// SPDX-License-Identifier: GPL-2.0-only /* * VMware VMCI Driver * * Copyright (C) 2012 VMware, Inc. All rights reserved. */ #include <linux/vmw_vmci_defs.h> #include <linux/vmw_vmci_api.h> #include <linux/highmem.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/pagemap.h> #include <linux/pci.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/uio.h> #include <linux/wait.h> #include <linux/vmalloc.h> #include <linux/skbuff.h> #include "vmci_handle_array.h" #include "vmci_queue_pair.h" #include "vmci_datagram.h" #include "vmci_resource.h" #include "vmci_context.h" #include "vmci_driver.h" #include "vmci_event.h" #include "vmci_route.h" /* * In the following, we will distinguish between two kinds of VMX processes - * the ones with versions lower than VMCI_VERSION_NOVMVM that use specialized * VMCI page files in the VMX and supporting VM to VM communication and the * newer ones that use the guest memory directly. We will in the following * refer to the older VMX versions as old-style VMX'en, and the newer ones as * new-style VMX'en. * * The state transition datagram is as follows (the VMCIQPB_ prefix has been * removed for readability) - see below for more details on the transtions: * * -------------- NEW ------------- * | | * \_/ \_/ * CREATED_NO_MEM <-----------------> CREATED_MEM * | | | * | o-----------------------o | * | | | * \_/ \_/ \_/ * ATTACHED_NO_MEM <----------------> ATTACHED_MEM * | | | * | o----------------------o | * | | | * \_/ \_/ \_/ * SHUTDOWN_NO_MEM <----------------> SHUTDOWN_MEM * | | * | | * -------------> gone <------------- * * In more detail. When a VMCI queue pair is first created, it will be in the * VMCIQPB_NEW state. It will then move into one of the following states: * * - VMCIQPB_CREATED_NO_MEM: this state indicates that either: * * - the created was performed by a host endpoint, in which case there is * no backing memory yet. * * - the create was initiated by an old-style VMX, that uses * vmci_qp_broker_set_page_store to specify the UVAs of the queue pair at * a later point in time. This state can be distinguished from the one * above by the context ID of the creator. A host side is not allowed to * attach until the page store has been set. * * - VMCIQPB_CREATED_MEM: this state is the result when the queue pair * is created by a VMX using the queue pair device backend that * sets the UVAs of the queue pair immediately and stores the * information for later attachers. At this point, it is ready for * the host side to attach to it. * * Once the queue pair is in one of the created states (with the exception of * the case mentioned for older VMX'en above), it is possible to attach to the * queue pair. Again we have two new states possible: * * - VMCIQPB_ATTACHED_MEM: this state can be reached through the following * paths: * * - from VMCIQPB_CREATED_NO_MEM when a new-style VMX allocates a queue * pair, and attaches to a queue pair previously created by the host side. * * - from VMCIQPB_CREATED_MEM when the host side attaches to a queue pair * already created by a guest. * * - from VMCIQPB_ATTACHED_NO_MEM, when an old-style VMX calls * vmci_qp_broker_set_page_store (see below). * * - VMCIQPB_ATTACHED_NO_MEM: If the queue pair already was in the * VMCIQPB_CREATED_NO_MEM due to a host side create, an old-style VMX will * bring the queue pair into this state. Once vmci_qp_broker_set_page_store * is called to register the user memory, the VMCIQPB_ATTACH_MEM state * will be entered. * * From the attached queue pair, the queue pair can enter the shutdown states * when either side of the queue pair detaches. If the guest side detaches * first, the queue pair will enter the VMCIQPB_SHUTDOWN_NO_MEM state, where * the content of the queue pair will no longer be available. If the host * side detaches first, the queue pair will either enter the * VMCIQPB_SHUTDOWN_MEM, if the guest memory is currently mapped, or * VMCIQPB_SHUTDOWN_NO_MEM, if the guest memory is not mapped * (e.g., the host detaches while a guest is stunned). * * New-style VMX'en will also unmap guest memory, if the guest is * quiesced, e.g., during a snapshot operation. In that case, the guest * memory will no longer be available, and the queue pair will transition from * *_MEM state to a *_NO_MEM state. The VMX may later map the memory once more, * in which case the queue pair will transition from the *_NO_MEM state at that * point back to the *_MEM state. Note that the *_NO_MEM state may have changed, * since the peer may have either attached or detached in the meantime. The * values are laid