xnu-344.49.tar.gz

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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The 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, QUIET ENJOYMENT 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 <kern/thread_act.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;
        }

        /* Make sure that the version requested is supported */
        version = save->save_r3;                                        /* Pick up passed in version */
        if (((version >> 16) < kVmmMinMajorVersion) || ((version >> 16) > (kVmmCurrentVersion >> 16))) {
                save->save_r3 = KERN_FAILURE;                   /* Return failure */
                return 1;
        }

        if((version & 0xFFFF) > kVmmCurMinorVersion) {  /* Check for valid minor */
                save->save_r3 = KERN_FAILURE;                   /* Return failure */
                return 1;
        }

        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, 
                VM_WIMG_USE_DEFAULT, 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].vmmContextPhys = (vmm_state_page_t *)conphys; /* Remember the state page physical addr */
        CTable->vmmc[cvi].vmmContextUser = vmm_user_state;              /* Remember user address of comm area */
        
        CTable->vmmc[cvi].vmmFacCtx.FPUsave = 0;        /* Clear facility context control */
        CTable->vmmc[cvi].vmmFacCtx.FPUlevel = 0;       /* Clear facility context control */
        CTable->vmmc[cvi].vmmFacCtx.FPUcpu = 0;         /* Clear facility context control */
        CTable->vmmc[cvi].vmmFacCtx.VMXsave = 0;        /* Clear facility context control */
        CTable->vmmc[cvi].vmmFacCtx.VMXlevel = 0;       /* Clear facility context control */
        CTable->vmmc[cvi].vmmFacCtx.VMXcpu = 0;         /* Clear facility context control */
        CTable->vmmc[cvi].vmmFacCtx.facAct = act;       /* Point back to the activation */

        hw_atomic_add((int *)&saveanchor.savetarget, 2);        /* Account for the number of extra saveareas we think we might "need" */

        if (!(act->map->pmap->vflags & pmapVMhost)) {
                simple_lock(&(act->map->pmap->lock));
                act->map->pmap->vflags |= pmapVMhost;
                simple_unlock(&(act->map->pmap->lock));
        }
        
        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((int *)&saveanchor.savetarget, 2);        /* We don't need these extra saveareas anymore */

        if(CEntry->vmmFacCtx.FPUsave) {                                 /* Is there any floating point context? */
                toss_live_fpu(&CEntry->vmmFacCtx);                      /* Get rid of any live context here */
                save_release((savearea *)CEntry->vmmFacCtx.FPUsave);    /* Release it */
        }

        if(CEntry->vmmFacCtx.VMXsave) {                                 /* Is there any vector context? */
                toss_live_vec(&CEntry->vmmFacCtx);                      /* Get rid of any live context here */
                save_release((savearea *)CEntry->vmmFacCtx.VMXsave);    /* 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->vmmFacCtx.FPUsave = 0;                                  /* Clear facility context control */
        CEntry->vmmFacCtx.FPUlevel = 0;                                 /* Clear facility context control */
        CEntry->vmmFacCtx.FPUcpu = 0;                                   /* Clear facility context control */
        CEntry->vmmFacCtx.VMXsave = 0;                                  /* Clear facility context control */
        CEntry->vmmFacCtx.VMXlevel = 0;                                 /* Clear facility context control */
        CEntry->vmmFacCtx.VMXcpu = 0;                                   /* Clear facility context control */
        CEntry->vmmFacCtx.facAct = 0;                                   /* Clear facility context control */
        
        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 = 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;
                }
                
                save->save_exception = kVmmBogusContext*4;      /* Indicate that this context is bogus now */
                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
**              ava   - virtual address within the alternate address
**                          space
**              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->physent) return KERN_FAILURE;  /* If there is no physical entry (e.g., I/O area), we won't map it */
                        
                        if(!(mpv->PTEr & 1)) break;                     /* If we are writable go ahead and map it... */
        
                        hw_unlock_bit((unsigned int *)&mpv->physent->phys_link, PHYS_LOCK);     /* Unlock the map before we try to fault the write bit on */
                }

                ml_set_interrupts_enabled(TRUE);                /* Enable interruptions */
                ret = vm_fault(map, trunc_page(cva), VM_PROT_READ | VM_PROT_WRITE, FALSE, NULL, 0);     /* 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... */
        }

