/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * VMware VMCI driver (vmciContext.h)
 *
 * Copyright (C) 2012 VMware, Inc. All rights reserved.
 */

#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 receive 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);
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_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_ */