xnu-124.13.tar.gz

[apple/xnu.git] / osfmk / ppc / vmachmon.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*-----------------------------------------------------------------------
** vmachmon.c
**
** C routines that we are adding to the MacOS X kernel.
**
** Weird Apple PSL stuff goes here...
**
** Until then, Copyright 2000, Connectix
-----------------------------------------------------------------------*/

#include <mach/mach_types.h>
#include <mach/kern_return.h>
#include <mach/host_info.h>
#include <kern/kern_types.h>
#include <kern/host.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <ppc/exception.h>
#include <ppc/mappings.h>
#include <ppc/thread_act.h>
#include <ppc/pmap_internals.h>
#include <vm/vm_kern.h>

#include <ppc/vmachmon.h>

extern struct   Saveanchor saveanchor;                  /* Aligned savearea anchor */
extern double FloatInit;
extern unsigned long QNaNbarbarian[4];

/*************************************************************************************
        Virtual Machine Monitor Internal Routines
**************************************************************************************/

/*-----------------------------------------------------------------------
** vmm_get_entry
**
** This function verifies and return a vmm context entry index
**
** Inputs:
**              act - pointer to current thread activation
**              index - index into vmm control table (this is a "one based" value)
**
** Outputs:
**              address of a vmmCntrlEntry or 0 if not found
-----------------------------------------------------------------------*/

vmmCntrlEntry *vmm_get_entry(
        thread_act_t            act,
        vmm_thread_index_t      index)
{
        vmmCntrlTable *CTable;
        vmmCntrlEntry *CEntry;

        if (act->mact.vmmControl == 0) return NULL;                             /* No control table means no vmm */
        if ((index - 1) >= kVmmMaxContextsPerThread) return NULL;       /* Index not in range */        

        CTable = act->mact.vmmControl;                                                  /* Make the address a bit more convienient */
        CEntry = &CTable->vmmc[index - 1];                                              /* Point to the entry */
        
        if (!(CEntry->vmmFlags & vmmInUse)) return NULL;                /* See if the slot is actually in use */
        
        return CEntry;
}



/*************************************************************************************
        Virtual Machine Monitor Exported Functionality
        
        The following routines are used to implement a quick-switch mechanism for
        virtual machines that need to execute within their own processor envinroment
        (including register and MMU state).
**************************************************************************************/

/*-----------------------------------------------------------------------
** vmm_get_version
**
** This function returns the current version of the virtual machine
** interface. It is divided into two portions. The top 16 bits
** represent the major version number, and the bottom 16 bits
** represent the minor version number. Clients using the Vmm
** functionality should make sure they are using a verison new
** enough for them.
**
** Inputs:
**              none
**
** Outputs:
**              32-bit number representing major/minor version of 
**                              the Vmm module
-----------------------------------------------------------------------*/

int vmm_get_version(struct savearea *save)
{
        save->save_r3 = kVmmCurrentVersion;             /* Return the version */
        return 1;
}


/*-----------------------------------------------------------------------
** Vmm_get_features
**
** This function returns a set of flags that represents the functionality
** supported by the current verison of the Vmm interface. Clients should
** use this to determine whether they can run on this system.
**
** Inputs:
**              none
**
** Outputs:
**              32-bit number representing functionality supported by this
**                              version of the Vmm module
-----------------------------------------------------------------------*/

int vmm_get_features(struct savearea *save)
{
        save->save_r3 = kVmmCurrentFeatures;            /* Return the features */
        return 1;
}


/*-----------------------------------------------------------------------
** vmm_init_context
**
** This function initializes an  emulation context. It allocates
** a new pmap (address space) and fills in the initial processor
** state within the specified structure. The structure, mapped
** into the client's logical address space, must be page-aligned.
**
** Inputs:
**              act - pointer to current thread activation
**              version - requested version of the Vmm interface (allowing
**                      future versions of the interface to change, but still
**                      support older clients)
**              vmm_user_state - pointer to a logical page within the
**                      client's address space
**
** Outputs:
**              kernel return code indicating success or failure
-----------------------------------------------------------------------*/

int vmm_init_context(struct savearea *save)
{

        thread_act_t            act;
        vmm_version_t           version;
        vmm_state_page_t *      vmm_user_state;
        vmmCntrlTable           *CTable;
        vm_offset_t                     conkern;
        vmm_state_page_t *      vks;
        vm_offset_t                     conphys;
        kern_return_t           ret;
        pmap_t                          new_pmap;       
        int                                     cvi, i;
    task_t                              task;
    thread_act_t                fact, gact;

        vmm_user_state = (vmm_state_page_t *)save->save_r4;             /* Get the user address of the comm area */
        if ((unsigned int)vmm_user_state & (PAGE_SIZE - 1)) {   /* Make sure the comm area is page aligned */
                save->save_r3 = KERN_FAILURE;                   /* Return failure */
                return 1;
        }

