diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/misc/vmw_vmci/vmci_context.c | 1225 |
1 files changed, 1225 insertions, 0 deletions
diff --git a/drivers/misc/vmw_vmci/vmci_context.c b/drivers/misc/vmw_vmci/vmci_context.c new file mode 100644 index 000000000..26e20b091 --- /dev/null +++ b/drivers/misc/vmw_vmci/vmci_context.c @@ -0,0 +1,1225 @@ +/* + * VMware VMCI Driver + * + * Copyright (C) 2012 VMware, Inc. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation version 2 and no later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + */ + +#include <linux/vmw_vmci_defs.h> +#include <linux/vmw_vmci_api.h> +#include <linux/highmem.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/cred.h> +#include <linux/slab.h> + +#include "vmci_queue_pair.h" +#include "vmci_datagram.h" +#include "vmci_doorbell.h" +#include "vmci_context.h" +#include "vmci_driver.h" +#include "vmci_event.h" + +/* Use a wide upper bound for the maximum contexts. */ +#define VMCI_MAX_CONTEXTS 2000 + +/* + * List of current VMCI contexts. Contexts can be added by + * vmci_ctx_create() and removed via vmci_ctx_destroy(). + * These, along with context lookup, are protected by the + * list structure's lock. + */ +static struct { + struct list_head head; + spinlock_t lock; /* Spinlock for context list operations */ +} ctx_list = { + .head = LIST_HEAD_INIT(ctx_list.head), + .lock = __SPIN_LOCK_UNLOCKED(ctx_list.lock), +}; + +/* Used by contexts that did not set up notify flag pointers */ +static bool ctx_dummy_notify; + +static void ctx_signal_notify(struct vmci_ctx *context) +{ + *context->notify = true; +} + +static void ctx_clear_notify(struct vmci_ctx *context) +{ + *context->notify = false; +} + +/* + * If nothing requires the attention of the guest, clears both + * notify flag and call. + */ +static void ctx_clear_notify_call(struct vmci_ctx *context) +{ + if (context->pending_datagrams == 0 && + vmci_handle_arr_get_size(context->pending_doorbell_array) == 0) + ctx_clear_notify(context); +} + +/* + * Sets the context's notify flag iff datagrams are pending for this + * context. Called from vmci_setup_notify(). + */ +void vmci_ctx_check_signal_notify(struct vmci_ctx *context) +{ + spin_lock(&context->lock); + if (context->pending_datagrams) + ctx_signal_notify(context); + spin_unlock(&context->lock); +} + +/* + * Allocates and initializes a VMCI context. + */ +struct vmci_ctx *vmci_ctx_create(u32 cid, u32 priv_flags, + uintptr_t event_hnd, + int user_version, + const struct cred *cred) +{ + struct vmci_ctx *context; + int error; + + if (cid == VMCI_INVALID_ID) { + pr_devel("Invalid context ID for VMCI context\n"); + error = -EINVAL; + goto err_out; + } + + if (priv_flags & ~VMCI_PRIVILEGE_ALL_FLAGS) { + pr_devel("Invalid flag (flags=0x%x) for VMCI context\n", + priv_flags); + error = -EINVAL; + goto err_out; + } + + if (user_version == 0) { + pr_devel("Invalid suer_version %d\n", user_version); + error = -EINVAL; + goto err_out; + } + + context = kzalloc(sizeof(*context), GFP_KERNEL); + if (!context) { + pr_warn("Failed to allocate memory for VMCI context\n"); + error = -EINVAL; + goto err_out; + } + + kref_init(&context->kref); + spin_lock_init(&context->lock); + INIT_LIST_HEAD(&context->list_item); + INIT_LIST_HEAD(&context->datagram_queue); + INIT_LIST_HEAD(&context->notifier_list); + + /* Initialize host-specific VMCI context. */ + init_waitqueue_head(&context->host_context.wait_queue); + + context->queue_pair_array = + vmci_handle_arr_create(0, VMCI_MAX_GUEST_QP_COUNT); + if (!context->queue_pair_array) { + error = -ENOMEM; + goto err_free_ctx; + } + + context->doorbell_array = + vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT); + if (!context->doorbell_array) { + error = -ENOMEM; + goto err_free_qp_array; + } + + context->pending_doorbell_array = + vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT); + if (!context->pending_doorbell_array) { + error = -ENOMEM; + goto err_free_db_array; + } + + context->user_version = user_version; + + context->priv_flags = priv_flags; + + if (cred) + context->cred = get_cred(cred); + + context->notify = &ctx_dummy_notify; + context->notify_page = NULL; + + /* + * If we collide with an existing context we generate a new + * and use it instead. The VMX will determine if regeneration + * is okay. Since there isn't 4B - 16 VMs running on a given + * host, the below loop will terminate. + */ + spin_lock(&ctx_list.lock); + + while (vmci_ctx_exists(cid)) { + /* We reserve the lowest 16 ids for fixed contexts. */ + cid = max(cid, VMCI_RESERVED_CID_LIMIT - 1) + 1; + if (cid == VMCI_INVALID_ID) + cid = VMCI_RESERVED_CID_LIMIT; + } + context->cid = cid; + + list_add_tail_rcu(&context->list_item, &ctx_list.head); + spin_unlock(&ctx_list.lock); + + return context; + + err_free_db_array: + vmci_handle_arr_destroy(context->doorbell_array); + err_free_qp_array: + vmci_handle_arr_destroy(context->queue_pair_array); + err_free_ctx: + kfree(context); + err_out: + return ERR_PTR(error); +} + +/* + * Destroy VMCI context. + */ +void vmci_ctx_destroy(struct vmci_ctx *context) +{ + spin_lock(&ctx_list.lock); + list_del_rcu(&context->list_item); + spin_unlock(&ctx_list.lock); + synchronize_rcu(); + + vmci_ctx_put(context); +} + +/* + * Fire notification for all contexts interested in given cid. + */ +static int ctx_fire_notification(u32 context_id, u32 priv_flags) +{ + u32 i, array_size; + struct vmci_ctx *sub_ctx; + struct vmci_handle_arr *subscriber_array; + struct vmci_handle context_handle = + vmci_make_handle(context_id, VMCI_EVENT_HANDLER); + + /* + * We create an array to hold the subscribers we find when + * scanning through all contexts. + */ + subscriber_array = vmci_handle_arr_create(0, VMCI_MAX_CONTEXTS); + if (subscriber_array == NULL) + return VMCI_ERROR_NO_MEM; + + /* + * Scan all contexts to find who is interested in being + * notified about given contextID. + */ + rcu_read_lock(); + list_for_each_entry_rcu(sub_ctx, &ctx_list.head, list_item) { + struct vmci_handle_list *node; + + /* + * We only deliver notifications of the removal of + * contexts, if the two contexts are allowed to + * interact. + */ + if (vmci_deny_interaction(priv_flags, sub_ctx->priv_flags)) + continue; + + list_for_each_entry_rcu(node, &sub_ctx->notifier_list, node) { + if (!vmci_handle_is_equal(node->handle, context_handle)) + continue; + + vmci_handle_arr_append_entry(&subscriber_array, + vmci_make_handle(sub_ctx->cid, + VMCI_EVENT_HANDLER)); + } + } + rcu_read_unlock(); + + /* Fire event to all subscribers. */ + array_size = vmci_handle_arr_get_size(subscriber_array); + for (i = 0; i < array_size; i++) { + int result; + struct vmci_event_ctx ev; + + ev.msg.hdr.dst = vmci_handle_arr_get_entry(subscriber_array, i); + ev.msg.hdr.src = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID, + VMCI_CONTEXT_RESOURCE_ID); + ev.msg.hdr.payload_size = sizeof(ev) - sizeof(ev.msg.hdr); + ev.msg.event_data.event = VMCI_EVENT_CTX_REMOVED; + ev.payload.context_id = context_id; + + result = vmci_datagram_dispatch(VMCI_HYPERVISOR_CONTEXT_ID, + &ev.msg.hdr, false); + if (result < VMCI_SUCCESS) { + pr_devel("Failed to enqueue event datagram (type=%d) for context (ID=0x%x)\n", + ev.msg.event_data.event, + ev.msg.hdr.dst.context); + /* We continue to enqueue on next subscriber. */ + } + } + vmci_handle_arr_destroy(subscriber_array); + + return VMCI_SUCCESS; +} + +/* + * Returns the current number of pending datagrams. The call may + * also serve as a synchronization point for the datagram queue, + * as no enqueue operations can occur concurrently. + */ +int vmci_ctx_pending_datagrams(u32 cid, u32 *pending) +{ + struct vmci_ctx *context; + + context = vmci_ctx_get(cid); + if (context == NULL) + return VMCI_ERROR_INVALID_ARGS; + + spin_lock(&context->lock); + if (pending) + *pending = context->pending_datagrams; + spin_unlock(&context->lock); + vmci_ctx_put(context); + + return VMCI_SUCCESS; +} + +/* + * Queues a VMCI datagram for the appropriate target VM context. + */ +int vmci_ctx_enqueue_datagram(u32 cid, struct vmci_datagram *dg) +{ + struct vmci_datagram_queue_entry *dq_entry; + struct vmci_ctx *context; + struct vmci_handle dg_src; + size_t vmci_dg_size; + + vmci_dg_size = VMCI_DG_SIZE(dg); + if (vmci_dg_size > VMCI_MAX_DG_SIZE) { + pr_devel("Datagram too large (bytes=%zu)\n", vmci_dg_size); + return VMCI_ERROR_INVALID_ARGS; + } + + /* Get the target VM's VMCI context. */ + context = vmci_ctx_get(cid); + if (!context) { + pr_devel("Invalid context (ID=0x%x)\n", cid); + return VMCI_ERROR_INVALID_ARGS; + } + + /* Allocate guest call entry and add it to the target VM's queue. */ + dq_entry = kmalloc(sizeof(*dq_entry), GFP_KERNEL); + if (dq_entry == NULL) { + pr_warn("Failed to allocate memory for datagram\n"); + vmci_ctx_put(context); + return VMCI_ERROR_NO_MEM; + } + dq_entry->dg = dg; + dq_entry->dg_size = vmci_dg_size; + dg_src = dg->src; + INIT_LIST_HEAD(&dq_entry->list_item); + + spin_lock(&context->lock); + + /* + * We put a higher limit on datagrams from the hypervisor. If + * the pending datagram is not from hypervisor, then we check + * if enqueueing it would exceed the + * VMCI_MAX_DATAGRAM_QUEUE_SIZE limit on the destination. If + * the pending datagram is from hypervisor, we allow it to be + * queued at the destination side provided we don't reach the + * VMCI_MAX_DATAGRAM_AND_EVENT_QUEUE_SIZE limit. + */ + if (context->datagram_queue_size + vmci_dg_size >= + VMCI_MAX_DATAGRAM_QUEUE_SIZE && + (!vmci_handle_is_equal(dg_src, + vmci_make_handle + (VMCI_HYPERVISOR_CONTEXT_ID, + VMCI_CONTEXT_RESOURCE_ID)) || + context->datagram_queue_size + vmci_dg_size >= + VMCI_MAX_DATAGRAM_AND_EVENT_QUEUE_SIZE)) { + spin_unlock(&context->lock); + vmci_ctx_put(context); + kfree(dq_entry); + pr_devel("Context (ID=0x%x) receive queue is full\n", cid); + return VMCI_ERROR_NO_RESOURCES; + } + + list_add(&dq_entry->list_item, &context->datagram_queue); + context->pending_datagrams++; + context->datagram_queue_size += vmci_dg_size; + ctx_signal_notify(context); + wake_up(&context->host_context.wait_queue); + spin_unlock(&context->lock); + vmci_ctx_put(context); + + return vmci_dg_size; +} + +/* + * Verifies whether a context with the specified context ID exists. + * FIXME: utility is dubious as no decisions can be reliably made + * using this data as context can appear and disappear at any time. + */ +bool vmci_ctx_exists(u32 cid) +{ + struct vmci_ctx *context; + bool exists = false; + + rcu_read_lock(); + + list_for_each_entry_rcu(context, &ctx_list.head, list_item) { + if (context->cid == cid) { + exists = true; + break; + } + } + + rcu_read_unlock(); + return exists; +} + +/* + * Retrieves VMCI context corresponding to the given cid. + */ +struct vmci_ctx *vmci_ctx_get(u32 cid) +{ + struct vmci_ctx *c, *context = NULL; + + if (cid == VMCI_INVALID_ID) + return NULL; + + rcu_read_lock(); + list_for_each_entry_rcu(c, &ctx_list.head, list_item) { + if (c->cid == cid) { + /* + * The context owner drops its own reference to the + * context only after removing it from the list and + * waiting for RCU grace period to expire. This + * means that we are not about to increase the + * reference count of something that is in the + * process of being destroyed. + */ + context = c; + kref_get(&context->kref); + break; + } + } + rcu_read_unlock(); + + return context; +} + +/* + * Deallocates all parts of a context data structure. This + * function doesn't lock the context, because it assumes that + * the caller was holding the last reference to context. + */ +static void ctx_free_ctx(struct kref *kref) +{ + struct vmci_ctx *context = container_of(kref, struct vmci_ctx, kref); + struct vmci_datagram_queue_entry *dq_entry, *dq_entry_tmp; + struct vmci_handle temp_handle; + struct vmci_handle_list *notifier, *tmp; + + /* + * Fire event to all contexts interested in knowing this + * context is dying. + */ + ctx_fire_notification(context->cid, context->priv_flags); + + /* + * Cleanup all queue pair resources attached to context. If + * the VM dies without cleaning up, this code will make sure + * that no