Paolo Bonzini 460df4c1fc
KVM: race-free exit from KVM_RUN without POSIX signals ...
The purpose of the KVM_SET_SIGNAL_MASK API is to let userspace "kick"
a VCPU out of KVM_RUN through a POSIX signal. A signal is attached
to a dummy signal handler; by blocking the signal outside KVM_RUN and
unblocking it inside, this possible race is closed:
VCPU thread service thread
--------------------------------------------------------------
check flag
set flag
raise signal
(signal handler does nothing)
KVM_RUN
However, one issue with KVM_SET_SIGNAL_MASK is that it has to take
tsk->sighand->siglock on every KVM_RUN. This lock is often on a
remote NUMA node, because it is on the node of a thread's creator.
Taking this lock can be very expensive if there are many userspace
exits (as is the case for SMP Windows VMs without Hyper-V reference
time counter).
As an alternative, we can put the flag directly in kvm_run so that
KVM can see it:
VCPU thread service thread
--------------------------------------------------------------
raise signal
signal handler
set run->immediate_exit
KVM_RUN
check run->immediate_exit
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com >
Reviewed-by: David Hildenbrand <david@redhat.com >
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com >
2017-02-17 12:27:37 +01:00
2016-03-17 15:09:34 -07:00
2016-06-17 15:39:46 +02:00
2016-09-09 09:53:35 -03:00
2016-08-22 22:43:35 +02:00
2016-10-01 17:06:02 +01:00
2016-11-29 09:00:30 +01:00
2016-12-07 19:16:46 -05:00
2016-11-22 08:58:17 -08:00
2017-01-16 14:03:31 -05:00
2017-01-02 10:55:28 +02:00
2016-11-13 12:35:13 -05:00
2016-12-14 14:06:40 -08:00
2016-10-11 15:06:31 -07:00
2016-03-15 16:55:16 -07:00
2016-10-11 15:06:31 -07:00
2016-08-09 07:54:43 +02:00
2016-10-18 10:05:42 -06:00
2016-09-02 10:46:44 -07:00
2016-12-08 14:25:13 -05:00
2016-11-13 00:57:53 -05:00
2016-09-29 19:05:06 -05:00
2016-04-28 11:06:41 +02:00
2016-10-03 18:52:14 +02:00
2016-12-07 10:45:57 +01:00
2016-08-02 17:31:41 -04:00
2016-11-16 15:43:10 -02:00
2016-11-16 15:43:10 -02:00
2016-05-03 14:59:30 -07:00
2016-10-25 11:08:30 +08:00
2016-11-24 16:01:14 -05:00
2016-07-20 23:49:49 -04:00
2016-11-21 09:52:02 -05:00
2016-02-12 16:01:32 +01:00
2016-02-08 11:21:50 +11:00
2016-07-20 12:37:39 -07:00
2016-08-05 09:00:54 -04:00
2016-11-18 12:12:14 -05:00
2016-01-20 17:09:18 -08:00
2016-10-03 09:11:14 -07:00
2016-11-04 14:45:23 -04:00
2016-12-14 09:17:42 -08:00
2016-10-01 07:32:32 +02:00
2016-04-26 12:00:49 -04:00
2016-10-27 16:16:09 -04:00
2016-06-15 09:29:17 +02:00
2016-06-07 16:25:49 -07:00
2015-12-20 15:27:12 +02:00
2016-11-18 17:23:17 +00:00
2016-06-17 13:24:05 +02:00
2016-06-18 22:11:39 -07:00
2016-08-18 23:18:42 -07:00
2016-10-20 14:51:08 -04:00
2016-11-30 10:27:20 -05:00
2016-07-25 10:55:39 -07:00
2016-12-10 23:29:11 -05:00
2016-08-22 16:25:15 -07:00
2016-09-25 23:34:19 +02:00
