/* 
 * This file is part of the Palacios Virtual Machine Monitor developed
 * by the V3VEE Project with funding from the United States National 
 * Science Foundation and the Department of Energy.  
 *
 * The V3VEE Project is a joint project between Northwestern University
 * and the University of New Mexico.  You can find out more at 
 * http://www.v3vee.org
 *
 * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu> 
 * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org> 
 * All rights reserved.
 *
 * Author: Jack Lange <jarusl@cs.northwestern.edu>
 *
 * This is free software.  You are permitted to use,
 * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
 */

#include <palacios/vmm_hypercall.h>
#include <palacios/vmm.h>
#include <palacios/vm_guest.h>


static int hcall_test(struct guest_info * info, hcall_id_t hcall_id, void * private_data) {
    info->vm_regs.rbx = 0x1111;
    info->vm_regs.rcx = 0x2222;
    info->vm_regs.rdx = 0x3333;
    info->vm_regs.rsi = 0x4444;
    info->vm_regs.rdi = 0x5555;
    return 0;
}


struct hypercall {
    uint_t id;
  
    int (*hcall_fn)(struct guest_info * info, hcall_id_t hcall_id, void * priv_data);
    void * priv_data;
  
    struct rb_node tree_node;
};

static int free_hypercall(struct v3_vm_info * vm, struct hypercall * hcall);

void v3_init_hypercall_map(struct v3_vm_info * vm) {
    vm->hcall_map.rb_node = NULL;

    v3_register_hypercall(vm, TEST_HCALL, hcall_test, NULL);
}

int v3_deinit_hypercall_map(struct v3_vm_info * vm) {
    struct rb_node * node = NULL;
    struct hypercall * hcall = NULL;
    struct rb_node * tmp_node = NULL;

    v3_remove_hypercall(vm, TEST_HCALL);

    node = v3_rb_first(&(vm->hcall_map));

    while (node) {
	hcall = rb_entry(node, struct hypercall, tree_node);
	tmp_node = node;
	node = v3_rb_next(node);

	free_hypercall(vm, hcall);
    }
    
    return 0;
}





static inline struct hypercall * __insert_hypercall(struct v3_vm_info * vm, struct hypercall * hcall) {
    struct rb_node ** p = &(vm->hcall_map.rb_node);
    struct rb_node * parent = NULL;
    struct hypercall * tmp_hcall = NULL;

    while (*p) {
	parent = *p;
	tmp_hcall = rb_entry(parent, struct hypercall, tree_node);

	if (hcall->id < tmp_hcall->id) {
	    p = &(*p)->rb_left;
	} else if (hcall->id > tmp_hcall->id) {
	    p = &(*p)->rb_right;
	} else {
	    return tmp_hcall;
	}
    }

    rb_link_node(&(hcall->tree_node), parent, p);

    return NULL;
}


static inline struct hypercall * insert_hypercall(struct v3_vm_info * vm, struct hypercall * hcall) {
    struct hypercall * ret;

    if ((ret = __insert_hypercall(vm, hcall))) {
	return ret;
    }

    v3_rb_insert_color(&(hcall->tree_node), &(vm->hcall_map));

    return NULL;
}


static struct hypercall * get_hypercall(struct v3_vm_info * vm, hcall_id_t id) {
    struct rb_node * n = vm->hcall_map.rb_node;
    struct hypercall * hcall = NULL;

    while (n) {
	hcall = rb_entry(n, struct hypercall, tree_node);
    
	if (id < hcall->id) {
	    n = n->rb_left;
	} else if (id > hcall->id) {
	    n = n->rb_right;
	} else {
	    return hcall;
	}
    }

    return NULL;
}


int v3_register_hypercall(struct v3_vm_info * vm, hcall_id_t hypercall_id, 
			  int (*hypercall)(struct guest_info * info, hcall_id_t hcall_id, void * priv_data), 
			  void * priv_data) {

    struct hypercall * hcall = (struct hypercall *)V3_Malloc(sizeof(struct hypercall));

    if (!hcall) {
        PrintError(vm, VCORE_NONE, "Cannot allocate in registering hypercall\n");
	return -1;
    }

    hcall->id = hypercall_id;
    hcall->priv_data = priv_data;
    hcall->hcall_fn = hypercall;

    if (insert_hypercall(vm, hcall)) {
	V3_Free(hcall);
	return -1;
    }

    return 0;
}



static int free_hypercall(struct v3_vm_info * vm, struct hypercall * hcall) {
    v3_rb_erase(&(hcall->tree_node), &(vm->hcall_map));
    V3_Free(hcall);

    return 0;
}

int v3_remove_hypercall(struct v3_vm_info * vm, hcall_id_t hypercall_id) {
    struct hypercall * hcall = get_hypercall(vm, hypercall_id);

    if (hcall == NULL) {
	PrintError(vm, VCORE_NONE, "Attempted to remove non existant hypercall\n");
	return -1;
    }

    free_hypercall(vm, hcall);

    return 0;
}


int v3_handle_hypercall(struct guest_info * info) {
    hcall_id_t hypercall_id = *(uint_t *)&info->vm_regs.rax;
    struct hypercall * hcall = get_hypercall(info->vm_info, hypercall_id);

    if (!hcall) {
        PrintError(info->vm_info, info,  "Invalid Hypercall (%d(0x%x) not registered) => ignored with rax=-1\n", 
		   hypercall_id, hypercall_id);
	info->vm_regs.rax=-1;
	return 0;
    }

    if (hcall->hcall_fn(info, hypercall_id, hcall->priv_data) != 0) {
	PrintError(info->vm_info, info, "Error handling hypercall\n");
	return -1;
    }

    return 0;
}