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lguest: write more information to userspace about pending traps.

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This is preparation for userspace handling MMIO and ioport accesses.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2015-02-11 15:15:09 +10:30
parent 18c137371b
commit 69a09dc174
6 changed files with 42 additions and 18 deletions
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14
drivers/lguest/lguest_user.c
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@@ -29,6 +29,10 @@ bool send_notify_to_eventfd(struct lg_cpu *cpu)
unsigned int i;
struct lg_eventfd_map *map;
/* We only connect LHCALL_NOTIFY to event fds, not other traps. */
if (cpu->pending.trap != LGUEST_TRAP_ENTRY)
return false;
/*
* This "rcu_read_lock()" helps track when someone is still looking at
* the (RCU-using) eventfds array. It's not actually a lock at all;
@@ -52,9 +56,9 @@ bool send_notify_to_eventfd(struct lg_cpu *cpu)
* we'll continue to use the old array and just won't see the new one.
*/
for (i = 0; i < map->num; i++) {
if (map->map[i].addr == cpu->pending_notify) {
if (map->map[i].addr == cpu->pending.addr) {
eventfd_signal(map->map[i].event, 1);
cpu->pending_notify = 0;
cpu->pending.trap = 0;
break;
}
}
@@ -62,7 +66,7 @@ bool send_notify_to_eventfd(struct lg_cpu *cpu)
rcu_read_unlock();
/* If we cleared the notification, it's because we found a match. */
return cpu->pending_notify == 0;
return cpu->pending.trap == 0;
}
/*L:055
@@ -282,8 +286,8 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o)
* If we returned from read() last time because the Guest sent I/O,
* clear the flag.
*/
if (cpu->pending_notify)
cpu->pending_notify = 0;
if (cpu->pending.trap)
cpu->pending.trap = 0;
/* Run the Guest until something interesting happens. */
return run_guest(cpu, (unsigned long __user *)user);