#include <xeno/config.h>
#include <xeno/init.h>
#include <xeno/lib.h>
#include <xeno/errno.h>
#include <xeno/sched.h>
#include <xeno/mm.h>
#include <xeno/skbuff.h>
#include <xeno/interrupt.h>
#include <xeno/delay.h>
#include <xeno/event.h>
#include <xeno/time.h>
#include <xeno/dom0_ops.h>
#include <asm/io.h>
#include <asm/domain_page.h>
#include <asm/flushtlb.h>
#include <asm/msr.h>
#include <xeno/multiboot.h>
#include <xeno/blkdev.h>

#define L1_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_USER|_PAGE_ACCESSED)
#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_USER|_PAGE_ACCESSED|_PAGE_DIRTY)

extern int nr_mods;
extern module_t *mod;
extern unsigned char *cmdline;

rwlock_t tasklist_lock __cacheline_aligned = RW_LOCK_UNLOCKED;

/*
 * create a new domain
 */
struct task_struct *do_newdomain(unsigned int dom_id, unsigned int cpu)
{
    int retval;
    struct task_struct *p = NULL;
    unsigned long flags;

    retval = -ENOMEM;
    p = alloc_task_struct();
    if (!p) goto newdomain_out;
    memset(p, 0, sizeof(*p));

    atomic_set(&p->refcnt, 1);

    p->domain    = dom_id;
    p->processor = cpu;

    spin_lock_init(&p->blk_ring_lock);

    p->shared_info = (void *)get_free_page(GFP_KERNEL);
    memset(p->shared_info, 0, PAGE_SIZE);
    SHARE_PFN_WITH_DOMAIN(virt_to_page(p->shared_info), dom_id);

    init_blkdev_info(p);

    SET_GDT_ENTRIES(p, DEFAULT_GDT_ENTRIES);
    SET_GDT_ADDRESS(p, DEFAULT_GDT_ADDRESS);

    p->addr_limit = USER_DS;
    p->state      = TASK_UNINTERRUPTIBLE;
    p->active_mm  = &p->mm;
    p->num_net_vifs = 0;

    p->net_ring_base = (net_ring_t *)(p->shared_info + 1);
    INIT_LIST_HEAD(&p->pg_head);
    p->tot_pages = 0;
    write_lock_irqsave(&tasklist_lock, flags);
    SET_LINKS(p);
    write_unlock_irqrestore(&tasklist_lock, flags);

 newdomain_out:
    return(p);
}

/* Get a pointer to the specified domain.  Consider replacing this
 * with a hash lookup later.
 *
 * Also, kill_other_domain should call this instead of scanning on its own.
 */
struct task_struct *find_domain_by_id(unsigned int dom)
{
    struct task_struct *p = &idle0_task;

    read_lock_irq(&tasklist_lock);
    do {
        if ( (p->domain == dom) ) {
            get_task_struct(p); /* increment the refcnt for caller */
            read_unlock_irq(&tasklist_lock);
            return (p);
        }
    } while ( (p = p->next_task) != &idle0_task );
    read_unlock_irq(&tasklist_lock);

    return 0;
}


void kill_domain_with_errmsg(const char *err)
{
    printk("DOM%d FATAL ERROR: %s\n", 
           current->domain, err);
    kill_domain();
}


/* Kill the currently executing domain. */
void kill_domain(void)
{
    if ( current->domain == 0 )
    {
        extern void machine_restart(char *);
        printk("Domain 0 killed: rebooting machine!\n");
        machine_restart(0);
    }

    printk("Killing domain %d\n", current->domain);
    current->state = TASK_DYING;
    schedule();
    BUG(); /* never get here */
}


long kill_other_domain(unsigned int dom, int force)
{
    struct task_struct *p;
    unsigned long cpu_mask = 0;

    p = find_domain_by_id(dom);
    if ( p == NULL ) return -ESRCH;

    if ( force )
    {
        cpu_mask = mark_hyp_event(p, _HYP_EVENT_DIE);
        hyp_event_notify(cpu_mask);
    }
    else
    {
        cpu_mask = mark_guest_event(p, _EVENT_DIE);
        guest_event_notify(cpu_mask);
    }

    free_task_struct(p);
    return 0;
}


unsigned int alloc_new_dom_mem(struct task_struct *p, unsigned int kbytes)
{
    struct list_head *temp;
    struct pfn_info *pf;
    unsigned int alloc_pfns;
    unsigned int req_pages;
    unsigned long flags;

