| Message ID | 1453361977-19589-3-git-send-email-aik@ozlabs.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jan 21, 2016 at 06:39:33PM +1100, Alexey Kardashevskiy wrote: > At the moment spapr_tce_tables is not protected against races. That's not really true - it's protected by the kvm->lock mutex. > This makes > use of RCU-variants of list helpers. As some bits are executed in real > mode, this makes use of just introduced list_for_each_entry_rcu_notrace(). > > This converts release_spapr_tce_table() to a RCU scheduled handler. The change itself is fine, though. > Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > arch/powerpc/include/asm/kvm_host.h | 1 + > arch/powerpc/kvm/book3s.c | 2 +- > arch/powerpc/kvm/book3s_64_vio.c | 20 +++++++++++--------- > 3 files changed, 13 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h > index 271fefb..c7ee696 100644 > --- a/arch/powerpc/include/asm/kvm_host.h > +++ b/arch/powerpc/include/asm/kvm_host.h > @@ -184,6 +184,7 @@ struct kvmppc_spapr_tce_table { > struct kvm *kvm; > u64 liobn; > u32 window_size; > + struct rcu_head rcu; > struct page *pages[0]; > }; > > diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c > index 638c6d9..b34220d 100644 > --- a/arch/powerpc/kvm/book3s.c > +++ b/arch/powerpc/kvm/book3s.c > @@ -807,7 +807,7 @@ int kvmppc_core_init_vm(struct kvm *kvm) > { > > #ifdef CONFIG_PPC64 > - INIT_LIST_HEAD(&kvm->arch.spapr_tce_tables); > + INIT_LIST_HEAD_RCU(&kvm->arch.spapr_tce_tables); > INIT_LIST_HEAD(&kvm->arch.rtas_tokens); > #endif > > diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c > index 54cf9bc..9526c34 100644 > --- a/arch/powerpc/kvm/book3s_64_vio.c > +++ b/arch/powerpc/kvm/book3s_64_vio.c > @@ -45,19 +45,16 @@ static long kvmppc_stt_npages(unsigned long window_size) > * sizeof(u64), PAGE_SIZE) / PAGE_SIZE; > } > > -static void release_spapr_tce_table(struct kvmppc_spapr_tce_table *stt) > +static void release_spapr_tce_table(struct rcu_head *head) > { > - struct kvm *kvm = stt->kvm; > + struct kvmppc_spapr_tce_table *stt = container_of(head, > + struct kvmppc_spapr_tce_table, rcu); > int i; > > - mutex_lock(&kvm->lock); > - list_del(&stt->list); > for (i = 0; i < kvmppc_stt_npages(stt->window_size); i++) > __free_page(stt->pages[i]); > + > kfree(stt); > - mutex_unlock(&kvm->lock); > - > - kvm_put_kvm(kvm); > } > > static int kvm_spapr_tce_fault(struct vm_area_struct *vma, struct vm_fault *vmf) > @@ -88,7 +85,12 @@ static int kvm_spapr_tce_release(struct inode *inode, struct file *filp) > { > struct kvmppc_spapr_tce_table *stt = filp->private_data; > > - release_spapr_tce_table(stt); > + list_del_rcu(&stt->list); > + > + kvm_put_kvm(stt->kvm); > + > + call_rcu(&stt->rcu, release_spapr_tce_table); > + > return 0; > } > > @@ -131,7 +133,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, > kvm_get_kvm(kvm); > > mutex_lock(&kvm->lock); > - list_add(&stt->list, &kvm->arch.spapr_tce_tables); > + list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables); > > mutex_unlock(&kvm->lock); >
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 271fefb..c7ee696 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -184,6 +184,7 @@ struct kvmppc_spapr_tce_table { struct kvm *kvm; u64 liobn; u32 window_size; + struct rcu_head rcu; struct page *pages[0]; }; diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index 638c6d9..b34220d 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -807,7 +807,7 @@ int kvmppc_core_init_vm(struct kvm *kvm) { #ifdef CONFIG_PPC64 - INIT_LIST_HEAD(&kvm->arch.spapr_tce_tables); + INIT_LIST_HEAD_RCU(&kvm->arch.spapr_tce_tables); INIT_LIST_HEAD(&kvm->arch.rtas_tokens); #endif diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 54cf9bc..9526c34 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -45,19 +45,16 @@ static long kvmppc_stt_npages(unsigned long window_size) * sizeof(u64), PAGE_SIZE) / PAGE_SIZE; } -static void release_spapr_tce_table(struct kvmppc_spapr_tce_table *stt) +static void release_spapr_tce_table(struct rcu_head *head) { - struct kvm *kvm = stt->kvm; + struct kvmppc_spapr_tce_table *stt = container_of(head, + struct kvmppc_spapr_tce_table, rcu); int i; - mutex_lock(&kvm->lock); - list_del(&stt->list); for (i = 0; i < kvmppc_stt_npages(stt->window_size); i++) __free_page(stt->pages[i]); + kfree(stt); - mutex_unlock(&kvm->lock); - - kvm_put_kvm(kvm); } static int kvm_spapr_tce_fault(struct vm_area_struct *vma, struct vm_fault *vmf) @@ -88,7 +85,12 @@ static int kvm_spapr_tce_release(struct inode *inode, struct file *filp) { struct kvmppc_spapr_tce_table *stt = filp->private_data; - release_spapr_tce_table(stt); + list_del_rcu(&stt->list); + + kvm_put_kvm(stt->kvm); + + call_rcu(&stt->rcu, release_spapr_tce_table); + return 0; } @@ -131,7 +133,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, kvm_get_kvm(kvm); mutex_lock(&kvm->lock); - list_add(&stt->list, &kvm->arch.spapr_tce_tables); + list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables); mutex_unlock(&kvm->lock);