        /* If the client is requesting a newer major version than */
        /* we currently support, we'll have to fail. In the future, */
        /* we can add new major versions and support the older ones. */
        version = save->save_r3;                                        /* Pick up passed in version */
        if ((version >> 16) > (kVmmCurrentVersion >> 16)) {
        }
        
        act = current_act();                                            /* Pick up our activation */
        
        ml_set_interrupts_enabled(TRUE);                        /* This can take a bit of time so pass interruptions */
        
        task = current_task();                                          /* Figure out who we are */

        task_lock(task);                                                        /* Lock our task */

        fact = (thread_act_t)task->thr_acts.next;       /* Get the first activation on task */
        gact = 0;                                                                       /* Pretend we didn't find it yet */

        for(i = 0; i < task->thr_act_count; i++) {      /* All of the activations */
                if(fact->mact.vmmControl) {                             /* Is this a virtual machine monitor? */
                        gact = fact;                                            /* Yeah... */
                        break;                                                          /* Bail the loop... */
                }
                fact = (thread_act_t)fact->thr_acts.next;       /* Go to the next one */
        }
        

/*
 *      We only allow one thread per task to be a virtual machine monitor right now.  This solves
 *      a number of potential problems that I can't put my finger on right now.
 *
 *      Utlimately, I think we want to move the controls and make all this task based instead of
 *      thread based.  That would allow an emulator architecture to spawn a kernel thread for each
 *      VM (if they want) rather than hand dispatch contexts.
 */

        if(gact && (gact != act)) {                                     /* Check if another thread is a vmm or trying to be */
                task_unlock(task);                                              /* Release task lock */
                ml_set_interrupts_enabled(FALSE);               /* Set back interruptions */
                save->save_r3 = KERN_FAILURE;                   /* We must play alone... */
                return 1;
        }
        
        if(!gact) act->mact.vmmControl = (vmmCntrlTable *)1;    /* Temporarily mark that we are the vmm thread */

        task_unlock(task);                                                      /* Safe to release now (because we've marked ourselves) */

        CTable = act->mact.vmmControl;                          /* Get the control table address */
        if ((unsigned int)CTable == 1) {                        /* If we are marked, try to allocate a new table, otherwise we have one */
                if(!(CTable = (vmmCntrlTable *)kalloc(sizeof(vmmCntrlTable)))) {        /* Get a fresh emulation control table */
                        act->mact.vmmControl = 0;                       /* Unmark us as vmm 'cause we failed */
                        ml_set_interrupts_enabled(FALSE);       /* Set back interruptions */
                        save->save_r3 = KERN_RESOURCE_SHORTAGE;         /* No storage... */
                        return 1;
                }
                
                bzero((void *)CTable, sizeof(vmmCntrlTable));   /* Clean it up */
                act->mact.vmmControl = CTable;                  /* Initialize the table anchor */
        }

        for(cvi = 0; cvi < kVmmMaxContextsPerThread; cvi++) {   /* Search to find a free slot */
                if(!(CTable->vmmc[cvi].vmmFlags & vmmInUse)) break;     /* Bail if we find an unused slot */
        }
        
        if(cvi >= kVmmMaxContextsPerThread) {           /* Did we find one? */
                ml_set_interrupts_enabled(FALSE);               /* Set back interruptions */
                save->save_r3 = KERN_RESOURCE_SHORTAGE; /* No empty slots... */ 
                return 1;
        }

        ret = vm_map_wire(                                                      /* Wire the virtual machine monitor's context area */
                act->map,
                (vm_offset_t)vmm_user_state,
                (vm_offset_t)vmm_user_state + PAGE_SIZE,
                VM_PROT_READ | VM_PROT_WRITE,
                FALSE);                                                                                                                 
                
        if (ret != KERN_SUCCESS)                                        /* The wire failed, return the code */
                goto return_in_shame;

        /* Map the vmm state into the kernel's address space. */
        conphys = pmap_extract(act->map->pmap, (vm_offset_t)vmm_user_state);

        /* Find a virtual address to use. */
        ret = kmem_alloc_pageable(kernel_map, &conkern, PAGE_SIZE);
        if (ret != KERN_SUCCESS) {                                      /* Did we find an address? */
                (void) vm_map_unwire(act->map,                  /* No, unwire the context area */
                        (vm_offset_t)vmm_user_state,
                        (vm_offset_t)vmm_user_state + PAGE_SIZE,
                        TRUE);
                goto return_in_shame;
        }
        
        /* Map it into the kernel's address space. */
        pmap_enter(kernel_pmap, conkern, conphys, VM_PROT_READ | VM_PROT_WRITE, TRUE);
        
        /* Clear the vmm state structure. */
        vks = (vmm_state_page_t *)conkern;
        bzero((char *)vks, PAGE_SIZE);
        
        /* Allocate a new pmap for the new vmm context. */
        new_pmap = pmap_create(0);
        if (new_pmap == PMAP_NULL) {
                (void) vm_map_unwire(act->map,                  /* Couldn't get a pmap, unwire the user page */
                        (vm_offset_t)vmm_user_state,
                        (vm_offset_t)vmm_user_state + PAGE_SIZE,
                        TRUE);
                
                kmem_free(kernel_map, conkern, PAGE_SIZE);      /* Release the kernel address */
                goto return_in_shame;
        }
        
        /* We're home free now. Simply fill in the necessary info and return. */
        
        vks->interface_version = version;                       /* Set our version code */
        vks->thread_index = cvi + 1;                            /* Tell the user the index for this virtual machine */
        