/*
 *      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 */
        if (!((per_proc_info[cpu_number()].spcFlags) & FamVMmode))
                CEntry->vmmFlags |= vmmMapDone;                         /* Set that we did a map operation */

        return KERN_SUCCESS;
}


/*-----------------------------------------------------------------------
** vmm_map_execute
**
** This function maps a page from within the client's logical
** address space into the alternate address space of the
** Virtual Machine Monitor context and then directly starts executing.
**
**      See description of vmm_map_page for details. 
**
** Outputs:
**              Normal exit is to run the VM.  Abnormal exit is triggered via a 
**              non-KERN_SUCCESS return from vmm_map_page or later during the 
**              attempt to transition into the VM. 
-----------------------------------------------------------------------*/

vmm_return_code_t vmm_map_execute(
        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;

        CEntry = vmm_get_entry(act, index);                     /* Get and validate the index */

        if (CEntry == NULL) return kVmmBogusContext;    /* Return bogus context */
        
        if (((per_proc_info[cpu_number()].spcFlags) & FamVMmode) && (CEntry != act->mact.vmmCEntry))
                return kVmmBogusContext;                        /* Yes, invalid index in Fam */
        
        ret = vmm_map_page(act, index, cva, ava, prot); /* Go try to map the page on in */
        
        if(ret == KERN_SUCCESS) {
                CEntry->vmmFlags |= vmmMapDone;                 /* Set that we did a map operation */
                vmm_execute_vm(act, index);                             /* Return was ok, launch the VM */
        }
        
        return kVmmInvalidAddress;                                      /* We had trouble mapping in the page */        
        
}

/*-----------------------------------------------------------------------
** vmm_map_list
**
** This function maps a list of pages into the alternate's logical
** address space.
**
** Inputs:
**              act   - pointer to current thread activation
**              index - index of vmm state for this page
**              count - number of pages to release
**              vmcpComm in the comm page contains up to kVmmMaxMapPages to map
**
** Outputs:
**              kernel return code indicating success or failure
**              KERN_FAILURE is returned if kVmmMaxUnmapPages is exceeded
**              or the vmm_map_page call fails.
-----------------------------------------------------------------------*/

kern_return_t vmm_map_list(
        thread_act_t            act,
        vmm_thread_index_t      index,
        unsigned int            cnt)
{
        vmmCntrlEntry           *CEntry;
        boolean_t                       ret;
        unsigned int            i;
        vmmMapList                      *lst;
        vm_offset_t             cva;
        vm_offset_t             ava;
        vm_prot_t                       prot;

        CEntry = vmm_get_entry(act, index);                             /* Get and validate the index */
        if (CEntry == NULL)return -1;                                   /* No good, failure... */
        
        if(cnt > kVmmMaxMapPages) return KERN_FAILURE;  /* They tried to map too many */
        if(!cnt) return KERN_SUCCESS;                                   /* If they said none, we're done... */
        
        lst = (vmmMapList *)(&((vmm_comm_page_t *)CEntry->vmmContextKern)->vmcpComm[0]);        /* Point to the first entry */
        
        for(i = 0; i < cnt; i++) {                                              /* Step and release all pages in list */
                cva = lst[i].vmlva;                                                     /* Get the actual address */    
                ava = lst[i].vmlava & -vmlFlgs;                         /* Get the alternate address */ 
                prot = lst[i].vmlava & vmlProt;                         /* Get the protection bits */   
                ret = vmm_map_page(act, index, cva, ava, prot); /* Go try to map the page on in */
                if(ret != KERN_SUCCESS) return KERN_FAILURE;    /* Bail if any error */
        }
        
        return KERN_SUCCESS     ;                                                       /* Return... */
}

/*-----------------------------------------------------------------------
** 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_list
**
** This function unmaps a list of pages from the alternate's logical
** address space.
**
** Inputs:
**              act   - pointer to current thread activation
**              index - index of vmm state for this page
**              count - number of pages to release
**              vmcpComm in the comm page contains up to kVmmMaxUnmapPages to unmap
**
** Outputs:
**              kernel return code indicating success or failure
**              KERN_FAILURE is returned if kVmmMaxUnmapPages is exceeded
-----------------------------------------------------------------------*/

kern_return_t vmm_unmap_list(
        thread_act_t            act,
        vmm_thread_index_t      index,
        unsigned int            cnt)
{
        vmmCntrlEntry           *CEntry;
        boolean_t                       ret;
        kern_return_t           kern_result = KERN_SUCCESS;
        unsigned int            *pgaddr, i;

