[PATCH 03/10] VMCI: doorbell implementation.

George Zhang
2012-10-16T00:37:59Z

VMCI doorbell code allows for notifcations between host and guest.

Signed-off-by: George Zhang <georgezhang@vmware.com>
---
drivers/misc/vmw_vmci/vmci_doorbell.c | 674 +++++++++++++++++++++++++++++++++
drivers/misc/vmw_vmci/vmci_doorbell.h | 53 +++
2 files changed, 727 insertions(+), 0 deletions(-)
create mode 100644 drivers/misc/vmw_vmci/vmci_doorbell.c
create mode 100644 drivers/misc/vmw_vmci/vmci_doorbell.h

diff --git a/drivers/misc/vmw_vmci/vmci_doorbell.c b/drivers/misc/vmw_vmci/vmci_doorbell.c
new file mode 100644
index 0000000..0a8a6e5
--- /dev/null
+++ b/drivers/misc/vmw_vmci/vmci_doorbell.c
@@ -0,0 +1,674 @@
+/*
+ * 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/completion.h>
+#include <linux/hash.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "vmci_common_int.h"
+#include "vmci_datagram.h"
+#include "vmci_doorbell.h"
+#include "vmci_resource.h"
+#include "vmci_driver.h"
+#include "vmci_route.h"
+
+
+#define VMCI_DOORBELL_INDEX_BITS 6
+#define VMCI_DOORBELL_INDEX_TABLE_SIZE (1 << VMCI_DOORBELL_INDEX_BITS)
+#define VMCI_DOORBELL_HASH(_idx) hash_32(_idx, VMCI_DOORBELL_INDEX_BITS)
+
+/*
+ * DoorbellEntry describes the a doorbell notification handle allocated by the
+ * host.
+ */
+struct dbell_entry {
+ struct vmci_resource resource;
+ struct hlist_node node;
+ struct work_struct work;
+ vmci_callback notify_cb;
+ void *client_data;
+ u32 idx;
+ u32 priv_flags;
+ bool run_delayed;
+ atomic_t active; /* Only used by guest personality */
+};
+
+/* The VMCI index table keeps track of currently registered doorbells. */
+struct dbell_index_table {
+ spinlock_t lock; /* Index table lock */
+ struct hlist_head entries[VMCI_DOORBELL_INDEX_TABLE_SIZE];
+};
+
+static struct dbell_index_table vmci_doorbell_it = {
+ .lock = __SPIN_LOCK_UNLOCKED(vmci_doorbell_it.lock),
+};
+
+/*
+ * The max_notify_idx is one larger than the currently known bitmap index in
+ * use, and is used to determine how much of the bitmap needs to be scanned.
+ */
+static u32 max_notify_idx;
+
+/*
+ * The notify_idx_count is used for determining whether there are free entries
+ * within the bitmap (if notify_idx_count + 1 < max_notify_idx).
+ */
+static u32 notify_idx_count;
+
+/*
+ * The last_notify_idx_reserved is used to track the last index handed out - in
+ * the case where multiple handles share a notification index, we hand out
+ * indexes round robin based on last_notify_idx_reserved.
+ */
+static u32 last_notify_idx_reserved;
+
+/* This is a one entry cache used to by the index allocation. */
+static u32 last_notify_idx_released = PAGE_SIZE;
+
+
+/*
+ * Utility function that retrieves the privilege flags associated
+ * with a given doorbell handle. For guest endpoints, the
+ * privileges are determined by the context ID, but for host
+ * endpoints privileges are associated with the complete
+ * handle. Hypervisor endpoints are not yet supported.
+ */
+int vmci_dbell_get_priv_flags(struct vmci_handle handle, u32 *priv_flags)
+{
+ if (priv_flags == NULL || handle.context == VMCI_INVALID_ID)
+ return VMCI_ERROR_INVALID_ARGS;
+
+ if (handle.context == VMCI_HOST_CONTEXT_ID) {
+ struct dbell_entry *entry;
+ struct vmci_resource *resource;
+
+ resource = vmci_resource_by_handle(handle,
+ VMCI_RESOURCE_TYPE_DOORBELL);
+ if (!resource)
+ return VMCI_ERROR_NOT_FOUND;
+
+ entry = container_of(resource, struct dbell_entry, resource);
+ *priv_flags = entry->priv_flags;
+ vmci_resource_put(resource);
+ } else if (handle.context == VMCI_HYPERVISOR_CONTEXT_ID) {
+ /*
+ * Hypervisor endpoints for notifications are not
+ * supported (yet).
