At the moment spapr_tce_tables is not protected against races. 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.
Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
Changes:
* total rework
* kfree() for kvmppc_spapr_tce_table is moved to call_rcu_sched() callback
* used new list_for_each_entry_rcu_notrace
---
arch/powerpc/include/asm/kvm_host.h | 1 +
arch/powerpc/kvm/book3s.c | 2 +-
arch/powerpc/kvm/book3s_64_vio.c | 23 +++++++++++++----------
arch/powerpc/kvm/book3s_64_vio_hv.c | 6 ++++--
4 files changed, 19 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_host.h
b/arch/powerpc/include/asm/kvm_host.h
index bb66d8b..cd22c31 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -180,6 +180,7 @@ 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 c254c27..9e17d19 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -886,7 +886,7 @@ 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..5958f7d 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]);
+ kvm_put_kvm(stt->kvm);
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)
@@ -87,8 +84,13 @@ static int kvm_spapr_tce_mmap(struct file *file, struct
vm_area_struct *vma)
static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
{
struct kvmppc_spapr_tce_table *stt = filp->private_data;
+ struct kvm *kvm = stt->kvm;
+
+ mutex_lock(&kvm->lock);
+ list_del_rcu(&stt->list);
+ call_rcu_sched(&stt->rcu, release_spapr_tce_table);
+ mutex_unlock(&kvm->lock);
- release_spapr_tce_table(stt);
return 0;
}
@@ -106,7 +108,8 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
int i;
/* Check this LIOBN hasn't been previously allocated */
- list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) {
+ list_for_each_entry_rcu_notrace(stt, &kvm->arch.spapr_tce_tables,
+ list) {
if (stt->liobn == args->liobn)
return -EBUSY;
}
@@ -131,7 +134,7 @@ 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/kvm/book3s_64_vio_hv.c
b/arch/powerpc/kvm/book3s_64_vio_hv.c
index 89e96b3..b1914d9 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -50,7 +50,8 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long
liobn,
/* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
/* liobn, ioba, tce); */
- list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) {
+ list_for_each_entry_rcu_notrace(stt, &kvm->arch.spapr_tce_tables,
+ list) {
if (stt->liobn == liobn) {
unsigned long idx = ioba >> SPAPR_TCE_SHIFT;
struct page *page;
@@ -82,7 +83,8 @@ long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long
liobn,
struct kvm *kvm = vcpu->kvm;
struct kvmppc_spapr_tce_table *stt;
- list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) {
+ list_for_each_entry_rcu_notrace(stt, &kvm->arch.spapr_tce_tables,
+ list) {
if (stt->liobn == liobn) {
unsigned long idx = ioba >> SPAPR_TCE_SHIFT;
struct page *page;
--
2.0.0
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