Allow non-privileged tasks to wire 64KiB task memory

* doc/mach.texi (vm_wire): Document that the host port does not have to be
privileged.
* include/mach/mach_hosts.defs (vm_wire): Use mach_port_t instead of
host_priv_t.
* vm/vm_map.h (vm_map): Add user_wired field.
* vm/vm_map.c (vm_map_setup): Initialize user_wired field to 0.
(vm_map_pageable_common, vm_map_entry_delete, vm_map_copy_overwrite,
vm_map_copyout_page_list, vm_map_copyin_page_list): When switching
user_wired_count field of entry between 0 and non-0, accumulate the
corresponding size into the user_wired field of map.
* vm/vm_user.c (vm_wire): Turn host parameter into port parameter, and
inline a version of convert_port_to_host_priv which records whether the host
port is privileged or not.  When it is not privileged, check whether
the additional amount to user_wired will overcome 64KiB.

3 files changed, 40 insertions, 3 deletions

diff --git a/vm/vm_map.c b/vm/vm_map.c
index 6b13724e..ae3ce21f 100644
--- a/vm/vm_map.c
+++ b/vm/vm_map.c
@@ -208,6 +208,7 @@ void vm_map_setup(
 	rbtree_init(&map->hdr.tree);
 
 	map->size = 0;
+	map->user_wired = 0;
 	map->ref_count = 1;
 	map->pmap = pmap;
 	map->min_offset = min;
@@ -1409,7 +1410,10 @@ kern_return_t vm_map_pageable_common(
 
 		    if (user_wire) {
 			if (--(entry->user_wired_count) == 0)
+			{
+			    map->user_wired -= entry->vme_end - entry->vme_start;
 			    entry->wired_count--;
+			}
 		    }
 		    else {
 			entry->wired_count--;
@@ -1486,7 +1490,10 @@ kern_return_t vm_map_pageable_common(
 
 		    if (user_wire) {
 			if ((entry->user_wired_count)++ == 0)
+			{
+			    map->user_wired += entry->vme_end - entry->vme_start;
 			    entry->wired_count++;
+			}
 		    }
 		    else {
 			entry->wired_count++;
@@ -1512,6 +1519,7 @@ kern_return_t vm_map_pageable_common(
 				(entry->vme_end > start)) {
 				    if (user_wire) {
 					if (--(entry->user_wired_count) == 0)
+					    map->user_wired -= entry->vme_end - entry->vme_start;
 					    entry->wired_count--;
 				    }
 				    else {
@@ -1627,6 +1635,8 @@ void vm_map_entry_delete(
 	    if (entry->wired_count != 0) {
 		vm_fault_unwire(map, entry);
 		entry->wired_count = 0;
+		if (entry->user_wired_count)
+		    map->user_wired -= entry->vme_end - entry->vme_start;
 		entry->user_wired_count = 0;
 	    }
 
@@ -2274,6 +2284,8 @@ start_pass_1:
 			entry->offset = copy_entry->offset;
 			entry->needs_copy = copy_entry->needs_copy;
 			entry->wired_count = 0;
+			if (entry->user_wired_count)
+			    dst_map->user_wired -= entry->vme_end - entry->vme_start;
 			entry->user_wired_count = 0;
 
 			vm_map_copy_entry_unlink(copy, copy_entry);
@@ -2869,6 +2881,7 @@ create_object:
 
 	if (must_wire) {
 		entry->wired_count = 1;
+		dst_map->user_wired += entry->vme_end - entry->vme_start;
 		entry->user_wired_count = 1;
 	} else {
 		entry->wired_count = 0;
@@ -3954,6 +3967,8 @@ retry:
 
 					assert(src_entry->wired_count > 0);
 				        src_entry->wired_count = 0;
+					if (src_entry->user_wired_count)
+					    src_map->user_wired -= src_entry->vme_end - src_entry->vme_start;
 				        src_entry->user_wired_count = 0;
 					unwire_end = src_entry->vme_end;
 				        pmap_pageable(vm_map_pmap(src_map),
diff --git a/vm/vm_map.h b/vm/vm_map.h
index fc7730a2..9b31f90a 100644
--- a/vm/vm_map.h
+++ b/vm/vm_map.h
@@ -170,6 +170,7 @@ struct vm_map {
 #define max_offset		hdr.links.end	/* end of range */
 	pmap_t			pmap;		/* Physical map */
 	vm_size_t		size;		/* virtual size */
+	vm_size_t		user_wired;	/* wired by user size */
 	int			ref_count;	/* Reference count */
 	decl_simple_lock_data(,	ref_lock)	/* Lock for ref_count field */
 	vm_map_entry_t		hint;		/* hint for quick lookups */
diff --git a/vm/vm_user.c b/vm/vm_user.c
index f7c87cc0..8c7a5d8f 100644
--- a/vm/vm_user.c
+++ b/vm/vm_user.c
@@ -405,15 +405,32 @@ kern_return_t vm_map(
  *
  *	[ To unwire the pages, specify VM_PROT_NONE. ]
  */
-kern_return_t vm_wire(host, map, start, size, access)
-	const host_t		host;
+kern_return_t vm_wire(port, map, start, size, access)
+	const ipc_port_t	port;
 	vm_map_t		map;
 	vm_offset_t		start;
 	vm_size_t		size;
 	vm_prot_t		access;
 {
-	if (host == HOST_NULL)
+	host_t host;
+	boolean_t priv;
+
+	if (!IP_VALID(port))
+		return KERN_INVALID_HOST;
+
+	ip_lock(port);
+	if (!ip_active(port) ||
+		  (ip_kotype(port) != IKOT_HOST_PRIV
+		&& ip_kotype(port) != IKOT_HOST))
+	{
+		ip_unlock(port);
 		return KERN_INVALID_HOST;
+	}
+
+	priv = ip_kotype(port) == IKOT_HOST_PRIV;
+	ip_unlock(port);
+
+	host = (host_t) port->ip_kobject;
 
 	if (map == VM_MAP_NULL)
 		return KERN_INVALID_TASK;
@@ -426,6 +443,10 @@ kern_return_t vm_wire(host, map, start, size, access)
 	if (projected_buffer_in_range(map, start, start+size))
 		return(KERN_INVALID_ARGUMENT);
 
+	/* TODO: make it tunable */
+	if (!priv && access != VM_PROT_NONE && map->user_wired + size > 65536)
+		return KERN_NO_ACCESS;
+
 	return vm_map_pageable_user(map,
 				    trunc_page(start),
 				    round_page(start+size),