+ */
+ return VMCI_ERROR_INVALID_ARGS;
+ } else {
+ *priv_flags = vmci_context_get_priv_flags(handle.context);
+ }
+
+ return VMCI_SUCCESS;
+}
+
+/*
+ * Find doorbell entry by bitmap index.
+ */
+static struct dbell_entry *dbell_index_table_find(u32 idx)
+{
+ u32 bucket = VMCI_DOORBELL_HASH(idx);
+ struct dbell_entry *dbell;
+ struct hlist_node *node;
+
+ BUG_ON(!vmci_guest_code_active());
+
+ hlist_for_each_entry(dbell, node, &vmci_doorbell_it.entries[bucket],
+ node) {
+ if (idx == dbell->idx)
+ return dbell;
+ }
+
+ return NULL;
+}
+
+/*
+ * Add the given entry to the index table. This willi take a reference to the
+ * entry's resource so that the entry is not deleted before it is removed from
+ * the * table.
+ */
+static void dbell_index_table_add(struct dbell_entry *entry)
+{
+ u32 bucket;
+ u32 new_notify_idx;
+
+ BUG_ON(!entry);
+ BUG_ON(!vmci_guest_code_active());
+
+ vmci_resource_get(&entry->resource);
+
+ spin_lock_bh(&vmci_doorbell_it.lock);
+
+ /*
+ * Below we try to allocate an index in the notification
+ * bitmap with "not too much" sharing between resources. If we
+ * use less that the full bitmap, we either add to the end if
+ * there are no unused flags within the currently used area,
+ * or we search for unused ones. If we use the full bitmap, we
+ * allocate the index round robin.
+ */
+ if (max_notify_idx < PAGE_SIZE || notify_idx_count < PAGE_SIZE) {
+ if (last_notify_idx_released < max_notify_idx &&
+ !dbell_index_table_find(last_notify_idx_released)) {
+ new_notify_idx = last_notify_idx_released;
+ last_notify_idx_released = PAGE_SIZE;
+ } else {
+ bool reused = false;
+ new_notify_idx = last_notify_idx_reserved;
+ if (notify_idx_count + 1 < max_notify_idx) {
+ do {
+ if (!dbell_index_table_find
+ (new_notify_idx)) {
+ reused = true;
+ break;
+ }
+ new_notify_idx = (new_notify_idx + 1) %
+ max_notify_idx;
+ } while (new_notify_idx !=
+ last_notify_idx_released);
+ }
+ if (!reused) {
+ new_notify_idx = max_notify_idx;
+ max_notify_idx++;
+ }
+ }
+ } else {
+ new_notify_idx = (last_notify_idx_reserved + 1) % PAGE_SIZE;
+ }
+
+ last_notify_idx_reserved = new_notify_idx;
+ notify_idx_count++;
+
+ entry->idx = new_notify_idx;
+ bucket = VMCI_DOORBELL_HASH(entry->idx);
+ hlist_add_head(&entry->node, &vmci_doorbell_it.entries[bucket]);
+
+ spin_unlock_bh(&vmci_doorbell_it.lock);
+}
+
+/*
+ * Remove the given entry from the index table. This will release() the
+ * entry's resource.
+ */
+static void dbell_index_table_remove(struct dbell_entry *entry)
+{
+ BUG_ON(!entry);
+ BUG_ON(!vmci_guest_code_active());
+
+ spin_lock_bh(&vmci_doorbell_it.lock);
+
+ hlist_del_init(&entry->node);
+
+ notify_idx_count--;
+ if (entry->idx == max_notify_idx - 1) {
+ /*
+ * If we delete an entry with the maximum known
+ * notification index, we take the opportunity to
+ * prune the current max. As there might be other
+ * unused indices immediately below, we lower the
+ * maximum until we hit an index in use.
+ */
+ while (max_notify_idx > 0 &&
+ !dbell_index_table_find(max_notify_idx - 1))
+ max_notify_idx--;
+ }
+
+ last_notify_idx_released = entry->idx;
+
+ spin_unlock_bh(&vmci_doorbell_it.lock);
+
+ vmci_resource_put(&entry->resource);
+}
+
+/*
+ * Creates a link between the given doorbell handle and the given
+ * index in the bitmap in the device backend. A notification state
+ * is created in hypervisor.
