/*- * Copyright (c) 2018 VMware, Inc. * * SPDX-License-Identifier: (BSD-2-Clause OR GPL-2.0) */ /* This file implements Queue accessor methods. */ /* * vmci_qpair is an interface that hides the queue pair internals. Rather than * access each queue in a pair directly, operations are performed on the queue * as a whole. This is simpler and less error-prone, and allows for future * queue pair features to be added under the hood with no change to the client * code. */ #include #include "vmci_kernel_api.h" #include "vmci_kernel_defs.h" #include "vmci_kernel_if.h" #include "vmci_queue.h" #include "vmci_queue_pair.h" /* This structure is opaque to the clients. */ struct vmci_qpair { struct vmci_handle handle; struct vmci_queue *produce_q; struct vmci_queue *consume_q; uint64_t produce_q_size; uint64_t consume_q_size; vmci_id peer; uint32_t flags; vmci_privilege_flags priv_flags; uint32_t blocked; vmci_event event; }; static void vmci_qpair_get_queue_headers(const struct vmci_qpair *qpair, struct vmci_queue_header **produce_q_header, struct vmci_queue_header **consume_q_header); /* *------------------------------------------------------------------------------ * * vmci_queue_add_producer_tail -- * * Helper routine to increment the Producer Tail. * * Results: * VMCI_ERROR_NOT_FOUND if the vmm_world registered with the queue cannot * be found. Otherwise VMCI_SUCCESS. * * Side effects: * None. * *------------------------------------------------------------------------------ */ static inline int vmci_queue_add_producer_tail(struct vmci_queue *queue, size_t add, uint64_t queue_size) { vmci_queue_header_add_producer_tail(queue->q_header, add, queue_size); return (VMCI_SUCCESS); } /* *------------------------------------------------------------------------------ * * vmci_queue_add_consumer_head -- * * Helper routine to increment the Consumer Head. * * Results: * VMCI_ERROR_NOT_FOUND if the vmm_world registered with the queue cannot * be found. Otherwise VMCI_SUCCESS. * * Side effects: * None. * *------------------------------------------------------------------------------ */ static inline int vmci_queue_add_consumer_head(struct vmci_queue *queue, size_t add, uint64_t queue_size) { vmci_queue_header_add_consumer_head(queue->q_header, add, queue_size); return (VMCI_SUCCESS); } /* *------------------------------------------------------------------------------ * * vmci_qpair_get_queue_headers -- * * Helper routine that will retrieve the produce and consume headers of a * given queue pair. * * Results: * VMCI_SUCCESS if either current or saved queue headers are found. * Appropriate error code otherwise. * * Side effects: * None. * *------------------------------------------------------------------------------ */ static void vmci_qpair_get_queue_headers(const struct vmci_qpair *qpair, struct vmci_queue_header **produce_q_header, struct vmci_queue_header **consume_q_header) { ASSERT((qpair->produce_q != NULL) && (qpair->consume_q != NULL)); *produce_q_header = qpair->produce_q->q_header; *consume_q_header = qpair->consume_q->q_header; } /* *------------------------------------------------------------------------------ * * vmci_qpair_alloc -- * * This is the client interface for allocating the memory for a vmci_qpair * structure and then attaching to the underlying queue. If an error occurs * allocating the memory for the vmci_qpair structure, no attempt is made to * attach. If an error occurs attaching, then there's the vmci_qpair * structure is freed. * * Results: * An err, if < 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ int vmci_qpair_alloc(struct vmci_qpair **qpair, struct vmci_handle *handle, uint64_t produce_q_size, uint64_t consume_q_size, vmci_id peer, uint32_t flags, vmci_privilege_flags priv_flags) { struct vmci_qpair *my_qpair; int