VMCI: context implementation.

VMCI Context code maintains state for vmci and allows the driver to communicate
with multiple VMs.
Signed-off-by: NGeorge Zhang <georgezhang@vmware.com>
Acked-by: NAndy king <acking@vmware.com>
Acked-by: NDmitry Torokhov <dtor@vmware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/vmw_vmci/vmci_context.h

+/*
+ * VMware VMCI driver (vmciContext.h)
+ *
+ * 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_CONTEXT_H_
+#define _VMCI_CONTEXT_H_
+
+#include <linux/vmw_vmci_defs.h>
+#include <linux/atomic.h>
+#include <linux/kref.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include "vmci_handle_array.h"
+#include "vmci_datagram.h"
+
+/* Used to determine what checkpoint state to get and set. */
+enum {
+	VMCI_NOTIFICATION_CPT_STATE = 1,
+	VMCI_WELLKNOWN_CPT_STATE    = 2,
+	VMCI_DG_OUT_STATE           = 3,
+	VMCI_DG_IN_STATE            = 4,
+	VMCI_DG_IN_SIZE_STATE       = 5,
+	VMCI_DOORBELL_CPT_STATE     = 6,
+};
+
+/* Host specific struct used for signalling */
+struct vmci_host {
+	wait_queue_head_t wait_queue;
+};
+
+struct vmci_handle_list {
+	struct list_head node;
+	struct vmci_handle handle;
+};
+
+struct vmci_ctx {
+	struct list_head list_item;       /* For global VMCI list. */
+	u32 cid;
+	struct kref kref;
+	struct list_head datagram_queue;  /* Head of per VM queue. */
+	u32 pending_datagrams;
+	size_t datagram_queue_size;	  /* Size of datagram queue in bytes. */
+
+	/*
+	 * Version of the code that created
+	 * this context; e.g., VMX.
+	 */
+	int user_version;
+	spinlock_t lock;  /* Locks callQueue and handle_arrays. */
+
+	/*
+	 * queue_pairs attached to.  The array of
+	 * handles for queue pairs is accessed
+	 * from the code for QP API, and there
+	 * it is protected by the QP lock.  It
+	 * is also accessed from the context
+	 * clean up path, which does not
+	 * require a lock.  VMCILock is not
+	 * used to protect the QP array field.
+	 */
+	struct vmci_handle_arr *queue_pair_array;
+
+	/* Doorbells created by context. */
+	struct vmci_handle_arr *doorbell_array;
+
+	/* Doorbells pending for context. */
+	struct vmci_handle_arr *pending_doorbell_array;
+
+	/* Contexts current context is subscribing to. */
+	struct list_head notifier_list;
+	unsigned int n_notifiers;
+
+	struct vmci_host host_context;
+	u32 priv_flags;
+
+	const struct cred *cred;
+	bool *notify;		/* Notify flag pointer - hosted only. */
+	struct page *notify_page;	/* Page backing the notify UVA. */
+};
+
+/* VMCINotifyAddRemoveInfo: Used to add/remove remote context notifications. */
+struct vmci_ctx_info {
+	u32 remote_cid;
+	int result;
+};
+
+/* VMCICptBufInfo: Used to set/get current context's checkpoint state. */
+struct vmci_ctx_chkpt_buf_info {
+	u64 cpt_buf;
+	u32 cpt_type;
+	u32 buf_size;
+	s32 result;
+	u32 _pad;
+};
+
+/*
+ * VMCINotificationReceiveInfo: Used to recieve pending notifications
+ * for doorbells and queue pairs.
+ */
+struct vmci_ctx_notify_recv_info {
+	u64 db_handle_buf_uva;
+	u64 db_handle_buf_size;
+	u64 qp_handle_buf_uva;
+	u64 qp_handle_buf_size;
+	s32 result;
+	u32 _pad;
+};
+
+/*
+ * Utilility function that checks whether two entities are allowed
+ * to interact. If one of them is restricted, the other one must
+ * be trusted.
+ */
+static inline bool vmci_deny_interaction(u32 part_one, u32 part_two)
+{
+	return ((part_one & VMCI_PRIVILEGE_FLAG_RESTRICTED) &&
+		!(part_two & VMCI_PRIVILEGE_FLAG_TRUSTED)) ||
+	       ((part_two & VMCI_PRIVILEGE_FLAG_RESTRICTED) &&
+		!(part_one & VMCI_PRIVILEGE_FLAG_TRUSTED));
+}
+
+struct vmci_ctx *vmci_ctx_create(u32 cid, u32 flags,
+				 uintptr_t event_hnd, int version,
+				 const struct cred *cred);
+void vmci_ctx_destroy(struct vmci_ctx *context);
+
+bool vmci_ctx_supports_host_qp(struct vmci_ctx *context);
+int vmci_ctx_enqueue_datagram(u32 cid, struct vmci_datagram *dg);
+int vmci_ctx_dequeue_datagram(struct vmci_ctx *context,
+			      size_t *max_size, struct vmci_datagram **dg);
+int vmci_ctx_pending_datagrams(u32 cid, u32 *pending);
+struct vmci_ctx *vmci_ctx_get(u32 cid);
+void vmci_ctx_put(struct vmci_ctx *context);
+bool vmci_ctx_exists(u32 cid);
+
+int vmci_ctx_add_notification(u32 context_id, u32 remote_cid);
+int vmci_ctx_remove_notification(u32 context_id, u32 remote_cid);
+int vmci_ctx_get_chkpt_state(u32 context_id, u32 cpt_type,
+			     u32 *num_cids, void **cpt_buf_ptr);
+int vmci_ctx_set_chkpt_state(u32 context_id, u32 cpt_type,
+			     u32 num_cids, void *cpt_buf);
+
+int vmci_ctx_qp_create(struct vmci_ctx *context, struct vmci_handle handle);
+int vmci_ctx_qp_destroy(struct vmci_ctx *context, struct vmci_handle handle);
+bool vmci_ctx_qp_exists(struct vmci_ctx *context, struct vmci_handle handle);
+
+void vmci_ctx_check_signal_notify(struct vmci_ctx *context);
+void vmci_ctx_unset_notify(struct vmci_ctx *context);
+
+int vmci_ctx_dbell_create(u32 context_id, struct vmci_handle handle);
+int vmci_ctx_dbell_destroy(u32 context_id, struct vmci_handle handle);
+int vmci_ctx_dbell_destroy_all(u32 context_id);
+int vmci_ctx_notify_dbell(u32 cid, struct vmci_handle handle,
+			  u32 src_priv_flags);
+
+int vmci_ctx_rcv_notifications_get(u32 context_id, struct vmci_handle_arr
+				   **db_handle_array, struct vmci_handle_arr
+				   **qp_handle_array);
+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);
+
+static inline u32 vmci_ctx_get_id(struct vmci_ctx *context)
+{
+	if (!context)
+		return VMCI_INVALID_ID;
+	return context->cid;
+}
+
+#endif /* _VMCI_CONTEXT_H_ */