+ */
+static int dbell_link(struct vmci_handle handle, u32 notify_idx)
+{
+ struct vmci_doorbell_link_msg link_msg;
+
+ BUG_ON(VMCI_HANDLE_INVALID(handle));
+ BUG_ON(!vmci_guest_code_active());
+
+ link_msg.hdr.dst = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID,
+ VMCI_DOORBELL_LINK);
+ link_msg.hdr.src = VMCI_ANON_SRC_HANDLE;
+ link_msg.hdr.payload_size = sizeof(link_msg) - VMCI_DG_HEADERSIZE;
+ link_msg.handle = handle;
+ link_msg.notify_idx = notify_idx;
+
+ return vmci_send_datagram((struct vmci_datagram *)&link_msg);
+}
+
+/*
+ * Unlinks the given doorbell handle from an index in the bitmap in
+ * the device backend. The notification state is destroyed in hypervisor.
+ */
+static int dbell_unlink(struct vmci_handle handle)
+{
+ struct vmci_doorbell_unlink_msg unlink_msg;
+
+ BUG_ON(VMCI_HANDLE_INVALID(handle));
+ BUG_ON(!vmci_guest_code_active());
+
+ unlink_msg.hdr.dst = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID,
+ VMCI_DOORBELL_UNLINK);
+ unlink_msg.hdr.src = VMCI_ANON_SRC_HANDLE;
+ unlink_msg.hdr.payload_size = sizeof(unlink_msg) - VMCI_DG_HEADERSIZE;
+ unlink_msg.handle = handle;
+
+ return vmci_send_datagram((struct vmci_datagram *)&unlink_msg);
+}
+
+/*
+ * Notify another guest or the host. We send a datagram down to the
+ * host via the hypervisor with the notification info.
+ */
+static int dbell_notify_as_guest(struct vmci_handle handle, u32 priv_flags)
+{
+ struct vmci_doorbell_notify_msg notify_msg;
+
+ BUG_ON(!vmci_guest_code_active());
+
+ notify_msg.hdr.dst = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID,
+ VMCI_DOORBELL_NOTIFY);
+ notify_msg.hdr.src = VMCI_ANON_SRC_HANDLE;
+ notify_msg.hdr.payload_size = sizeof(notify_msg) - VMCI_DG_HEADERSIZE;
+ notify_msg.handle = handle;
+
+ return vmci_send_datagram((struct vmci_datagram *)&notify_msg);
+}
+
+/*
+ * Calls the specified callback in a delayed context.
+ */
+static void dbell_delayed_dispatch(struct work_struct *work)
+{
+ struct dbell_entry *entry = container_of(work,
+ struct dbell_entry, work);
+
+ entry->notify_cb(entry->client_data);
+ vmci_resource_put(&entry->resource);
+}
+
+/*
+ * Dispatches a doorbell notification to the host context.
+ */
+int vmci_dbell_host_context_notify(u32 src_cid, struct vmci_handle handle)
+{
+ struct dbell_entry *entry;
+ struct vmci_resource *resource;
+
+ BUG_ON(!vmci_host_code_active());
+
+ if (VMCI_HANDLE_INVALID(handle)) {
+ pr_devel("Notifying an invalid doorbell (handle=0x%x:0x%x).",
+ handle.context, handle.resource);
+ return VMCI_ERROR_INVALID_ARGS;
+ }
+
+ resource = vmci_resource_by_handle(handle,
+ VMCI_RESOURCE_TYPE_DOORBELL);
+ if (!resource) {
+ pr_devel("Notifying an unknown doorbell (handle=0x%x:0x%x).",
+ handle.context, handle.resource);
+ return VMCI_ERROR_NOT_FOUND;
+ }
+
+ entry = container_of(resource, struct dbell_entry, resource);
+ if (entry->run_delayed) {
+ schedule_work(&entry->work);
+ } else {
+ entry->notify_cb(entry->client_data);
+ vmci_resource_put(resource);
+ }
+
+ return VMCI_SUCCESS;
+}
+
+/*
+ * When a guest leaves hibernation, the device driver state is out of sync
+ * with the device state, since the driver state has doorbells registered
+ * that aren't known to the device. This function takes care of
+ * reregistering any doorbells. In case an error occurs during
+ * reregistration (this is highly unlikely since 1) it succeeded the first
+ * time 2) the device driver is the only source of doorbell registrations),
+ * we simply log the error. The doorbell can still be destroyed using
+ * vmci_doorbell_destroy.