        CTable->vmmc[cvi].vmmFlags = vmmInUse;          /* Mark the slot in use and make sure the rest are clear */
        CTable->vmmc[cvi].vmmPmap = new_pmap;           /* Remember the pmap for this guy */
        CTable->vmmc[cvi].vmmContextKern = vks;         /* Remember the kernel address of comm area */
        CTable->vmmc[cvi].vmmContextUser = vmm_user_state;              /* Remember user address of comm area */
        CTable->vmmc[cvi].vmmFPU_pcb = 0;                       /* Clear saved floating point context */
        CTable->vmmc[cvi].vmmFPU_cpu = -1;                      /* Invalidate CPU saved fp context is valid on */
        CTable->vmmc[cvi].vmmVMX_pcb = 0;                       /* Clear saved vector context */
        CTable->vmmc[cvi].vmmVMX_cpu = -1;                      /* Invalidate CPU saved vector context is valid on */

        hw_atomic_add(&saveanchor.saveneed, 2);         /* Account for the number of extra saveareas we think we might "need" */
        
        ml_set_interrupts_enabled(FALSE);                       /* Set back interruptions */
        save->save_r3 = KERN_SUCCESS;                           /* Hip, hip, horay... */        
        return 1;

return_in_shame:
        if(!gact) kfree((vm_offset_t)CTable, sizeof(vmmCntrlTable));    /* Toss the table if we just allocated it */
        act->mact.vmmControl = 0;                                       /* Unmark us as vmm 'cause we failed */
        ml_set_interrupts_enabled(FALSE);                       /* Set back interruptions */
        save->save_r3 = ret;                                            /* Pass back return code... */  
        return 1;

}


/*-----------------------------------------------------------------------
** vmm_tear_down_context
**
** This function uninitializes an emulation context. It deallocates
** internal resources associated with the context block.
**
** Inputs:
**              act - pointer to current thread activation structure
**              index - index returned by vmm_init_context
**
** Outputs:
**              kernel return code indicating success or failure
-----------------------------------------------------------------------*/

kern_return_t vmm_tear_down_context(
        thread_act_t            act,
        vmm_thread_index_t      index)
{
        vmmCntrlEntry           *CEntry;
        vmmCntrlTable           *CTable;
        int                                     cvi;
        register savearea       *sv;

        CEntry = vmm_get_entry(act, index);                             /* Convert index to entry */            
        if (CEntry == NULL) return KERN_FAILURE;                /* Either this isn't vmm thread or the index is bogus */

        ml_set_interrupts_enabled(TRUE);                                /* This can take a bit of time so pass interruptions */

        hw_atomic_sub(&saveanchor.saveneed, 2);                 /* We don't need these extra saveareas anymore */

        if(CEntry->vmmFPU_pcb) {                                                /* Is there any floating point context? */
                sv = (savearea *)CEntry->vmmFPU_pcb;            /* Make useable */
                sv->save_flags  &= ~SAVfpuvalid;                        /* Clear in use bit */
                if(!(sv->save_flags & SAVinuse)) {                      /* Anyone left with this one? */                        
                        save_release(sv);                                               /* Nope, release it */
                }
        }

        if(CEntry->vmmVMX_pcb) {                                                /* Is there any vector context? */
                sv = (savearea *)CEntry->vmmVMX_pcb;            /* Make useable */
                sv->save_flags  &= ~SAVvmxvalid;                        /* Clear in use bit */
                if(!(sv->save_flags & SAVinuse)) {                      /* Anyone left with this one? */                        
                        save_release(sv);                                               /* Nope, release it */
                }
        }
        
        mapping_remove(CEntry->vmmPmap, 0xFFFFF000);    /* Remove final page explicitly because we might have mapped it */      
        pmap_remove(CEntry->vmmPmap, 0, 0xFFFFF000);    /* Remove all entries from this map */
        pmap_destroy(CEntry->vmmPmap);                                  /* Toss the pmap for this context */
        CEntry->vmmPmap = NULL;                                                 /* Clean it up */
        
        (void) vm_map_unwire(                                                   /* Unwire the user comm page */
                act->map,
                (vm_offset_t)CEntry->vmmContextUser,
                (vm_offset_t)CEntry->vmmContextUser + PAGE_SIZE,
                FALSE);
        
        kmem_free(kernel_map, (vm_offset_t)CEntry->vmmContextKern, PAGE_SIZE);  /* Remove kernel's view of the comm page */
        
        CEntry->vmmFlags = 0;                                                   /* Clear out all of the flags for this entry including in use */
        CEntry->vmmPmap = 0;                                                    /* Clear pmap pointer */
        CEntry->vmmContextKern = 0;                                             /* Clear the kernel address of comm area */
        CEntry->vmmContextUser = 0;                                             /* Clear the user address of comm area */
        CEntry->vmmFPU_pcb = 0;                                                 /* Clear saved floating point context */
        CEntry->vmmFPU_cpu = -1;                                                /* Invalidate CPU saved fp context is valid on */
        CEntry->vmmVMX_pcb = 0;                                                 /* Clear saved vector context */
        CEntry->vmmVMX_cpu = -1;                                                /* Invalidate CPU saved vector context is valid on */
        