retval; /* * Restrict the size of a queuepair. Though the device enforces a limit * on the total amount of memory that can be allocated to queuepairs for * a guest, we avoid unnecessarily allocating a lot of memory. Also, we * try to allocate this memory before we make the queuepair allocation * hypercall. * * (Note that this doesn't prevent all cases; a user with only this much * physical memory could still get into trouble.) The error used by the * device is NO_RESOURCES, so use that here too. */ if (produce_q_size + consume_q_size < MAX(produce_q_size, consume_q_size) || produce_q_size + consume_q_size > VMCI_MAX_GUEST_QP_MEMORY) return (VMCI_ERROR_NO_RESOURCES); if (flags & VMCI_QPFLAG_NONBLOCK) return (VMCI_ERROR_INVALID_ARGS); my_qpair = vmci_alloc_kernel_mem(sizeof(*my_qpair), VMCI_MEMORY_NORMAL); if (!my_qpair) return (VMCI_ERROR_NO_MEM); my_qpair->produce_q_size = produce_q_size; my_qpair->consume_q_size = consume_q_size; my_qpair->peer = peer; my_qpair->flags = flags; my_qpair->priv_flags = priv_flags; retval = vmci_queue_pair_alloc(handle, &my_qpair->produce_q, my_qpair->produce_q_size, &my_qpair->consume_q, my_qpair->consume_q_size, my_qpair->peer, my_qpair->flags, my_qpair->priv_flags); if (retval < VMCI_SUCCESS) { vmci_free_kernel_mem(my_qpair, sizeof(*my_qpair)); return (retval); } *qpair = my_qpair; my_qpair->handle = *handle; return (retval); } /* *------------------------------------------------------------------------------ * * vmci_qpair_detach -- * * This is the client interface for detaching from a vmci_qpair. Note that * this routine will free the memory allocated for the vmci_qpair structure, * too. * * Results: * An error, if < 0. * * Side effects: * Will clear the caller's pointer to the vmci_qpair structure. * *------------------------------------------------------------------------------ */ int vmci_qpair_detach(struct vmci_qpair **qpair) { struct vmci_qpair *old_qpair; int result; if (!qpair || !(*qpair)) return (VMCI_ERROR_INVALID_ARGS); old_qpair = *qpair; result = vmci_queue_pair_detach(old_qpair->handle); /* * The guest can fail to detach for a number of reasons, and if it does * so, it will cleanup the entry (if there is one). We need to release * the qpair struct here; there isn't much the caller can do, and we * don't want to leak. */ if (old_qpair->flags & VMCI_QPFLAG_LOCAL) vmci_destroy_event(&old_qpair->event); vmci_free_kernel_mem(old_qpair, sizeof(*old_qpair)); *qpair = NULL; return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_get_produce_indexes -- * * 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. * * Results: * err, if < 0 * Success otherwise. * * Side effects: * None. * *------------------------------------------------------------------------------ */ int vmci_qpair_get_produce_indexes(const struct vmci_qpair *qpair, uint64_t *producer_tail, uint64_t *consumer_head) { struct vmci_queue_header *consume_q_header; struct vmci_queue_header *produce_q_header; if (!qpair) return (VMCI_ERROR_INVALID_ARGS); vmci_qpair_get_queue_headers(qpair, &produce_q_header, &consume_q_header); vmci_queue_header_get_pointers(produce_q_header, consume_q_header, producer_tail, consumer_head); if ((producer_tail && *producer_tail >= qpair->produce_q_size) || (consumer_head && *consumer_head >= qpair->produce_q_size)) return (VMCI_ERROR_INVALID_SIZE); return (VMCI_SUCCESS); } /* *------------------------------------------------------------------------------ * * vmci_qpair_get_consume_indexes -- * * 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. * * Results: * err, if < 0 * Success otherwise. * * Side effects: * None. * *------------------------------------------------------------------------------ */ int vmci_qpair_get_consume_indexes(const struct vmci_qpair *qpair, uint64_t *consumer_tail, uint64_t *producer_head) { struct vmci_queue_header *consume_q_header; struct vmci_queue_header *produce_q_header; if (!qpair) return (VMCI_ERROR_INVALID_ARGS); vmci_qpair_get_queue_headers(qpair, &produce_q_header, &consume_q_header); vmci_queue_header_get_pointers(consume_q_header, produce_q_header, consumer_tail, producer_head); if ((consumer_tail && *consumer_tail >= qpair->consume_q_size) || (producer_head && *producer_head >= qpair->consume_q_size)) return (VMCI_ERROR_INVALID_SIZE); return (VMCI_SUCCESS); } /* *------------------------------------------------------------------------------ * * vmci_qpair_produce_free_space -- * * 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. * * Results: * Err, if < 0. * Full queue if = 0. * Number of available bytes into which data can be enqueued if > 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ int64_t vmci_qpair_produce_free_space(const struct vmci_qpair *qpair) { struct vmci_queue_header *consume_q_header; struct vmci_queue_header *produce_q_header; int64_t result; if (!qpair) return (VMCI_ERROR_INVALID_ARGS); vmci_qpair_get_queue_headers(qpair, &produce_q_header, &consume_q_header); result = vmci_queue_header_free_space(produce_q_header, consume_q_header, qpair->produce_q_size); return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_consume_free_space -- * * 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 (see vmci_qpair_Produce_free_space(), above). * * Results: * Err, if < 0. * Full queue if = 0. * Number of available bytes into which data can be enqueued if > 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ int64_t vmci_qpair_consume_free_space(const struct vmci_qpair *qpair) { struct vmci_queue_header *consume_q_header; struct vmci_queue_header *produce_q_header; int64_t result; if (!qpair) return (VMCI_ERROR_INVALID_ARGS); vmci_qpair_get_queue_headers(qpair, &produce_q_header, &consume_q_header); result = vmci_queue_header_free_space(consume_q_header, produce_q_header, qpair->consume_q_size); return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_produce_buf_ready -- * * 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 (see vmci_qpair_Consume_buf_ready(), above). * * Results: * Err, if < 0. * Empty queue if = 0. * Number of bytes ready to be dequeued if > 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ int64_t vmci_qpair_produce_buf_ready(const struct vmci_qpair *qpair) { struct vmci_queue_header *consume_q_header; struct vmci_queue_header *produce_q_header; int64_t result; if (!qpair) return (VMCI_ERROR_INVALID_ARGS); vmci_qpair_get_queue_headers(qpair, &produce_q_header, &consume_q_header); result = vmci_queue_header_buf_ready(produce_q_header, consume_q_header, qpair->produce_q_size); return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_consume_buf_ready -- * * 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. * * Results: * Err, if < 0. * Empty queue if = 0. * Number of bytes ready to be dequeued if > 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ int64_t vmci_qpair_consume_buf_ready(const struct vmci_qpair *qpair) { struct vmci_queue_header *consume_q_header; struct vmci_queue_header *produce_q_header; int64_t result; if (!qpair) return (VMCI_ERROR_INVALID_ARGS); vmci_qpair_get_queue_headers(qpair, &produce_q_header, &consume_q_header); result = vmci_queue_header_buf_ready(consume_q_header, produce_q_header, qpair->consume_q_size); return (result); } /* *------------------------------------------------------------------------------ * * enqueue -- * * Enqueues a given buffer to the produce queue using the provided function. * As many bytes as possible (space available in the queue) are enqueued. * * Results: * 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 occurred 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. * * Side