    /* how many pages do we need to alloc? */
    req_pages = kbytes >> (PAGE_SHIFT - 10);

    spin_lock_irqsave(&free_list_lock, flags);
    
    /* is there enough mem to serve the request? */   
    if ( req_pages > free_pfns ) return -1;
    
    /* allocate pages and build a thread through frame_table */
    temp = free_list.next;
    for ( alloc_pfns = 0; alloc_pfns < req_pages; alloc_pfns++ )
    {
        pf = list_entry(temp, struct pfn_info, list);
        pf->flags |= p->domain;
        pf->type_count = pf->tot_count = 0;
        temp = temp->next;
        list_del(&pf->list);
        list_add_tail(&pf->list, &p->pg_head);
        free_pfns--;
    }
   
    spin_unlock_irqrestore(&free_list_lock, flags);
    
    p->tot_pages = req_pages;

    return 0;
}
 

void free_all_dom_mem(struct task_struct *p)
{
    struct list_head *list_ent, *tmp;

    list_for_each_safe(list_ent, tmp, &p->pg_head)
    {
        struct pfn_info *pf = list_entry(list_ent, struct pfn_info, list);
        pf->type_count = pf->tot_count = pf->flags = 0;
        list_del(list_ent);
        list_add(list_ent, &free_list);
    }

    p->tot_pages = 0;
}


/* Release resources belonging to task @p. */
void release_task(struct task_struct *p)
{
    ASSERT(p->state == TASK_DYING);
    ASSERT(!p->has_cpu);
    write_lock_irq(&tasklist_lock);
    REMOVE_LINKS(p);
    write_unlock_irq(&tasklist_lock);

    /*
     * Safe! Only queue skbuffs with tasklist_lock held.
     * Only access shared_info with tasklist_lock held.
     * And free_task_struct() only releases if refcnt == 0.
     */
    while ( p->num_net_vifs )
    {
        destroy_net_vif(p);
    }
    if ( p->mm.perdomain_pt ) free_page((unsigned long)p->mm.perdomain_pt);

    destroy_blkdev_info(p);

    UNSHARE_PFN(virt_to_page(p->shared_info));
    free_page((unsigned long)p->shared_info);

    free_all_dom_mem(p);

    free_task_struct(p);
}


/* final_setup_guestos is used for final setup and launching of domains other
 * than domain 0. ie. the domains that are being built by the userspace dom0
 * domain builder.
 *
 * Initial load map:
 *  start_address:
 *     OS image
 *      ....
 *  stack_start:
 *  start_info:
 *      <one page>
 *  page tables:
 *      <enough pages>
 *  end_address:
 *  shared_info:
 *      <one page>
 */

int final_setup_guestos(struct task_struct * p, dom_meminfo_t * meminfo)
{
    l2_pgentry_t * l2tab;
    l1_pgentry_t * l1tab;
    start_info_t * virt_startinfo_addr;
    unsigned long virt_stack_addr;
    unsigned long phys_l2tab;
    net_ring_t *net_ring;
    net_vif_t *net_vif;

    /* entries 0xe0000000 onwards in page table must contain hypervisor
     * mem mappings - set them up.
     */
    phys_l2tab = meminfo->l2_pgt_addr;
    l2tab = map_domain_mem(phys_l2tab); 
    memcpy(l2tab + DOMAIN_ENTRIES_PER_L2_PAGETABLE, 
        ((l2_pgentry_t *)idle_pg_table[p->processor]) + 
        DOMAIN_ENTRIES_PER_L2_PAGETABLE, 
        (ENTRIES_PER_L2_PAGETABLE - DOMAIN_ENTRIES_PER_L2_PAGETABLE) 
        * sizeof(l2_pgentry_t));
    l2tab[PERDOMAIN_VIRT_START >> L2_PAGETABLE_SHIFT] = 
        mk_l2_pgentry(__pa(p->mm.perdomain_pt) | PAGE_HYPERVISOR);
    p->mm.pagetable = mk_pagetable(phys_l2tab);
    unmap_domain_mem(l2tab);

    /* map in the shared info structure */
    phys_l2tab = pagetable_val(p->mm.pagetable); 
    l2tab = map_domain_mem(phys_l2tab);
    l2tab += l2_table_offset(meminfo->virt_shinfo_addr);
    l1tab = map_domain_mem(l2_pgentry_to_phys(*l2tab));
    l1tab += l1_table_offset(meminfo->virt_shinfo_addr);
    *l1tab = mk_l1_pgentry(__pa(p->shared_info) | L1_PROT);
    unmap_domain_mem((void *)((unsigned long)l2tab & PAGE_MASK));
    unmap_domain_mem((void *)((unsigned long)l1tab & PAGE_MASK));