        CTable = act->mact.vmmControl;                                  /* Get the control table address */
        for(cvi = 0; cvi < kVmmMaxContextsPerThread; cvi++) {   /* Search to find a free slot */
                if(CTable->vmmc[cvi].vmmFlags & vmmInUse) {     /* Return if there are still some in use */
                        ml_set_interrupts_enabled(FALSE);               /* No more interruptions */
                        return KERN_SUCCESS;                                    /* Leave... */
                }
        }

        kfree((vm_offset_t)CTable, sizeof(vmmCntrlTable));      /* Toss the table because to tossed the last context */
        act->mact.vmmControl = 0;                                               /* Unmark us as vmm */

        ml_set_interrupts_enabled(FALSE);                               /* No more interruptions */
        
        return KERN_SUCCESS;
}

/*-----------------------------------------------------------------------
** vmm_tear_down_all
**
** This function uninitializes all emulation contexts. If there are
** any vmm contexts, it calls vmm_tear_down_context for each one.
**
** Note: this can also be called from normal thread termination.  Because of
** that, we will context switch out of an alternate if we are currenty in it.
** It will be terminated with no valid return code set because we don't expect 
** the activation to ever run again.
**
** Inputs:
**              activation to tear down
**
** Outputs:
**              All vmm contexts released and VMM shut down
-----------------------------------------------------------------------*/
void vmm_tear_down_all(thread_act_t act) {

        vmmCntrlTable           *CTable;
        int                                     cvi;
        kern_return_t           ret;
        savearea                        *save;
        spl_t                           s;
        
        if(act->mact.specFlags & runningVM) {                   /* Are we actually in a context right now? */
                save = (savearea *)find_user_regs(act);         /* Find the user state context */
                if(!save) {                                                                     /* Did we find it? */
                        panic("vmm_tear_down_all: runningVM marked but no user state context\n");
                        return;
                }
                
                s = splhigh();                                                          /* Make sure interrupts are off */
                vmm_force_exit(act, save);                                      /* Force and exit from VM state */
                splx(s);                                                                        /* Restore interrupts */
        }
        
        if(CTable = act->mact.vmmControl) {                             /* Do we have a vmm control block? */

                for(cvi = 1; cvi <= kVmmMaxContextsPerThread; cvi++) {  /* Look at all slots */
                        if(CTable->vmmc[cvi - 1].vmmFlags & vmmInUse) { /* Is this one in use */
                                ret = vmm_tear_down_context(act, cvi);  /* Take down the found context */
                                if(ret != KERN_SUCCESS) {                       /* Did it go away? */
                                        panic("vmm_tear_down_all: vmm_tear_down_context failed; ret=%08X, act = %08X, cvi = %d\n",
                                          ret, act, cvi);
                                }
                        }
                }               
                if(act->mact.vmmControl) {                                              /* Did we find one? */
                        panic("vmm_tear_down_all: control table did not get deallocated\n");    /* Table did not go away */
                }
        }

        return;
}

/*-----------------------------------------------------------------------
** vmm_map_page
**
** This function maps a page from within the client's logical
** address space into the alternate address space of the
** Virtual Machine Monitor context. 
**
** The page need not be locked or resident.  If not resident, it will be faulted
** in by this code, which may take some time.   Also, if the page is not locked,
** it, and this mapping may disappear at any time, even before it gets used.  Note also
** that reference and change information is NOT preserved when a page is unmapped, either
** explicitly or implicitly (e.g., a pageout, being unmapped in the non-alternate address
** space).  This means that if RC is needed, the page MUST be wired.
**
** Note that if there is already a mapping at the address, it is removed and all 
** information (including RC) is lost BEFORE an attempt is made to map it. Also,
** if the map call fails, the old address is still unmapped..
**
** Inputs:
**              act   - pointer to current thread activation
**              index - index of vmm state for this page
**              va    - virtual address within the client's address
**                          space (must be page aligned)
**              ava   - virtual address within the alternate address
**                          space (must be page aligned)
**              prot - protection flags
**
**      Note that attempted mapping of areas in nested pmaps (shared libraries) or block mapped
**  areas are not allowed and will fail. Same with directly mapped I/O areas.
**
** Input conditions:
**      Interrupts disabled (from fast trap)
**
** Outputs:
**              kernel return code indicating success or failure
**      if success, va resident and alternate mapping made
-----------------------------------------------------------------------*/

kern_return_t vmm_map_page(
        thread_act_t            act,
        vmm_thread_index_t      index,
        vm_offset_t             cva,
        vm_offset_t             ava,
        vm_prot_t                       prot)
{
        kern_return_t           ret;
        vmmCntrlEntry           *CEntry;
        vm_offset_t                     phys_addr;
        register mapping        *mpv, *mp, *nmpv, *nmp;
        struct phys_entry       *pp;
        pmap_t                          mpmap;
        vm_map_t                        map;

        CEntry = vmm_get_entry(act, index);                     /* Get and validate the index */
        if (CEntry == NULL)return KERN_FAILURE;         /* No good, failure... */
        