effects: * Updates the tail pointer of the produce queue. * *------------------------------------------------------------------------------ */ static ssize_t enqueue(struct vmci_queue *produce_q, struct vmci_queue *consume_q, const uint64_t produce_q_size, const void *buf, size_t buf_size, int buf_type, vmci_memcpy_to_queue_func memcpy_to_queue, bool can_block) { ssize_t result; size_t written; int64_t free_space; uint64_t tail; ASSERT((produce_q != NULL) && (consume_q != NULL)); free_space = vmci_queue_header_free_space(produce_q->q_header, consume_q->q_header, produce_q_size); if (free_space == 0) return (VMCI_ERROR_QUEUEPAIR_NOSPACE); if (free_space < VMCI_SUCCESS) return ((ssize_t)free_space); written = (size_t)(free_space > buf_size ? buf_size : free_space); tail = vmci_queue_header_producer_tail(produce_q->q_header); if (LIKELY(tail + written < produce_q_size)) result = memcpy_to_queue(produce_q, tail, buf, 0, written, buf_type, can_block); else { /* Tail pointer wraps around. */ const size_t tmp = (size_t)(produce_q_size - tail); result = memcpy_to_queue(produce_q, tail, buf, 0, tmp, buf_type, can_block); if (result >= VMCI_SUCCESS) result = memcpy_to_queue(produce_q, 0, buf, tmp, written - tmp, buf_type, can_block); } if (result < VMCI_SUCCESS) return (result); result = vmci_queue_add_producer_tail(produce_q, written, produce_q_size); if (result < VMCI_SUCCESS) return (result); return (written); } /* *------------------------------------------------------------------------------ * * dequeue -- * * Dequeues data (if available) from the given consume queue. Writes data * to the user provided buffer using the provided function. * * 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 occurred when accessing the buffer. * VMCI_ERROR_NOT_FOUND, if the vmm_world registered with the queue pair * cannot be found. * Otherwise the number of bytes dequeued is returned. * * Side effects: * Updates the head pointer of the consume queue. * *------------------------------------------------------------------------------ */ static ssize_t dequeue(struct vmci_queue *produce_q, struct vmci_queue *consume_q, const uint64_t consume_q_size, void *buf, size_t buf_size, int buf_type, vmci_memcpy_from_queue_func memcpy_from_queue, bool update_consumer, bool can_block) { ssize_t result; size_t read; int64_t buf_ready; uint64_t head; ASSERT((produce_q != NULL) && (consume_q != NULL)); buf_ready = vmci_queue_header_buf_ready(consume_q->q_header, produce_q->q_header, consume_q_size); if (buf_ready == 0) return (VMCI_ERROR_QUEUEPAIR_NODATA); if (buf_ready < VMCI_SUCCESS) return ((ssize_t)buf_ready); read = (size_t)(buf_ready > buf_size ? buf_size : buf_ready); head = vmci_queue_header_consumer_head(produce_q->q_header); if (LIKELY(head + read < consume_q_size)) result = memcpy_from_queue(buf, 0, consume_q, head, read, buf_type, can_block); else { /* Head pointer wraps around. */ const size_t tmp = (size_t)(consume_q_size - head); result = memcpy_from_queue(buf, 0, consume_q, head, tmp, buf_type, can_block); if (result >= VMCI_SUCCESS) result = memcpy_from_queue(buf, tmp, consume_q, 0, read - tmp, buf_type, can_block); } if (result < VMCI_SUCCESS) return (result); if (update_consumer) { result = vmci_queue_add_consumer_head(produce_q, read, consume_q_size); if (result < VMCI_SUCCESS) return (result); } return (read); } /* *------------------------------------------------------------------------------ * * vmci_qpair_enqueue -- * * This is the client interface for enqueueing data into the queue. * * Results: * Err, if < 0. * Number of bytes enqueued if >= 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ ssize_t vmci_qpair_enqueue(struct vmci_qpair *qpair, const void *buf, size_t buf_size, int buf_type) { ssize_t result; if (!qpair || !buf) return (VMCI_ERROR_INVALID_ARGS); result = enqueue(qpair->produce_q, qpair->consume_q, qpair->produce_q_size, buf, buf_size, buf_type, qpair->flags & VMCI_QPFLAG_LOCAL? vmci_memcpy_to_queue_local : vmci_memcpy_to_queue, !