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-rw-r--r--virt/kvm/kvm_main.c48
1 files changed, 41 insertions, 7 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0c28176..32449e0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -66,6 +66,9 @@
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");
+unsigned int halt_poll_ns = 0;
+module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR);
+
/*
* Ordering of locks:
*
@@ -1813,29 +1816,60 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(mark_page_dirty);
+static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
+{
+ if (kvm_arch_vcpu_runnable(vcpu)) {
+ kvm_make_request(KVM_REQ_UNHALT, vcpu);
+ return -EINTR;
+ }
+ if (kvm_cpu_has_pending_timer(vcpu))
+ return -EINTR;
+ if (signal_pending(current))
+ return -EINTR;
+
+ return 0;
+}
+
/*
* The vCPU has executed a HLT instruction with in-kernel mode enabled.
*/
void kvm_vcpu_block(struct kvm_vcpu *vcpu)
{
+ ktime_t start, cur;
DEFINE_WAIT(wait);
+ bool waited = false;
+
+ start = cur = ktime_get();
+ if (halt_poll_ns) {
+ ktime_t stop = ktime_add_ns(ktime_get(), halt_poll_ns);
+ do {
+ /*
+ * This sets KVM_REQ_UNHALT if an interrupt
+ * arrives.
+ */
+ if (kvm_vcpu_check_block(vcpu) < 0) {
+ ++vcpu->stat.halt_successful_poll;
+ goto out;
+ }
+ cur = ktime_get();
+ } while (single_task_running() && ktime_before(cur, stop));
+ }
for (;;) {
prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
- if (kvm_arch_vcpu_runnable(vcpu)) {
- kvm_make_request(KVM_REQ_UNHALT, vcpu);
- break;
- }
- if (kvm_cpu_has_pending_timer(vcpu))
- break;
- if (signal_pending(current))
+ if (kvm_vcpu_check_block(vcpu) < 0)
break;
+ waited = true;
schedule();
}
finish_wait(&vcpu->wq, &wait);
+ cur = ktime_get();
+
+out:
+ trace_kvm_vcpu_wakeup(ktime_to_ns(cur) - ktime_to_ns(start), waited);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_block);
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