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Commit 34bb10b7 authored by Rik van Riel's avatar Rik van Riel Committed by Marcelo Tosatti
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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: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 77c100c8

include/linux/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ struct kvm_vcpu { 
	int fpu_active;

	int guest_fpu_loaded, guest_xcr0_loaded;

	wait_queue_head_t wq;

	struct pid *pid;

	int sigset_active;

	sigset_t sigset;

	struct kvm_vcpu_stat stat;

virt/kvm/kvm_main.c

+10 −0
Original line number Diff line number Diff line
@@ -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);

}