initiating outgoing requests(e.g. DMA, MSIx, etc.) but still must accept incoming operations. Signed-off-by: Yishai Hadas <yishaih@nvidia.com> Link: https://lore.kernel.org/r/20241113115200.209269-6-yishaih@nvidia.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
- Loading branch information
Yishai Hadas
authored and
Alex Williamson
committed
Nov 13, 2024
1 parent
52a22c0
commit 0bbc82e
Showing
4 changed files
with
1,285 additions
and
25 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,3 +1,3 @@ | ||
| # SPDX-License-Identifier: GPL-2.0-only | ||
| obj-$(CONFIG_VIRTIO_VFIO_PCI) += virtio-vfio-pci.o | ||
| virtio-vfio-pci-y := main.o | ||
| virtio-vfio-pci-y := main.o migrate.o |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,104 @@ | ||
| /* SPDX-License-Identifier: GPL-2.0 */ | ||
|
|
||
| #ifndef VIRTIO_VFIO_COMMON_H | ||
| #define VIRTIO_VFIO_COMMON_H | ||
|
|
||
| #include <linux/kernel.h> | ||
| #include <linux/virtio.h> | ||
| #include <linux/vfio_pci_core.h> | ||
| #include <linux/virtio_pci.h> | ||
|
|
||
| enum virtiovf_migf_state { | ||
| VIRTIOVF_MIGF_STATE_ERROR = 1, | ||
| }; | ||
|
|
||
| enum virtiovf_load_state { | ||
| VIRTIOVF_LOAD_STATE_READ_HEADER, | ||
| VIRTIOVF_LOAD_STATE_PREP_HEADER_DATA, | ||
| VIRTIOVF_LOAD_STATE_READ_HEADER_DATA, | ||
| VIRTIOVF_LOAD_STATE_PREP_CHUNK, | ||
| VIRTIOVF_LOAD_STATE_READ_CHUNK, | ||
| VIRTIOVF_LOAD_STATE_LOAD_CHUNK, | ||
| }; | ||
|
|
||
| struct virtiovf_data_buffer { | ||
| struct sg_append_table table; | ||
| loff_t start_pos; | ||
| u64 length; | ||
| u64 allocated_length; | ||
| struct list_head buf_elm; | ||
| u8 include_header_object:1; | ||
| struct virtiovf_migration_file *migf; | ||
| /* Optimize virtiovf_get_migration_page() for sequential access */ | ||
| struct scatterlist *last_offset_sg; | ||
| unsigned int sg_last_entry; | ||
| unsigned long last_offset; | ||
| }; | ||
|
|
||
| enum virtiovf_migf_header_flags { | ||
| VIRTIOVF_MIGF_HEADER_FLAGS_TAG_MANDATORY = 0, | ||
| VIRTIOVF_MIGF_HEADER_FLAGS_TAG_OPTIONAL = 1 << 0, | ||
| }; | ||
|
|
||
| enum virtiovf_migf_header_tag { | ||
| VIRTIOVF_MIGF_HEADER_TAG_DEVICE_DATA = 0, | ||
| }; | ||
|
|
||
| struct virtiovf_migration_header { | ||
| __le64 record_size; | ||
| /* For future use in case we may need to change the kernel protocol */ | ||
| __le32 flags; /* Use virtiovf_migf_header_flags */ | ||
| __le32 tag; /* Use virtiovf_migf_header_tag */ | ||
| __u8 data[]; /* Its size is given in the record_size */ | ||
| }; | ||
|
|
||
| struct virtiovf_migration_file { | ||
| struct file *filp; | ||
| /* synchronize access to the file state */ | ||
| struct mutex lock; | ||
| loff_t max_pos; | ||
| u64 record_size; | ||
| u32 record_tag; | ||
| u8 has_obj_id:1; | ||
| u32 obj_id; | ||
| enum virtiovf_migf_state state; | ||
| enum virtiovf_load_state load_state; | ||
| /* synchronize access to the lists */ | ||
| spinlock_t list_lock; | ||
| struct list_head buf_list; | ||
| struct list_head avail_list; | ||
| struct virtiovf_data_buffer *buf; | ||
| struct virtiovf_data_buffer *buf_header; | ||
| struct virtiovf_pci_core_device *virtvdev; | ||
| }; | ||
|
|
||
| struct virtiovf_pci_core_device { | ||
| struct vfio_pci_core_device core_device; | ||
| u8 *bar0_virtual_buf; | ||
| /* synchronize access to the virtual buf */ | ||
| struct mutex bar_mutex; | ||
| void __iomem *notify_addr; | ||
| u64 notify_offset; | ||
| __le32 pci_base_addr_0; | ||
| __le16 pci_cmd; | ||
| u8 bar0_virtual_buf_size; | ||
| u8 notify_bar; | ||
|
|
||
| /* LM related */ | ||
| u8 migrate_cap:1; | ||
| u8 deferred_reset:1; | ||
| /* protect migration state */ | ||
| struct mutex state_mutex; | ||
| enum vfio_device_mig_state mig_state; | ||
| /* protect the reset_done flow */ | ||
| spinlock_t reset_lock; | ||
| struct virtiovf_migration_file *resuming_migf; | ||
| struct virtiovf_migration_file *saving_migf; | ||
| }; | ||
|
|
||
| void virtiovf_set_migratable(struct virtiovf_pci_core_device *virtvdev); | ||
| void virtiovf_open_migration(struct virtiovf_pci_core_device *virtvdev); | ||
| void virtiovf_close_migration(struct virtiovf_pci_core_device *virtvdev); | ||
| void virtiovf_migration_reset_done(struct pci_dev *pdev); | ||
|
|
||
| #endif /* VIRTIO_VFIO_COMMON_H */ |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.