    /* set up the shared info structure */
    update_dom_time(p->shared_info);
    p->shared_info->cpu_freq	 = cpu_freq;
    p->shared_info->domain_time  = 0;

    /* we pass start info struct to guest os as function parameter on stack */
    virt_startinfo_addr = (start_info_t *)meminfo->virt_startinfo_addr;
    virt_stack_addr = (unsigned long)virt_startinfo_addr;       

    /* we need to populate start_info struct within the context of the
     * new domain. thus, temporarely install its pagetables.
     */
    __cli();
    __asm__ __volatile__ ( 
        "mov %%eax,%%cr3" : : "a" (pagetable_val(p->mm.pagetable)));

    memset(virt_startinfo_addr, 0, sizeof(*virt_startinfo_addr));
    virt_startinfo_addr->nr_pages = p->tot_pages;
    virt_startinfo_addr->shared_info = (shared_info_t *)meminfo->virt_shinfo_addr;
    virt_startinfo_addr->pt_base = meminfo->virt_load_addr + 
                    ((p->tot_pages - 1) << PAGE_SHIFT);
    
    /* Add virtual network interfaces and point to them in startinfo. */
    while (meminfo->num_vifs-- > 0) {
        net_vif = create_net_vif(p->domain);
        net_ring = net_vif->net_ring;
        if (!net_ring) panic("no network ring!\n");
    }

/* XXX SMH: horrible hack to convert hypervisor VAs in SHIP to guest VAs  */
#define SH2G(_x) (meminfo->virt_shinfo_addr | (((unsigned long)(_x)) & 0xFFF))

    virt_startinfo_addr->net_rings = (net_ring_t *)SH2G(p->net_ring_base); 
    virt_startinfo_addr->num_net_rings = p->num_net_vifs;

    /* Add block io interface */
    virt_startinfo_addr->blk_ring = virt_to_phys(p->blk_ring_base);

    /* Copy the command line */
    strcpy(virt_startinfo_addr->cmd_line, meminfo->cmd_line);

    /* Reinstate the caller's page tables. */
    __asm__ __volatile__ (
        "mov %%eax,%%cr3" : : "a" (pagetable_val(current->mm.pagetable)));    
    __sti();
    
    new_thread(p, 
               (unsigned long)meminfo->virt_load_addr, 
               (unsigned long)virt_stack_addr, 
               (unsigned long)virt_startinfo_addr);

    return 0;
}

static unsigned long alloc_page_from_domain(unsigned long * cur_addr, 
    unsigned long * index)
{
    unsigned long ret = *cur_addr;
    struct list_head *ent = frame_table[ret >> PAGE_SHIFT].list.prev;
    *cur_addr = list_entry(ent, struct pfn_info, list) - frame_table;
    *cur_addr <<= PAGE_SHIFT;
    (*index)--;    
    return ret;
}

/* setup_guestos is used for building dom0 solely. other domains are built in
 * userspace dom0 and final setup is being done by final_setup_guestos.
 */
int setup_guestos(struct task_struct *p, dom0_newdomain_t *params)
{

    struct list_head *list_ent;
    char *src, *dst;
    int i, dom = p->domain;
    unsigned long phys_l1tab, phys_l2tab;
    unsigned long cur_address, alloc_address;
    unsigned long virt_load_address, virt_stack_address, virt_shinfo_address;
    start_info_t  *virt_startinfo_address;
    unsigned long count;
    unsigned long alloc_index;
    l2_pgentry_t *l2tab, *l2start;
    l1_pgentry_t *l1tab = NULL, *l1start = NULL;
    struct pfn_info *page = NULL;
    net_ring_t *net_ring;
    net_vif_t *net_vif;