2016-12-06 10:43:32 -05:00
2016-04-26 01:27:07 -04:00
2016-11-03 15:41:11 -04:00
2016-11-03 15:41:11 -04:00
2016-10-23 19:35:24 -04:00
2016-11-30 08:59:26 -08:00
2016-08-17 11:13:08 +02:00
2016-04-25 15:09:11 -04:00
2016-02-11 04:27:35 -05:00
2016-12-03 23:21:37 -05:00
2016-08-22 16:25:15 -07:00
2017-01-10 18:31:55 -08:00
2016-03-09 16:36:14 -05:00
2016-03-22 15:36:02 -07:00
2016-03-04 16:10:36 -05:00
2016-06-27 16:31:25 +01:00
2016-04-12 19:54:58 +01:00
2017-02-07 18:16:45 +01:00
2017-02-17 12:27:37 +01:00
2016-12-10 23:29:11 -05:00
2016-08-22 16:25:15 -07:00
2016-01-12 08:21:18 -07:00
2016-07-11 10:49:52 -03:00
2016-12-02 10:51:49 -05:00
2016-10-30 19:10:14 -06:00
2016-10-24 08:12:35 -02:00
2016-09-09 11:16:36 -03:00
2016-08-23 16:28:04 -03:00
2016-08-12 16:57:20 -07:00
2016-03-04 16:10:36 -05:00
2016-11-22 13:11:55 -07:00
2016-08-15 11:07:21 -07:00
2016-04-23 20:13:24 -04:00
2016-11-30 10:04:25 -05:00
2016-03-13 21:54:44 -04:00
2016-11-03 10:56:17 +01:00
2016-06-16 14:00:50 -07:00
2016-02-18 11:42:18 -05:00
2016-09-26 15:20:37 -04:00
2016-08-02 19:35:21 -04:00
2016-08-02 19:35:21 -04:00
2017-01-11 16:34:25 +01:00
2016-09-22 19:59:41 -05:00
2016-05-17 17:14:21 -06:00
2016-11-13 00:51:02 -05:00
2016-12-12 10:05:22 -06:00
2016-05-30 12:41:44 -03:00
2017-01-16 14:03:31 -05:00
2016-09-23 07:19:06 -04:00
2016-09-27 21:52:00 -04:00
2016-09-27 21:52:00 -04:00
2016-03-03 14:23:43 -08:00
2016-05-08 23:46:14 -04:00
2016-04-26 12:00:48 -04:00
2016-02-24 09:04:25 +01:00
2016-08-02 19:35:31 -04:00
2016-05-05 17:38:53 -07:00
2016-11-04 14:45:23 -04:00
2016-02-16 13:04:58 -05:00
2016-08-08 12:51:58 -07:00
2016-11-09 20:40:06 -05:00
2016-11-09 20:40:06 -05:00
2016-11-09 20:40:06 -05:00
2016-11-09 20:40:06 -05:00
2016-05-20 20:57:27 -07:00
2016-09-27 12:55:50 +02:00
2016-07-12 13:42:10 -03:00
2016-05-04 08:34:14 +02:00
2016-08-25 16:43:11 -07:00
2016-04-04 22:11:20 -04:00
2016-10-31 10:56:47 -04:00
2016-03-30 12:50:17 +02:00
2016-05-05 17:38:53 -07:00
2016-09-20 18:12:38 +05:30
2016-08-02 17:31:41 -04:00
2016-03-10 21:49:09 -08:00
2016-04-23 20:13:24 -04:00
2016-11-30 10:04:25 -05:00
2017-01-10 18:31:55 -08:00
2016-08-26 21:38:41 -07:00
2016-07-26 14:26:42 -07:00
2016-04-30 09:26:55 -07:00
2016-12-16 00:13:39 +02:00
2016-05-10 12:25:04 -04:00
2015-12-18 17:48:51 -08:00
2016-11-22 12:07:02 +01:00
2016-03-05 12:05:01 -08:00
2016-05-20 17:58:30 -07:00
2016-02-01 08:47:05 -02:00
2016-11-16 16:16:08 -02:00
2016-11-16 15:13:18 -02:00
2016-11-17 08:33:20 -07:00
2016-12-16 00:13:38 +02:00
2016-11-23 20:04:22 -02:00
2016-03-17 15:09:34 -07:00
2016-03-02 17:01:59 +02:00
2016-08-01 21:44:52 +03:00
2016-12-16 00:13:32 +02:00
2016-12-16 00:13:32 +02:00
2016-06-10 23:03:55 -07:00
2016-12-16 00:13:41 +02:00
2016-08-09 13:42:38 +03:00
2016-04-30 09:26:55 -07:00
2016-11-28 01:31:31 +02:00
2016-06-09 10:14:39 +02:00
2016-09-09 09:10:07 +02:00
460df4c1fc