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- /*
- * 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/module.h>
- #include <linux/sched.h>
- #include <linux/slab.h>
- #include <linux/bug.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"
- /*
- * struct datagram_entry describes the datagram entity. It is used for datagram
- * entities created only on the host.
- */
- struct datagram_entry {
- struct vmci_resource resource;
- u32 flags;
- bool run_delayed;
- vmci_datagram_recv_cb recv_cb;
- void *client_data;
- u32 priv_flags;
- };
- struct delayed_datagram_info {
- struct datagram_entry *entry;
- struct work_struct work;
- bool in_dg_host_queue;
- /* msg and msg_payload must be together. */
- struct vmci_datagram msg;
- u8 msg_payload[];
- };
- /* Number of in-flight host->host datagrams */
- static atomic_t delayed_dg_host_queue_size = ATOMIC_INIT(0);
- /*
- * Create a datagram entry given a handle pointer.
- */
- static int dg_create_handle(u32 resource_id,
- u32 flags,
- u32 priv_flags,
- vmci_datagram_recv_cb recv_cb,
- void *client_data, struct vmci_handle *out_handle)
- {
- int result;
- u32 context_id;
- struct vmci_handle handle;
- struct datagram_entry *entry;
- if ((flags & VMCI_FLAG_WELLKNOWN_DG_HND) != 0)
- return VMCI_ERROR_INVALID_ARGS;
- if ((flags & VMCI_FLAG_ANYCID_DG_HND) != 0) {
- context_id = VMCI_INVALID_ID;
- } else {
- context_id = vmci_get_context_id();
- if (context_id == VMCI_INVALID_ID)
- return VMCI_ERROR_NO_RESOURCES;
- }
- handle = vmci_make_handle(context_id, resource_id);
- entry = kmalloc(sizeof(*entry), GFP_KERNEL);
- if (!entry) {
- pr_warn("Failed allocating memory for datagram entry\n");
- return VMCI_ERROR_NO_MEM;
- }
- entry->run_delayed = (flags & VMCI_FLAG_DG_DELAYED_CB) ? true : false;
- entry->flags = flags;
- entry->recv_cb = recv_cb;
- entry->client_data = client_data;
- entry->priv_flags = priv_flags;
- /* Make datagram resource live. */
- result = vmci_resource_add(&entry->resource,
- VMCI_RESOURCE_TYPE_DATAGRAM,
- handle);
- if (result != VMCI_SUCCESS) {
- pr_warn("Failed to add new resource (handle=0x%x:0x%x), error: %d\n",
- handle.context, handle.resource, result);
- kfree(entry);
- return result;
- }
- *out_handle = vmci_resource_handle(&entry->resource);
- return VMCI_SUCCESS;
- }
- /*
- * Internal utility function with the same purpose as
- * vmci_datagram_get_priv_flags that also takes a context_id.
- */
- static int vmci_datagram_get_priv_flags(u32 context_id,
- struct vmci_handle handle,
- u32 *priv_flags)
- {
- if (context_id == VMCI_INVALID_ID)
- return VMCI_ERROR_INVALID_ARGS;
- if (context_id == VMCI_HOST_CONTEXT_ID) {
- struct datagram_entry *src_entry;
- struct vmci_resource *resource;
- resource = vmci_resource_by_handle(handle,
- VMCI_RESOURCE_TYPE_DATAGRAM);
- if (!resource)
- return VMCI_ERROR_INVALID_ARGS;
- src_entry = container_of(resource, struct datagram_entry,
- resource);
- *priv_flags = src_entry->priv_flags;
- vmci_resource_put(resource);
- } else if (context_id == VMCI_HYPERVISOR_CONTEXT_ID)
- *priv_flags = VMCI_MAX_PRIVILEGE_FLAGS;
- else
- *priv_flags = vmci_context_get_priv_flags(context_id);
- return VMCI_SUCCESS;
- }
- /*
- * Calls the specified callback in a delayed context.
