osfmk/kern/hv_support.c

   1 /*
   2  * Copyright (c) 2013 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <kern/ast.h>
  30 #include <kern/locks.h>
  31 #include <kern/task.h>
  32 #include <kern/thread.h>
  33 #include <libkern/OSAtomic.h>
  34 #include <vm/vm_pageout.h>
  35
  36 #if defined(__x86_64__) && CONFIG_VMX
  37 #include <i386/vmx/vmx_cpu.h>
  38 #endif
  39
  40 #include <kern/hv_support.h>
  41
  42 int hv_support_available = 0;
  43
  44 /* callbacks for tasks/threads with associated hv objects */
  45 hv_callbacks_t hv_callbacks = {
  46         .dispatch = NULL,               /* thread is being dispatched for execution */
  47         .preempt = NULL,                /* thread is being preempted */
  48         .suspend = NULL,                /* system is being suspended */
  49         .thread_destroy = NULL, /* thread is being destroyed */
  50         .task_destroy = NULL,   /* task is being destroyed */
  51         .volatile_state = NULL, /* thread state is becoming volatile */
  52 };
  53
  54 /* trap tables for hv_*_trap syscalls */
  55 static hv_trap_table_t hv_trap_table[] = {
  56         [HV_TASK_TRAP] = {
  57                 .traps = NULL,
  58                 .trap_count = 0
  59         },
  60         [HV_THREAD_TRAP] = {
  61                 .traps = NULL,
  62                 .trap_count = 0
  63         }
  64 };
  65
  66 static int hv_callbacks_enabled = 0;
  67 static lck_grp_t *hv_support_lck_grp = NULL;
  68 static lck_mtx_t *hv_support_lck_mtx = NULL;
  69
  70 /* hv_support boot initialization */
  71 void
  72 hv_support_init(void)
  73 {
  74 #if defined(__x86_64__) && CONFIG_VMX
  75         hv_support_available = vmx_hv_support();
  76 #endif
  77
  78         hv_support_lck_grp = lck_grp_alloc_init("hv_support", LCK_GRP_ATTR_NULL);
  79         assert(hv_support_lck_grp);
  80
  81         hv_support_lck_mtx = lck_mtx_alloc_init(hv_support_lck_grp, LCK_ATTR_NULL);
  82         assert(hv_support_lck_mtx);
  83 }
  84
  85 /* returns true if hv_support is available on this machine */
  86 int
  87 hv_get_support(void)
  88 {
  89         return hv_support_available;
  90 }
  91
  92 /* associate an hv object with the current task */
  93 void
  94 hv_set_task_target(void *target)
  95 {
  96         current_task()->hv_task_target = target;
  97 }
  98
  99 /* associate an hv object with the current thread */
 100 void
 101 hv_set_thread_target(void *target)
 102 {
 103         current_thread()->hv_thread_target = target;
 104 }
 105
 106 /* get hv object associated with the current task */
 107 void*
 108 hv_get_task_target(void)
 109 {
 110         return current_task()->hv_task_target;
 111 }
 112
 113 /* get hv object associated with the current thread */
 114 void*
 115 hv_get_thread_target(void)
 116 {
 117         return current_thread()->hv_thread_target;
 118 }
 119
 120 /* test if a given thread state may be volatile between dispatch
 121  *  and preemption */
 122 int
 123 hv_get_volatile_state(hv_volatile_state_t state)
 124 {
 125         int is_volatile = 0;
 126
 127 #if (defined(__x86_64__))
 128         if (state == HV_DEBUG_STATE) {
 129                 is_volatile = (current_thread()->machine.ids != NULL);
 130         }
 131 #endif
 132
 133         return is_volatile;
 134 }
 135
 136 /* register a list of trap handlers for the hv_*_trap syscalls */
 137 kern_return_t
 138 hv_set_traps(hv_trap_type_t trap_type, const hv_trap_t *traps,
 139     unsigned trap_count)
 140 {
 141         hv_trap_table_t *trap_table = &hv_trap_table[trap_type];
 142         kern_return_t kr = KERN_FAILURE;
 143
 144         lck_mtx_lock(hv_support_lck_mtx);
 145         if (trap_table->trap_count == 0) {
 146                 trap_table->traps = traps;
 147                 OSMemoryBarrier();
 148                 trap_table->trap_count = trap_count;
 149                 kr = KERN_SUCCESS;
 150         }
 151         lck_mtx_unlock(hv_support_lck_mtx);
 152
 153         return kr;
 154 }
 155
 156 /* release hv_*_trap traps */
 157 void
 158 hv_release_traps(hv_trap_type_t trap_type)
 159 {
 160         hv_trap_table_t *trap_table = &hv_trap_table[trap_type];
 161
 162         lck_mtx_lock(hv_support_lck_mtx);
 163         trap_table->trap_count = 0;
 164         OSMemoryBarrier();
 165         trap_table->traps = NULL;
 166         lck_mtx_unlock(hv_support_lck_mtx);
 167 }
 168
 169 /* register callbacks for certain task/thread events for tasks/threads with
 170  *  associated hv objects */
 171 kern_return_t
 172 hv_set_callbacks(hv_callbacks_t callbacks)
 173 {
 174         kern_return_t kr = KERN_FAILURE;
 175
 176         lck_mtx_lock(hv_support_lck_mtx);
 177         if (hv_callbacks_enabled == 0) {
 178                 hv_callbacks = callbacks;
 179                 hv_callbacks_enabled = 1;
 180                 kr = KERN_SUCCESS;
 181         }
 182         lck_mtx_unlock(hv_support_lck_mtx);
 183
 184         return kr;
 185 }
 186
 187 /* release callbacks for task/thread events */
 188 void
 189 hv_release_callbacks(void)
 190 {
 191         lck_mtx_lock(hv_support_lck_mtx);
 192         hv_callbacks = (hv_callbacks_t) {
 193                 .dispatch = NULL,
 194                 .preempt = NULL,
 195                 .suspend = NULL,
 196                 .thread_destroy = NULL,
 197                 .task_destroy = NULL,
 198                 .volatile_state = NULL,
 199                 .memory_pressure = NULL
 200         };
 201
 202         hv_callbacks_enabled = 0;
 203         lck_mtx_unlock(hv_support_lck_mtx);
 204 }
 205
 206 /* system suspend notification */
 207 void
 208 hv_suspend(void)
 209 {
 210         if (hv_callbacks_enabled) {
 211                 hv_callbacks.suspend();
 212         }
 213 }
 214
 215 /* dispatch hv_task_trap/hv_thread_trap syscalls to trap handlers,
 216  *  fail for invalid index or absence of trap handlers, trap handler is
 217  *  responsible for validating targets */
 218 #define HV_TRAP_DISPATCH(type, index, target, argument) \
 219         ((__probable(index < hv_trap_table[type].trap_count)) ? \
 220                 hv_trap_table[type].traps[index](target, argument) \
 221                         : KERN_INVALID_ARGUMENT)
 222
 223 kern_return_t
 224 hv_task_trap(uint64_t index, uint64_t arg)
 225 {
 226         return HV_TRAP_DISPATCH(HV_TASK_TRAP, index, hv_get_task_target(), arg);
 227 }
 228
 229 kern_return_t
 230 hv_thread_trap(uint64_t index, uint64_t arg)
 231 {
 232         return HV_TRAP_DISPATCH(HV_THREAD_TRAP, index, hv_get_thread_target(), arg);
 233 }
 234
 235 boolean_t
 236 hv_ast_pending(void)
 237 {
 238         return current_cpu_datap()->cpu_pending_ast & (AST_APC | AST_BSD);
 239 }