(qpair->flags & VMCI_QPFLAG_NONBLOCK)); return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_dequeue -- * * This is the client interface for dequeueing data from the queue. * * Results: * Err, if < 0. * Number of bytes dequeued if >= 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ ssize_t vmci_qpair_dequeue(struct vmci_qpair *qpair, void *buf, size_t buf_size, int buf_type) { ssize_t result; if (!qpair || !buf) return (VMCI_ERROR_INVALID_ARGS); result = dequeue(qpair->produce_q, qpair->consume_q, qpair->consume_q_size, buf, buf_size, buf_type, qpair->flags & VMCI_QPFLAG_LOCAL? vmci_memcpy_from_queue_local : vmci_memcpy_from_queue, true, !(qpair->flags & VMCI_QPFLAG_NONBLOCK)); return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_peek -- * * This is the client interface for peeking into a queue. (I.e., copy * data from the queue without updating the head pointer.) * * Results: * Err, if < 0. * Number of bytes peeked, if >= 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ ssize_t vmci_qpair_peek(struct vmci_qpair *qpair, void *buf, size_t buf_size, int buf_type) { ssize_t result; if (!qpair || !buf) return (VMCI_ERROR_INVALID_ARGS); result = dequeue(qpair->produce_q, qpair->consume_q, qpair->consume_q_size, buf, buf_size, buf_type, qpair->flags & VMCI_QPFLAG_LOCAL? vmci_memcpy_from_queue_local : vmci_memcpy_from_queue, false, !(qpair->flags & VMCI_QPFLAG_NONBLOCK)); return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_enquev -- * * This is the client interface for enqueueing data into the queue. * * Results: * Err, if < 0. * Number of bytes enqueued if >= 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ ssize_t vmci_qpair_enquev(struct vmci_qpair *qpair, void *iov, size_t iov_size, int buf_type) { ssize_t result; if (!qpair || !iov) return (VMCI_ERROR_INVALID_ARGS); result = enqueue(qpair->produce_q, qpair->consume_q, qpair->produce_q_size, iov, iov_size, buf_type, qpair->flags & VMCI_QPFLAG_LOCAL? vmci_memcpy_to_queue_v_local : vmci_memcpy_to_queue_v, !(qpair->flags & VMCI_QPFLAG_NONBLOCK)); return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_dequev -- * * This is the client interface for dequeueing data from the queue. * * Results: * Err, if < 0. * Number of bytes dequeued if >= 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ ssize_t vmci_qpair_dequev(struct vmci_qpair *qpair, void *iov, size_t iov_size, int buf_type) { ssize_t result; if (!qpair || !iov) return (VMCI_ERROR_INVALID_ARGS); result = dequeue(qpair->produce_q, qpair->consume_q, qpair->consume_q_size, iov, iov_size, buf_type, qpair->flags & VMCI_QPFLAG_LOCAL? vmci_memcpy_from_queue_v_local : vmci_memcpy_from_queue_v, true, !(qpair->flags & VMCI_QPFLAG_NONBLOCK)); return (result); } /* *------------------------------------------------------------------------------ * * vmci_qpair_peekv -- * * This is the client interface for peeking into a queue. (I.e., copy * data from the queue without updating the head pointer.) * * Results: * Err, if < 0. * Number of bytes peeked, if >= 0. * * Side effects: * None. * *------------------------------------------------------------------------------ */ ssize_t vmci_qpair_peekv(struct vmci_qpair *qpair, void *iov, size_t iov_size, int buf_type) { ssize_t result; if (!qpair || !iov) return (VMCI_ERROR_INVALID_ARGS); result = dequeue(qpair->produce_q, qpair->consume_q, qpair->consume_q_size, iov, iov_size, buf_type, qpair->flags & VMCI_QPFLAG_LOCAL? vmci_memcpy_from_queue_v_local : vmci_memcpy_from_queue_v, false, !(qpair->flags & VMCI_QPFLAG_NONBLOCK)); return (result); }