/*
 *      Find out if we have already mapped the address and toss it out if so.
 */
        mp = hw_lock_phys_vir(CEntry->vmmPmap->space, ava);     /* See if there is already a mapping */
        if((unsigned int)mp & 1) {                                      /* Did we timeout? */
                panic("vmm_map_page: timeout locking physical entry for alternate virtual address (%08X)\n", ava);      /* Yeah, scream about it! */
                return KERN_FAILURE;                                    /* Bad hair day, return FALSE... */
        }
        if(mp) {                                                                        /* If it was there, toss it */
                mpv = hw_cpv(mp);                                               /* Convert mapping block to virtual */
                hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* We're done, unlock the physical entry */
                (void)mapping_remove(CEntry->vmmPmap, ava);     /* Throw away the mapping. we're about to replace it */
        }
        map = current_act()->map;                                       /* Get the current map */
        
        while(1) {                                                                      /* Keep trying until we get it or until we fail */
                if(hw_cvp_blk(map->pmap, cva)) return KERN_FAILURE;     /* Make sure that there is no block map at this address */

                mp = hw_lock_phys_vir(map->pmap->space, cva);   /* Lock the physical entry for emulator's page */
                if((unsigned int)mp&1) {                                /* Did we timeout? */
                        panic("vmm_map_page: timeout locking physical entry for emulator virtual address (%08X)\n", cva);       /* Yeah, scream about it! */
                        return KERN_FAILURE;                            /* Bad hair day, return FALSE... */
                }
                
                if(mp) {                                                                /* We found it... */
                        mpv = hw_cpv(mp);                                       /* Convert mapping block to virtual */
                        if(!(mpv->PTEr & 1)) break;                     /* If we are not write protected, we are ok... */
                }

                ml_set_interrupts_enabled(TRUE);                /* Enable interruptions */
                ret = vm_fault(map, trunc_page(cva), VM_PROT_READ | VM_PROT_WRITE, FALSE);      /* Didn't find it, try to fault it in read/write... */
                ml_set_interrupts_enabled(FALSE);               /* Disable interruptions */
                if (ret != KERN_SUCCESS) return KERN_FAILURE;   /* There isn't a page there, return... */
        }


        if(!mpv->physent) {                                                     /* Is this an I/O area, e.g., framebuffer? */
                return KERN_FAILURE;                                    /* Yes, we won't map it... */
        }

/*
 *      Now we make a mapping using all of the attributes of the source page except for protection.
 *      Also specify that the physical entry is locked.
 */
        nmpv = mapping_make(CEntry->vmmPmap, mpv->physent, (ava & -PAGE_SIZE),
                (mpv->physent->pte1 & -PAGE_SIZE), prot, ((mpv->physent->pte1 >> 3) & 0xF), 1); 

        hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* Unlock the physical entry now, we're done with it */
        
        CEntry->vmmLastMap = ava & -PAGE_SIZE;          /* Remember the last mapping we made */
        CEntry->vmmFlags |= vmmMapDone;                         /* Set that we did a map operation */

        return KERN_SUCCESS;
}


/*-----------------------------------------------------------------------
** vmm_get_page_mapping
**
** This function determines whether the specified VMM
** virtual address is mapped.
**
** Inputs:
**              act   - pointer to current thread activation
**              index - index of vmm state for this page
**              va    - virtual address within the alternate's address
**                          space
**
** Outputs:
**              Non-alternate's virtual address (page aligned) or -1 if not mapped or any failure
**
** Note:
**      If there are aliases to the page in the non-alternate address space,
**          this call could return the wrong one.  Moral of the story: no aliases.
-----------------------------------------------------------------------*/

vm_offset_t vmm_get_page_mapping(
        thread_act_t            act,
        vmm_thread_index_t      index,
        vm_offset_t             va)
{
        vmmCntrlEntry           *CEntry;
        vm_offset_t                     ova;
        register mapping        *mpv, *mp, *nmpv, *nmp;
        pmap_t                          pmap;

        CEntry = vmm_get_entry(act, index);                                             /* Get and validate the index */
        if (CEntry == NULL)return -1;                                                   /* No good, failure... */

        mp = hw_lock_phys_vir(CEntry->vmmPmap->space, va);              /* Look up the mapping */
        if((unsigned int)mp & 1) {                                                              /* Did we timeout? */
                panic("vmm_get_page_mapping: timeout locking physical entry for alternate virtual address (%08X)\n", va);       /* Yeah, scream about it! */
                return -1;                                                                                      /* Bad hair day, return FALSE... */
        }
        if(!mp) return -1;                                                                              /* Not mapped, return -1 */

        mpv = hw_cpv(mp);                                                                               /* Convert mapping block to virtual */
        pmap = current_act()->map->pmap;                                                /* Get the current pmap */
        ova = -1;                                                                                               /* Assume failure for now */
        
        for(nmpv = hw_cpv(mpv->physent->phys_link); nmpv; nmpv = hw_cpv(nmpv->next)) {  /* Scan 'em all */
                
                if(nmpv->pmap != pmap) continue;                                        /* Skip all the rest if this is not the right pmap... */ 
                
                ova = ((((unsigned int)nmpv->PTEhash & -64) << 6) ^ (pmap->space  << 12)) & 0x003FF000; /* Backward hash to the wrapped VADDR */
                ova = ova | ((nmpv->PTEv << 1) & 0xF0000000);           /* Move in the segment number */
                ova = ova | ((nmpv->PTEv << 22) & 0x0FC00000);          /* Add in the API for the top of the address */
                break;                                                                                          /* We're done now, pass virtual address back */
        }

        hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* We're done, unlock the physical entry */
        
        if(ova == -1) panic("vmm_get_page_mapping: could not back-map alternate va (%08X)\n", va);      /* We are bad wrong if we can't find it */

        return ova;
}

/*-----------------------------------------------------------------------
** vmm_unmap_page
**
** This function unmaps a page from the alternate's logical
** address space.
**
** Inputs:
**              act   - pointer to current thread activation
**              index - index of vmm state for this page
**              va    - virtual address within the vmm's address
**                          space
**
** Outputs:
**              kernel return code indicating success or failure
-----------------------------------------------------------------------*/

kern_return_t vmm_unmap_page(
        thread_act_t            act,
        vmm_thread_index_t      index,
        vm_offset_t             va)
{
        vmmCntrlEntry           *CEntry;
        boolean_t                       ret;
        kern_return_t           kern_result = KERN_SUCCESS;

