From eaee9424a120c289abc3eeeff331cb0d45efe971 Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Thu, 9 Jul 2015 14:13:25 +0200 Subject: 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. --- vm/vm_map.c | 15 +++++++++++++++ vm/vm_map.h | 1 + vm/vm_user.c | 27 ++++++++++++++++++++++++--- 3 files changed, 40 insertions(+), 3 deletions(-) (limited to 'vm') diff --git a/vm/vm_map.c b/vm/vm_map.c index 6b13724..ae3ce21 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 fc7730a..9b31f90 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 f7c87cc..8c7a5d8 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), -- cgit v1.2.3