[PATCH 02/10] VMCI: datagram implementation.

George Zhang
2012-10-16T00:28:16Z

VMCI datagram Implements datagrams to allow data to be sent between host and guest.

Signed-off-by: George Zhang <georgezhang@vmware.com>
---
drivers/misc/vmw_vmci/vmci_datagram.c | 522 +++++++++++++++++++++++++++++++++
drivers/misc/vmw_vmci/vmci_datagram.h | 55 +++
2 files changed, 577 insertions(+), 0 deletions(-)
create mode 100644 drivers/misc/vmw_vmci/vmci_datagram.c
create mode 100644 drivers/misc/vmw_vmci/vmci_datagram.h

diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c
new file mode 100644
index 0000000..ea9bb04
--- /dev/null
+++ b/drivers/misc/vmw_vmci/vmci_datagram.c
@@ -0,0 +1,522 @@
+/*
+ * 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_common_int.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 vmci_datagram msg;
+ struct work_struct work;
+ bool in_dg_host_queue;
+};
+
+static atomic_t delayed_dg_host_queue_size;
+
+
+/*
+ * 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;
+
+ ASSERT(recv_cb != NULL);
+ ASSERT(out_handle != NULL);
+ ASSERT(!(priv_flags & ~VMCI_PRIVILEGE_ALL_FLAGS));
+
+ 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 == NULL) {
+ pr_warn("Failed allocating memory for datagram entry.");
+ 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",
+ handle.context, handle.resource, result);
+ kfree(entry);
+ return result;
+ }
+
+ *out_handle = vmci_resource_handle(&entry->resource);
+ return VMCI_SUCCESS;
+}
+
+int __init vmci_datagram_init(void)
+{
+ atomic_set(&delayed_dg_host_queue_size, 0);
+ return VMCI_SUCCESS;
+}
+
+/*
+ * Internal utilility 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)
+{
+ ASSERT(priv_flags);
+ ASSERT(context_id != VMCI_INVALID_ID);
+
+ 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 VMCIDatagramDispatch.
+ * 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;
+
+ ASSERT(dg);
+ ASSERT(vmci_host_code_active());
+
+ dg_size = VMCI_DG_SIZE(dg);
+
+ if (context_id == VMCI_HOST_CONTEXT_ID &&
+ dg->dst.context == VMCI_HYPERVISOR_CONTEXT_ID)
+ return VMCI_ERROR_DST_UNREACHABLE;
+
+ ASSERT(dg->dst.context != VMCI_HYPERVISOR_CONTEXT_ID);
+
+ /* 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).",
+ 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).",
+ 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).",
+ 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;
+ }
+ ASSERT(dst_entry->recv_cb);
+
+ /*
+ * 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).",
+ context_id, dg->dst.context);
+ return VMCI_ERROR_DST_UNREACHABLE;
+ }
+ }
+
+ /* We make a copy to enqueue. */
+ new_dg = kmalloc(dg_size, GFP_KERNEL);
+ if (new_dg == NULL)
+ return VMCI_ERROR_NO_MEM;
+
+ memcpy(new_dg, dg, dg_size);
+ 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;
+
+ ASSERT(dg);
+ BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24);
+
+ if (VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
+ pr_devel("Payload (size=%llu bytes) too big to "
+ "send.", (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).", 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.", 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;
+
+ ASSERT(dg);
+
+ resource = vmci_resource_by_handle(dg->dst,
+ VMCI_RESOURCE_TYPE_DATAGRAM);
+ if (!resource) {
+ pr_devel("destination (handle=0x%x:0x%x) doesn't exist.",
+ 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.");
+ 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(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(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).",
+ 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(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(vmci_datagram_send);
diff --git a/drivers/misc/vmw_vmci/vmci_datagram.h b/drivers/misc/vmw_vmci/vmci_datagram.h
new file mode 100644
index 0000000..28a2c11
--- /dev/null
+++ b/drivers/misc/vmw_vmci/vmci_datagram.h
@@ -0,0 +1,55 @@
+/*
+ * 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_DATAGRAM_H_
+#define _VMCI_DATAGRAM_H_
+
+#include <linux/types.h>
+#include <linux/list.h>
+
+#include "vmci_context.h"
+
+#define VMCI_MAX_DELAYED_DG_HOST_QUEUE_SIZE 256
+
+/*
+ * The struct vmci_datagram_queue_entry is a queue header for the in-kernel VMCI
+ * datagram queues. It is allocated in non-paged memory, as the
+ * content is accessed while holding a spinlock. The pending datagram
+ * itself may be allocated from paged memory. We shadow the size of
+ * the datagram in the non-paged queue entry as this size is used
+ * while holding the same spinlock as above.
+ */
+struct vmci_datagram_queue_entry {
+ struct list_head list_item; /* For queuing. */
+ size_t dg_size; /* Size of datagram. */
+ struct vmci_datagram *dg; /* Pending datagram. */
+};
+
+/* VMCIDatagramSendRecvInfo */
+struct vmci_datagram_snd_rcv_info {
+ u64 addr;
+ u32 len;
+ s32 result;
+};
+
+/* Init functions. */
+int vmci_datagram_init(void);
+
+/* Datagram API for non-public use. */
+int vmci_datagram_dispatch(u32 context_id, struct vmci_datagram *dg,
+ bool from_guest);
+int vmci_datagram_invoke_guest_handler(struct vmci_datagram *dg);
+
+#endif /* _VMCI_DATAGRAM_H_ */