sys/kern/sys_vmm.c

   1 /*
   2  * Copyright (c) 2013 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Mihai Carabas <mihai.carabas@gmail.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/sysproto.h>
  38 #include <sys/proc.h>
  39 #include <sys/user.h>
  40 #include <sys/wait.h>
  41 #include <sys/vmm.h>
  42
  43 #include <sys/thread2.h>
  44 #include <sys/spinlock2.h>
  45
  46 #include <machine/cpu.h>
  47 #include <machine/vmm.h>
  48
  49 /*
  50  * vmm guest system call:
  51  * - init the calling thread structure
  52  * - prepare for running in non-root mode
  53  */
  54 int
  55 sys_vmm_guest_ctl(struct vmm_guest_ctl_args *uap)
  56 {
  57         int error = 0;
  58         struct vmm_guest_options options;
  59         struct trapframe *tf = uap->sysmsg_frame;
  60         unsigned long stack_limit = USRSTACK;
  61         unsigned char stack_page[PAGE_SIZE];
  62
  63         clear_quickret();
  64
  65         switch (uap->op) {
  66                 case VMM_GUEST_RUN:
  67                         error = copyin(uap->options, &options,
  68                             sizeof(struct vmm_guest_options));
  69                         if (error) {
  70                                 kprintf("%s: error copyin vmm_guest_options\n",
  71                                     __func__);
  72                                 goto out;
  73                         }
  74
  75                         while(stack_limit > tf->tf_sp) {
  76                                 stack_limit -= PAGE_SIZE;
  77                                 options.new_stack -= PAGE_SIZE;
  78
  79                                 error = copyin((const void *)stack_limit,
  80                                     (void *)stack_page, PAGE_SIZE);
  81                                 if (error) {
  82                                         kprintf("%s: error copyin stack\n",
  83                                             __func__);
  84                                         goto out;
  85                                 }
  86
  87                                 error = copyout((const void *)stack_page,
  88                                     (void *)options.new_stack, PAGE_SIZE);
  89                                 if (error) {
  90                                         kprintf("%s: error copyout stack\n",
  91                                             __func__);
  92                                         goto out;
  93                                 }
  94                         }
  95
  96                         bcopy(tf, &options.tf, sizeof(struct trapframe));
  97
  98                         error = vmm_vminit(&options);
  99                         if (error) {
 100                                 if (error == ENODEV) {
 101                                         kprintf("%s: vmm_vminit failed - "
 102                                             "no VMM available \n", __func__);
 103                                         goto out;
 104                                 }
 105                                 kprintf("%s: vmm_vminit failed\n", __func__);
 106                                 goto out_exit;
 107                         }
 108
 109                         generic_lwp_return(curthread->td_lwp, tf);
 110
 111                         error = vmm_vmrun();
 112
 113                         break;
 114                 default:
 115                         kprintf("%s: INVALID op\n", __func__);
 116                         error = EINVAL;
 117                         goto out;
 118         }
 119 out_exit:
 120         exit1(W_EXITCODE(error, 0));
 121 out:
 122         return (error);
 123 }
 124
 125 static void
 126 vmm_exit_vmm(void *dummy __unused)
 127 {
 128 }
 129
 130 int
 131 sys_vmm_guest_sync_addr(struct vmm_guest_sync_addr_args *uap)
 132 {
 133         int error = 0;
 134         cpulock_t olock;
 135         cpulock_t nlock;
 136         cpumask_t mask;
 137         long val;
 138         struct proc *p = curproc;
 139
 140         if (p->p_vmm == NULL)
 141                 return ENOSYS;
 142
 143         crit_enter_id("vmm_inval");
 144
 145         /*
 146          * Acquire CPULOCK_EXCL, spin while we wait.
 147          */
 148         KKASSERT(CPUMASK_TESTMASK(p->p_vmm_cpumask, mycpu->gd_cpumask) == 0);
 149         for (;;) {
 150                 olock = p->p_vmm_cpulock & ~CPULOCK_EXCL;
 151                 cpu_ccfence();
 152                 nlock = olock | CPULOCK_EXCL;
 153                 if (atomic_cmpset_int(&p->p_vmm_cpulock, olock, nlock))
 154                         break;
 155                 lwkt_process_ipiq();
 156                 cpu_pause();
 157         }
 158
 159         /*
 160          * Wait for other cpu's to exit VMM mode (for this vkernel).  No
 161          * new cpus will enter VMM mode while we hold the lock.  New waiters
 162          * may turn-up though so the wakeup() later on has to be
 163          * unconditional.
 164          *
 165          * We must test on p_vmm_cpulock's counter, not the mask, because
 166          * VMM entries will set the mask bit unconditionally first
 167          * (interlocking our IPI below) and then conditionally bump the
 168          * counter.
 169          */
 170         if (olock & CPULOCK_CNTMASK) {
 171                 mask = p->p_vmm_cpumask;
 172                 CPUMASK_ANDMASK(mask, mycpu->gd_other_cpus);
 173                 lwkt_send_ipiq_mask(mask, vmm_exit_vmm, NULL);
 174                 while (p->p_vmm_cpulock & CPULOCK_CNTMASK) {
 175                         lwkt_process_ipiq();
 176                         cpu_pause();
 177                 }
 178         }
 179
 180         /*
 181          * Make the requested modification, wakeup any waiters.
 182          */
 183         if (uap->srcaddr) {
 184                 copyin(uap->srcaddr, &val, sizeof(long));
 185                 copyout(&val, uap->dstaddr, sizeof(long));
 186         }
 187
 188         atomic_clear_int(&p->p_vmm_cpulock, CPULOCK_EXCL);
 189         wakeup(&p->p_vmm_cpulock);
 190
 191         crit_exit_id("vmm_inval");
 192
 193         return error;
 194 }