// SPDX-License-Identifier: GPL-2.0-only
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/*
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* VMware VMCI Driver
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*
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* Copyright (C) 2012 VMware, Inc. All rights reserved.
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*/
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#include <linux/vmw_vmci_defs.h>
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#include <linux/vmw_vmci_api.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/bug.h>
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#include "vmci_datagram.h"
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#include "vmci_resource.h"
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#include "vmci_context.h"
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#include "vmci_driver.h"
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#include "vmci_event.h"
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#include "vmci_route.h"
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/*
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* struct datagram_entry describes the datagram entity. It is used for datagram
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* entities created only on the host.
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*/
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struct datagram_entry {
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struct vmci_resource resource;
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u32 flags;
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bool run_delayed;
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vmci_datagram_recv_cb recv_cb;
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void *client_data;
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u32 priv_flags;
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};
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struct delayed_datagram_info {
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struct datagram_entry *entry;
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struct work_struct work;
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bool in_dg_host_queue;
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/* msg and msg_payload must be together. */
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struct vmci_datagram msg;
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u8 msg_payload[];
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};
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/* Number of in-flight host->host datagrams */
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static atomic_t delayed_dg_host_queue_size = ATOMIC_INIT(0);
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/*
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* Create a datagram entry given a handle pointer.
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*/
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static int dg_create_handle(u32 resource_id,
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u32 flags,
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u32 priv_flags,
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vmci_datagram_recv_cb recv_cb,
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void *client_data, struct vmci_handle *out_handle)
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{
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int result;
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u32 context_id;
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struct vmci_handle handle;
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struct datagram_entry *entry;
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if ((flags & VMCI_FLAG_WELLKNOWN_DG_HND) != 0)
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return VMCI_ERROR_INVALID_ARGS;
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if ((flags & VMCI_FLAG_ANYCID_DG_HND) != 0) {
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context_id = VMCI_INVALID_ID;
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} else {
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context_id = vmci_get_context_id();
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if (context_id == VMCI_INVALID_ID)
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return VMCI_ERROR_NO_RESOURCES;
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}
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handle = vmci_make_handle(context_id, resource_id);
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entry = kmalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry) {
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pr_warn("Failed allocating memory for datagram entry\n");
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return VMCI_ERROR_NO_MEM;
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}
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entry->run_delayed = (flags & VMCI_FLAG_DG_DELAYED_CB) ? true : false;
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entry->flags = flags;
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entry->recv_cb = recv_cb;
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entry->client_data = client_data;
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entry->priv_flags = priv_flags;
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/* Make datagram resource live. */
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result = vmci_resource_add(&entry->resource,
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VMCI_RESOURCE_TYPE_DATAGRAM,
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handle);
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if (result != VMCI_SUCCESS) {
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pr_warn("Failed to add new resource (handle=0x%x:0x%x), error: %d\n",
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handle.context, handle.resource, result);
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kfree(entry);
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return result;
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}
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*out_handle = vmci_resource_handle(&entry->resource);
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return VMCI_SUCCESS;
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}
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/*
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* Internal utility function with the same purpose as
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* vmci_datagram_get_priv_flags that also takes a context_id.
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*/
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static int vmci_datagram_get_priv_flags(u32 context_id,
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struct vmci_handle handle,
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u32 *priv_flags)
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{
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if (context_id == VMCI_INVALID_ID)
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return VMCI_ERROR_INVALID_ARGS;
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if (context_id == VMCI_HOST_CONTEXT_ID) {
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struct datagram_entry *src_entry;
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struct vmci_resource *resource;
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resource = vmci_resource_by_handle(handle,
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VMCI_RESOURCE_TYPE_DATAGRAM);
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if (!resource)
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return VMCI_ERROR_INVALID_ARGS;
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src_entry = container_of(resource, struct datagram_entry,
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resource);
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*priv_flags = src_entry->priv_flags;
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vmci_resource_put(resource);
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} else if (context_id == VMCI_HYPERVISOR_CONTEXT_ID)
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*priv_flags = VMCI_MAX_PRIVILEGE_FLAGS;
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else
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*priv_flags = vmci_context_get_priv_flags(context_id);
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return VMCI_SUCCESS;
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}
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/*
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* Calls the specified callback in a delayed context.
