If a guest sets very short timeouts, and asks for a timer to be reloaded on
timeout, QEMU can go to 100%CPU utilisation and become unresponsive,
as it is spending all its time generating timeout interrupts. On real
hardware this doesn't matter, as the interrupts are just coalesced,
and the effect is to have the interrupt asserted all the time.
This patch is a band-aid, that prevents timeouts less than 10
microseconds from being set. 10 microseconds is a limit that was
determined empirically on a variety of machines as the shortest that
allowed QEMU to pick up a control-a c sequence to get at the monitor.
Reported-by: Anna Lyons <anna.lyons@nicta.com.au>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Correct typos of "licenced" to "licensed".
Reviewed-by: Stefan Weil <weil@mail.berlios.de>
Reviewed-by: Andreas F=E4rber <andreas.faerber@web.de>
Signed-off-by: Matthew Fernandez <matthew.fernandez@gmail.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
It was a half conversion. Finish it.
enabled can only get values of 0, 1 or 2, was declared as an int but
sent as an unint8_t, change its type.
Signed-off-by: Juan Quintela <quintela@redhat.com>
This was done with:
sed -i 's/qemu_get_clock\>/qemu_get_clock_ns/' \
$(git grep -l 'qemu_get_clock\>' )
sed -i 's/qemu_new_timer\>/qemu_new_timer_ns/' \
$(git grep -l 'qemu_new_timer\>' )
after checking that get_clock and new_timer never occur twice
on the same line. There were no missed occurrences; however, even
if there had been, they would have been caught by the compiler.
There was exactly one false positive in qemu_run_timers:
- current_time = qemu_get_clock (clock);
+ current_time = qemu_get_clock_ns (clock);
which is of course not in this patch.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In a later patch, we introduce pre_save() and post_save() functions.
The whole point of that operation is to change things in the state.
Without this patch, we have to remove the const qualifier in each
use with a cast
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