- */
- static void dg_delayed_dispatch(struct work_struct *work)
- {
- struct delayed_datagram_info *dg_info =
- container_of(work, struct delayed_datagram_info, work);
- dg_info->entry->recv_cb(dg_info->entry->client_data, &dg_info->msg);
- vmci_resource_put(&dg_info->entry->resource);
- if (dg_info->in_dg_host_queue)
- atomic_dec(&delayed_dg_host_queue_size);
- kfree(dg_info);
- }
- /*
- * Dispatch datagram as a host, to the host, or other vm context. This
- * function cannot dispatch to hypervisor context handlers. This should
- * have been handled before we get here by vmci_datagram_dispatch.
- * Returns number of bytes sent on success, error code otherwise.
- */
- static int dg_dispatch_as_host(u32 context_id, struct vmci_datagram *dg)
- {
- int retval;
- size_t dg_size;
- u32 src_priv_flags;
- dg_size = VMCI_DG_SIZE(dg);
- /* Host cannot send to the hypervisor. */
- if (dg->dst.context == VMCI_HYPERVISOR_CONTEXT_ID)
- return VMCI_ERROR_DST_UNREACHABLE;
- /* Check that source handle matches sending context. */
- if (dg->src.context != context_id) {
- pr_devel("Sender context (ID=0x%x) is not owner of src datagram entry (handle=0x%x:0x%x)\n",
- context_id, dg->src.context, dg->src.resource);
- return VMCI_ERROR_NO_ACCESS;
- }
- /* Get hold of privileges of sending endpoint. */
- retval = vmci_datagram_get_priv_flags(context_id, dg->src,
- &src_priv_flags);
- if (retval != VMCI_SUCCESS) {
- pr_warn("Couldn't get privileges (handle=0x%x:0x%x)\n",
- dg->src.context, dg->src.resource);
- return retval;
- }
- /* Determine if we should route to host or guest destination. */
- if (dg->dst.context == VMCI_HOST_CONTEXT_ID) {
- /* Route to host datagram entry. */
- struct datagram_entry *dst_entry;
- struct vmci_resource *resource;
- if (dg->src.context == VMCI_HYPERVISOR_CONTEXT_ID &&
- dg->dst.resource == VMCI_EVENT_HANDLER) {
- return vmci_event_dispatch(dg);
- }
- resource = vmci_resource_by_handle(dg->dst,
- VMCI_RESOURCE_TYPE_DATAGRAM);
- if (!resource) {
- pr_devel("Sending to invalid destination (handle=0x%x:0x%x)\n",
- dg->dst.context, dg->dst.resource);
- return VMCI_ERROR_INVALID_RESOURCE;
- }
- dst_entry = container_of(resource, struct datagram_entry,
- resource);
- if (vmci_deny_interaction(src_priv_flags,
- dst_entry->priv_flags)) {
- vmci_resource_put(resource);
- return VMCI_ERROR_NO_ACCESS;
- }
- /*
- * If a VMCI datagram destined for the host is also sent by the
- * host, we always run it delayed. This ensures that no locks
- * are held when the datagram callback runs.
- */
- if (dst_entry->run_delayed ||
- dg->src.context == VMCI_HOST_CONTEXT_ID) {
- struct delayed_datagram_info *dg_info;
- if (atomic_add_return(1, &delayed_dg_host_queue_size)
- == VMCI_MAX_DELAYED_DG_HOST_QUEUE_SIZE) {
- atomic_dec(&delayed_dg_host_queue_size);
- vmci_resource_put(resource);
- return VMCI_ERROR_NO_MEM;
- }
- dg_info = kmalloc(sizeof(*dg_info) +
- (size_t) dg->payload_size, GFP_ATOMIC);
- if (!dg_info) {
- atomic_dec(&delayed_dg_host_queue_size);
- vmci_resource_put(resource);
- return VMCI_ERROR_NO_MEM;
- }
- dg_info->in_dg_host_queue = true;
- dg_info->entry = dst_entry;
- memcpy(&dg_info->msg, dg, dg_size);
- INIT_WORK(&dg_info->work, dg_delayed_dispatch);
- schedule_work(&dg_info->work);
- retval = VMCI_SUCCESS;
- } else {
- retval = dst_entry->recv_cb(dst_entry->client_data, dg);
- vmci_resource_put(resource);
- if (retval < VMCI_SUCCESS)
- return retval;
- }
- } else {
- /* Route to destination VM context. */
- struct vmci_datagram *new_dg;
- if (context_id != dg->dst.context) {
- if (vmci_deny_interaction(src_priv_flags,
- vmci_context_get_priv_flags
- (dg->dst.context))) {
- return VMCI_ERROR_NO_ACCESS;
- } else if (VMCI_CONTEXT_IS_VM(context_id)) {
- /*
- * If the sending context is a VM, it
- * cannot reach another VM.