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*/
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static void dg_delayed_dispatch(struct work_struct *work)
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{
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struct delayed_datagram_info *dg_info =
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container_of(work, struct delayed_datagram_info, work);
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dg_info->entry->recv_cb(dg_info->entry->client_data, &dg_info->msg);
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vmci_resource_put(&dg_info->entry->resource);
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if (dg_info->in_dg_host_queue)
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atomic_dec(&delayed_dg_host_queue_size);
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kfree(dg_info);
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}
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/*
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* Dispatch datagram as a host, to the host, or other vm context. This
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* function cannot dispatch to hypervisor context handlers. This should
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* have been handled before we get here by vmci_datagram_dispatch.
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* Returns number of bytes sent on success, error code otherwise.
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*/
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static int dg_dispatch_as_host(u32 context_id, struct vmci_datagram *dg)
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{
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int retval;
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size_t dg_size;
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u32 src_priv_flags;
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dg_size = VMCI_DG_SIZE(dg);
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/* Host cannot send to the hypervisor. */
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if (dg->dst.context == VMCI_HYPERVISOR_CONTEXT_ID)
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return VMCI_ERROR_DST_UNREACHABLE;
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/* Check that source handle matches sending context. */
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if (dg->src.context != context_id) {
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pr_devel("Sender context (ID=0x%x) is not owner of src datagram entry (handle=0x%x:0x%x)\n",
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context_id, dg->src.context, dg->src.resource);
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return VMCI_ERROR_NO_ACCESS;
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}
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/* Get hold of privileges of sending endpoint. */
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retval = vmci_datagram_get_priv_flags(context_id, dg->src,
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&src_priv_flags);
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if (retval != VMCI_SUCCESS) {
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pr_warn("Couldn't get privileges (handle=0x%x:0x%x)\n",
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dg->src.context, dg->src.resource);
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return retval;
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}
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/* Determine if we should route to host or guest destination. */
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if (dg->dst.context == VMCI_HOST_CONTEXT_ID) {
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/* Route to host datagram entry. */
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struct datagram_entry *dst_entry;
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struct vmci_resource *resource;
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if (dg->src.context == VMCI_HYPERVISOR_CONTEXT_ID &&
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dg->dst.resource == VMCI_EVENT_HANDLER) {
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return vmci_event_dispatch(dg);
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}
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resource = vmci_resource_by_handle(dg->dst,
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VMCI_RESOURCE_TYPE_DATAGRAM);
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if (!resource) {
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pr_devel("Sending to invalid destination (handle=0x%x:0x%x)\n",
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dg->dst.context, dg->dst.resource);
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return VMCI_ERROR_INVALID_RESOURCE;
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}
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dst_entry = container_of(resource, struct datagram_entry,
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resource);
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if (vmci_deny_interaction(src_priv_flags,
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dst_entry->priv_flags)) {
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vmci_resource_put(resource);
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return VMCI_ERROR_NO_ACCESS;
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}
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/*
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* If a VMCI datagram destined for the host is also sent by the
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* host, we always run it delayed. This ensures that no locks
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* are held when the datagram callback runs.
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*/
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if (dst_entry->run_delayed ||
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dg->src.context == VMCI_HOST_CONTEXT_ID) {
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struct delayed_datagram_info *dg_info;
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if (atomic_add_return(1, &delayed_dg_host_queue_size)
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== VMCI_MAX_DELAYED_DG_HOST_QUEUE_SIZE) {
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atomic_dec(&delayed_dg_host_queue_size);
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vmci_resource_put(resource);
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return VMCI_ERROR_NO_MEM;
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}
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dg_info = kmalloc(sizeof(*dg_info) +
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(size_t) dg->payload_size, GFP_ATOMIC);
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if (!dg_info) {
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atomic_dec(&delayed_dg_host_queue_size);
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vmci_resource_put(resource);
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return VMCI_ERROR_NO_MEM;
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}
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dg_info->in_dg_host_queue = true;
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dg_info->entry = dst_entry;
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memcpy(&dg_info->msg, dg, dg_size);
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INIT_WORK(&dg_info->work, dg_delayed_dispatch);
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schedule_work(&dg_info->work);
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retval = VMCI_SUCCESS;
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} else {
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retval = dst_entry->recv_cb(dst_entry->client_data, dg);
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vmci_resource_put(resource);
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if (retval < VMCI_SUCCESS)
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return retval;
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}
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} else {
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/* Route to destination VM context. */
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struct vmci_datagram *new_dg;
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if (context_id != dg->dst.context) {
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if (vmci_deny_interaction(src_priv_flags,
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vmci_context_get_priv_flags
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(dg->dst.context))) {
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return VMCI_ERROR_NO_ACCESS;
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} else if (VMCI_CONTEXT_IS_VM(context_id)) {
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/*
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* If the sending context is a VM, it
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* cannot reach another VM.
