/* this will start the vm thread, and return when the thread has blocked,
* with the right info in vmctl. */
static void run_vmthread(struct vmctl *vmctl)
{
struct vm_trapframe *vm_tf;
if (!vm_thread) {
/* first time through, we make the vm thread. the_ball was already
* grabbed right after it was alloc'd. */
if (pthread_create(&vm_thread, NULL, run_vm, vmctl)) {
perror("pth_create");
exit(-1);
}
/* hack in our own handlers for some 2LS ops */
old_thread_refl = sched_ops->thread_refl_fault;
sched_ops->thread_refl_fault = vmm_thread_refl_fault;
} else {
copy_vmctl_to_vmtf(vmctl, &vm_thread->uthread.u_ctx.tf.vm_tf);
uth_mutex_lock(the_ball); /* grab it for the vm_thread */
uthread_runnable((struct uthread*)vm_thread);
}
uth_mutex_lock(the_ball);
/* We woke due to a vm exit. Need to unlock for the next time we're run */
uth_mutex_unlock(the_ball);
/* the vm stopped. we can do whatever we want before rerunning it. since
* we're controlling the uth, we need to handle its vmexits. we'll fill in
* the vmctl, since that's the current framework. */
copy_vmtf_to_vmctl(&vm_thread->uthread.u_ctx.tf.vm_tf, vmctl);
}
void uth_cond_wait(uth_cond_t *c, uth_mutex_t *t) {
if (!prv_active_thread) {
uth_init_main_thread();
}
// fprintf(stdout, "uth_cond_wait: active=%p\n", prv_active_thread);
prv_active_thread->next = c->waiters;
c->waiters = prv_active_thread;
uth_mutex_unlock(t);
uth_thread_block();
uth_mutex_lock(t);
}
static void vmm_thread_refl_fault(struct uthread *uth,
struct user_context *ctx)
{
struct pthread_tcb *pthread = (struct pthread_tcb*)uth;
/* Hack to call the original pth 2LS op */
if (!ctx->type == ROS_VM_CTX) {
old_thread_refl(uth, ctx);
return;
}
__pthread_generic_yield(pthread);
/* normally we'd handle the vmexit here. to work within the existing
* framework, we just wake the controller thread. It'll look at our ctx
* then make us runnable again */
pthread->state = PTH_BLK_MUTEX;
uth_mutex_unlock(the_ball); /* wake the run_vmthread */
}
/* Blocks a guest pcore / thread until it has an IRQ pending. Syncs with
* vmm_interrupt_guest(). */
static void sleep_til_irq(struct guest_thread *gth)
{
struct vmm_gpcore_init *gpci = gth_to_gpci(gth);
/* The invariant is that if an IRQ is posted, but not delivered, we will not
* sleep. Anyone who posts an IRQ must signal after setting it.
* vmm_interrupt_guest() does this. If we use alternate sources of IRQ
* posting, we'll need to revist this.
*
* Although vmm_interrupt_guest() only writes OUTSTANDING_NOTIF, it's
* possible that the hardware attempted to post the interrupt. In SDM
* parlance, the processor could have "recognized" the virtual IRQ, but not
* delivered it yet. This could happen if the guest had executed "sti", but
* not "hlt" yet. The IRQ was posted and recognized, but not delivered
* ("sti blocking"). Then the guest executes "hlt", and vmexits.
* OUTSTANDING_NOTIF will be clear in this case. RVI should be set - at
* least to the vector we just sent, but possibly to a greater vector if
* multiple were sent. RVI should only be cleared after virtual IRQs were
* actually delivered. So checking OUTSTANDING_NOTIF and RVI should
* suffice.
*
* Generally, we should also check GUEST_INTERRUPTIBILITY_INFO to see if
* there's some reason to not deliver the interrupt and check things like
* the VPPR (priority register). But since we're emulating a halt, mwait,
* or something else that needs to be woken by an IRQ, we can ignore that
* and just wake them up. Note that we won't actually deliver the IRQ,
* we'll just restart the guest and the hardware will deliver the virtual
* IRQ at the appropriate time. So in the event that something weird
* happens, the halt/mwait just returns spuriously.
*
* The more traditional race here is if the halt starts concurrently with
* the post; that's why we sync with the mutex to make sure there is an
* ordering between the actual halt (this function) and the posting. */
uth_mutex_lock(gth->halt_mtx);
while (!(pir_notif_is_set(gpci) || rvi_is_set(gth)))
uth_cond_var_wait(gth->halt_cv, gth->halt_mtx);
uth_mutex_unlock(gth->halt_mtx);
}
extern "C" void __malloc_unlock(struct _reent *reent)
{
uth_mutex_unlock(&prv_malloc_mutex);
}