- */
- pr_devel("Datagram communication between VMs not supported (src=0x%x, dst=0x%x)\n",
- context_id, dg->dst.context);
- return VMCI_ERROR_DST_UNREACHABLE;
- }
- }
- /* We make a copy to enqueue. */
- new_dg = kmemdup(dg, dg_size, GFP_KERNEL);
- if (new_dg == NULL)
- return VMCI_ERROR_NO_MEM;
- retval = vmci_ctx_enqueue_datagram(dg->dst.context, new_dg);
- if (retval < VMCI_SUCCESS) {
- kfree(new_dg);
- return retval;
- }
- }
- /*
- * We currently truncate the size to signed 32 bits. This doesn't
- * matter for this handler as it only support 4Kb messages.
- */
- return (int)dg_size;
- }
- /*
- * Dispatch datagram as a guest, down through the VMX and potentially to
- * the host.
- * Returns number of bytes sent on success, error code otherwise.
- */
- static int dg_dispatch_as_guest(struct vmci_datagram *dg)
- {
- int retval;
- struct vmci_resource *resource;
- resource = vmci_resource_by_handle(dg->src,
- VMCI_RESOURCE_TYPE_DATAGRAM);
- if (!resource)
- return VMCI_ERROR_NO_HANDLE;
- retval = vmci_send_datagram(dg);
- vmci_resource_put(resource);
- return retval;
- }
- /*
- * Dispatch datagram. This will determine the routing for the datagram
- * and dispatch it accordingly.
- * Returns number of bytes sent on success, error code otherwise.
- */
- int vmci_datagram_dispatch(u32 context_id,
- struct vmci_datagram *dg, bool from_guest)
- {
- int retval;
- enum vmci_route route;
- BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24);
- if (dg->payload_size > VMCI_MAX_DG_SIZE ||
- VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
- pr_devel("Payload (size=%llu bytes) too big to send\n",
- (unsigned long long)dg->payload_size);
- return VMCI_ERROR_INVALID_ARGS;
- }
- retval = vmci_route(&dg->src, &dg->dst, from_guest, &route);
- if (retval < VMCI_SUCCESS) {
- pr_devel("Failed to route datagram (src=0x%x, dst=0x%x, err=%d)\n",
- dg->src.context, dg->dst.context, retval);
- return retval;
- }
- if (VMCI_ROUTE_AS_HOST == route) {
- if (VMCI_INVALID_ID == context_id)
- context_id = VMCI_HOST_CONTEXT_ID;
- return dg_dispatch_as_host(context_id, dg);
- }
- if (VMCI_ROUTE_AS_GUEST == route)
- return dg_dispatch_as_guest(dg);
- pr_warn("Unknown route (%d) for datagram\n", route);
- return VMCI_ERROR_DST_UNREACHABLE;
- }
- /*
- * Invoke the handler for the given datagram. This is intended to be
- * called only when acting as a guest and receiving a datagram from the
- * virtual device.
- */
- int vmci_datagram_invoke_guest_handler(struct vmci_datagram *dg)
- {
- struct vmci_resource *resource;
- struct datagram_entry *dst_entry;
- resource = vmci_resource_by_handle(dg->dst,
- VMCI_RESOURCE_TYPE_DATAGRAM);
- if (!resource) {
- pr_devel("destination (handle=0x%x:0x%x) doesn't exist\n",
- dg->dst.context, dg->dst.resource);
- return VMCI_ERROR_NO_HANDLE;
- }
- dst_entry = container_of(resource, struct datagram_entry, resource);
- if (dst_entry->run_delayed) {
- struct delayed_datagram_info *dg_info;
- dg_info = kmalloc(sizeof(*dg_info) + (size_t)dg->payload_size,
- GFP_ATOMIC);
- if (!dg_info) {
- vmci_resource_put(resource);
- return VMCI_ERROR_NO_MEM;
- }
- dg_info->in_dg_host_queue = false;
- dg_info->entry = dst_entry;
- memcpy(&dg_info->msg, dg, VMCI_DG_SIZE(dg));
- INIT_WORK(&dg_info->work, dg_delayed_dispatch);
- schedule_work(&dg_info->work);
- } else {
- dst_entry->recv_cb(dst_entry->client_data, dg);
- vmci_resource_put(resource);
- }
- return VMCI_SUCCESS;
- }
- /*
- * vmci_datagram_create_handle_priv() - Create host context datagram endpoint
- * @resource_id: The resource ID.
