diff options
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/vfio.h | 406 |
1 files changed, 195 insertions, 211 deletions
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index ef33ea002b0b..fea86061b44e 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -323,7 +323,7 @@ struct vfio_region_info_cap_type { #define VFIO_REGION_TYPE_PCI_VENDOR_MASK (0xffff) #define VFIO_REGION_TYPE_GFX (1) #define VFIO_REGION_TYPE_CCW (2) -#define VFIO_REGION_TYPE_MIGRATION (3) +#define VFIO_REGION_TYPE_MIGRATION_DEPRECATED (3) /* sub-types for VFIO_REGION_TYPE_PCI_* */ @@ -405,225 +405,29 @@ struct vfio_region_gfx_edid { #define VFIO_REGION_SUBTYPE_CCW_CRW (3) /* sub-types for VFIO_REGION_TYPE_MIGRATION */ -#define VFIO_REGION_SUBTYPE_MIGRATION (1) - -/* - * The structure vfio_device_migration_info is placed at the 0th offset of - * the VFIO_REGION_SUBTYPE_MIGRATION region to get and set VFIO device related - * migration information. Field accesses from this structure are only supported - * at their native width and alignment. Otherwise, the result is undefined and - * vendor drivers should return an error. - * - * device_state: (read/write) - * - The user application writes to this field to inform the vendor driver - * about the device state to be transitioned to. - * - The vendor driver should take the necessary actions to change the - * device state. After successful transition to a given state, the - * vendor driver should return success on write(device_state, state) - * system call. If the device state transition fails, the vendor driver - * should return an appropriate -errno for the fault condition. - * - On the user application side, if the device state transition fails, - * that is, if write(device_state, state) returns an error, read - * device_state again to determine the current state of the device from - * the vendor driver. - * - The vendor driver should return previous state of the device unless - * the vendor driver has encountered an internal error, in which case - * the vendor driver may report the device_state VFIO_DEVICE_STATE_ERROR. - * - The user application must use the device reset ioctl to recover the - * device from VFIO_DEVICE_STATE_ERROR state. If the device is - * indicated to be in a valid device state by reading device_state, the - * user application may attempt to transition the device to any valid - * state reachable from the current state or terminate itself. - * - * device_state consists of 3 bits: - * - If bit 0 is set, it indicates the _RUNNING state. If bit 0 is clear, - * it indicates the _STOP state. When the device state is changed to - * _STOP, driver should stop the device before write() returns. - * - If bit 1 is set, it indicates the _SAVING state, which means that the - * driver should start gathering device state information that will be - * provided to the VFIO user application to save the device's state. - * - If bit 2 is set, it indicates the _RESUMING state, which means that - * the driver should prepare to resume the device. Data provided through - * the migration region should be used to resume the device. - * Bits 3 - 31 are reserved for future use. To preserve them, the user - * application should perform a read-modify-write operation on this - * field when modifying the specified bits. - * - * +------- _RESUMING - * |+------ _SAVING - * ||+----- _RUNNING - * ||| - * 000b => Device Stopped, not saving or resuming - * 001b => Device running, which is the default state - * 010b => Stop the device & save the device state, stop-and-copy state - * 011b => Device running and save the device state, pre-copy state - * 100b => Device stopped and the device state is resuming - * 101b => Invalid state - * 110b => Error state - * 111b => Invalid state - * - * State transitions: - * - * _RESUMING _RUNNING Pre-copy Stop-and-copy _STOP - * (100b) (001b) (011b) (010b) (000b) - * 0. Running or default state - * | - * - * 1. Normal Shutdown (optional) - * |------------------------------------->| - * - * 2. Save the state or suspend - * |------------------------->|---------->| - * - * 3. Save the state during live migration - * |----------->|------------>|---------->| - * - * 4. Resuming - * |<---------| - * - * 5. Resumed - * |--------->| - * - * 0. Default state of VFIO device is _RUNNING when the user application starts. - * 1. During normal shutdown of the user application, the user application may - * optionally change the VFIO device state from _RUNNING to _STOP. This - * transition is optional. The vendor driver must support this transition but - * must not require it. - * 2. When the user application saves state or suspends the application, the - * device state transitions from _RUNNING to stop-and-copy and then to _STOP. - * On state transition from _RUNNING to stop-and-copy, driver must stop the - * device, save the device state and send it to the application through the - * migration region. The sequence to be followed for such transition is given - * below. - * 3. In live migration of user application, the state transitions from _RUNNING - * to pre-copy, to stop-and-copy, and to _STOP. - * On state transition from _RUNNING to pre-copy, the driver should start - * gathering the device state while the application is still running and send - * the device state data to application through the migration region. - * On