        CEntry = vmm_get_entry(act, index);                                             /* Get and validate the index */
        if (CEntry == NULL)return -1;                                                   /* No good, failure... */
        
        if(cnt > kVmmMaxUnmapPages) return KERN_FAILURE;                /* They tried to unmap too many */
        if(!cnt) return KERN_SUCCESS;                                                   /* If they said none, we're done... */
        
        pgaddr = &((vmm_comm_page_t *)CEntry->vmmContextKern)->vmcpComm[0];     /* Point to the first entry */
        
        for(i = 0; i < cnt; i++) {                                                              /* Step and release all pages in list */
        
                (void)mapping_remove(CEntry->vmmPmap, pgaddr[i]);       /* Toss the mapping */
        }
        
        return KERN_SUCCESS     ;                                                                       /* 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_protect_page
**
** This function sets the protection bits of a mapped page
**
** Inputs:
**              act   - pointer to current thread activation
**              index - index of vmm state for this page
**              va    - virtual address within the vmm's address
**                          space
**              prot  - Protection flags
**
** Outputs:
**              none
**              Protection bits of the mapping are modifed
**
-----------------------------------------------------------------------*/

kern_return_t vmm_protect_page(
        thread_act_t            act,
        vmm_thread_index_t      index,
        vm_offset_t             va,
        vm_prot_t                       prot)
{
        vmmCntrlEntry           *CEntry;
        register mapping        *mpv, *mp;
        unsigned int            RC;

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

        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 */

        CEntry->vmmLastMap = va & -PAGE_SIZE;                                   /* Remember the last mapping we changed */
        if (!((per_proc_info[cpu_number()].spcFlags) & FamVMmode))
                CEntry->vmmFlags |= vmmMapDone;                                         /* Set that we did a map operation */

        return KERN_SUCCESS;                                                                    /* Return */
}


/*-----------------------------------------------------------------------
** vmm_protect_execute
**
** This function sets the protection bits of a mapped page
** and then directly starts executing.
**
**      See description of vmm_protect_page for details. 
**
** Outputs:
**              Normal exit is to run the VM.  Abnormal exit is triggered via a 
**              non-KERN_SUCCESS return from vmm_map_page or later during the 
**              attempt to transition into the VM. 
-----------------------------------------------------------------------*/

vmm_return_code_t vmm_protect_execute(
        thread_act_t            act,
        vmm_thread_index_t      index,
        vm_offset_t             va,
        vm_prot_t                       prot)
{
        kern_return_t           ret;
        vmmCntrlEntry           *CEntry;

        CEntry = vmm_get_entry(act, index);                                     /* Get and validate the index */

        if (CEntry == NULL) return kVmmBogusContext;            /* Return bogus context */
        
        if (((per_proc_info[cpu_number()].spcFlags) & FamVMmode) && (CEntry != act->mact.vmmCEntry))
                return kVmmBogusContext;                        /* Yes, invalid index in Fam */
        
        ret = vmm_protect_page(act, index, va, prot);           /* Go try to change access */
        
        if(ret == KERN_SUCCESS) {
                CEntry->vmmFlags |= vmmMapDone;                                 /* Set that we did a map operation */
                vmm_execute_vm(act, index);                                             /* Return was ok, launch the VM */
        }
        
        return kVmmInvalidAddress;                                                      /* We had trouble of some kind (shouldn't happen) */    
        
}


/*-----------------------------------------------------------------------
** 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_fpu *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 */

        fpu_save(&CEntry->vmmFacCtx);                                   /* Save context if live */

