Messages in this thread Patch in this message |  | | Date | Tue, 4 Sep 2018 08:46:21 +0800 | From | Fengguang Wu <> | Subject | Re: [RFC][PATCH 1/5] [PATCH 1/5] kvm: register in task_struct |
| |
On Tue, Sep 04, 2018 at 08:28:18AM +0800, Fengguang Wu wrote: >Hi Christian and Nikita, > >On Mon, Sep 03, 2018 at 06:03:49PM +0200, Christian Borntraeger wrote: >> >> >>On 09/03/2018 04:10 PM, Nikita Leshenko wrote: >>> On September 2, 2018 5:21:15 AM, fengguang.wu@intel.com wrote: >>>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >>>> index 8b47507faab5..0c483720de8d 100644 >>>> --- a/virt/kvm/kvm_main.c >>>> +++ b/virt/kvm/kvm_main.c >>>> @@ -3892,6 +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; >>> >>> Is it OK to store `kvm` on the task_struct? What if the thread that >>> originally created the VM exits? From the documentation it seems >>> like a VM is associated with an address space and not a specific >>> thread, so maybe it should be stored on mm_struct? >> >>Yes, ioctls accessing the kvm can happen from all threads. > >Good point, thank you for the tips! I'll move kvm pointer to mm_struct. > >>> From Documentation/virtual/kvm/api.txt: >>> Only run VM ioctls from the same process (address space) that was used >>> to create the VM. >>> >>> -Nikita
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; } else if (type == KVM_EVENT_DESTROY_VM) { add_uevent_var(env, "EVENT=destroy"); }
|  |