state transition from pre-copy to stop-and-copy, the driver must stop - * the device, save the device state and send it to the user application - * through the migration region. - * Vendor drivers must support the pre-copy state even for implementations - * where no data is provided to the user before the stop-and-copy state. The - * user must not be required to consume all migration data before the device - * transitions to a new state, including the stop-and-copy state. - * The sequence to be followed for above two transitions is given below. - * 4. To start the resuming phase, the device state should be transitioned from - * the _RUNNING to the _RESUMING state. - * In the _RESUMING state, the driver should use the device state data - * received through the migration region to resume the device. - * 5. After providing saved device data to the driver, the application should - * change the state from _RESUMING to _RUNNING. - * - * reserved: - * Reads on this field return zero and writes are ignored. - * - * pending_bytes: (read only) - * The number of pending bytes still to be migrated from the vendor driver. - * - * data_offset: (read only) - * The user application should read data_offset field from the migration - * region. The user application should read the device data from this - * offset within the migration region during the _SAVING state or write - * the device data during the _RESUMING state. See below for details of - * sequence to be followed. - * - * data_size: (read/write) - * The user application should read data_size to get the size in bytes of - * the data copied in the migration region during the _SAVING state and - * write the size in bytes of the data copied in the migration region - * during the _RESUMING state. - * - * The format of the migration region is as follows: - * ------------------------------------------------------------------ - * |vfio_device_migration_info| data section | - * | | /////////////////////////////// | - * ------------------------------------------------------------------ - * ^ ^ - * offset 0-trapped part data_offset - * - * The structure vfio_device_migration_info is always followed by the data - * section in the region, so data_offset will always be nonzero. The offset - * from where the data is copied is decided by the kernel driver. The data - * section can be trapped, mmapped, or partitioned, depending on how the kernel - * driver defines the data section. The data section partition can be defined - * as mapped by the sparse mmap capability. If mmapped, data_offset must be - * page aligned, whereas initial section which contains the - * vfio_device_migration_info structure, might not end at the offset, which is - * page aligned. The user is not required to access through mmap regardless - * of the capabilities of the region mmap. - * The vendor driver should determine whether and how to partition the data - * section. The vendor driver should return data_offset accordingly. - * - * The sequence to be followed while in pre-copy state and stop-and-copy state - * is as follows: - * a. Read pending_bytes, indicating the start of a new iteration to get device - * data. Repeated read on pending_bytes at this stage should have no side - * effects. - * If pending_bytes == 0, the user application should not iterate to get data - * for that device. - * If pending_bytes > 0, perform the following steps. - * b. Read data_offset, indicating that the vendor driver should make data - * available through the data section. The vendor driver should return this - * read operation only after data is available from (region + data_offset) - * to (region + data_offset + data_size). - * c. Read data_size, which is the amount of data in bytes available through - * the migration region. - * Read on data_offset and data_size should return the offset and size of - * the current buffer if the user application reads data_offset and - * data_size more than once here. - * d. Read data_size bytes of data from (region + data_offset) from the - * migration region. - * e. Process the data. - * f. Read pending_bytes, which indicates that the data from the previous - * iteration has been read. If pending_bytes > 0, go to step b. - * - * The user application can transition from the _SAVING|_RUNNING - * (pre-copy state) to the _SAVING (stop-and-copy) state regardless of the - * number of pending bytes. The user application should iterate in _SAVING - * (stop-and-copy) until pending_bytes is 0. - * - * The sequence to be followed while _RESUMING device state is as follows: - * While data for this device is available, repeat the following steps: - * a. Read data_offset from where the user application should write data. - * b. Write migration data starting at the migration region + data_offset for - * the length determined by data_size from the migration source. - * c. Write data_size, which indicates to the vendor driver that data is - * written in the migration region. Vendor driver must return this write - * operations on consuming data. Vendor driver should apply the - * user-provided migration region data to the device resume state. - * - * If an error occurs during the above sequences, the vendor driver can return - * an error code for next read() or write() operation, which will terminate the - * loop. The user application should then