        CEntry->vmmContextKern->vmm_proc_state.ppcFPSCRshadow.i[0] = CEntry->vmmContextKern->vmm_proc_state.ppcFPSCR.i[0];      /* Copy FPSCR */
        CEntry->vmmContextKern->vmm_proc_state.ppcFPSCRshadow.i[1] = CEntry->vmmContextKern->vmm_proc_state.ppcFPSCR.i[1];      /* Copy FPSCR */
        
        if(sv = CEntry->vmmFacCtx.FPUsave) {                    /* Is there context yet? */
                bcopy((char *)&sv->save_fp0, (char *)&(CEntry->vmmContextKern->vmm_proc_state.ppcFPRs), 32 * 8); /* 32 registers */
                return KERN_SUCCESS;
        }


        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_vec *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 */

        vec_save(&CEntry->vmmFacCtx);                                   /* Save context if live */
        
        act->mact.specFlags &= ~vectorCng;                              /* Clear the special flag */
        CEntry->vmmContextKern->vmmStat &= ~vmmVectCngd;        /* Clear the change indication */
        
        for(j=0; j < 4; j++) {                                                  /* Set value for vscr */
                CEntry->vmmContextKern->vmm_proc_state.ppcVSCRshadow.i[j] = CEntry->vmmContextKern->vmm_proc_state.ppcVSCR.i[j];
        }

        if(sv = CEntry->vmmFacCtx.VMXsave) {                    /* Is there context yet? */

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

                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(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 = ((uint64_t)timerhi << 32) | timerlo;
        
        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 >> 32);    /* Return the last timer value */
        CEntry->vmmContextKern->return_params[1] = (uint32_t)CEntry->vmmTimer;  /* 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;
        uint64_t                        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 = 0xFFFFFFFFFFFFFFFFULL;                                /* Max time */

        clock_get_uptime(&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 == 0) {           /* 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 (CTable->vmmc[cvi].vmmTimer <= now) {
                        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 = 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 = kVmmReturnNull*4;  /* 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 (CTable->vmmc[cvi].vmmTimer < soonest)
                        soonest = CTable->vmmc[cvi].vmmTimer;
        }
        
        if(any) {
                if (act->mact.qactTimer == 0 || soonest <= act->mact.qactTimer)
                        act->mact.qactTimer = soonest;  /* Set lowest timer */
        }

        return;
}



/*-----------------------------------------------------------------------
** vmm_stop_vm
**
** This function prevents the specified VM(s) to from running.
** If any is currently executing, the execution is intercepted
** with a code of kVmmStopped.  Note that execution of the VM is
** blocked until a vmmExecuteVM is called with the start flag set to 1.
** This provides the ability for a thread to stop execution of a VM and
** insure that it will not be run until the emulator has processed the
** "virtual" interruption.
**
** Inputs:
**              vmmask - 32 bit mask corresponding to the VMs to put in stop state
**                               NOTE: if this mask is all 0s, any executing VM is intercepted with
*                        a kVmmStopped (but not marked stopped), otherwise this is a no-op. Also note that there
**                               note that there is a potential race here and the VM may not stop.
**
** Outputs:
**              kernel return code indicating success
**      or if no VMs are enabled, an invalid syscall exception.
-----------------------------------------------------------------------*/

int vmm_stop_vm(struct savearea *save)
{

        thread_act_t            act;
        vmmCntrlTable           *CTable;
        int                                     cvi, i;
    task_t                              task;
    thread_act_t                fact;
    unsigned int                vmmask;
    ReturnHandler               *stopapc;

        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 */
        act = 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? */
                        act = fact;                                                     /* Yeah... */
                        break;                                                          /* Bail the loop... */
                }
                fact = (thread_act_t)fact->thr_acts.next;       /* Go to the next one */
        }

        if(!((unsigned int)act)) {                                      /* See if we have VMMs yet */
                task_unlock(task);                                              /* No, unlock the task */
                ml_set_interrupts_enabled(FALSE);               /* Set back interruptions */
                return 0;                                                               /* Go generate a syscall exception */
        }

        act_lock_thread(act);                                           /* Make sure this stays 'round */
        task_unlock(task);                                                      /* Safe to release now */

