Messages in this thread | | | From | Punit Agrawal <> | Subject | Re: [RFC v2 PATCH 2/7] KVM: Track the pid of the VM process | Date | Tue, 06 Sep 2016 10:51:27 +0100 |
| |
Hi Christoffer,
Christoffer Dall <christoffer.dall@linaro.org> writes:
> On Mon, Sep 05, 2016 at 05:31:32PM +0100, Punit Agrawal wrote: >> Userspace tools such as perf can be used to profile individual >> processes. >> >> Track the PID of the virtual machine process to match profiling requests >> targeted at it. This can be used to take appropriate action to enable >> the requested profiling operations for the VMs of interest. >> >> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> >> Cc: Paolo Bonzini <pbonzini@redhat.com> >> Cc: "Radim Krčmář" <rkrcmar@redhat.com> >> Cc: Christoffer Dall <christoffer.dall@linaro.org> >> Cc: Marc Zyngier <marc.zyngier@arm.com> >> --- >> include/linux/kvm_host.h | 1 + >> virt/kvm/kvm_main.c | 2 ++ >> 2 files changed, 3 insertions(+) >> >> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h >> index 9c28b4d..7c42c94 100644 >> --- a/include/linux/kvm_host.h >> +++ b/include/linux/kvm_host.h >> @@ -374,6 +374,7 @@ struct kvm_memslots { >> struct kvm { >> spinlock_t mmu_lock; >> struct mutex slots_lock; >> + struct pid *pid; >> struct mm_struct *mm; /* userspace tied to this vm */ >> struct kvm_memslots *memslots[KVM_ADDRESS_SPACE_NUM]; >> struct srcu_struct srcu; >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >> index 1950782..ab2535a 100644 >> --- a/virt/kvm/kvm_main.c >> +++ b/virt/kvm/kvm_main.c >> @@ -613,6 +613,7 @@ static struct kvm *kvm_create_vm(unsigned long type) >> spin_lock_init(&kvm->mmu_lock); >> atomic_inc(¤t->mm->mm_count); >> kvm->mm = current->mm; >> + kvm->pid = get_task_pid(current, PIDTYPE_PID); > > How dooes this deal with threading? Is the idea that the user by > specifying the main thread's pid will enable trapping for all vcpu > threads belonging to that VM?
Yes that's correct - specifying the main thread PID will enable trapping for the VM (all vcpus).
I am happy to move to a more suitable identifier if available.
Thanks, Punit
> >> kvm_eventfd_init(kvm); >> mutex_init(&kvm->lock); >> mutex_init(&kvm->irq_lock); >> @@ -712,6 +713,7 @@ static void kvm_destroy_vm(struct kvm *kvm) >> int i; >> struct mm_struct *mm = kvm->mm; >> >> + put_pid(kvm->pid); >> kvm_destroy_vm_debugfs(kvm); >> kvm_arch_sync_events(kvm); >> spin_lock(&kvm_lock); >> -- >> 2.8.1 >> > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
| |