Commit Graph

5 Commits

Author SHA1 Message Date
Marcelo Tosatti
041b1359a2 KVM: x86: document KVM_REQ_PENDING_TIMER usage
Document that KVM_REQ_PENDING_TIMER is implicitly used during guest
entry.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:16:40 +03:00
Jan Kiszka
681405bfc7 KVM: Drop useless atomic test from timer function
The current code tries to optimize the setting of
KVM_REQ_PENDING_TIMER but used atomic_inc_and_test - which always
returns true unless pending had the invalid value of -1 on entry. This
patch drops the test part preserving the original semantic but
expressing it less confusingly.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:57 +03:00
Jan Kiszka
f7104db26a KVM: Fix racy event propagation in timer
Minor issue that likely had no practical relevance: the kvm timer
function so far incremented the pending counter and then may reset it
again to 1 in case reinjection was disabled. This opened a small racy
window with the corresponding VCPU loop that may have happened to run
on another (real) CPU and already consumed the value.

Fix it by skipping the incrementation in case pending is already > 0.
This opens a different race windows, but may only rarely cause lost
events in case we do not care about them anyway (!reinject).

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:57 +03:00
Gleb Natapov
1ed0ce000a KVM: Use pointer to vcpu instead of vcpu_id in timer code.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:52 +03:00
Marcelo Tosatti
d3c7b77d1a KVM: unify part of generic timer handling
Hide the internals of vcpu awakening / injection from the in-kernel
emulated timers. This makes future changes in this logic easier and
decreases the distance to more generic timer handling.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:25 +03:00