+ */
+void vmci_dbell_hibernate(bool enter_hibernate)
+{
+ struct dbell_entry *dbell;
+ struct hlist_node *node;
+ int i;
+
+ if (!vmci_guest_code_active() || enter_hibernate)
+ return;
+
+ spin_lock_bh(&vmci_doorbell_it.lock);
+
+ for (i = 0; i < ARRAY_SIZE(vmci_doorbell_it.entries); i++) {
+ hlist_for_each_entry(dbell, node,
+ &vmci_doorbell_it.entries[i], node) {
+ int result;
+ struct vmci_handle h;
+
+ h = vmci_resource_handle(&dbell->resource);
+ result = dbell_link(h, dbell->idx);
+ if (result != VMCI_SUCCESS &&
+ result != VMCI_ERROR_DUPLICATE_ENTRY) {
+ pr_warn("Failed to reregister doorbell (handle=0x%x:0x%x) to index (error=%d).",
+ h.context, h.resource, result);
+ }
+ }
+ }
+
+ spin_unlock_bh(&vmci_doorbell_it.lock);
+}
+
+/*
+ * Register the notification bitmap with the host.
+ */
+bool vmci_dbell_register_notification_bitmap(u32 bitmap_ppn)
+{
+ int result;
+ struct vmci_notify_bm_set_msg bitmap_set_msg;
+
+ /*
+ * Do not ASSERT() on the guest device here. This function
+ * can get called during device initialization, so the
+ * ASSERT() will fail even though the device is (almost) up.
+ */
+ bitmap_set_msg.hdr.dst = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID,
+ VMCI_SET_NOTIFY_BITMAP);
+ bitmap_set_msg.hdr.src = VMCI_ANON_SRC_HANDLE;
+ bitmap_set_msg.hdr.payload_size = sizeof(bitmap_set_msg) -
+ VMCI_DG_HEADERSIZE;
+ bitmap_set_msg.bitmap_ppn = bitmap_ppn;
+
+ result = vmci_send_datagram((struct vmci_datagram *)&bitmap_set_msg);
+ if (result != VMCI_SUCCESS) {
+ pr_devel("Failed to register (PPN=%u) as notification bitmap (error=%d).",
+ bitmap_ppn, result);
+ return false;
+ }
+ return true;
+}
+
+/*
+ * Executes or schedules the handlers for a given notify index.
+ */
+static void dbell_fire_entries(u32 notify_idx)
+{
+ u32 bucket = VMCI_DOORBELL_HASH(notify_idx);
+ struct dbell_entry *dbell;
+ struct hlist_node *node;
+
+ BUG_ON(!vmci_guest_code_active());
+
+ spin_lock_bh(&vmci_doorbell_it.lock);
+
+ hlist_for_each_entry(dbell, node,
+ &vmci_doorbell_it.entries[bucket], node) {
+ if (dbell->idx == notify_idx &&
+ atomic_read(&dbell->active) == 1) {
+ BUG_ON(!dbell->notify_cb);
+ if (dbell->run_delayed) {
+ vmci_resource_get(&dbell->resource);
+ schedule_work(&dbell->work);
+ } else {
+ dbell->notify_cb(dbell->client_data);
+ }
+ }
+ }
+
+ spin_unlock_bh(&vmci_doorbell_it.lock);
+}
+
+/*
+ * Scans the notification bitmap, collects pending notifications,
+ * resets the bitmap and invokes appropriate callbacks.
+ */
+void vmci_dbell_scan_notification_entries(u8 *bitmap)
+{
+ u32 idx;
+
+ BUG_ON(!bitmap);
+ BUG_ON(!vmci_guest_code_active());
+
+ for (idx = 0; idx < max_notify_idx; idx++) {
+ if (bitmap[idx] & 0x1) {
+ bitmap[idx] &= ~1;
+ dbell_fire_entries(idx);
+ }
+ }
+}
+
+/*
+ * vmci_doorbell_create() - Creates a doorbell
+ * @handle: A handle used to track the resource. Can be invalid.
+ * @flags: Flag that determines context of callback.
+ * @priv_flags: Privileges flags.
+ * @notify_cb: The callback to be ivoked when the doorbell fires.
+ * @client_data: A parameter to be passed to the callback.