out such that ++ on a state will move from a *_NO_MEM to a * *_MEM state, and vice versa. */ /* The Kernel specific component of the struct vmci_queue structure. */ struct vmci_queue_kern_if { … }; /* * This structure is opaque to the clients. */ struct vmci_qp { … }; enum qp_broker_state { … }; #define QPBROKERSTATE_HAS_MEM(_qpb) … /* * In the queue pair broker, we always use the guest point of view for * the produce and consume queue values and references, e.g., the * produce queue size stored is the guests produce queue size. The * host endpoint will need to swap these around. The only exception is * the local queue pairs on the host, in which case the host endpoint * that creates the queue pair will have the right orientation, and * the attaching host endpoint will need to swap. */ struct qp_entry { … }; struct qp_broker_entry { … }; struct qp_guest_endpoint { … }; struct qp_list { … }; static struct qp_list qp_broker_list = …; static struct qp_list qp_guest_endpoints = …; #define INVALID_VMCI_GUEST_MEM_ID … #define QPE_NUM_PAGES(_QPE) … #define QP_SIZES_ARE_VALID(_prod_qsize, _cons_qsize) … /* * Frees kernel VA space for a given queue and its queue header, and * frees physical data pages. */ static void qp_free_queue(void *q, u64 size) { … } /* * Allocates kernel queue pages of specified size with IOMMU mappings, * plus space for the queue structure/kernel interface and the queue * header. */ static void *qp_alloc_queue(u64 size, u32 flags) { … } /* * Copies from a given buffer or iovector to a VMCI Queue. Uses * kmap_local_page() to dynamically map required portions of the queue * by traversing the offset -> page translation structure for the queue. * Assumes that offset + size does not wrap around in the queue. */ static int qp_memcpy_to_queue_iter(struct vmci_queue *queue, u64 queue_offset, struct iov_iter *from, size_t size) { … } /* * Copies to a given buffer or iovector from a VMCI Queue. Uses * kmap_local_page() to dynamically map required portions of the queue * by traversing the offset -> page translation structure for the queue. * Assumes that offset + size does not wrap around in the queue. */ static int qp_memcpy_from_queue_iter(struct iov_iter *to, const struct vmci_queue *queue, u64 queue_offset, size_t size) { … } /* * Allocates two list of PPNs --- one for the pages in the produce queue, * and the other for the pages in the consume queue. Intializes the list * of PPNs with the page frame numbers of the KVA for the two queues (and * the queue headers). */ static int qp_alloc_ppn_set(void *prod_q, u64 num_produce_pages, void *cons_q, u64 num_consume_pages, struct ppn_set *ppn_set) { … } /* * Frees the two list of PPNs for a queue pair. */ static void qp_free_ppn_set(struct ppn_set *ppn_set) { … } /* * Populates the list of PPNs in the hypercall structure with the PPNS * of the produce queue and the consume queue. */ static int qp_populate_ppn_set(u8 *call_buf, const struct ppn_set *ppn_set) { … } /* * Allocates kernel VA space of specified size plus space for the queue * and kernel interface. This is different from the guest queue allocator, * because we do not allocate our own queue header/data pages here but * share those of the guest. */ static struct vmci_queue *qp_host_alloc_queue(u64 size) { … } /* * Frees kernel memory for a given queue (header plus translation * structure). */ static void qp_host_free_queue(struct vmci_queue *queue, u64 queue_size) { … } /* * Initialize the mutex for the pair of queues. This mutex is used to * protect the q_header and the buffer from changing out from under any * users of either queue. Of course, it's only any good if the mutexes * are actually acquired. Queue structure must lie on non-paged memory * or we cannot guarantee access to the mutex. */ static void qp_init_queue_mutex(struct vmci_queue *produce_q, struct vmci_queue *consume_q) { … } /* * Cleans up the mutex for the pair of queues. */ static void qp_cleanup_queue_mutex(struct vmci_queue *produce_q, struct vmci_queue *consume_q) { … } /* * Acquire the mutex for the queue. Note that the produce_q and * the consume_q share a mutex. So, only one of the two need to * be passed in to this routine. Either will work just fine. */ static void qp_acquire_queue_mutex(struct vmci_queue *queue) { … } /* * Release the mutex for the queue. Note that the produce_q and * the consume_q share a mutex. So, only one of the two need to * be passed in to this routine. Either will work just fine. */ static void qp_release_queue_mutex(struct vmci_queue *queue) { … } /* * Helper function