resources are leaked. + */ + temp_handle = vmci_handle_arr_get_entry(context->queue_pair_array, 0); + while (!vmci_handle_is_equal(temp_handle, VMCI_INVALID_HANDLE)) { + if (vmci_qp_broker_detach(temp_handle, + context) < VMCI_SUCCESS) { + /* + * When vmci_qp_broker_detach() succeeds it + * removes the handle from the array. If + * detach fails, we must remove the handle + * ourselves. + */ + vmci_handle_arr_remove_entry(context->queue_pair_array, + temp_handle); + } + temp_handle = + vmci_handle_arr_get_entry(context->queue_pair_array, 0); + } + + /* + * It is fine to destroy this without locking the callQueue, as + * this is the only thread having a reference to the context. + */ + list_for_each_entry_safe(dq_entry, dq_entry_tmp, + &context->datagram_queue, list_item) { + WARN_ON(dq_entry->dg_size != VMCI_DG_SIZE(dq_entry->dg)); + list_del(&dq_entry->list_item); + kfree(dq_entry->dg); + kfree(dq_entry); + } + + list_for_each_entry_safe(notifier, tmp, + &context->notifier_list, node) { + list_del(¬ifier->node); + kfree(notifier); + } + + vmci_handle_arr_destroy(context->queue_pair_array); + vmci_handle_arr_destroy(context->doorbell_array); + vmci_handle_arr_destroy(context->pending_doorbell_array); + vmci_ctx_unset_notify(context); + if (context->cred) + put_cred(context->cred); + kfree(context); +} + +/* + * Drops reference to VMCI context. If this is the last reference to + * the context it will be deallocated. A context is created with + * a reference count of one, and on destroy, it is removed from + * the context list before its reference count is decremented. Thus, + * if we reach zero, we are sure that nobody else are about to increment + * it (they need the entry in the context list for that), and so there + * is no need for locking. + */ +void vmci_ctx_put(struct vmci_ctx *context) +{ + kref_put(&context->kref, ctx_free_ctx); +} + +/* + * Dequeues the next datagram and returns it to caller. + * The caller passes in a pointer to the max size datagram + * it can handle and the datagram is only unqueued if the + * size is less than max_size. If larger max_size is set to + * the size of the datagram to give the caller a chance to + * set up a larger buffer for the guestcall. + */ +int vmci_ctx_dequeue_datagram(struct vmci_ctx *context, + size_t *max_size, + struct vmci_datagram **dg) +{ + struct vmci_datagram_queue_entry *dq_entry; + struct list_head *list_item; + int rv; + + /* Dequeue the next datagram entry. */ + spin_lock(&context->lock); + if (context->pending_datagrams == 0) { + ctx_clear_notify_call(context); + spin_unlock(&context->lock); + pr_devel("No datagrams pending\n"); + return VMCI_ERROR_NO_MORE_DATAGRAMS; + } + + list_item = context->datagram_queue.next; + + dq_entry = + list_entry(list_item, struct vmci_datagram_queue_entry, list_item); + + /* Check size of caller's buffer. */ + if (*max_size < dq_entry->dg_size) { + *max_size = dq_entry->dg_size; + spin_unlock(&context->lock); + pr_devel("Caller's buffer should be at least (size=%u bytes)\n", + (u32) *max_size); + return VMCI_ERROR_NO_MEM; + } + + list_del(list_item); + context->pending_datagrams--; + context->datagram_queue_size -= dq_entry->dg_size; + if (context->pending_datagrams == 0) { + ctx_clear_notify_call(context); + rv = VMCI_SUCCESS; + } else { + /* + * Return the size of the next datagram. + */ + struct vmci_datagram_queue_entry *next_entry; + + list_item = context->datagram_queue.next; + next_entry = + list_entry(list_item, struct vmci_datagram_queue_entry, + list_item); + + /* + * The following size_t -> int truncation is fine as + * the maximum size of a (routable) datagram is 68KB. + */ + rv = (int)next_entry->dg_size; + } + spin_unlock(&context->lock); + + /* Caller must free datagram. */ + *dg = dq_entry->dg; + dq_entry->dg = NULL; + kfree(dq_entry); + + return rv; +} + +/* + * Reverts actions set up by vmci_setup_notify(). Unmaps and unlocks the + * page mapped/locked by vmci_setup_notify(). + */ +void vmci_ctx_unset_notify(struct vmci_ctx *context) +{ + struct