On Tue, Sep 04, 2018 at 08:37:03AM +0200, Nikita Leshenko wrote:
On 4 Sep 2018, at 2:46, Fengguang Wu <fengguang.wu@xxxxxxxxx> wrote:
Here it goes:
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 99ce070e7dcb..27c5446f3deb 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -27,6 +27,7 @@ typedef int vm_fault_t;
struct address_space;
struct mem_cgroup;
struct hmm;
+struct kvm;
/*
* Each physical page in the system has a struct page associated with
@@ -489,10 +490,19 @@ struct mm_struct {
/* HMM needs to track a few things per mm */
struct hmm *hmm;
#endif
+#if IS_ENABLED(CONFIG_KVM)
+ struct kvm *kvm;
+#endif
} __randomize_layout;
extern struct mm_struct init_mm;
+#if IS_ENABLED(CONFIG_KVM)
+static inline struct kvm *mm_kvm(struct mm_struct *mm) { return mm->kvm; }
+#else
+static inline struct kvm *mm_kvm(struct mm_struct *mm) { return NULL; }
+#endif
+
static inline void mm_init_cpumask(struct mm_struct *mm)
{
#ifdef CONFIG_CPUMASK_OFFSTACK
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0c483720de8d..dca6156a7b35 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3892,7 +3892,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
if (type == KVM_EVENT_CREATE_VM) {
add_uevent_var(env, "EVENT=create");
kvm->userspace_pid = task_pid_nr(current);
- current->kvm = kvm;
+ current->mm->kvm = kvm;
I think you also need to reset kvm to NULL once the VM is
destroyed, otherwise it would point to dangling memory.
Good point! Here is the incremental patch:
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3894,6 +3894,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
kvm->userspace_pid = task_pid_nr(current);
current->mm->kvm = kvm;
} else if (type == KVM_EVENT_DESTROY_VM) {
+ current->mm->kvm = NULL;
add_uevent_var(env, "EVENT=destroy");
}
add_uevent_var(env, "PID=%d", kvm->userspace_pid);
Thanks,
Fengguang