+ *
+ * Creates a doorbell with the given callback. If the handle is
+ * VMCI_INVALID_HANDLE, a free handle will be assigned, if
+ * possible. The callback can be run immediately (potentially with
+ * locks held - the default) or delayed (in a kernel thread) by
+ * specifying the flag VMCI_FLAG_DELAYED_CB. If delayed execution
+ * is selected, a given callback may not be run if the kernel is
+ * unable to allocate memory for the delayed execution (highly
+ * unlikely).
+ */
+int vmci_doorbell_create(struct vmci_handle *handle,
+ u32 flags,
+ u32 priv_flags,
+ vmci_callback notify_cb, void *client_data)
+{
+ struct dbell_entry *entry;
+ struct vmci_handle new_handle;
+ int result;
+
+ if (!handle || !notify_cb || flags & ~VMCI_FLAG_DELAYED_CB ||
+ priv_flags & ~VMCI_PRIVILEGE_ALL_FLAGS)
+ return VMCI_ERROR_INVALID_ARGS;
+
+ entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+ if (entry == NULL) {
+ pr_warn("Failed allocating memory for datagram entry.");
+ return VMCI_ERROR_NO_MEM;
+ }
+
+ if (VMCI_HANDLE_INVALID(*handle)) {
+ u32 context_id = vmci_get_context_id();
+
+ /* Let resource code allocate a free ID for us */
+ new_handle = vmci_make_handle(context_id, VMCI_INVALID_ID);
+ } else {
+ bool valid_context = false;
+
+ /*
+ * Validate the handle. We must do both of the checks below
+ * because we can be acting as both a host and a guest at the
+ * same time. We always allow the host context ID, since the
+ * host functionality is in practice always there with the
+ * unified driver.
+ */
+ if (handle->context == VMCI_HOST_CONTEXT_ID ||
+ (vmci_guest_code_active() &&
+ vmci_get_context_id() == handle->context)) {
+ valid_context = true;
+ }
+
+ if (!valid_context || handle->resource == VMCI_INVALID_ID) {
+ pr_devel("Invalid argument (handle=0x%x:0x%x).",
+ handle->context, handle->resource);
+ result = VMCI_ERROR_INVALID_ARGS;
+ goto free_mem;
+ }
+
+ new_handle = *handle;
+ }
+
+ entry->idx = 0;
+ INIT_HLIST_NODE(&entry->node);
+ entry->priv_flags = priv_flags;
+ INIT_WORK(&entry->work, dbell_delayed_dispatch);
+ entry->run_delayed = flags & VMCI_FLAG_DELAYED_CB;
+ entry->notify_cb = notify_cb;
+ entry->client_data = client_data;
+ atomic_set(&entry->active, 0);
+
+ result = vmci_resource_add(&entry->resource,
+ VMCI_RESOURCE_TYPE_DOORBELL,
+ new_handle);
+ if (result != VMCI_SUCCESS) {
+ pr_warn("Failed to add new resource (handle=0x%x:0x%x), error: %d",
+ new_handle.context, new_handle.resource, result);
+ goto free_mem;
+ }
+
+ if (vmci_guest_code_active()) {
+ dbell_index_table_add(entry);
+ result = dbell_link(new_handle, entry->idx);
+ if (VMCI_SUCCESS != result)
+ goto destroy_resource;
+
+ atomic_set(&entry->active, 1);
+ }
+
+ *handle = vmci_resource_handle(&entry->resource);
+
+ return result;
+
+ destroy_resource:
+ dbell_index_table_remove(entry);
+ vmci_resource_remove(&entry->resource);
+ free_mem:
+ kfree(entry);
+ return result;
+}
+EXPORT_SYMBOL(vmci_doorbell_create);
+
+/*
+ * vmci_doorbell_destroy() - Destroy a doorbell.
+ * @handle: The handle tracking the resource.
+ *
+ * Destroys a doorbell previously created with vmcii_doorbell_create. This
+ * operation may block waiting for a callback to finish.
+ */
+int vmci_doorbell_destroy(struct vmci_handle handle)
+{
+ struct dbell_entry *entry;
+ struct vmci_resource *resource;
+
+ if (VMCI_HANDLE_INVALID(handle))
+ return VMCI_ERROR_INVALID_ARGS;
+
+ resource = vmci_resource_by_handle(handle,
+ VMCI_RESOURCE_TYPE_DOORBELL);
+ if (!resource) {
+ pr_devel("Failed to destroy doorbell (handle=0x%x:0x%x).",
+ handle.context, handle.resource);
+ return VMCI_ERROR_NOT_FOUND;
+ }
+
+ entry = container_of(resource, struct dbell_entry, resource);
+
+ if (vmci_guest_code_active()) {
+ int result;
+
+ dbell_index_table_remove(entry);
+
+ result = dbell_unlink(handle);
+ if (VMCI_SUCCESS != result) {
+
+ /*
+ * The only reason this should fail would be
+ * an inconsistency between guest and
+ * hypervisor state, where the guest believes
+ * it has an active registration whereas the
+ * hypervisor doesn't. One case where this may
+ * happen is if a doorbell is unregistered
+ * following a hibernation at a time where the
+ * doorbell state hasn't been restored on the
+ * hypervisor side yet. Since the handle has
+ * now been removed in the guest, we just
+ * print a warning and return success.