    /* Sanity! */
    if ( p->domain != 0 ) BUG();

    if ( strncmp(__va(mod[0].mod_start), "XenoGues", 8) )
    {
        printk("DOM%d: Invalid guest OS image\n", dom);
        return -1;
    }

    virt_load_address = *(unsigned long *)__va(mod[0].mod_start + 8);
    if ( (virt_load_address & (PAGE_SIZE-1)) )
    {
        printk("DOM%d: Guest OS load address not page-aligned (%08lx)\n",
               dom, virt_load_address);
        return -1;
    }

    if ( alloc_new_dom_mem(p, params->memory_kb) ) return -ENOMEM;
    alloc_address = list_entry(p->pg_head.prev, struct pfn_info, list) -
        frame_table;
    alloc_address <<= PAGE_SHIFT;
    alloc_index = p->tot_pages;

    if ( (mod[nr_mods-1].mod_end-mod[0].mod_start) > 
         (params->memory_kb << 9) )
    {
        printk("DOM%d: Guest OS image is too large\n"
               "       (%luMB is greater than %uMB limit for a\n"
               "        %uMB address space)\n",
               dom, (mod[nr_mods-1].mod_end-mod[0].mod_start)>>20,
               (params->memory_kb)>>11,
               (params->memory_kb)>>10);
        free_all_dom_mem(p);
        return -1;
    }

    printk("DOM%d: Guest OS virtual load address is %08lx\n", dom,
           virt_load_address);
    
    /*
     * WARNING: The new domain must have its 'processor' field
     * filled in by now !!
     */
    phys_l2tab = alloc_page_from_domain(&alloc_address, &alloc_index);
    l2start = l2tab = map_domain_mem(phys_l2tab);
    memcpy(l2tab, idle_pg_table[p->processor], PAGE_SIZE);
    l2tab[PERDOMAIN_VIRT_START >> L2_PAGETABLE_SHIFT] =
        mk_l2_pgentry(__pa(p->mm.perdomain_pt) | __PAGE_HYPERVISOR);
    memset(l2tab, 0, DOMAIN_ENTRIES_PER_L2_PAGETABLE*sizeof(l2_pgentry_t));
    p->mm.pagetable = mk_pagetable(phys_l2tab);

    /*
     * NB. The upper limit on this loop does one extra page. This is to make 
     * sure a pte exists when we want to map the shared_info struct.
     */

    l2tab += l2_table_offset(virt_load_address);
    cur_address = list_entry(p->pg_head.next, struct pfn_info, list) -
        frame_table;
    cur_address <<= PAGE_SHIFT;
    for ( count = 0; count < p->tot_pages + 1; count++ )
    {
        if ( !((unsigned long)l1tab & (PAGE_SIZE-1)) )
        {
            if ( l1tab != NULL ) unmap_domain_mem(l1start);
            phys_l1tab = alloc_page_from_domain(&alloc_address, &alloc_index);
            *l2tab++ = mk_l2_pgentry(phys_l1tab|L2_PROT);
            l1start = l1tab = map_domain_mem(phys_l1tab);
            clear_page(l1tab);
            l1tab += l1_table_offset(
                virt_load_address + (count << PAGE_SHIFT));
        }
        *l1tab++ = mk_l1_pgentry(cur_address|L1_PROT);
        
        if ( count < p->tot_pages )
        {
            page = frame_table + (cur_address >> PAGE_SHIFT);
            page->flags = dom | PGT_writeable_page;
            page->type_count = page->tot_count = 1;
            /* Set up the MPT entry. */
            machine_to_phys_mapping[cur_address >> PAGE_SHIFT] = count;
        }

        list_ent = frame_table[cur_address >> PAGE_SHIFT].list.next;
        cur_address = list_entry(list_ent, struct pfn_info, list) -
            frame_table;
        cur_address <<= PAGE_SHIFT;
    }
    unmap_domain_mem(l1start);

    /* pages that are part of page tables must be read only */
    cur_address = list_entry(p->pg_head.next, struct pfn_info, list) -
        frame_table;
    cur_address <<= PAGE_SHIFT;
    for ( count = 0; count < alloc_index; count++ ) 
    {
        list_ent = frame_table[cur_address >> PAGE_SHIFT].list.next;
        cur_address = list_entry(list_ent, struct pfn_info, list) -
            frame_table;
        cur_address <<= PAGE_SHIFT;
    }

    l2tab = l2start + l2_table_offset(virt_load_address + 
        (alloc_index << PAGE_SHIFT));
    l1start = l1tab = map_domain_mem(l2_pgentry_to_phys(*l2tab));
    l1tab += l1_table_offset(virt_load_address + (alloc_index << PAGE_SHIFT));
    l2tab++;
    for ( count = alloc_index; count < p->tot_pages; count++ ) 
    {
        *l1tab++ = mk_l1_pgentry(l1_pgentry_val(*l1tab) & ~_PAGE_RW);
        if( !((unsigned long)l1tab & (PAGE_SIZE - 1)) )
        {
            unmap_domain_mem(l1start);
            l1start = l1tab = map_domain_mem(l2_pgentry_to_phys(*l2tab));
            l2tab++;
        }
        page = frame_table + (cur_address >> PAGE_SHIFT);
        page->flags = dom | PGT_l1_page_table;
        page->tot_count++;
        