        CEntry = vmm_get_entry(act, index);                                             /* Get and validate the index */
        if (CEntry == NULL)return -1;                                                   /* No good, failure... */
        
        ret = mapping_remove(CEntry->vmmPmap, va);                              /* Toss the mapping */
        
        return (ret ? KERN_SUCCESS : KERN_FAILURE);                             /* Return... */
}

/*-----------------------------------------------------------------------
** vmm_unmap_all_pages
**
** This function unmaps all pages from the alternates's logical
** address space.
**
** Inputs:
**              act   - pointer to current thread activation
**              index - index of context state
**
** Outputs:
**              none
**
** Note:
**      All pages are unmapped, but the address space (i.e., pmap) is still alive
-----------------------------------------------------------------------*/

void vmm_unmap_all_pages(
        thread_act_t            act,
        vmm_thread_index_t      index)
{
        vmmCntrlEntry           *CEntry;

        CEntry = vmm_get_entry(act, index);                                             /* Convert index to entry */            
        if (CEntry == NULL) return;                                                             /* Either this isn't vmm thread or the index is bogus */
        
/*
 *      Note: the pmap code won't deal with the last page in the address space, so handle it explicitly
 */
        mapping_remove(CEntry->vmmPmap, 0xFFFFF000);                    /* Remove final page explicitly because we might have mapped it */      
        pmap_remove(CEntry->vmmPmap, 0, 0xFFFFF000);                    /* Remove all entries from this map */
        return;
}


/*-----------------------------------------------------------------------
** vmm_get_page_dirty_flag
**
** This function returns the changed flag of the page
** and optionally clears clears the flag.
**
** Inputs:
**              act   - pointer to current thread activation
**              index - index of vmm state for this page
**              va    - virtual address within the vmm's address
**                          space
**              reset - Clears dirty if true, untouched if not
**
** Outputs:
**              the dirty bit
**              clears the dirty bit in the pte if requested
**
**      Note:
**              The RC bits are merged into the global physical entry
-----------------------------------------------------------------------*/

boolean_t vmm_get_page_dirty_flag(
        thread_act_t                            act,
        vmm_thread_index_t      index,
        vm_offset_t             va,
        unsigned int            reset)
{
        vmmCntrlEntry           *CEntry;
        register mapping        *mpv, *mp;
        unsigned int            RC;

        CEntry = vmm_get_entry(act, index);                                             /* Convert index to entry */            
        if (CEntry == NULL) return 1;                                                   /* Either this isn't vmm thread or the index is bogus */
        
        mp = hw_lock_phys_vir(CEntry->vmmPmap->space, va);              /* Look up the mapping */
        if((unsigned int)mp & 1) {                                                              /* Did we timeout? */
                panic("vmm_get_page_dirty_flag: timeout locking physical entry for alternate virtual address (%08X)\n", va);    /* Yeah, scream about it! */
                return 1;                                                                                       /* Bad hair day, return dirty... */
        }
        if(!mp) return 1;                                                                               /* Not mapped, return dirty... */
        
        RC = hw_test_rc(mp, reset);                                                             /* Fetch the RC bits and clear if requested */  

        mpv = hw_cpv(mp);                                                                               /* Convert mapping block to virtual */
        hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);             /* We're done, unlock the physical entry */

        return (RC & 1);                                                                                /* Return the change bit */
}

/*-----------------------------------------------------------------------
** vmm_get_float_state
**
** This function causes the current floating point state to 
** be saved into the shared context area.  It also clears the
** vmmFloatCngd changed flag.
**
** Inputs:
**              act - pointer to current thread activation structure
**              index - index returned by vmm_init_context
**
** Outputs:
**              context saved
-----------------------------------------------------------------------*/

kern_return_t vmm_get_float_state(
        thread_act_t            act,
        vmm_thread_index_t      index)
{
        vmmCntrlEntry           *CEntry;
        vmmCntrlTable           *CTable;
        int                                     i;
        register struct savearea *sv;

        CEntry = vmm_get_entry(act, index);                             /* Convert index to entry */            
        if (CEntry == NULL) return KERN_FAILURE;                /* Either this isn't vmm thread or the index is bogus */
        
        act->mact.specFlags &= ~floatCng;                               /* Clear the special flag */
        CEntry->vmmContextKern->vmmStat &= ~vmmFloatCngd;       /* Clear the change indication */
        
        if(sv = (struct savearea *)CEntry->vmmFPU_pcb) {        /* Is there context yet? */
                bcopy((char *)&sv->save_fp0, (char *)&(CEntry->vmmContextKern->vmm_proc_state.ppcFPRs[0].d), sizeof(vmm_processor_state_t)); /* 32 registers plus status and pad */
                return KERN_SUCCESS;
        }

