diff options
| -rw-r--r-- | drivers/vfio/vfio.c | 87 | ||||
| -rw-r--r-- | include/linux/vfio.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/vfio.h | 36 |
3 files changed, 104 insertions, 20 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index b37ab27b511f..a4555014bd1e 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1577,39 +1577,56 @@ int vfio_mig_get_next_state(struct vfio_device *device, enum vfio_device_mig_state new_fsm, enum vfio_device_mig_state *next_fsm) { - enum { VFIO_DEVICE_NUM_STATES = VFIO_DEVICE_STATE_RESUMING + 1 }; + enum { VFIO_DEVICE_NUM_STATES = VFIO_DEVICE_STATE_RUNNING_P2P + 1 }; /* - * The coding in this table requires the driver to implement 6 - * FSM arcs: + * The coding in this table requires the driver to implement the + * following FSM arcs: * RESUMING -> STOP - * RUNNING -> STOP * STOP -> RESUMING - * STOP -> RUNNING * STOP -> STOP_COPY * STOP_COPY -> STOP * - * The coding will step through multiple states for these combination - * transitions: - * RESUMING -> STOP -> RUNNING + * If P2P is supported then the driver must also implement these FSM + * arcs: + * RUNNING -> RUNNING_P2P + * RUNNING_P2P -> RUNNING + * RUNNING_P2P -> STOP + * STOP -> RUNNING_P2P + * Without P2P the driver must implement: + * RUNNING -> STOP + * STOP -> RUNNING + * + * The coding will step through multiple states for some combination + * transitions; if all optional features are supported, this means the + * following ones: + * RESUMING -> STOP -> RUNNING_P2P + * RESUMING -> STOP -> RUNNING_P2P -> RUNNING * RESUMING -> STOP -> STOP_COPY - * RUNNING -> STOP -> RESUMING - * RUNNING -> STOP -> STOP_COPY + * RUNNING -> RUNNING_P2P -> STOP + * RUNNING -> RUNNING_P2P -> STOP -> RESUMING + * RUNNING -> RUNNING_P2P -> STOP -> STOP_COPY + * RUNNING_P2P -> STOP -> RESUMING + * RUNNING_P2P -> STOP -> STOP_COPY + * STOP -> RUNNING_P2P -> RUNNING * STOP_COPY -> STOP -> RESUMING - * STOP_COPY -> STOP -> RUNNING + * STOP_COPY -> STOP -> RUNNING_P2P + * STOP_COPY -> STOP -> RUNNING_P2P -> RUNNING */ static const u8 vfio_from_fsm_table[VFIO_DEVICE_NUM_STATES][VFIO_DEVICE_NUM_STATES] = { [VFIO_DEVICE_STATE_STOP] = { [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_STOP, - [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP_COPY, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_RESUMING, + [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, }, [VFIO_DEVICE_STATE_RUNNING] = { - [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING, - [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP, - [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_RUNNING_P2P, + [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_RUNNING_P2P, + [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, }, [VFIO_DEVICE_STATE_STOP_COPY] = { @@ -1617,6 +1634,7 @@ int vfio_mig_get_next_state(struct vfio_device *device, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP_COPY, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, }, [VFIO_DEVICE_STATE_RESUMING] = { @@ -1624,6 +1642,15 @@ int vfio_mig_get_next_state(struct vfio_device *device, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_RESUMING, + [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, + }, + [VFIO_DEVICE_STATE_RUNNING_P2P] = { + [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, }, [VFIO_DEVICE_STATE_ERROR] = { @@ -1631,17 +1658,41 @@ int vfio_mig_get_next_state(struct vfio_device *device, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_ERROR, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_ERROR, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_ERROR, + [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_ERROR, [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, }, }; - if (WARN_ON(cur_fsm >= ARRAY_SIZE(vfio_from_fsm_table))) + static const unsigned int state_flags_table[VFIO_DEVICE_NUM_STATES] = { + [VFIO_DEVICE_STATE_STOP] = VFIO_MIGRATION_STOP_COPY, + [VFIO_DEVICE_STATE_RUNNING] = VFIO_MIGRATION_STOP_COPY, + [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_MIGRATION_STOP_COPY, + [VFIO_DEVICE_STATE_RESUMING] = VFIO_MIGRATION_STOP_COPY, + [VFIO_DEVICE_STATE_RUNNING_P2P] = + VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P, + [VFIO_DEVICE_STATE_ERROR] = ~0U, + }; + + if (WARN_ON(cur_fsm >= ARRAY_SIZE(vfio_from_fsm_table) || + (state_flags_table[cur_fsm] & device->migration_flags) != + state_flags_table[cur_fsm])) return -EINVAL; - if (new_fsm >= ARRAY_SIZE(vfio_from_fsm_table)) + if (new_fsm >= ARRAY_SIZE(vfio_from_fsm_table) || + (state_flags_table[new_fsm] & device->migration_flags) != + state_flags_table[new_fsm]) return -EINVAL; + /* + * Arcs touching optional and unsupported states are skipped over. The + * driver will instead see an arc from the original state to the next + * logical state, as per the above comment. + */ *next_fsm = vfio_from_fsm_table[cur_fsm][new_fsm]; + while ((state_flags_table[*next_fsm] & device->migration_flags) != + state_flags_table[*next_fsm]) + *next_fsm = vfio_from_fsm_table[*next_fsm][new_fsm]; + return (*next_fsm != VFIO_DEVICE_STATE_ERROR) ? 0 : -EINVAL; } EXPORT_SYMBOL_GPL(vfio_mig_get_next_state); @@ -1731,7 +1782,7 @@ static int vfio_ioctl_device_feature_migration(struct vfio_device *device, size_t argsz) { struct vfio_device_feature_migration mig = { - .flags = VFIO_MIGRATION_STOP_COPY, + .flags = device->migration_flags, }; int ret; diff --git a/include/linux/vfio.h b/include/linux/vfio.h index c44e80bbbd3b..66dda06ec42d 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -33,6 +33,7 @@ struct vfio_device { struct vfio_group *group; struct vfio_device_set *dev_set; struct list_head dev_set_list; + unsigned int migration_flags; /* Members below here are private, not for driver use */ refcount_t refcount; diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 22ed358c04c5..26a66f68371d 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -1011,10 +1011,16 @@ struct vfio_device_feature { * * 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 @@ -1065,10 +1071,13 @@ struct vfio_device_feature_mig_state { * 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 -> STOP + * 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. @@ -1095,11 +1104,16 @@ struct vfio_device_feature_mig_state { * * To abort a RESUMING session the device must be reset. * - * STOP -> RUNNING + * 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. @@ -1129,6 +1143,18 @@ struct vfio_device_feature_mig_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: @@ -1141,6 +1167,11 @@ struct vfio_device_feature_mig_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, @@ -1148,6 +1179,7 @@ enum vfio_device_mig_state { 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 -------- */ |