From 34bb10b79de7df118de832f6832efb630e646577 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Tue, 1 Feb 2011 09:52:41 -0500 Subject: [PATCH] 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 Signed-off-by: Avi Kivity --- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 10 ++++++++++ 2 files changed, 11 insertions(+) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c8dee22b1945..4721b11b922a 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -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; 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); } -- 2.30.2