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authorRik van Riel <riel@redhat.com>2011-02-01 09:52:41 -0500
committerMarcelo Tosatti <mtosatti@redhat.com>2011-03-17 13:08:29 -0300
commit34bb10b79de7df118de832f6832efb630e646577 (patch)
tree2284a88be869a13a55b0435eafa572cde9ae53aa /virt
parent77c100c83e84316ced2507c5799f79c2c80bc6b9 (diff)
downloadlinux-stericsson-34bb10b79de7df118de832f6832efb630e646577.tar.gz
KVM: keep track of which task is running a KVM vcpu
Keep track of which task is running a KVM vcpu. This helps us figure out later what task to wake up if we want to boost a vcpu that got preempted. Unfortunately there are no guarantees that the same task always keeps the same vcpu, so we can only track the task across a single "run" of the vcpu. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 002fe0b12c9f..bc8bfd15ab71 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -137,6 +137,14 @@ void vcpu_load(struct kvm_vcpu *vcpu)
int cpu;
mutex_lock(&vcpu->mutex);
+ if (unlikely(vcpu->pid != current->pids[PIDTYPE_PID].pid)) {
+ /* The thread running this VCPU changed. */
+ struct pid *oldpid = vcpu->pid;
+ struct pid *newpid = get_task_pid(current, PIDTYPE_PID);
+ rcu_assign_pointer(vcpu->pid, newpid);
+ synchronize_rcu();
+ put_pid(oldpid);
+ }
cpu = get_cpu();
preempt_notifier_register(&vcpu->preempt_notifier);
kvm_arch_vcpu_load(vcpu, cpu);
@@ -212,6 +220,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
vcpu->cpu = -1;
vcpu->kvm = kvm;
vcpu->vcpu_id = id;
+ vcpu->pid = NULL;
init_waitqueue_head(&vcpu->wq);
kvm_async_pf_vcpu_init(vcpu);
@@ -236,6 +245,7 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_init);
void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
{
+ put_pid(vcpu->pid);
kvm_arch_vcpu_uninit(vcpu);
free_page((unsigned long)vcpu->run);
}