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*/
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pr_devel("Datagram communication between VMs not supported (src=0x%x, dst=0x%x)\n",
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context_id, dg->dst.context);
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return VMCI_ERROR_DST_UNREACHABLE;
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}
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}
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/* We make a copy to enqueue. */
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new_dg = kmemdup(dg, dg_size, GFP_KERNEL);
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if (new_dg == NULL)
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return VMCI_ERROR_NO_MEM;
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retval = vmci_ctx_enqueue_datagram(dg->dst.context, new_dg);
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if (retval < VMCI_SUCCESS) {
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kfree(new_dg);
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return retval;
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}
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}
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/*
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* We currently truncate the size to signed 32 bits. This doesn't
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* matter for this handler as it only support 4Kb messages.
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*/
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return (int)dg_size;
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}
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/*
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* Dispatch datagram as a guest, down through the VMX and potentially to
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* the host.
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* Returns number of bytes sent on success, error code otherwise.
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*/
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static int dg_dispatch_as_guest(struct vmci_datagram *dg)
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{
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int retval;
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struct vmci_resource *resource;
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resource = vmci_resource_by_handle(dg->src,
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VMCI_RESOURCE_TYPE_DATAGRAM);
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if (!resource)
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return VMCI_ERROR_NO_HANDLE;
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retval = vmci_send_datagram(dg);
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vmci_resource_put(resource);
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return retval;
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}
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/*
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* Dispatch datagram. This will determine the routing for the datagram
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* and dispatch it accordingly.
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* Returns number of bytes sent on success, error code otherwise.
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*/
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int vmci_datagram_dispatch(u32 context_id,
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struct vmci_datagram *dg, bool from_guest)
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{
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int retval;
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enum vmci_route route;
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BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24);
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if (dg->payload_size > VMCI_MAX_DG_SIZE ||
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VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
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pr_devel("Payload (size=%llu bytes) too big to send\n",
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(unsigned long long)dg->payload_size);
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return VMCI_ERROR_INVALID_ARGS;
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}
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retval = vmci_route(&dg->src, &dg->dst, from_guest, &route);
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if (retval < VMCI_SUCCESS) {
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pr_devel("Failed to route datagram (src=0x%x, dst=0x%x, err=%d)\n",
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dg->src.context, dg->dst.context, retval);
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return retval;
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}
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if (VMCI_ROUTE_AS_HOST == route) {
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if (VMCI_INVALID_ID == context_id)
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context_id = VMCI_HOST_CONTEXT_ID;
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return dg_dispatch_as_host(context_id, dg);
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}
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if (VMCI_ROUTE_AS_GUEST == route)
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return dg_dispatch_as_guest(dg);
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pr_warn("Unknown route (%d) for datagram\n", route);
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return VMCI_ERROR_DST_UNREACHABLE;
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}
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/*
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* Invoke the handler for the given datagram. This is intended to be
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* called only when acting as a guest and receiving a datagram from the
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* virtual device.
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*/
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int vmci_datagram_invoke_guest_handler(struct vmci_datagram *dg)
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{
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struct vmci_resource *resource;
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struct datagram_entry *dst_entry;
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resource = vmci_resource_by_handle(dg->dst,
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VMCI_RESOURCE_TYPE_DATAGRAM);
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if (!resource) {
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pr_devel("destination (handle=0x%x:0x%x) doesn't exist\n",
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dg->dst.context, dg->dst.resource);
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return VMCI_ERROR_NO_HANDLE;
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}
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dst_entry = container_of(resource, struct datagram_entry, resource);
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if (dst_entry->run_delayed) {
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struct delayed_datagram_info *dg_info;
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dg_info = kmalloc(sizeof(*dg_info) + (size_t)dg->payload_size,
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GFP_ATOMIC);
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if (!dg_info) {
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vmci_resource_put(resource);
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return VMCI_ERROR_NO_MEM;
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}
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dg_info->in_dg_host_queue = false;
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dg_info->entry = dst_entry;
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memcpy(&dg_info->msg, dg, VMCI_DG_SIZE(dg));
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INIT_WORK(&dg_info->work, dg_delayed_dispatch);
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schedule_work(&dg_info->work);
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} else {
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dst_entry->recv_cb(dst_entry->client_data, dg);
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vmci_resource_put(resource);
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}
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return VMCI_SUCCESS;
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}
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/*
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* vmci_datagram_create_handle_priv() - Create host context datagram endpoint
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* @resource_id: The resource ID.