        CEntry->vmmContextKern->vmm_proc_state.ppcFPSCR.i[0] = 0;       /* Clear FPSCR */
        CEntry->vmmContextKern->vmm_proc_state.ppcFPSCR.i[1] = 0;       /* Clear FPSCR */

        for(i = 0; i < 32; i++) {                                       /* Initialize floating points */
                CEntry->vmmContextKern->vmm_proc_state.ppcFPRs[i].d = FloatInit;        /* Initial value */
        }

        return KERN_SUCCESS;
}

/*-----------------------------------------------------------------------
** vmm_get_vector_state
**
** This function causes the current vector state to 
** be saved into the shared context area.  It also clears the
** vmmVectorCngd changed flag.
**
** Inputs:
**              act - pointer to current thread activation structure
**              index - index returned by vmm_init_context
**
** Outputs:
**              context saved
-----------------------------------------------------------------------*/

kern_return_t vmm_get_vector_state(
        thread_act_t            act,
        vmm_thread_index_t      index)
{
        vmmCntrlEntry           *CEntry;
        vmmCntrlTable           *CTable;
        int                                     i, j;
        unsigned int            vrvalidwrk;
        register struct savearea *sv;

        CEntry = vmm_get_entry(act, index);                             /* Convert index to entry */            
        if (CEntry == NULL) return KERN_FAILURE;                /* Either this isn't vmm thread or the index is bogus */
        
        act->mact.specFlags &= ~vectorCng;                              /* Clear the special flag */
        CEntry->vmmContextKern->vmmStat &= ~vmmVectCngd;        /* Clear the change indication */
        
        if(sv = (savearea *)CEntry->vmmVMX_pcb) {                                       /* Is there context yet? */

                vrvalidwrk = sv->save_vrvalid;                          /* Get the valid flags */

                for(j=0; j < 4; j++) {                                          /* Set value for vscr */
                        CEntry->vmmContextKern->vmm_proc_state.ppcVSCR.i[j] = sv->save_vscr[j];
                }
                
                for(i = 0; i < 32; i++) {                                       /* Copy the saved registers and invalidate the others */
                        if(vrvalidwrk & 0x80000000) {                   /* Do we have a valid value here? */
                                for(j = 0; j < 4; j++) {                        /* If so, copy it over */
                                        CEntry->vmmContextKern->vmm_proc_state.ppcVRs[i].i[j] = ((unsigned int *)&(sv->save_vr0))[(i * 4) + j];
                                }
                        }
                        else {
                                for(j = 0; j < 4; j++) {                        /* Otherwise set to empty value */
                                        CEntry->vmmContextKern->vmm_proc_state.ppcVRs[i].i[j] = QNaNbarbarian[j];
                                }
                        }
                        
                        vrvalidwrk = vrvalidwrk << 1;                   /* Shift over to the next */
                        
                }

                return KERN_SUCCESS;
        }

        for(j = 0; j < 4; j++) {                                                /* Initialize vscr to java mode */
                CEntry->vmmContextKern->vmm_proc_state.ppcVSCR.i[j] = 0;        /* Initial value */
        }

        for(i = 0; i < 32; i++) {                                               /* Initialize vector registers */
                for(j=0; j < 4; j++) {                                          /* Do words */
                        CEntry->vmmContextKern->vmm_proc_state.ppcVRs[i].i[j] = QNaNbarbarian[j];               /* Initial value */
                }
        }

        return KERN_SUCCESS;
}

/*-----------------------------------------------------------------------
** vmm_set_timer
**
** This function causes a timer (in AbsoluteTime) for a specific time
** to be set  It also clears the vmmTimerPop flag if the timer is actually 
** set, it is cleared otherwise.
**
** A timer is cleared by setting setting the time to 0. This will clear
** the vmmTimerPop bit. Simply setting the timer to earlier than the
** current time clears the internal timer request, but leaves the
** vmmTimerPop flag set.
** 
**
** Inputs:
**              act - pointer to current thread activation structure
**              index - index returned by vmm_init_context
**              timerhi - high order word of AbsoluteTime to pop
**              timerlo - low order word of AbsoluteTime to pop
**
** Outputs:
**              timer set, vmmTimerPop cleared
-----------------------------------------------------------------------*/

kern_return_t vmm_set_timer(
        thread_act_t            act,
        vmm_thread_index_t      index,
        unsigned int            timerhi, 
        unsigned int            timerlo)
{
        vmmCntrlEntry           *CEntry;
                
        CEntry = vmm_get_entry(act, index);                             /* Convert index to entry */            
        if (CEntry == NULL) return KERN_FAILURE;                /* Either this isn't vmm thread or the index is bogus */
        
        CEntry->vmmTimer.hi = timerhi;                                  /* Set the high order part */
        CEntry->vmmTimer.lo = timerlo;                                  /* Set the low order part */
        
        vmm_timer_pop(act);                                                             /* Go adjust all of the timer stuff */
        return KERN_SUCCESS;                                                    /* Leave now... */
}


