[RFC PATCH 1/3] kvm: keep track of which task is running a KVM vcpu

[Rik van Riel]

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 <r...@redhat.com>

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 5fbdb55..cb73a73 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -79,6 +79,7 @@ struct kvm_vcpu {
 #endif
        int vcpu_id;
        struct mutex mutex;
+       struct task_struct *task;
        int   cpu;
        struct kvm_run *run;
        unsigned long requests;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 050577a..2bffa47 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -741,6 +741,7 @@ void vcpu_load(struct kvm_vcpu *vcpu)
        int cpu;
 
        mutex_lock(&vcpu->mutex);
+       vcpu->task = current;
        cpu = get_cpu();
        preempt_notifier_register(&vcpu->preempt_notifier);
        kvm_arch_vcpu_load(vcpu, cpu);
@@ -749,6 +750,7 @@ void vcpu_load(struct kvm_vcpu *vcpu)
 
 void vcpu_put(struct kvm_vcpu *vcpu)
 {
+       vcpu->task = NULL;
        preempt_disable();
        kvm_arch_vcpu_put(vcpu);
        preempt_notifier_unregister(&vcpu->preempt_notifier);



-- 
All rights reversed.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html