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/locks.h>
  30 #include <kern/task.h>
  31 #include <kern/thread.h>
  32 #include <libkern/OSAtomic.h>
  33 #include <vm/vm_pageout.h>
  34
  35 #if defined(__x86_64__) && CONFIG_VMX
  36 #include <i386/vmx/vmx_cpu.h>
  37 #endif
  38
  39 #include <kern/hv_support.h>
  40
  41 int hv_support_available = 0;
  42
  43 /* callbacks for tasks/threads with associated hv objects */
  44 hv_callbacks_t hv_callbacks = {
  45         .dispatch = NULL,               /* thread is being dispatched for execution */
  46         .preempt = NULL,                /* thread is being preempted */
  47         .suspend = NULL,                /* system is being suspended */
  48         .thread_destroy = NULL, /* thread is being destroyed */
  49         .task_destroy = NULL,   /* task is being destroyed */
  50         .volatile_state = NULL, /* thread state is becoming volatile */
  51 };
  52
  53 /* trap tables for hv_*_trap syscalls */
  54 static hv_trap_table_t hv_trap_table[] = {
  55         [HV_TASK_TRAP] = {
  56                 .traps = NULL,
  57                 .trap_count = 0
  58         },
  59         [HV_THREAD_TRAP] = {
  60                 .traps = NULL,
  61                 .trap_count = 0
  62         }
  63 };
  64
  65 static int hv_callbacks_enabled = 0;
  66 static lck_grp_t *hv_support_lck_grp = NULL;
  67 static lck_mtx_t *hv_support_lck_mtx = NULL;
  68
  69 /* hv_support boot initialization */
  70 void
  71 hv_support_init(void) {
  72 #if defined(__x86_64__) && CONFIG_VMX
  73         hv_support_available = vmx_hv_support();
  74 #endif
  75
  76         hv_support_lck_grp = lck_grp_alloc_init("hv_support", LCK_GRP_ATTR_NULL);
  77         assert(hv_support_lck_grp);
  78
  79         hv_support_lck_mtx = lck_mtx_alloc_init(hv_support_lck_grp, LCK_ATTR_NULL);
  80         assert(hv_support_lck_mtx);
  81 }
  82
  83 /* returns true if hv_support is available on this machine */
  84 int
  85 hv_get_support(void) {
  86         return hv_support_available;
  87 }
  88
  89 /* associate an hv object with the current task */
  90 void
  91 hv_set_task_target(void *target) {
  92         current_task()->hv_task_target = target;
  93 }
  94
  95 /* associate an hv object with the current thread */
  96 void
  97 hv_set_thread_target(void *target) {
  98         current_thread()->hv_thread_target = target;
  99 }
 100
 101 /* get hv object associated with the current task */
 102 void*
 103 hv_get_task_target(void) {
 104         return current_task()->hv_task_target;
 105 }
 106
 107 /* get hv object associated with the current thread */
 108 void*
 109 hv_get_thread_target(void) {
 110         return current_thread()->hv_thread_target;
 111 }
 112
 113 /* test if a given thread state may be volatile between dispatch
 114    and preemption */
 115 int
 116 hv_get_volatile_state(hv_volatile_state_t state) {
 117         int is_volatile = 0;
 118
 119 #if (defined(__x86_64__))
 120         if (state == HV_DEBUG_STATE) {
 121                 is_volatile = (current_thread()->machine.ids != NULL);
 122         }
 123 #endif
 124
 125         return is_volatile;
 126 }
 127
 128 /* register a list of trap handlers for the hv_*_trap syscalls */
 129 kern_return_t
 130 hv_set_traps(hv_trap_type_t trap_type, const hv_trap_t *traps,
 131         unsigned trap_count)
 132 {
 133         hv_trap_table_t *trap_table = &hv_trap_table[trap_type];
 134         kern_return_t kr = KERN_FAILURE;
 135
 136         lck_mtx_lock(hv_support_lck_mtx);
 137         if (trap_table->trap_count == 0) {
 138                 trap_table->traps = traps;
 139                 OSMemoryBarrier();
 140                 trap_table->trap_count = trap_count;
 141                 kr = KERN_SUCCESS;
 142         }
 143         lck_mtx_unlock(hv_support_lck_mtx);
 144
 145         return kr;
 146 }
 147
 148 /* release hv_*_trap traps */
 149 void
 150 hv_release_traps(hv_trap_type_t trap_type) {
 151         hv_trap_table_t *trap_table = &hv_trap_table[trap_type];
 152
 153         lck_mtx_lock(hv_support_lck_mtx);
 154         trap_table->trap_count = 0;
 155         OSMemoryBarrier();
 156         trap_table->traps = NULL;
 157         lck_mtx_unlock(hv_support_lck_mtx);
 158 }
 159
 160 /* register callbacks for certain task/thread events for tasks/threads with
 161    associated hv objects */
 162 kern_return_t
 163 hv_set_callbacks(hv_callbacks_t callbacks) {
 164         kern_return_t kr = KERN_FAILURE;
 165
 166         lck_mtx_lock(hv_support_lck_mtx);
 167         if (hv_callbacks_enabled == 0) {
 168                 hv_callbacks = callbacks;
 169                 hv_callbacks_enabled = 1;
 170                 kr = KERN_SUCCESS;
 171         }
 172         lck_mtx_unlock(hv_support_lck_mtx);
 173
 174         return kr;
 175 }
 176
 177 /* release callbacks for task/thread events */
 178 void
 179 hv_release_callbacks(void) {
 180         lck_mtx_lock(hv_support_lck_mtx);
 181         hv_callbacks = (hv_callbacks_t) {
 182                 .dispatch = NULL,
 183                 .preempt = NULL,
 184                 .suspend = NULL,
 185                 .thread_destroy = NULL,
 186                 .task_destroy = NULL,
 187                 .volatile_state = NULL,
 188                 .memory_pressure = NULL
 189         };
 190
 191         hv_callbacks_enabled = 0;
 192         lck_mtx_unlock(hv_support_lck_mtx);
 193 }
 194
 195 /* system suspend notification */
 196 void
 197 hv_suspend(void) {
 198         if (hv_callbacks_enabled) {
 199                 hv_callbacks.suspend();
 200         }
 201 }
 202
 203 /* dispatch hv_task_trap/hv_thread_trap syscalls to trap handlers,
 204    fail for invalid index or absence of trap handlers, trap handler is
 205    responsible for validating targets */
 206 #define HV_TRAP_DISPATCH(type, index, target, argument)\
 207         ((__probable(index < hv_trap_table[type].trap_count)) ? \
 208                 hv_trap_table[type].traps[index](target, argument) \
 209                         : KERN_INVALID_ARGUMENT)
 210
 211 kern_return_t hv_task_trap(uint64_t index, uint64_t arg) {
 212         return HV_TRAP_DISPATCH(HV_TASK_TRAP, index, hv_get_task_target(), arg);
 213 }
 214
 215 kern_return_t hv_thread_trap(uint64_t index, uint64_t arg) {
 216         return HV_TRAP_DISPATCH(HV_THREAD_TRAP, index, hv_get_thread_target(), arg);
 217 }