        CTable = act->mact.vmmControl;                          /* Get the pointer to the table */
        
        if(!((unsigned int)CTable & -2)) {                      /* Are there any all the way up yet? */
                act_unlock_thread(act);                                 /* Unlock the activation */
                ml_set_interrupts_enabled(FALSE);               /* Set back interruptions */
                return 0;                                                               /* Go generate a syscall exception */
        }
        
        if(!(vmmask = save->save_r3)) {                         /* Get the stop mask and check if all zeros */
                act_unlock_thread(act);                                 /* Unlock the activation */
                ml_set_interrupts_enabled(FALSE);               /* Set back interruptions */
                save->save_r3 = KERN_SUCCESS;                   /* Set success */       
                return 1;                                                               /* Return... */
        }

        for(cvi = 0; cvi < kVmmMaxContextsPerThread; cvi++) {   /* Search slots */
                if((0x80000000 & vmmask) && (CTable->vmmc[cvi].vmmFlags & vmmInUse)) {  /* See if we need to stop and if it is in use */
                        hw_atomic_or(&CTable->vmmc[cvi].vmmFlags, vmmXStop);    /* Set this one to stop */
                }
                vmmask = vmmask << 1;                                   /* Slide mask over */
        }
        
        if(hw_compare_and_store(0, 1, &act->mact.emPendRupts)) {        /* See if there is already a stop pending and lock out others if not */
                act_unlock_thread(act);                                 /* Already one pending, unlock the activation */
                ml_set_interrupts_enabled(FALSE);               /* Set back interruptions */
                save->save_r3 = KERN_SUCCESS;                   /* Say we did it... */  
                return 1;                                                               /* Leave */
        }

        if(!(stopapc = (ReturnHandler *)kalloc(sizeof(ReturnHandler)))) {       /* Get a return handler control block */
                act->mact.emPendRupts = 0;                              /* No memory, say we have given up request */
                act_unlock_thread(act);                                 /* Unlock the activation */
                ml_set_interrupts_enabled(FALSE);               /* Set back interruptions */
                save->save_r3 = KERN_RESOURCE_SHORTAGE; /* No storage... */
                return 1;                                                               /* Return... */
        }

        ml_set_interrupts_enabled(FALSE);                       /* Disable interruptions for now */

        stopapc->handler = vmm_interrupt;                       /* Set interruption routine */

        stopapc->next = act->handlers;                          /* Put our interrupt at the start of the list */
        act->handlers = stopapc;                                        /* Point to us */

        act_set_apc(act);                                                       /* Set an APC AST */
        ml_set_interrupts_enabled(TRUE);                        /* Enable interruptions now */

        act_unlock_thread(act);                                         /* Unlock the activation */
        
        ml_set_interrupts_enabled(FALSE);                       /* Set back interruptions */
        save->save_r3 = KERN_SUCCESS;                           /* Hip, hip, horay... */        
        return 1;
}

/*-----------------------------------------------------------------------
** vmm_interrupt
**
** This function is executed asynchronously from an APC AST.
** It is to be used for anything that needs to interrupt a running VM.
** This include any kind of interruption generation (other than timer pop)
** or entering the stopped state.
**
** Inputs:
**              ReturnHandler *rh - the return handler control block as required by the APC.
**              thread_act_t act  - the activation
**
** Outputs:
**              Whatever needed to be done is done.
-----------------------------------------------------------------------*/

void vmm_interrupt(ReturnHandler *rh, thread_act_t act) {

        vmmCntrlTable           *CTable;
        savearea                        *sv;
        boolean_t                       inter;



        kfree((vm_offset_t)rh, sizeof(ReturnHandler));  /* Release the return handler block */
        
        inter  = ml_set_interrupts_enabled(FALSE);      /* Disable interruptions for now */

        act->mact.emPendRupts = 0;                                      /* Say that there are no more interrupts pending */
        CTable = act->mact.vmmControl;                          /* Get the pointer to the table */
        
        if(!((unsigned int)CTable & -2)) return;        /* Leave if we aren't doing VMs any more... */

        if(act->mact.vmmCEntry && (act->mact.vmmCEntry->vmmFlags & vmmXStop)) { /* Do we need to stop the running guy? */
                sv = find_user_regs(act);                               /* Get the user state registers */
                if(!sv) {                                                               /* Did we find something? */
                        panic("vmm_interrupt: no user context; act = %08X\n", act);
                }
                sv->save_exception = kVmmStopped*4;             /* Set a "stopped" exception */
                vmm_force_exit(act, sv);                                /* Intercept a running VM */
        }
        ml_set_interrupts_enabled(inter);                       /* Put interrupts back to what they were */

        return;
}