/*H:100
* Hypercalls
*
* Remember from the Guest, hypercalls come in two flavors: normal and
* asynchronous. This file handles both of types.
*/
void do_hypercalls(struct lg_cpu *cpu)
{
/* Not initialized yet? This hypercall must do it. */
if (unlikely(!cpu->lg->lguest_data)) {
/* Set up the "struct lguest_data" */
initialize(cpu);
/* Hcall is done. */
cpu->hcall = NULL;
return;
}
/* The Guest has initialized.
*
* Look in the hypercall ring for the async hypercalls: */
do_async_hcalls(cpu);
/* If we stopped reading the hypercall ring because the Guest did a
* NOTIFY to the Launcher, we want to return now. Otherwise we do
* the hypercall. */
if (!cpu->pending_notify) {
do_hcall(cpu, cpu->hcall);
/* Tricky point: we reset the hcall pointer to mark the
* hypercall as "done". We use the hcall pointer rather than
* the trap number to indicate a hypercall is pending.
* Normally it doesn't matter: the Guest will run again and
* update the trap number before we come back here.
*
* However, if we are signalled or the Guest sends I/O to the
* Launcher, the run_guest() loop will exit without running the
* Guest. When it comes back it would try to re-run the
* hypercall. Finding that bug sucked. */
cpu->hcall = NULL;
}
}
void do_hypercalls(struct lg_cpu *cpu)
{
if (unlikely(!cpu->lg->lguest_data)) {
initialize(cpu);
cpu->hcall = NULL;
return;
}
do_async_hcalls(cpu);
if (!cpu->pending_notify) {
do_hcall(cpu, cpu->hcall);
cpu->hcall = NULL;
}
}