to release pages in the PageStoreAttachInfo * previously obtained using get_user_pages. */ static void qp_release_pages(struct page **pages, u64 num_pages, bool dirty) { … } /* * Lock the user pages referenced by the {produce,consume}Buffer * struct into memory and populate the {produce,consume}Pages * arrays in the attach structure with them. */ static int qp_host_get_user_memory(u64 produce_uva, u64 consume_uva, struct vmci_queue *produce_q, struct vmci_queue *consume_q) { … } /* * Registers the specification of the user pages used for backing a queue * pair. Enough information to map in pages is stored in the OS specific * part of the struct vmci_queue structure. */ static int qp_host_register_user_memory(struct vmci_qp_page_store *page_store, struct vmci_queue *produce_q, struct vmci_queue *consume_q) { … } /* * Releases and removes the references to user pages stored in the attach * struct. Pages are released from the page cache and may become * swappable again. */ static void qp_host_unregister_user_memory(struct vmci_queue *produce_q, struct vmci_queue *consume_q) { … } /* * Once qp_host_register_user_memory has been performed on a * queue, the queue pair headers can be mapped into the * kernel. Once mapped, they must be unmapped with * qp_host_unmap_queues prior to calling * qp_host_unregister_user_memory. * Pages are pinned. */ static int qp_host_map_queues(struct vmci_queue *produce_q, struct vmci_queue *consume_q) { … } /* * Unmaps previously mapped queue pair headers from the kernel. * Pages are unpinned. */ static int qp_host_unmap_queues(u32 gid, struct vmci_queue *produce_q, struct vmci_queue *consume_q) { … } /* * Finds the entry in the list corresponding to a given handle. Assumes * that the list is locked. */ static struct qp_entry *qp_list_find(struct qp_list *qp_list, struct vmci_handle handle) { … } /* * Finds the entry in the list corresponding to a given handle. */ static struct qp_guest_endpoint * qp_guest_handle_to_entry(struct vmci_handle handle) { … } /* * Finds the entry in the list corresponding to a given handle. */ static struct qp_broker_entry * qp_broker_handle_to_entry(struct vmci_handle handle) { … } /* * Dispatches a queue pair event message directly into the local event * queue. */ static int qp_notify_peer_local(bool attach, struct vmci_handle handle) { … } /* * Allocates and initializes a qp_guest_endpoint structure. * Allocates a queue_pair rid (and handle) iff the given entry has * an invalid handle. 0 through VMCI_RESERVED_RESOURCE_ID_MAX * are reserved handles. Assumes that the QP list mutex is held * by the caller. */ static struct qp_guest_endpoint * qp_guest_endpoint_create(struct vmci_handle handle, u32 peer, u32 flags, u64 produce_size, u64 consume_size, void *produce_q, void *consume_q) { … } /* * Frees a qp_guest_endpoint structure. */ static void qp_guest_endpoint_destroy(struct qp_guest_endpoint *entry) { … } /* * Helper to make a queue_pairAlloc hypercall when the driver is * supporting a guest device. */ static int qp_alloc_hypercall(const struct qp_guest_endpoint *entry) { … } /* * Helper to make a queue_pairDetach hypercall when the driver is * supporting a guest device. */ static int qp_detatch_hypercall(struct vmci_handle handle) { … } /* * Adds the given entry to the list. Assumes that the list is locked. */ static void qp_list_add_entry(struct qp_list *qp_list, struct qp_entry *entry) { … } /* * Removes the given entry from the list. Assumes that the list is locked. */ static void qp_list_remove_entry(struct qp_list *qp_list, struct qp_entry *entry) { … } /* * Helper for VMCI queue_pair detach interface. Frees the physical * pages for the queue pair. */ static int qp_detatch_guest_work(struct vmci_handle handle) { … } /* * This functions handles the actual allocation of a VMCI queue * pair guest endpoint. Allocates physical pages for the queue * pair. It makes OS dependent calls through generic wrappers. */ static int qp_alloc_guest_work(struct vmci_handle *handle, struct vmci_queue **produce_q, u64 produce_size, struct vmci_queue **consume_q, u64 consume_size, u32 peer, u32 flags, u32 priv_flags) { … } /* * The first endpoint issuing a queue pair allocation will create the state * of the queue pair in the queue pair broker. * * If the creator is a guest, it will associate a VMX virtual address range * with the queue pair as specified by the page_store. For compatibility with * older VMX'en, that would use a separate step to set the VMX virtual * address range, the virtual address range can be registered later using * vmci_qp_broker_set_page_store. In that case, a page_store of NULL should be * used. * * If the creator is the host, a page_store of NULL should be used as well, * since the host is not able to supply a page store for the queue pair. * * For older VMX and host callers, the queue pair will be created in the * VMCIQPB_CREATED_NO_MEM state, and for current VMX callers, it will be * created in VMCOQPB_CREATED_MEM state. */ static int qp_broker_create(struct vmci_handle handle, u32 peer, u32 flags, u32 priv_flags, u64 produce_size, u64 consume_size, struct vmci_qp_page_store *page_store, struct vmci_ctx *context, vmci_event_release_cb wakeup_cb, void *client_data, struct qp_broker_entry **ent) { … } /* * Enqueues an event datagram to notify the peer VM attached to * the given queue pair handle about attach/detach event by the * given VM. Returns Payload size of datagram enqueued on * success, error code otherwise. */ static int qp_notify_peer(bool attach, struct vmci_handle handle, u32 my_id, u32 peer_id) { … } /* * The second endpoint issuing a queue pair allocation will attach to * the queue pair registered with the queue pair broker. * * If the attacher is a guest, it will associate a VMX virtual address * range with the queue pair as specified by the page_store. At this * point, the already attach host endpoint may start using the queue * pair, and an attach event is sent to it. For compatibility with * older VMX'en, that used a separate step to set the VMX virtual * address range, the virtual address range can be registered later * using vmci_qp_broker_set_page_store. In that case, a page_store of * NULL should be used, and the attach event will be generated once * the actual page store has been set. * * If the attacher is the host, a page_store of NULL should be used as * well, since the page store information is already set by the guest. * * For new VMX and host callers, the queue pair will be moved to the * VMCIQPB_ATTACHED_MEM state, and for older VMX callers, it will be * moved to the VMCOQPB_ATTACHED_NO_MEM state. */ static int qp_broker_attach(struct qp_broker_entry *entry, u32 peer, u32 flags, u32 priv_flags, u64 produce_size, u64 consume_size, struct vmci_qp_page_store *page_store, struct vmci_ctx *context, vmci_event_release_cb wakeup_cb, void *client_data, struct qp_broker_entry **ent) { … } /* * queue_pair_Alloc for use when setting up queue pair endpoints * on the host. */ static int qp_broker_alloc(struct vmci_handle handle, u32 peer, u32 flags, u32 priv_flags, u64 produce_size, u64 consume_size, struct vmci_qp_page_store *page_store, struct vmci_ctx *context, vmci_event_release_cb wakeup_cb, void *client_data, struct qp_broker_entry **ent, bool *swap) { … } /* * This function implements the kernel API for allocating a queue * pair. */ static int qp_alloc_host_work(struct vmci_handle *handle, struct vmci_queue **produce_q, u64 produce_size, struct vmci_queue **consume_q, u64 consume_size, u32 peer, u32 flags, u32 priv_flags, vmci_event_release_cb wakeup_cb, void *client_data) { … } /* * Allocates a VMCI queue_pair. Only checks validity of input * arguments. The real work is done in the host or guest * specific function. */ int vmci_qp_alloc(struct vmci_handle *handle, struct vmci_queue **produce_q, u64 produce_size, struct vmci_queue **consume_q, u64 consume_size, u32 peer, u32 flags, u32 priv_flags, bool guest_endpoint, vmci_event_release_cb wakeup_cb, void *client_data) { … } /* * This function implements the host kernel API for detaching from * a queue pair. */ static int qp_detatch_host_work(struct vmci_handle handle) { … } /* * Detaches from a VMCI queue_pair. Only checks validity of input argument. * Real work is done in the host or guest specific function. */ static int qp_detatch(struct vmci_handle handle, bool guest_endpoint) { … } /* * Returns the entry from the head of the list. Assumes that the list is * locked. */ static struct qp_entry *qp_list_get_head(struct qp_list *qp_list) { … } void vmci_qp_broker_exit(void) { … } /* * Requests that a queue pair be allocated with the VMCI queue * pair broker. Allocates a queue pair entry if one does not * exist. Attaches to one if it exists, and retrieves the page * files backing that queue_pair. Assumes that the queue pair * broker lock is held. */ int vmci_qp_broker_alloc(struct vmci_handle handle, u32 peer, u32 flags, u32 priv_flags, u64 produce_size, u64 consume_size, struct vmci_qp_page_store *page_store, struct vmci_ctx *context) { … } /* * VMX'en with versions lower than VMCI_VERSION_NOVMVM use a separate * step