page *notify_page; + + spin_lock(&context->lock); + + notify_page = context->notify_page; + context->notify = &ctx_dummy_notify; + context->notify_page = NULL; + + spin_unlock(&context->lock); + + if (notify_page) { + kunmap(notify_page); + put_page(notify_page); + } +} + +/* + * Add remote_cid to list of contexts current contexts wants + * notifications from/about. + */ +int vmci_ctx_add_notification(u32 context_id, u32 remote_cid) +{ + struct vmci_ctx *context; + struct vmci_handle_list *notifier, *n; + int result; + bool exists = false; + + context = vmci_ctx_get(context_id); + if (!context) + return VMCI_ERROR_NOT_FOUND; + + if (VMCI_CONTEXT_IS_VM(context_id) && VMCI_CONTEXT_IS_VM(remote_cid)) { + pr_devel("Context removed notifications for other VMs not supported (src=0x%x, remote=0x%x)\n", + context_id, remote_cid); + result = VMCI_ERROR_DST_UNREACHABLE; + goto out; + } + + if (context->priv_flags & VMCI_PRIVILEGE_FLAG_RESTRICTED) { + result = VMCI_ERROR_NO_ACCESS; + goto out; + } + + notifier = kmalloc(sizeof(struct vmci_handle_list), GFP_KERNEL); + if (!notifier) { + result = VMCI_ERROR_NO_MEM; + goto out; + } + + INIT_LIST_HEAD(¬ifier->node); + notifier->handle = vmci_make_handle(remote_cid, VMCI_EVENT_HANDLER); + + spin_lock(&context->lock); + + if (context->n_notifiers < VMCI_MAX_CONTEXTS) { + list_for_each_entry(n, &context->notifier_list, node) { + if (vmci_handle_is_equal(n->handle, notifier->handle)) { + exists = true; + break; + } + } + + if (exists) { + kfree(notifier); + result = VMCI_ERROR_ALREADY_EXISTS; + } else { + list_add_tail_rcu(¬ifier->node, + &context->notifier_list); + context->n_notifiers++; + result = VMCI_SUCCESS; + } + } else { + kfree(notifier); + result = VMCI_ERROR_NO_MEM; + } + + spin_unlock(&context->lock); + + out: + vmci_ctx_put(context); + return result; +} + +/* + * Remove remote_cid from current context's list of contexts it is + * interested in getting notifications from/about. + */ +int vmci_ctx_remove_notification(u32 context_id, u32 remote_cid) +{ + struct vmci_ctx *context; + struct vmci_handle_list *notifier, *tmp; + struct vmci_handle handle; + bool found = false; + + context = vmci_ctx_get(context_id); + if (!context) + return VMCI_ERROR_NOT_FOUND; + + handle = vmci_make_handle(remote_cid, VMCI_EVENT_HANDLER); + + spin_lock(&context->lock); + list_for_each_entry_safe(notifier, tmp, + &context->notifier_list, node) { + if (vmci_handle_is_equal(notifier->handle, handle)) { + list_del_rcu(¬ifier->node); + context->n_notifiers--; + found = true; + break; + } + } + spin_unlock(&context->lock); + + if (found) { + synchronize_rcu(); + kfree(notifier); + } + + vmci_ctx_put(context); + + return found ? VMCI_SUCCESS : VMCI_ERROR_NOT_FOUND; +} + +static int vmci_ctx_get_chkpt_notifiers(struct vmci_ctx *context, + u32 *buf_size, void **pbuf) +{ + u32 *notifiers; + size_t data_size; + struct vmci_handle_list *entry; + int i = 0; + + if (context->n_notifiers == 0) { + *buf_size = 0; + *pbuf = NULL; + return VMCI_SUCCESS; + } + + data_size = context->n_notifiers * sizeof(*notifiers); + if (*buf_size < data_size) { + *buf_size = data_size; + return VMCI_ERROR_MORE_DATA; + } + + notifiers = kmalloc(data_size, GFP_ATOMIC); /* FIXME: want GFP_KERNEL */ + if (!notifiers) + return VMCI_ERROR_NO_MEM; + + list_for_each_entry(entry, &context->notifier_list, node) + notifiers[i++] = entry->handle.context; + + *buf_size = data_size; + *pbuf = notifiers; + return VMCI_SUCCESS; +} + +static int vmci_ctx_get_chkpt_doorbells(struct vmci_ctx *context, + u32 *buf_size, void **pbuf) +{ + struct dbell_cpt_state *dbells; + u32 i, n_doorbells; + + n_doorbells = vmci_handle_arr_get_size(context->doorbell_array); + if (n_doorbells > 0) { + size_t data_size = n_doorbells * sizeof(*dbells); + if (*buf_size < data_size) { + *buf_size = data_size; + return VMCI_ERROR_MORE_DATA; + } + + dbells = kzalloc(data_size, GFP_ATOMIC); + if (!dbells) + return VMCI_ERROR_NO_MEM; + + for (i = 0; i < n_doorbells; i++) + dbells[i].handle = vmci_handle_arr_get_entry( + context->doorbell_array, i); + + *buf_size = data_size; + *pbuf = dbells; + } else { + *buf_size = 0; + *pbuf = NULL; + } + + return VMCI_SUCCESS; +} + +/* + * Get current context's checkpoint state of given type. + */ +int vmci_ctx_get_chkpt_state(u32 context_id, + u32 cpt_type, + u32 *buf_size, + void **pbuf) +{ + struct vmci_ctx *context; + int result; + + context = vmci_ctx_get(context_id); + if (!context) + return VMCI_ERROR_NOT_FOUND; + + spin_lock(&context->lock); + + switch (cpt_type) { + case VMCI_NOTIFICATION_CPT_STATE: + result = vmci_ctx_get_chkpt_notifiers(context, buf_size, pbuf); + break; + + case VMCI_WELLKNOWN_CPT_STATE: + /* + * For compatibility with VMX'en with VM to VM communication, we + * always return zero wellknown handles. + */ + + *buf_size = 0; + *pbuf = NULL; + result = VMCI_SUCCESS; + break; + + case VMCI_DOORBELL_CPT_STATE: + result = vmci_ctx_get_chkpt_doorbells(context, buf_size, pbuf); + break; + + default: + pr_devel("Invalid cpt state (type=%d)\n", cpt_type); + result = VMCI_ERROR_INVALID_ARGS; + break; + } + + spin_unlock(&context->lock); + vmci_ctx_put(context); + + return result; +} + +/* + * Set current context's checkpoint state of given type. + */ +int vmci_ctx_set_chkpt_state(u32 context_id, + u32 cpt_type, + u32 buf_size, + void *cpt_buf) +{ + u32 i; + u32 current_id; + int result = VMCI_SUCCESS; + u32 num_ids = buf_size / sizeof(u32); + + if (cpt_type == VMCI_WELLKNOWN_CPT_STATE && num_ids > 0) { + /* + * We would end up here if VMX with VM to VM communication + * attempts to restore a checkpoint with wellknown handles. + */ + pr_warn("Attempt to restore checkpoint with obsolete wellknown handles\n"); + return VMCI_ERROR_OBSOLETE; + } + + if (cpt_type != VMCI_NOTIFICATION_CPT_STATE) { + pr_devel("Invalid cpt state (type=%d)\n", cpt_type); + return VMCI_ERROR_INVALID_ARGS; + } + + for (i = 0; i < num_ids && result == VMCI_SUCCESS; i++) { + current_id = ((u32 *)cpt_buf)[i]; + result = vmci_ctx_add_notification(context_id, current_id); + if (result != VMCI_SUCCESS) + break; + } + if (result != VMCI_SUCCESS) + pr_devel("Failed to set cpt state (type=%d) (error=%d)\n", + cpt_type, result); + + return result; +} + +/* + * Retrieves the specified context's pending notifications in the + * form of a handle array. The handle arrays returned are the + * actual data - not a copy and should not be modified by the + * caller. They must be released using + * vmci_ctx_rcv_notifications_release. + */ +int vmci_ctx_rcv_notifications_get(u32 context_id, + struct vmci_handle_arr **db_handle_array, + struct vmci_handle_arr **qp_handle_array) +{ + struct vmci_ctx *context; + int result = VMCI_SUCCESS; + + context = vmci_ctx_get(context_id); + if (context == NULL) + return VMCI_ERROR_NOT_FOUND; + + spin_lock(&context->lock); + + *db_handle_array = context->pending_doorbell_array; + context->pending_doorbell_array = + vmci_handle_arr_create(0, VMCI_MAX_GUEST_DOORBELL_COUNT); + if (!context->pending_doorbell_array) { + context->pending_doorbell_array = *db_handle_array; + *db_handle_array = NULL; + result = VMCI_ERROR_NO_MEM; + } + *qp_handle_array = NULL; + + spin_unlock(&context->lock); + vmci_ctx_put(context); + + return result; +} + +/* + * Releases handle arrays with pending notifications previously + * retrieved using vmci_ctx_rcv_notifications_get. If the + * notifications were not successfully handed over to the guest, + * success must be false. + */ +void vmci_ctx_rcv_notifications_release(u32 context_id, + struct vmci_handle_arr *db_handle_array, + struct vmci_handle_arr *qp_handle_array, + bool success) +{ + struct vmci_ctx *context = vmci_ctx_get(context_id); + + spin_lock(&context->lock); + if (!success) { + struct vmci_handle handle; + + /* + * New notifications may have been added while we were not + * holding the context lock, so we transfer any new pending + * doorbell notifications to the old array, and reinstate the + * old array. + */ + + handle = vmci_handle_arr_remove_tail( + context->pending_doorbell_array); + while (!vmci_handle_is_invalid(handle)) { + if (!vmci_handle_arr_has_entry(db_handle_array, + handle)) { + vmci_handle_arr_append_entry( + &db_handle_array, handle); + } + handle = vmci_handle_arr_remove_tail( + context->pending_doorbell_array); + } + vmci_handle_arr_destroy(context->pending_doorbell_array); + context->pending_doorbell_array = db_handle_array; + db_handle_array = NULL; + } else { + ctx_clear_notify_call(context); + } + spin_unlock(&context->lock); + vmci_ctx_put(context); + + if (db_handle_array) + vmci_handle_arr_destroy(db_handle_array); + + if (qp_handle_array) + vmci_handle_arr_destroy(qp_handle_array); +} + +/* + * Registers that a new doorbell handle has been allocated by the + * context. Only doorbell handles registered can be notified. + */ +int vmci_ctx_dbell_create(u32 context_id, struct vmci_handle handle) +{ + struct vmci_ctx *context; + int result; + + if (context_id == VMCI_INVALID_ID || vmci_handle_is_invalid(handle)) + return VMCI_ERROR_INVALID_ARGS; + + context = vmci_ctx_get(context_id); + if (context == NULL) + return VMCI_ERROR_NOT_FOUND; + + spin_lock(&context->lock); + if (!vmci_handle_arr_has_entry(context->doorbell_array, handle)) + result = vmci_handle_arr_append_entry(&context->doorbell_array, + handle); + else + result = VMCI_ERROR_DUPLICATE_ENTRY; + + spin_unlock(&context->lock); + vmci_ctx_put(context); + + return result; +} + +/* + * Unregisters a doorbell handle that was previously registered + * with vmci_ctx_dbell_create. + */ +int vmci_ctx_dbell_destroy(u32 context_id, struct vmci_handle handle) +{ + struct vmci_ctx *context; + struct vmci_handle removed_handle; + + if (context_id == VMCI_INVALID_ID || vmci_handle_is_invalid(handle)) + return VMCI_ERROR_INVALID_ARGS; + + context = vmci_ctx_get(context_id); + if (context == NULL) + return VMCI_ERROR_NOT_FOUND; + + spin_lock(&context->lock); + removed_handle = + vmci_handle_arr_remove_entry(context->doorbell_array, handle); + vmci_handle_arr_remove_entry(context->pending_doorbell_array, handle); + spin_unlock(&context->lock); + + vmci_ctx_put(context); + + return vmci_handle_is_invalid(removed_handle) ? + VMCI_ERROR_NOT_FOUND : VMCI_SUCCESS; +} + +/* + * Unregisters all doorbell handles that were previously + * registered with vmci_ctx_dbell_create. + */ +int vmci_ctx_dbell_destroy_all(u32 context_id) +{ + struct vmci_ctx *context; + struct vmci_handle handle; + + if (context_id == VMCI_INVALID_ID) + return VMCI_ERROR_INVALID_ARGS; + + context = vmci_ctx_get(context_id); + if (context == NULL) + return VMCI_ERROR_NOT_FOUND; + + spin_lock(&context->lock); + do { + struct vmci_handle_arr *arr = context->doorbell_array; + handle = vmci_handle_arr_remove_tail(arr); + } while (!vmci_handle_is_invalid(handle)); + do { + struct vmci_handle_arr *arr = context->pending_doorbell_array; + handle = vmci_handle_arr_remove_tail(arr); + } while (!vmci_handle_is_invalid(handle)); + spin_unlock(&context->lock); + + vmci_ctx_put(context); + + return VMCI_SUCCESS; +} + +/* + * Registers a notification of a doorbell handle initiated by the + * specified source context. The notification of doorbells are + * subject to the same isolation rules as datagram delivery. To + * allow host side senders of notifications a finer granularity + * of sender rights than those assigned to the sending context + * itself, the host context is required to specify a different + * set of privilege flags that will override the privileges of + * the source context. + */ +int vmci_ctx_notify_dbell(u32 src_cid, + struct vmci_handle handle, + u32 src_priv_flags) +{ + struct vmci_ctx *dst_context; + int result; + + if (vmci_handle_is_invalid(handle)) + return VMCI_ERROR_INVALID_ARGS; + + /* Get the target VM's VMCI context. */ + dst_context = vmci_ctx_get(handle.context); + if (!dst_context) { + pr_devel("Invalid context (ID=0x%x)\n", handle.context); + return VMCI_ERROR_NOT_FOUND; + } + + if (src_cid != handle.context) { + u32 dst_priv_flags; + + if (VMCI_CONTEXT_IS_VM(src_cid) && + VMCI_CONTEXT_IS_VM(handle.context)) { + pr_devel("Doorbell