        list_ent = frame_table[cur_address >> PAGE_SHIFT].list.next;
        cur_address = list_entry(list_ent, struct pfn_info, list) -
            frame_table;
        cur_address <<= PAGE_SHIFT;
    }
    page->type_count |= REFCNT_PIN_BIT;
    page->tot_count  |= REFCNT_PIN_BIT;
    page->flags = dom | PGT_l2_page_table;
    unmap_domain_mem(l1start);

    /* Map in the the shared info structure. */
    virt_shinfo_address = virt_load_address + (p->tot_pages << PAGE_SHIFT); 
    l2tab = l2start + l2_table_offset(virt_shinfo_address);
    l1start = l1tab = map_domain_mem(l2_pgentry_to_phys(*l2tab));
    l1tab += l1_table_offset(virt_shinfo_address);
    *l1tab = mk_l1_pgentry(__pa(p->shared_info)|L1_PROT);
    unmap_domain_mem(l1start);

    /* Set up shared info area. */
	update_dom_time(p->shared_info);
	p->shared_info->cpu_freq	 = cpu_freq;
    p->shared_info->domain_time  = 0;


    virt_startinfo_address = (start_info_t *)
        (virt_load_address + ((alloc_index - 1) << PAGE_SHIFT));
    virt_stack_address  = (unsigned long)virt_startinfo_address;
    
    unmap_domain_mem(l2start);

    /* Install the new page tables. */
    __cli();
    __write_cr3_counted(pagetable_val(p->mm.pagetable));

    /* Copy the guest OS image. */
    src = (char *)__va(mod[0].mod_start + 12);
    dst = (char *)virt_load_address;
    while ( src < (char *)__va(mod[nr_mods-1].mod_end) ) *dst++ = *src++;

    /* Set up start info area. */
    memset(virt_startinfo_address, 0, sizeof(*virt_startinfo_address));
    virt_startinfo_address->nr_pages = p->tot_pages;
    virt_startinfo_address->shared_info = 
        (shared_info_t *)virt_shinfo_address;
    virt_startinfo_address->pt_base = virt_load_address + 
        ((p->tot_pages - 1) << PAGE_SHIFT); 

    /* Add virtual network interfaces and point to them in startinfo. */
    while (params->num_vifs-- > 0) {
        net_vif = create_net_vif(dom);
        net_ring = net_vif->net_ring;
        if (!net_ring) panic("no network ring!\n");
    }

/* XXX SMH: horrible hack to convert hypervisor VAs in SHIP to guest VAs  */
#define SHIP2GUEST(_x) (virt_shinfo_address | (((unsigned long)(_x)) & 0xFFF))

    virt_startinfo_address->net_rings = 
	(net_ring_t *)SHIP2GUEST(p->net_ring_base); 
    virt_startinfo_address->num_net_rings = p->num_net_vifs;

    /* Add block io interface */
    virt_startinfo_address->blk_ring = virt_to_phys(p->blk_ring_base); 

    /* We tell OS about any modules we were given. */
    if ( nr_mods > 1 )
    {
        virt_startinfo_address->mod_start = 
            (mod[1].mod_start-mod[0].mod_start-12) + virt_load_address;
        virt_startinfo_address->mod_len = 
            mod[nr_mods-1].mod_end - mod[1].mod_start;
    }

    dst = virt_startinfo_address->cmd_line;
    if ( mod[0].string )
    {
        char *modline = (char *)__va(mod[0].string);
        for ( i = 0; i < 255; i++ )
        {
            if ( modline[i] == '\0' ) break;
            *dst++ = modline[i];
        }
    }
    *dst = '\0';

    /* Reinstate the caller's page tables. */
    __write_cr3_counted(pagetable_val(current->mm.pagetable));
    __sti();

    new_thread(p, 
               (unsigned long)virt_load_address, 
               (unsigned long)virt_stack_address, 
               (unsigned long)virt_startinfo_address);

    return 0;
}


void __init domain_init(void)
{
	printk("Initialising domains\n");
}