to add the UVAs of the VMX mapping of the queue pair. This function * provides backwards compatibility with such VMX'en, and takes care of * registering the page store for a queue pair previously allocated by the * VMX during create or attach. This function will move the queue pair state * to either from VMCIQBP_CREATED_NO_MEM to VMCIQBP_CREATED_MEM or * VMCIQBP_ATTACHED_NO_MEM to VMCIQBP_ATTACHED_MEM. If moving to the * attached state with memory, the queue pair is ready to be used by the * host peer, and an attached event will be generated. * * Assumes that the queue pair broker lock is held. * * This function is only used by the hosted platform, since there is no * issue with backwards compatibility for vmkernel. */ int vmci_qp_broker_set_page_store(struct vmci_handle handle, u64 produce_uva, u64 consume_uva, struct vmci_ctx *context) { … } /* * Resets saved queue headers for the given QP broker * entry. Should be used when guest memory becomes available * again, or the guest detaches. */ static void qp_reset_saved_headers(struct qp_broker_entry *entry) { … } /* * The main entry point for detaching from a queue pair registered with the * queue pair broker. If more than one endpoint is attached to the queue * pair, the first endpoint will mainly decrement a reference count and * generate a notification to its peer. The last endpoint will clean up * the queue pair state registered with the broker. * * When a guest endpoint detaches, it will unmap and unregister the guest * memory backing the queue pair. If the host is still attached, it will * no longer be able to access the queue pair content. * * If the queue pair is already in a state where there is no memory * registered for the queue pair (any *_NO_MEM state), it will transition to * the VMCIQPB_SHUTDOWN_NO_MEM state. This will also happen, if a guest * endpoint is the first of two endpoints to detach. If the host endpoint is * the first out of two to detach, the queue pair will move to the * VMCIQPB_SHUTDOWN_MEM state. */ int vmci_qp_broker_detach(struct vmci_handle handle, struct vmci_ctx *context) { … } /* * Establishes the necessary mappings for a queue pair given a * reference to the queue pair guest memory. This is usually * called when a guest is unquiesced and the VMX is allowed to * map guest memory once again. */ int vmci_qp_broker_map(struct vmci_handle handle, struct vmci_ctx *context, u64 guest_mem) { … } /* * Saves a snapshot of the queue headers for the given QP broker * entry. Should be used when guest memory is unmapped. * Results: * VMCI_SUCCESS on success, appropriate error code if guest memory * can't be accessed.. */ static int qp_save_headers(struct qp_broker_entry *entry) { … } /* * Removes all references to the guest memory of a given queue pair, and * will move the queue pair from state *_MEM to *_NO_MEM. It is usually * called when a VM is being quiesced where access to guest memory should * avoided. */ int vmci_qp_broker_unmap(struct vmci_handle handle, struct vmci_ctx *context, u32 gid) { … } /* * Destroys all guest queue pair endpoints. If active guest queue * pairs still exist, hypercalls to attempt detach from these * queue pairs will be made. Any failure to detach is silently * ignored. */ void vmci_qp_guest_endpoints_exit(void) { … } /* * Helper routine that will lock the queue pair before subsequent * operations. * Note: Non-blocking on the host side is currently only implemented in ESX. * Since non-blocking isn't yet implemented on the host personality we * have no reason to acquire a spin lock. So to avoid the use of an * unnecessary lock only acquire the mutex if we can block. */ static void qp_lock(const struct vmci_qp *qpair) { … } /* * Helper routine that unlocks the queue pair after calling * qp_lock. */ static void qp_unlock(const struct vmci_qp *qpair) { … } /* * The queue headers may not be mapped at all times. If a queue is * currently not mapped, it will be attempted to do so. */ static int qp_map_queue_headers(struct vmci_queue *produce_q, struct vmci_queue *consume_q) { … } /* * Helper routine that will retrieve the produce and consume * headers of a given queue pair. If the guest memory of the * queue pair is currently not available, the saved queue headers * will be returned, if these are available. */ static int qp_get_queue_headers(const struct vmci_qp *qpair, struct vmci_queue_header **produce_q_header, struct vmci_queue_header **consume_q_header) { … } /* * Callback from VMCI queue pair broker indicating that a queue * pair that was previously not ready, now either is ready