notification from VM to VM not supported (src=0x%x, dst=0x%x)\n", + src_cid, handle.context); + result = VMCI_ERROR_DST_UNREACHABLE; + goto out; + } + + result = vmci_dbell_get_priv_flags(handle, &dst_priv_flags); + if (result < VMCI_SUCCESS) { + pr_warn("Failed to get privilege flags for destination (handle=0x%x:0x%x)\n", + handle.context, handle.resource); + goto out; + } + + if (src_cid != VMCI_HOST_CONTEXT_ID || + src_priv_flags == VMCI_NO_PRIVILEGE_FLAGS) { + src_priv_flags = vmci_context_get_priv_flags(src_cid); + } + + if (vmci_deny_interaction(src_priv_flags, dst_priv_flags)) { + result = VMCI_ERROR_NO_ACCESS; + goto out; + } + } + + if (handle.context == VMCI_HOST_CONTEXT_ID) { + result = vmci_dbell_host_context_notify(src_cid, handle); + } else { + spin_lock(&dst_context->lock); + + if (!vmci_handle_arr_has_entry(dst_context->doorbell_array, + handle)) { + result = VMCI_ERROR_NOT_FOUND; + } else { + if (!vmci_handle_arr_has_entry( + dst_context->pending_doorbell_array, + handle)) { + result = vmci_handle_arr_append_entry( + &dst_context->pending_doorbell_array, + handle); + if (result == VMCI_SUCCESS) { + ctx_signal_notify(dst_context); + wake_up(&dst_context->host_context.wait_queue); + } + } else { + result = VMCI_SUCCESS; + } + } + spin_unlock(&dst_context->lock); + } + + out: + vmci_ctx_put(dst_context); + + return result; +} + +bool vmci_ctx_supports_host_qp(struct vmci_ctx *context) +{ + return context && context->user_version >= VMCI_VERSION_HOSTQP; +} + +/* + * Registers that a new queue pair handle has been allocated by + * the context. + */ +int vmci_ctx_qp_create(struct vmci_ctx *context, struct vmci_handle handle) +{ + int result; + + if (context == NULL || vmci_handle_is_invalid(handle)) + return VMCI_ERROR_INVALID_ARGS; + + if (!vmci_handle_arr_has_entry(context->queue_pair_array, handle)) + result = vmci_handle_arr_append_entry( + &context->queue_pair_array, handle); + else + result = VMCI_ERROR_DUPLICATE_ENTRY; + + return result; +} + +/* + * Unregisters a queue pair handle that was previously registered + * with vmci_ctx_qp_create. + */ +int vmci_ctx_qp_destroy(struct vmci_ctx *context, struct vmci_handle handle) +{ + struct vmci_handle hndl; + + if (context == NULL || vmci_handle_is_invalid(handle)) + return VMCI_ERROR_INVALID_ARGS; + + hndl = vmci_handle_arr_remove_entry(context->queue_pair_array, handle); + + return vmci_handle_is_invalid(hndl) ? + VMCI_ERROR_NOT_FOUND : VMCI_SUCCESS; +} + +/* + * Determines whether a given queue pair handle is registered + * with the given context. + */ +bool vmci_ctx_qp_exists(struct vmci_ctx *context, struct vmci_handle handle) +{ + if (context == NULL || vmci_handle_is_invalid(handle)) + return false; + + return vmci_handle_arr_has_entry(context->queue_pair_array, handle); +} + +/* + * vmci_context_get_priv_flags() - Retrieve privilege flags. + * @context_id: The context ID of the VMCI context. + * + * Retrieves privilege flags of the given VMCI context ID. + */ +u32 vmci_context_get_priv_flags(u32 context_id) +{ + if (vmci_host_code_active()) { + u32 flags; + struct vmci_ctx *context; + + context = vmci_ctx_get(context_id); + if (!context) + return VMCI_LEAST_PRIVILEGE_FLAGS; + + flags = context->priv_flags; + vmci_ctx_put(context); + return flags; + } + return VMCI_NO_PRIVILEGE_FLAGS; +} +EXPORT_SYMBOL_GPL(vmci_context_get_priv_flags); + +/* + * vmci_is_context_owner() - Determimnes if user is the context owner + * @context_id: The context ID of the VMCI context. + * @uid: The host user id (real kernel value). + * + * Determines whether a given UID is the owner of given VMCI context. + */ +bool vmci_is_context_owner(u32 context_id, kuid_t uid) +{ + bool is_owner = false; + + if (vmci_host_code_active()) { + struct vmci_ctx *context = vmci_ctx_get(context_id); + if (context) { + if (context->cred) + is_owner = uid_eq(context->cred->uid, uid); + vmci_ctx_put(context); + } + } + + return is_owner; +} +EXPORT_SYMBOL_GPL(vmci_is_context_owner); |