- * @flags: Datagram Flags.
- * @priv_flags: Privilege Flags.
- * @recv_cb: Callback when receiving datagrams.
- * @client_data: Pointer for a datagram_entry struct
- * @out_handle: vmci_handle that is populated as a result of this function.
- *
- * Creates a host context datagram endpoint and returns a handle to it.
- */
- int vmci_datagram_create_handle_priv(u32 resource_id,
- u32 flags,
- u32 priv_flags,
- vmci_datagram_recv_cb recv_cb,
- void *client_data,
- struct vmci_handle *out_handle)
- {
- if (out_handle == NULL)
- return VMCI_ERROR_INVALID_ARGS;
- if (recv_cb == NULL) {
- pr_devel("Client callback needed when creating datagram\n");
- return VMCI_ERROR_INVALID_ARGS;
- }
- if (priv_flags & ~VMCI_PRIVILEGE_ALL_FLAGS)
- return VMCI_ERROR_INVALID_ARGS;
- return dg_create_handle(resource_id, flags, priv_flags, recv_cb,
- client_data, out_handle);
- }
- EXPORT_SYMBOL_GPL(vmci_datagram_create_handle_priv);
- /*
- * vmci_datagram_create_handle() - Create host context datagram endpoint
- * @resource_id: Resource ID.
- * @flags: Datagram Flags.
- * @recv_cb: Callback when receiving datagrams.
- * @client_ata: Pointer for a datagram_entry struct
- * @out_handle: vmci_handle that is populated as a result of this function.
- *
- * Creates a host context datagram endpoint and returns a handle to
- * it. Same as vmci_datagram_create_handle_priv without the priviledge
- * flags argument.
- */
- int vmci_datagram_create_handle(u32 resource_id,
- u32 flags,
- vmci_datagram_recv_cb recv_cb,
- void *client_data,
- struct vmci_handle *out_handle)
- {
- return vmci_datagram_create_handle_priv(
- resource_id, flags,
- VMCI_DEFAULT_PROC_PRIVILEGE_FLAGS,
- recv_cb, client_data,
- out_handle);
- }
- EXPORT_SYMBOL_GPL(vmci_datagram_create_handle);
- /*
- * vmci_datagram_destroy_handle() - Destroys datagram handle
- * @handle: vmci_handle to be destroyed and reaped.
- *
- * Use this function to destroy any datagram handles created by
- * vmci_datagram_create_handle{,Priv} functions.
- */
- int vmci_datagram_destroy_handle(struct vmci_handle handle)
- {
- struct datagram_entry *entry;
- struct vmci_resource *resource;
- resource = vmci_resource_by_handle(handle, VMCI_RESOURCE_TYPE_DATAGRAM);
- if (!resource) {
- pr_devel("Failed to destroy datagram (handle=0x%x:0x%x)\n",
- handle.context, handle.resource);
- return VMCI_ERROR_NOT_FOUND;
- }
- entry = container_of(resource, struct datagram_entry, resource);
- vmci_resource_put(&entry->resource);
- vmci_resource_remove(&entry->resource);
- kfree(entry);
- return VMCI_SUCCESS;
- }
- EXPORT_SYMBOL_GPL(vmci_datagram_destroy_handle);
- /*
- * vmci_datagram_send() - Send a datagram
- * @msg: The datagram to send.
- *
- * Sends the provided datagram on its merry way.
- */
- int vmci_datagram_send(struct vmci_datagram *msg)
- {
- if (msg == NULL)
- return VMCI_ERROR_INVALID_ARGS;
- return vmci_datagram_dispatch(VMCI_INVALID_ID, msg, false);
- }
- EXPORT_SYMBOL_GPL(vmci_datagram_send);
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