or * gone forever. */ static int qp_wakeup_cb(void *client_data) { … } /* * Makes the calling thread wait for the queue pair to become * ready for host side access. Returns true when thread is * woken up after queue pair state change, false otherwise. */ static bool qp_wait_for_ready_queue(struct vmci_qp *qpair) { … } /* * Enqueues a given buffer to the produce queue using the provided * function. As many bytes as possible (space available in the queue) * are enqueued. Assumes the queue->mutex has been acquired. Returns * VMCI_ERROR_QUEUEPAIR_NOSPACE if no space was available to enqueue * data, VMCI_ERROR_INVALID_SIZE, if any queue pointer is outside the * queue (as defined by the queue size), VMCI_ERROR_INVALID_ARGS, if * an error occured when accessing the buffer, * VMCI_ERROR_QUEUEPAIR_NOTATTACHED, if the queue pair pages aren't * available. Otherwise, the number of bytes written to the queue is * returned. Updates the tail pointer of the produce queue. */ static ssize_t qp_enqueue_locked(struct vmci_queue *produce_q, struct vmci_queue *consume_q, const u64 produce_q_size, struct iov_iter *from) { … } /* * Dequeues data (if available) from the given consume queue. Writes data * to the user provided buffer using the provided function. * Assumes the queue->mutex has been acquired. * Results: * VMCI_ERROR_QUEUEPAIR_NODATA if no data was available to dequeue. * VMCI_ERROR_INVALID_SIZE, if any queue pointer is outside the queue * (as defined by the queue size). * VMCI_ERROR_INVALID_ARGS, if an error occured when accessing the buffer. * Otherwise the number of bytes dequeued is returned. * Side effects: * Updates the head pointer of the consume queue. */ static ssize_t qp_dequeue_locked(struct vmci_queue *produce_q, struct vmci_queue *consume_q, const u64 consume_q_size, struct iov_iter *to, bool update_consumer) { … } /* * vmci_qpair_alloc() - Allocates a queue pair. * @qpair: Pointer for the new vmci_qp struct. * @handle: Handle to track the resource. * @produce_qsize: Desired size of the producer queue. * @consume_qsize: Desired size of the consumer queue. * @peer: ContextID of the peer. * @flags: VMCI flags. * @priv_flags: VMCI priviledge flags. * * This is the client interface for allocating the memory for a * vmci_qp structure and then attaching to the underlying * queue. If an error occurs allocating the memory for the * vmci_qp structure no attempt is made to attach. If an * error occurs attaching, then the structure is freed. */ int vmci_qpair_alloc(struct vmci_qp **qpair, struct vmci_handle *handle, u64 produce_qsize, u64 consume_qsize, u32 peer, u32 flags, u32 priv_flags) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_detach() - Detatches the client from a queue pair. * @qpair: Reference of a pointer to the qpair struct. * * This is the client interface for detaching from a VMCIQPair. * Note that this routine will free the memory allocated for the * vmci_qp structure too. */ int vmci_qpair_detach(struct vmci_qp **qpair) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_get_produce_indexes() - Retrieves the indexes of the producer. * @qpair: Pointer to the queue pair struct. * @producer_tail: Reference used for storing producer tail index. * @consumer_head: Reference used for storing the consumer head index. * * This is the client interface for getting the current indexes of the * QPair from the point of the view of the caller as the producer. */ int vmci_qpair_get_produce_indexes(const struct vmci_qp *qpair, u64 *producer_tail, u64 *consumer_head) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_get_consume_indexes() - Retrieves the indexes of the consumer. * @qpair: Pointer to the queue pair struct. * @consumer_tail: Reference used for storing consumer tail index. * @producer_head: Reference used for storing the producer head index. * * This is the client interface for getting the current indexes of the * QPair from the point of the view of the caller as the consumer. */ int vmci_qpair_get_consume_indexes(const struct vmci_qp *qpair, u64 *consumer_tail, u64 *producer_head) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_produce_free_space() - Retrieves free space in producer queue. * @qpair: Pointer to the queue pair struct. * * This is the client interface for getting the amount of free * space in the QPair from the point of the view of the caller as * the producer which is the common case. Returns < 0 if err, else * available bytes into which data can be enqueued if > 0. */ s64 vmci_qpair_produce_free_space(const struct vmci_qp *qpair) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_consume_free_space() - Retrieves free space in consumer queue. * @qpair: Pointer to the queue pair struct. * * This is the client interface for getting the amount of free * space in the QPair from the point of the view of the caller as * the consumer which is not the common case. Returns < 0 if err, else * available bytes into which data can be enqueued if > 0. */ s64 vmci_qpair_consume_free_space(const struct vmci_qp *qpair) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_produce_buf_ready() - Gets bytes ready to read from * producer queue. * @qpair: Pointer to the queue pair struct. * * This is the client interface for getting the amount of * enqueued data in the QPair from the point of the view of the * caller as the producer which is not the common case. Returns < 0 if err, * else available bytes that may be read. */ s64 vmci_qpair_produce_buf_ready(const struct vmci_qp *qpair) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_consume_buf_ready() - Gets bytes ready to read from * consumer queue. * @qpair: Pointer to the queue pair struct. * * This is the client interface for getting the amount of * enqueued data in the QPair from the point of the view of the * caller as the consumer which is the normal case. Returns < 0 if err, * else available bytes that may be read. */ s64 vmci_qpair_consume_buf_ready(const struct vmci_qp *qpair) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_enqueue() - Throw data on the queue. * @qpair: Pointer to the queue pair struct. * @buf: Pointer to buffer containing data * @buf_size: Length of buffer. * @buf_type: Buffer type (Unused). * * This is the client interface for enqueueing data into the queue. * Returns number of bytes enqueued or < 0 on error. */ ssize_t vmci_qpair_enqueue(struct vmci_qp *qpair, const void *buf, size_t buf_size, int buf_type) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_dequeue() - Get data from the queue. * @qpair: Pointer to the queue pair struct. * @buf: Pointer to buffer for the data * @buf_size: Length of buffer. * @buf_type: Buffer type (Unused). * * This is the client interface for dequeueing data from the queue. * Returns number of bytes dequeued or < 0 on error. */ ssize_t vmci_qpair_dequeue(struct vmci_qp *qpair, void *buf, size_t buf_size, int buf_type) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_peek() - Peek at the data in the queue. * @qpair: Pointer to the queue pair struct. * @buf: Pointer to buffer for the data * @buf_size: Length of buffer. * @buf_type: Buffer type (Unused on Linux). * * This is the client interface for peeking into a queue. (I.e., * copy data from the queue without updating the head pointer.) * Returns number of bytes dequeued or < 0 on error. */ ssize_t vmci_qpair_peek(struct vmci_qp *qpair, void *buf, size_t buf_size, int buf_type) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_enquev() - Throw data on the queue using iov. * @qpair: Pointer to the queue pair struct. * @iov: Pointer to buffer containing data * @iov_size: Length of buffer. * @buf_type: Buffer type (Unused). * * This is the client interface for enqueueing data into the queue. * This function uses IO vectors to handle the work. Returns number * of bytes enqueued or < 0 on error. */ ssize_t vmci_qpair_enquev(struct vmci_qp *qpair, struct msghdr *msg, size_t iov_size, int buf_type) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_dequev() - Get data from the queue using iov. * @qpair: Pointer to the queue pair struct. * @iov: Pointer to buffer for the data * @iov_size: Length of buffer. * @buf_type: Buffer type (Unused). * * This is the client interface for dequeueing data from the queue. * This function uses IO vectors to handle the work. Returns number * of bytes dequeued or < 0 on error. */ ssize_t vmci_qpair_dequev(struct vmci_qp *qpair, struct msghdr *msg, size_t iov_size, int buf_type) { … } EXPORT_SYMBOL_GPL(…); /* * vmci_qpair_peekv() - Peek at the data in the queue using iov. * @qpair: Pointer to the queue pair struct. * @iov: Pointer to buffer for the data * @iov_size: Length of buffer. * @buf_type: Buffer type (Unused on Linux). * * This is the client interface for peeking into a queue. (I.e., * copy data from the queue without updating the head pointer.) * This function uses IO vectors to handle the work. Returns number * of bytes peeked or < 0 on error. */ ssize_t vmci_qpair_peekv(struct vmci_qp *qpair, struct msghdr *msg, size_t iov_size, int buf_type) { … } EXPORT_SYMBOL_GPL(…);
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