/*-----------------------------------------------------------------------
** vmm_get_timer
**
** This function causes the timer for a specified VM to be
** returned in return_params[0] and return_params[1].
** 
**
** Inputs:
**              act - pointer to current thread activation structure
**              index - index returned by vmm_init_context
**
** Outputs:
**              Timer value set in return_params[0] and return_params[1].
**              Set to 0 if timer is not set.
-----------------------------------------------------------------------*/

kern_return_t vmm_get_timer(
        thread_act_t            act,
        vmm_thread_index_t      index)
{
        vmmCntrlEntry           *CEntry;
        vmmCntrlTable           *CTable;

        CEntry = vmm_get_entry(act, index);                             /* Convert index to entry */            
        if (CEntry == NULL) return KERN_FAILURE;                /* Either this isn't vmm thread or the index is bogus */

        CEntry->vmmContextKern->return_params[0] = CEntry->vmmTimer.hi; /* Return the last timer value */
        CEntry->vmmContextKern->return_params[1] = CEntry->vmmTimer.lo; /* Return the last timer value */
        
        return KERN_SUCCESS;
}



/*-----------------------------------------------------------------------
** vmm_timer_pop
**
** This function causes all timers in the array of VMs to be updated.
** All appropriate flags are set or reset.  If a VM is currently
** running and its timer expired, it is intercepted.
**
** The qactTimer value is set to the lowest unexpired timer.  It is
** zeroed if all timers are expired or have been reset.
**
** Inputs:
**              act - pointer to current thread activation structure
**
** Outputs:
**              timers set, vmmTimerPop cleared or set
-----------------------------------------------------------------------*/

void vmm_timer_pop(
        thread_act_t            act)
{
        vmmCntrlEntry           *CEntry;
        vmmCntrlTable           *CTable;
        int                                     cvi, any;
        AbsoluteTime            now, soonest;
        savearea                        *sv;
                
        if(!((unsigned int)act->mact.vmmControl & 0xFFFFFFFE)) {        /* Are there any virtual machines? */
                panic("vmm_timer_pop: No virtual machines defined; act = %08X\n", act);
        }

        soonest.hi = 0xFFFFFFFF;                                                /* Max time */
        soonest.lo = 0xFFFFFFFF;                                                /* Max time */

        clock_get_uptime((AbsoluteTime *)&now);                 /* What time is it? */
        
        CTable = act->mact.vmmControl;                                  /* Make this easier */  
        any = 0;                                                                                /* Haven't found a running unexpired timer yet */
        
        for(cvi = 0; cvi < kVmmMaxContextsPerThread; cvi++) {   /* Cycle through all and check time now */

                if(!(CTable->vmmc[cvi].vmmFlags & vmmInUse)) continue;  /* Do not check if the entry is empty */
                
                if(!(CTable->vmmc[cvi].vmmTimer.hi | CTable->vmmc[cvi].vmmTimer.hi)) {  /* Is the timer reset? */
                        CTable->vmmc[cvi].vmmFlags &= ~vmmTimerPop;                     /* Clear timer popped */
                        CTable->vmmc[cvi].vmmContextKern->vmmStat &= ~vmmTimerPop;      /* Clear timer popped */
                        continue;                                                               /* Check next */
                }

                if (CMP_ABSOLUTETIME(&CTable->vmmc[cvi].vmmTimer, &now) <= 0) {
                        CTable->vmmc[cvi].vmmFlags |= vmmTimerPop;      /* Set timer popped here */
                        CTable->vmmc[cvi].vmmContextKern->vmmStat |= vmmTimerPop;       /* Set timer popped here */
                        if((unsigned int)&CTable->vmmc[cvi] == (unsigned int)act->mact.vmmCEntry) {     /* Is this the running VM? */
                                sv = (savearea *)find_user_regs(act);   /* Get the user state registers */
                                if(!sv) {                                                       /* Did we find something? */
                                        panic("vmm_timer_pop: no user context; act = %08X\n", act);
                                }
                                sv->save_exception = T_IN_VAIN;         /* Indicate that this is a null exception */
                                vmm_force_exit(act, sv);                        /* Intercept a running VM */
                        }
                        continue;                                                               /* Check the rest */
                }
                else {                                                                          /* It hasn't popped yet */
                        CTable->vmmc[cvi].vmmFlags &= ~vmmTimerPop;     /* Set timer not popped here */
                        CTable->vmmc[cvi].vmmContextKern->vmmStat &= ~vmmTimerPop;      /* Set timer not popped here */
                }
                
                any = 1;                                                                        /* Show we found an active unexpired timer */
                
                if (CMP_ABSOLUTETIME(&CTable->vmmc[cvi].vmmTimer, &soonest) < 0) {
                        soonest.hi = CTable->vmmc[cvi].vmmTimer.hi;     /* Set high order lowest timer */
                        soonest.lo = CTable->vmmc[cvi].vmmTimer.lo;     /* Set low order lowest timer */
                }
        }
        
        if(any) {
                if (!(act->mact.qactTimer.hi | act->mact.qactTimer.lo) || 
                        (CMP_ABSOLUTETIME(&soonest, &act->mact.qactTimer) <= 0)) {
                        act->mact.qactTimer.hi = soonest.hi;    /* Set high order lowest timer */
                        act->mact.qactTimer.lo = soonest.lo;    /* Set low order lowest timer */
                }
        }

        return;
}