On 11/25/2011 04:35 AM, Liu Ping Fan wrote: > From: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> > > Currently, vcpu can be destructed only when kvm instance destroyed. > Change this to vcpu as a refer to kvm, and then vcpu MUST and CAN be > destroyed before kvm's destroy. Qemu will take advantage of this to > exit the vcpu thread if the thread is no longer in use by guest. > > Signed-off-by: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> > --- > arch/x86/kvm/x86.c | 28 ++++++++-------------------- > include/linux/kvm_host.h | 2 ++ > virt/kvm/kvm_main.c | 31 +++++++++++++++++++++++++++++-- > 3 files changed, 39 insertions(+), 22 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index c38efd7..ea2315a 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -6560,27 +6560,16 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) > vcpu_put(vcpu); > } > > -static void kvm_free_vcpus(struct kvm *kvm) > +void kvm_arch_vcpu_zap(struct kref *ref) > { > - unsigned int i; > - struct kvm_vcpu *vcpu; > - > - /* > - * Unpin any mmu pages first. > - */ > - kvm_for_each_vcpu(i, vcpu, kvm) { > - kvm_clear_async_pf_completion_queue(vcpu); > - kvm_unload_vcpu_mmu(vcpu); > - } > - kvm_for_each_vcpu(i, vcpu, kvm) > - kvm_arch_vcpu_free(vcpu); > - > - mutex_lock(&kvm->lock); > - for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) > - kvm->vcpus[i] = NULL; > + struct kvm_vcpu *vcpu = container_of(ref, struct kvm_vcpu, refcount); > + struct kvm *kvm = vcpu->kvm; > > - atomic_set(&kvm->online_vcpus, 0); > - mutex_unlock(&kvm->lock); > + printk(KERN_INFO "%s, zap vcpu:0x%x\n", __func__, vcpu->vcpu_id); > + kvm_clear_async_pf_completion_queue(vcpu); > + kvm_unload_vcpu_mmu(vcpu); > + kvm_arch_vcpu_free(vcpu); > + kvm_put_kvm(kvm); > } > > void kvm_arch_sync_events(struct kvm *kvm) > @@ -6594,7 +6583,6 @@ void kvm_arch_destroy_vm(struct kvm *kvm) > kvm_iommu_unmap_guest(kvm); > kfree(kvm->arch.vpic); > kfree(kvm->arch.vioapic); > - kvm_free_vcpus(kvm); > if (kvm->arch.apic_access_page) > put_page(kvm->arch.apic_access_page); > if (kvm->arch.ept_identity_pagetable) > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index d526231..fe35078 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -113,6 +113,7 @@ enum { > > struct kvm_vcpu { > struct kvm *kvm; > + struct kref refcount; > #ifdef CONFIG_PREEMPT_NOTIFIERS > struct preempt_notifier preempt_notifier; > #endif > @@ -460,6 +461,7 @@ void kvm_arch_exit(void); > int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu); > void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu); > > +void kvm_arch_vcpu_zap(struct kref *ref); > void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu); > void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu); > void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu); > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index d9cfb78..f166bc8 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -580,6 +580,7 @@ static void kvm_destroy_vm(struct kvm *kvm) > kvm_arch_free_vm(kvm); > hardware_disable_all(); > mmdrop(mm); > + printk(KERN_INFO "%s finished\n", __func__); > } > > void kvm_get_kvm(struct kvm *kvm) > @@ -1503,6 +1504,16 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn) > mark_page_dirty_in_slot(kvm, memslot, gfn); > } > > +void kvm_vcpu_get(struct kvm_vcpu *vcpu) > +{ > + kref_get(&vcpu->refcount); > +} > + > +void kvm_vcpu_put(struct kvm_vcpu *vcpu) > +{ > + kref_put(&vcpu->refcount, kvm_arch_vcpu_zap); > +} > + > /* > * The vCPU has executed a HLT instruction with in-kernel mode enabled. > */ > @@ -1623,8 +1634,13 @@ static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma) > static int kvm_vcpu_release(struct inode *inode, struct file *filp) > { > struct kvm_vcpu *vcpu = filp->private_data; > + struct kvm *kvm = vcpu->kvm; > > - kvm_put_kvm(vcpu->kvm); > + filp->private_data = NULL; > + mutex_lock(&kvm->lock); > + atomic_sub(1, &kvm->online_vcpus); > + mutex_unlock(&kvm->lock); > + kvm_vcpu_put(vcpu); > return 0; > } > > @@ -1646,6 +1662,17 @@ static int create_vcpu_fd(struct kvm_vcpu *vcpu) > return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, O_RDWR); > } > > +static struct kvm_vcpu *kvm_vcpu_create(struct kvm *kvm, u32 id) > +{ > + struct kvm_vcpu *vcpu; > + vcpu = kvm_arch_vcpu_create(kvm, id); > + if (IS_ERR(vcpu)) > + return vcpu; > + > + kref_init(&vcpu->refcount); > + return vcpu; > +} > + > /* > * Creates some virtual cpus. Good luck creating more than one. > */ > @@ -1654,7 +1681,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) > int r; > struct kvm_vcpu *vcpu, *v; > > - vcpu = kvm_arch_vcpu_create(kvm, id); > + vcpu = kvm_vcpu_create(kvm, id); > if (IS_ERR(vcpu)) > return PTR_ERR(vcpu); > I don't think this is sufficient to actually remove a vcpu from the vcpu table. It may be referred to from other vcpus in the local APIC code. Practically the only thing that can accomplish this without a substantial effort is rcu. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html