+ */
+ pr_devel("Unlink of doorbell (handle=0x%x:0x%x) "
+ "unknown by hypervisor (error=%d).",
+ handle.context, handle.resource, result);
+ }
+ }
+
+ /*
+ * Now remove the resource from the table. It might still be in use
+ * after this, in a callback or still on the delayed work queue.
+ */
+ vmci_resource_put(&entry->resource);
+ vmci_resource_remove(&entry->resource);
+
+ kfree(entry);
+
+ return VMCI_SUCCESS;
+}
+EXPORT_SYMBOL(vmci_doorbell_destroy);
+
+/*
+ * vmci_doorbell_notify() - Ring the doorbell (and hide in the bushes).
+ * @dst: The handlle identifying the doorbell resource
+ * @priv_flags: Priviledge flags.
+ *
+ * Generates a notification on the doorbell identified by the
+ * handle. For host side generation of notifications, the caller
+ * can specify what the privilege of the calling side is.
+ */
+int vmci_doorbell_notify(struct vmci_handle dst, u32 priv_flags)
+{
+ int retval;
+ enum vmci_route route;
+ struct vmci_handle src;
+
+ if (VMCI_HANDLE_INVALID(dst) ||
+ (priv_flags & ~VMCI_PRIVILEGE_ALL_FLAGS))
+ return VMCI_ERROR_INVALID_ARGS;
+
+ src = VMCI_INVALID_HANDLE;
+ retval = vmci_route(&src, &dst, false, &route);
+ if (retval < VMCI_SUCCESS)
+ return retval;
+
+ if (VMCI_ROUTE_AS_HOST == route)
+ return vmci_ctx_notify_dbell(VMCI_HOST_CONTEXT_ID,
+ dst, priv_flags);
+
+ if (VMCI_ROUTE_AS_GUEST == route)
+ return dbell_notify_as_guest(dst, priv_flags);
+
+ pr_warn("Unknown route (%d) for doorbell.", route);
+ return VMCI_ERROR_DST_UNREACHABLE;
+}
+EXPORT_SYMBOL(vmci_doorbell_notify);
diff --git a/drivers/misc/vmw_vmci/vmci_doorbell.h b/drivers/misc/vmw_vmci/vmci_doorbell.h
new file mode 100644
index 0000000..09b138c
--- /dev/null
+++ b/drivers/misc/vmw_vmci/vmci_doorbell.h
@@ -0,0 +1,53 @@
+/*
+ * 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.
+ */
+
+#ifndef VMCI_DOORBELL_H
+#define VMCI_DOORBELL_H
+
+#include <linux/vmw_vmci_defs.h>
+#include <linux/types.h>
+
+#include "vmci_driver.h"
+
+/*
+ * VMCINotifyResourceInfo: Used to create and destroy doorbells, and
+ * generate a notification for a doorbell or queue pair.
+ */
+struct vmci_dbell_notify_resource_info {
+ struct vmci_handle handle;
+ u16 resource;
+ u16 action;
+ s32 result;
+};
+
+/*
+ * Structure used for checkpointing the doorbell mappings. It is
+ * written to the checkpoint as is, so changing this structure will
+ * break checkpoint compatibility.
+ */
+struct dbell_cpt_state {
+ struct vmci_handle handle;
+ u64 bitmap_idx;
+};
+
+void vmci_dbell_hibernate(bool enter_hibernation);
+
+int vmci_dbell_host_context_notify(u32 src_cid, struct vmci_handle handle);
+int vmci_dbell_get_priv_flags(struct vmci_handle handle, u32 *priv_flags);
+
+bool vmci_dbell_register_notification_bitmap(u32 bitmap_ppn);
+void vmci_dbell_scan_notification_entries(u8 *bitmap);
+
+#endif /* VMCI_DOORBELL_H */