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* @flags: Datagram Flags.
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* @priv_flags: Privilege Flags.
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* @recv_cb: Callback when receiving datagrams.
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* @client_data: Pointer for a datagram_entry struct
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* @out_handle: vmci_handle that is populated as a result of this function.
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*
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* Creates a host context datagram endpoint and returns a handle to it.
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*/
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int vmci_datagram_create_handle_priv(u32 resource_id,
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u32 flags,
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u32 priv_flags,
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vmci_datagram_recv_cb recv_cb,
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void *client_data,
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struct vmci_handle *out_handle)
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{
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if (out_handle == NULL)
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return VMCI_ERROR_INVALID_ARGS;
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if (recv_cb == NULL) {
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pr_devel("Client callback needed when creating datagram\n");
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return VMCI_ERROR_INVALID_ARGS;
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}
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if (priv_flags & ~VMCI_PRIVILEGE_ALL_FLAGS)
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return VMCI_ERROR_INVALID_ARGS;
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return dg_create_handle(resource_id, flags, priv_flags, recv_cb,
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client_data, out_handle);
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}
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EXPORT_SYMBOL_GPL(vmci_datagram_create_handle_priv);
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/*
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* vmci_datagram_create_handle() - Create host context datagram endpoint
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* @resource_id: Resource ID.
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* @flags: Datagram Flags.
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* @recv_cb: Callback when receiving datagrams.
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* @client_ata: Pointer for a datagram_entry struct
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* @out_handle: vmci_handle that is populated as a result of this function.
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*
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* Creates a host context datagram endpoint and returns a handle to
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* it. Same as vmci_datagram_create_handle_priv without the priviledge
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* flags argument.
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*/
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int vmci_datagram_create_handle(u32 resource_id,
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u32 flags,
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vmci_datagram_recv_cb recv_cb,
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void *client_data,
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struct vmci_handle *out_handle)
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{
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return vmci_datagram_create_handle_priv(
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resource_id, flags,
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VMCI_DEFAULT_PROC_PRIVILEGE_FLAGS,
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recv_cb, client_data,
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out_handle);
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}
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EXPORT_SYMBOL_GPL(vmci_datagram_create_handle);
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/*
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* vmci_datagram_destroy_handle() - Destroys datagram handle
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* @handle: vmci_handle to be destroyed and reaped.
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*
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* Use this function to destroy any datagram handles created by
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* vmci_datagram_create_handle{,Priv} functions.
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*/
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int vmci_datagram_destroy_handle(struct vmci_handle handle)
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{
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struct datagram_entry *entry;
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struct vmci_resource *resource;
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resource = vmci_resource_by_handle(handle, VMCI_RESOURCE_TYPE_DATAGRAM);
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if (!resource) {
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pr_devel("Failed to destroy datagram (handle=0x%x:0x%x)\n",
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handle.context, handle.resource);
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return VMCI_ERROR_NOT_FOUND;
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}
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entry = container_of(resource, struct datagram_entry, resource);
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vmci_resource_put(&entry->resource);
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vmci_resource_remove(&entry->resource);
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kfree(entry);
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return VMCI_SUCCESS;
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}
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EXPORT_SYMBOL_GPL(vmci_datagram_destroy_handle);
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/*
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* vmci_datagram_send() - Send a datagram
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* @msg: The datagram to send.
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*
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* Sends the provided datagram on its merry way.
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*/
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int vmci_datagram_send(struct vmci_datagram *msg)
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{
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if (msg == NULL)
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return VMCI_ERROR_INVALID_ARGS;
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return vmci_datagram_dispatch(VMCI_INVALID_ID, msg, false);
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}
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EXPORT_SYMBOL_GPL(vmci_datagram_send);
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