take the next necessary action, for - * example, failing migration or terminating the user application. - * - * For the user application, data is opaque. The user application should write - * data in the same order as the data is received and the data should be of - * same transaction size at the source. - */ +#define VFIO_REGION_SUBTYPE_MIGRATION_DEPRECATED (1) struct vfio_device_migration_info { __u32 device_state; /* VFIO device state */ -#define VFIO_DEVICE_STATE_STOP (0) -#define VFIO_DEVICE_STATE_RUNNING (1 << 0) -#define VFIO_DEVICE_STATE_SAVING (1 << 1) -#define VFIO_DEVICE_STATE_RESUMING (1 << 2) -#define VFIO_DEVICE_STATE_MASK (VFIO_DEVICE_STATE_RUNNING | \ - VFIO_DEVICE_STATE_SAVING | \ - VFIO_DEVICE_STATE_RESUMING) +#define VFIO_DEVICE_STATE_V1_STOP (0) +#define VFIO_DEVICE_STATE_V1_RUNNING (1 << 0) +#define VFIO_DEVICE_STATE_V1_SAVING (1 << 1) +#define VFIO_DEVICE_STATE_V1_RESUMING (1 << 2) +#define VFIO_DEVICE_STATE_MASK (VFIO_DEVICE_STATE_V1_RUNNING | \ + VFIO_DEVICE_STATE_V1_SAVING | \ + VFIO_DEVICE_STATE_V1_RESUMING) #define VFIO_DEVICE_STATE_VALID(state) \ - (state & VFIO_DEVICE_STATE_RESUMING ? \ - (state & VFIO_DEVICE_STATE_MASK) == VFIO_DEVICE_STATE_RESUMING : 1) + (state & VFIO_DEVICE_STATE_V1_RESUMING ? \ + (state & VFIO_DEVICE_STATE_MASK) == VFIO_DEVICE_STATE_V1_RESUMING : 1) #define VFIO_DEVICE_STATE_IS_ERROR(state) \ - ((state & VFIO_DEVICE_STATE_MASK) == (VFIO_DEVICE_STATE_SAVING | \ - VFIO_DEVICE_STATE_RESUMING)) + ((state & VFIO_DEVICE_STATE_MASK) == (VFIO_DEVICE_STATE_V1_SAVING | \ + VFIO_DEVICE_STATE_V1_RESUMING)) #define VFIO_DEVICE_STATE_SET_ERROR(state) \ - ((state & ~VFIO_DEVICE_STATE_MASK) | VFIO_DEVICE_SATE_SAVING | \ - VFIO_DEVICE_STATE_RESUMING) + ((state & ~VFIO_DEVICE_STATE_MASK) | VFIO_DEVICE_STATE_V1_SAVING | \ + VFIO_DEVICE_STATE_V1_RESUMING) __u32 reserved; __u64 pending_bytes; @@ -1002,6 +806,186 @@ struct vfio_device_feature { */ #define VFIO_DEVICE_FEATURE_PCI_VF_TOKEN (0) +/* + * Indicates the device can support the migration API through + * VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE. If this GET succeeds, the RUNNING and + * ERROR states are always supported. Support for additional states is + * indicated via the flags field; at least VFIO_MIGRATION_STOP_COPY must be + * set. + * + * VFIO_MIGRATION_STOP_COPY means that STOP, STOP_COPY and + * RESUMING are supported. + * + * VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P means that RUNNING_P2P + * is supported in addition to the STOP_COPY states. + * + * Other combinations of flags have behavior to be defined in the future. + */ +struct vfio_device_feature_migration { + __aligned_u64 flags; +#define VFIO_MIGRATION_STOP_COPY (1 << 0) +#define VFIO_MIGRATION_P2P (1 << 1) +}; +#define VFIO_DEVICE_FEATURE_MIGRATION 1 + +/* + * Upon VFIO_DEVICE_FEATURE_SET, execute a migration state change on the VFIO + * device. The new state is supplied in device_state, see enum + * vfio_device_mig_state for details + * + * The kernel migration driver must fully transition the device to the new state + * value before the operation returns to the user. + * + * The kernel migration driver must not generate asynchronous device state + * transitions outside of manipulation by the user or the VFIO_DEVICE_RESET + * ioctl as described above. + * + * If this function fails then current device_state may be the original + * operating state or some other state along the combination transition path. + * The user can then decide if it should execute a VFIO_DEVICE_RESET, attempt + * to return to the original state, or attempt to return to some other state + * such as RUNNING or STOP. + * + * If the new_state starts a new data transfer session then the FD associated + * with that session is returned in data_fd. The user is responsible to close + * this FD when it is finished. The user must consider the migration data stream + * carried over the FD to be opaque and must preserve the byte order of the + * stream. The user is not required to preserve buffer segmentation when writing + * the data stream during the RESUMING operation. + * + * Upon VFIO_DEVICE_FEATURE_GET, get the current migration state of the VFIO + * device, data_fd will be -1. + */ +struct vfio_device_feature_mig_state { + __u32 device_state; /* From enum vfio_device_mig_state */ + __s32 data_fd; +}; +#define VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE 2 + +/* + * The device migration Finite State Machine is described by the enum + * vfio_device_mig_state. Some of the FSM arcs will create a migration data + * transfer session by returning a FD, in this case the migration data will + * flow over the FD using read() and write() as discussed below. + * + * There are 5 states to support VFIO_MIGRATION_STOP_COPY: + * RUNNING - The device is running normally + * STOP - The device does not change the internal or external state + * STOP_COPY - The device internal state can be read out + * RESUMING - The device is stopped and is loading a new internal state + * ERROR - The device has failed and must be reset + * + * And 1 optional state to support VFIO_MIGRATION_P2P: + * RUNNING_P2P - RUNNING, except the device cannot do peer to peer DMA + * + * The FSM takes actions on the arcs between FSM states. The driver implements + * the following behavior for the FSM arcs: + * + * RUNNING_P2P -> STOP + * STOP_COPY -> STOP + * While in STOP the device must stop the operation of the device. The device + * must not generate interrupts, DMA, or any other change to external state. + * It must not change its internal state. When stopped the device and kernel + * migration driver must accept and respond to interaction to support external + * subsystems in the STOP state, for example PCI MSI-X and PCI config space. + * Failure by the user to restrict device access while in STOP must not result + * in error conditions outside the user context (ex. host system faults). + * + * The STOP_COPY arc will terminate a data transfer session. + * + * RESUMING -> STOP + * Leaving RESUMING terminates a data transfer session and indicates the + * device should complete processing of the data delivered by write(). The + * kernel migration driver should complete the incorporation of data written + * to the data transfer FD into the device internal state and perform + * final validity and consistency checking of the new device state. If the + * user provided data is found to be incomplete, inconsistent, or otherwise + * invalid, the migration driver must fail the SET_STATE ioctl and + * optionally go to the ERROR state as described below. + * + * While in STOP the device has the same behavior as other STOP states + * described above. + * + * To abort a RESUMING session the device must be reset. + * + * RUNNING_P2P -> RUNNING + * While in RUNNING the device is fully operational, the device may generate + * interrupts, DMA, respond to MMIO, all vfio device regions are functional, + * and the device may advance its internal state. + * + * RUNNING -> RUNNING_P2P + * STOP -> RUNNING_P2P + * While in RUNNING_P2P the device is partially running in the P2P quiescent + * state defined below. + * + * STOP -> STOP_COPY + * This arc begin the process of saving the device state and will return a + * new data_fd. + * + * While in the STOP_COPY state the device has the same behavior as STOP + * with the addition that the data transfers session continues to stream the + * migration state. End of stream on the FD indicates the entire device + * state has been transferred. + * + * The user should take steps to restrict access to vfio device regions while + * the device is in STOP_COPY or risk corruption of the device migration data + * stream. + * + * STOP -> RESUMING + * Entering the RESUMING state starts a process of restoring the device state + * and will return a new data_fd. The data stream fed into the data_fd should + * be taken from the data transfer output of a single FD during saving from + * a compatible device. The migration driver may alter/reset the internal + * device state for this arc if required to prepare the device to receive the + * migration data. + * + * any -> ERROR + * ERROR cannot be specified as a device state, however any transition request + * can be failed with an errno return and may then move the device_state into + * ERROR. In this case the device was unable to execute the requested arc and + * was also unable to restore the device to any valid device_state. + * To recover from ERROR VFIO_DEVICE_RESET must be used to return the + * device_state back to RUNNING. + * + * The optional peer to peer (P2P) quiescent state is intended to be a quiescent + * state for the device for the purposes of managing multiple devices within a + * user context where peer-to-peer DMA between devices may be active. The + * RUNNING_P2P states must prevent the device from initiating + * any new P2P DMA transactions. If the device can identify P2P transactions + * then it can stop only P2P DMA, otherwise it must stop all DMA. The migration + * driver must complete any such outstanding operations prior to completing the + * FSM arc into a P2P state. For the purpose of specification the states + * behave as though the device was fully running if not supported. Like while in + * STOP or STOP_COPY the user must not touch the device, otherwise the state + * can be exited. + * + * The remaining possible transitions are interpreted as combinations of the + * above FSM arcs. As there are multiple paths through the FSM arcs the path + * should be selected based on the following rules: + * - Select the shortest path. + * Refer to vfio_mig_get_next_state() for the result of the algorithm. + * + * The automatic transit through the FSM arcs that make up the combination + * transition is invisible to the user. When working with combination arcs the + * user may see any step along the path in the device_state if SET_STATE + * fails. When handling these types of errors users should anticipate future + * revisions of this protocol using new states and those states becoming + * visible in this case. + * + * The optional states cannot be used with SET_STATE if the device does not + * support them. The user can discover if these states are supported by using + * VFIO_DEVICE_FEATURE_MIGRATION. By using combination transitions the user can + * avoid knowing about these optional states if the kernel driver supports them. + */ +enum vfio_device_mig_state { + VFIO_DEVICE_STATE_ERROR = 0, + VFIO_DEVICE_STATE_STOP = 1, + VFIO_DEVICE_STATE_RUNNING = 2, + VFIO_DEVICE_STATE_STOP_COPY = 3, + VFIO_DEVICE_STATE_RESUMING = 4, + VFIO_DEVICE_STATE_RUNNING_P2P = 5, +}; + /* -------- API for Type1 VFIO IOMMU -------- */ /** |